Assessing autonomic nervous system via heart rate variability to measure responses during trauma-focused Narrative Exposure Therapy sessions: Protocol of a pretest-posttest quasi-experimental feasibility study

Assessing autonomic nervous system via heart rate variability to measure responses during trauma-focused Narrative Exposure Therapy sessions: Protocol of a pretest-posttest quasi-experimental feasibility study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Assessing autonomic nervous system via heart rate variability to measure responses during trauma-focused Narrative Exposure Therapy sessions: Protocol of a pretest-posttest quasi-experimental feasibility study Vanessa Nolasco Ferreira, Ashley Rebecca Bell-Mizori, Signe Alexandra Domogalla, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6779026/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Background The Russian invasion of Ukraine has led to repercussions, including the displacement of people, challenges to physical and mental health, and strains on health systems across Europe. Narrative Exposure Therapy as an evidence-based method aims to mitigate Posttraumatic Stress Disorder and its comorbidities; the physiological mechanisms underlying its results remain unexplored. Heart rate variability provides a non-invasive method to examine autonomic responses during therapy, offering insights into therapeutic outcomes and attitudes toward violence. The overall aim of the study is to assess the effectiveness of Narrative Exposure Therapy by examining biological biomarkers. Methods This study will involve Ukrainian refugees residing in Norway who meet the inclusion criteria. Eligible participants will engage in six to eight individual sessions of Narrative Exposure Therapy. During these therapy sessions, heart rate variability will be continuously monitored using commercially available Polar devices equipped with a chest strap. This data will be gathered to evaluate therapeutic outcomes. Primary objectives of the study are: (I) Compare pre- and post-treatment screening results to measure the effectiveness of Narrative Exposure Therapy in reducing symptoms of Posttraumatic Stress Disorder, depression, and dissociation six months post conclusion of the therapy amongst Ukrainian refugees in Norway; (II) Utilize biofeedback as an outcome measure to assess therapy functioning during exposure sessions in Narrative Exposure Therapy. Secondary objective: (III) Develop a comprehensive plan for providing mental health support to refugees arriving in Norway, aiming to mitigate trauma triggered by the consequences of the exposure to the Russian invasion. Conclusion This pretest-posttest quasi-experimental feasibility study aims to evaluate the use of biological feedback in measuring the effectiveness of narrative exposure therapy. The findings will help determine the feasibility of this approach, potentially informing the design and implementation of future randomized control trials. Trial registration: The trial is registered in the Regional Committees for Medical and Health Research Ethics under the reference number 588073, and in the Norwegian Agency for Shared Services in Education and Research under the reference number 662949. Narrative Exposure Therapy PTSD Trauma War Autonomic Nervous System Heart Rate Variability Cardiovascular System Background On February 24th, 2022, Russia invaded Ukraine, and this aggression has resulted in the displacement of 6.9 million individuals, and by March 3rd, 2025, approximately 80 thousand have sought refuge in Norway( 1 ). These individuals are experiencing psychological difficulties, including Posttraumatic Stress Disorder (PTSD)( 2 ). This crisis unfolded while European health systems were already strained by the ongoing recovery from the COVID-19 pandemic ( 3 ). Norway responded to the influx of Ukrainian refugees through measures such as a special asylum scheme established by the Norwegian Directorate of Immigration and initiatives by the Ministry of Education to integrate students and university personnel from Ukraine into Norwegian institutions( 4 ). While studies and reports have examined the mental health status of Ukrainians refugees residing in Norway( 5 , 6 ), this current study aims to contribute to the field by evaluating the effectives of receiving evidence-based trauma-focused treatment on Ukrainian refugees in Norway. As a response to the ongoing crisis, Kristiania University of Applied Sciences in Norway collaborates with the University of Konstanz in Germany to offer trauma-focused treatment to Ukrainian refugees. The aim it to assess the effectiveness of Narrative Exposure Therapy (NET) in the reduction of PTSD and its comorbidities using Heart Rate Variability (HRV) as an outcome measure (biomarker for NET) to build further plans for larger scale interventions. The prevalence of mental disorders—including depression, anxiety, PTSD, bipolar disorder, and schizophrenia—was estimated to be 22.1% at any given time among populations affected by conflict( 7 ). In what concerns PTSD, approximately 70% of individuals worldwide will encounter a potentially traumatic event at some point in their lives( 8 ); 5.6% will develop PTSD as a result ( 9 ). The probability of developing PTSD differs based on the nature of the traumatic event. For instance, individuals exposed to violent conflict or war have PTSD rates that are over three times higher (15.3%) the general population( 7 ). PTSD is defined( 10 ) as a mental health condition caused by exposure to actual or threatened death, serious injury, or sexual violence. The exposure can occur through direct experience, witnessing the event, learning that the event occurred to a close family member or friend, or repeated or extreme exposure to aversive details of the event, arising from a complex interaction of genetic, social, and psychological factors. The diagnostic criteria for PTSD include intrusion symptoms, avoidance, negative alterations in cognitions and mood and alterations in arousal and reactivity. These symptom clusters must persist for more than one month. The DSM-5-TR also includes specifiers for PTSD, such as "with dissociative symptoms" (depersonalization or derealization) and "with delayed expression" if the full criteria are not met until at least six months after the event( 10 ). Research indicates that repeated exposure to traumatic events significantly increases the likelihood of developing PTSD, a phenomenon known as the cumulative or "building block" effect( 11 – 13 ). Populations affected by armed conflicts consistently show higher prevalence rates of PTSD and depression compared to non-conflict populations( 14 ). NET is a psychotherapeutic intervention recommended for the prevention and treatment of PTSD( 15 , 16 ). NET has demonstrated efficacy in reducing symptom severity across diverse cultural and clinical contexts( 17 – 19 ). In NET the client supported by the therapist reconstructs a coherent chronological life narrative. With the chronological and detailed processing of traumatic experiences, the contextualisation of fragmented autobiographical memories allows for and reduction of symptoms( 20 ). Given that PTSD is associated with autonomic nervous system dysregulation( 21 , 22 ), physiological monitoring during NET may offer valuable insights into individuals’ internal regulatory responses during trauma processing. HRV is a well-established, non-invasive biomarker of autonomic nervous system function and reflects an individual's capacity for emotional and physiological regulation( 23 , 24 ). Notably, individuals with PTSD consistently exhibit lower HRV, particularly in both low-frequency and high-frequency components, indicating a reduced ability to modulate stress responses and maintain autonomic flexibility( 25 ). Although previous research has established that individuals with PTSD exhibit reduced HRV compared to healthy controls( 22 ), and that psychological interventions targeting stress and anxiety can lead to modest improvements in HRV over time( 23 ), there remains a significant gap in research directly evaluating HRV changes in the context of structured trauma-focused psychotherapies. While few investigations have systematically examined HRV in relation to therapeutic processes, to our knowledge, none have yet applied continuous HRV monitoring specifically within NET, despite its widespread application in populations exposed to cumulative trauma( 16 ). This study contributes to the research field by integrating continuous HRV monitoring within NET sessions delivered to Ukrainian refugees, providing a naturalistic assessment of autonomic function in relation to therapeutic engagement and outcome. Emotional activation is a core mechanism within NET, as trauma narration inherently evokes significant physiological arousal( 15 ). The integration of HRV monitoring into NET sessions provides a unique opportunity to track autonomic shifts in real time, offering a physiological link to the unfolding therapeutic process. Previous research has demonstrated that changes in HRV can correlate with moments of heightened emotional arousal or therapeutic breakthroughs within the narrative( 26 , 27 ). This intersection between narrative-based psychotherapy and real-time physiological assessment opens promising avenues for optimizing treatment delivery and deepening our understanding of the embodied dimensions of trauma recovery. Method Study Setting and Design This feasibility study has a pretest-posttest quasi-experimental design and will be conducted at Kristiania University of Applied Sciences in Norway in collaboration with University of Konstanz. Physiological data, specifically HRV, will be continuously recorded throughout individual NET sessions particularly during the exposure sessions of events symbolized by stones, flowers, candles or sticks( 16 ). The treatment sessions will take place in a dedicated room designed to minimize external distractions, featuring sound proofing, controlled lightning, and maintained ambient temperatures between 21–24°C. Objectives The overall aim of the study is to assess the effectiveness of NET by examining biological biomarkers through measurement of HRV. The study is structured around two primary and one secondary objective: Primary objectives Compare pre- and post-treatment screening results to measure the effectiveness of NET in reducing symptoms of PTSD, depression, and dissociation six months post conclusion of the therapy amongst Ukrainian refugees in Norway. Utilize biofeedback as an outcome measure to assess therapy functioning during exposure sessions in Narrative Exposure Therapy. Secondary Objective Develop a comprehensive plan for providing mental health support to refugees arriving in Norway, aiming to mitigate trauma triggered by the consequences of the exposure to the Russian invasion. Population and Recruitment The study plans to recruit between 5–20 Ukrainian refugees currently residing in Norway, who arrived after Russia´s invasion of Ukraine in February 2022. Participants are planned to be recruited through a public call published on the Kristiania University of Applied Sciences website. Additionally, a research assistant originally from Ukraine, is already employed in the project and will help to facilitate the recruitment by connecting the project team with the Ukrainian refugee communities in and around Oslo, Norway. The small sample size is understandable considering that this is a pilot feasibility study, which carries limitations for generalizing the results and detecting clinically significant statistical power in heart rate variability (HRV), known for its high intra- and inter-individual variability. Therefore, it is important to emphasize that any inferential statistics derived from this study are exploratory in nature and are intended to inform the design and implementation of a future larger randomized controlled trial (RCT). Inclusion criteria To be eligible for participation in the study, participants must fulfil the following criteria: Ukrainian nationality currently holding refugee status under collective protection in Norway having arrived after February 2022. Aged between 18–55 years (age group in which it is mandatory to take the ‘Introduction Program’ directed to immigrants and refugees in Norway). Enrolment in an introductory program designed for refugees, or participation in other educational activities, configurating being a student in addition to the refugee status. Fluent comprehension of English, Russian or Ukrainian. In case of Russian or Ukrainian language, sessions will be facilitated using a government certified interpreter. A diagnosis of PTSD, according to DSM-5-TR criteria, confirmed by the Posttraumatic Stress Disorder Symptom Scale Interview for DSM-5 (PSSI-5), or significant trauma-related or comorbid symptoms as identified by a screening battery that includes the Threats to Human Life Scale (THL), Life Events Checklist for DSM-5 (LEC-5), Patient Health Questionnaire-9 (PHQ-9), and Shutdown Dissociation Scale (Shut-D). In case the participant was enrolled directly in combat the Appetitive Aggression Scale (AAS) will be administrated. Willingness to participate in NET and physiological monitoring indicated by signing the consent form. Exclusion criteria Individuals will be excluded if they meet any of the following conditions: Individuals younger than 18 years or older than 55 years. Risk of developing severe mental health problems. Severe cardiovascular conditions that can potentially interfere with accurate HRV measurements. Current psychiatric instability contraindicating trauma-focused therapy or diagnosis of neurological disorder(s). Inability to speak and understand English, Russian or Ukrainian Data Collection Intervention Participants meeting inclusion criteria will undergo six to eight individual NET sessions lasting between 60 and 120 minutes each, delivered by trained NET therapists. HRV will be continuously monitored during each therapy session, with specific trauma “hot spots” identified and time-stamped for detailed physiological responses. During NET the client supported by the therapist will chronologically reconstruct the most important life events of the clients with a focus on fragmented trauma memories. By creating a chronological life story, individuals engage in meaning-making and cognitive restructuring, which aids in identity reconstruction and empowerment. This process, supported by validation and social support from the therapist, has been shown to effectively reduce PTSD symptoms by addressing avoidance behaviours and intrusive memories ( 28 ). Physiological data HRV metrics will be recorded using wearable devices (Polar H10 heart rate monitor). Analysis of synchronization will examine coherence between HRV patterns before, during, and after exposure to trauma narratives. Psychometric data Participants will complete standardized psychometric assessments pre and post intervention using PTSD, life event checks and scales to measure depression and dissociation. The instruments that will be used for screening and evaluation include: PTSD Symptom Scale – Interview for DSM-5 (PSS-I-5( 29 )) Threats to Human Life Scale (THL( 30 )) Life Events Checklist for DSM-5 Standard Version (LEC-5 ( 31 , 32 )) Patient Health Questionnaire (PHQ-9 ( 33 )) The Shutdown Dissociation Scale (Shut-D ( 34 )) Only in case the participant was enrolled in combat situation(s): Appetitive Aggression Scale (AAS ( 35 )) Qualitative data The narratives constructed alongside the NET process will be qualitatively analysed( 36 , 37 ) aiming to shed light on different aspects of the perceptions and experiences of the refugees taken into the project. Post-test data Participants will repeat the psychometric questionnaires listed above under psychometric data, excluding THL, LEC-5 and AAS, six months post-NET treatment to assess the long-term effect of the treatment intervention. During the semi-structured diagnostic interviews participants subjective experiences of NET and HRV monitoring will also be collected. Study Procedure on Data Processing and Statistical Analysis Physiological data analysis HRV procedure. Participants will be instructed to follow specific recommendation prior to HRV measurement sessions to ensure high-quality data. Specifically, participants will be advised to have adequate sleep the night before the measurement( 38 ), avoid strenuous aerobic physical training( 39 ), and refrain from alcohol( 40 , 41 ), nicotine( 42 ), and, whenever possible, medications both the day before and on the day of the measurement. For those who regularly take medications, details including medication names, dosage, and time of administration will be documented( 43 ). Additionally, participants will be asked to abstain from consuming caffeine-containing foods and drinks and to consume only a light meal approximately two hours before the assessment( 44 , 45 ). HRV data will be continuously collected using the Polar H10 heart rate monitor with a chest strap (Polar Electro Oy, Kempele, Finland). Before data collection, the heart rate sensor will be moistened and attached just below the participant's chest, following Polar’s guidelines. The sensor will be paired via Bluetooth to the EliteHRV© app (Elite HRV, Ashville, NC, USA) on a smartphone. Once the device connection is confirmed, data recording will be initiated by selecting the “open reading” option on the EliteHRV© app. Previous studies have validated HRV parameters obtained by the Polar H10 chest strap monitors via EliteHRV© app as comparable to electrocardiogram-derived data( 46 , 47 ). After the HRV device has been properly placed, participants will rest for 10 minutes before the session starts and for 5 minutes after its completion. During these baseline and recovery recordings, participants will be instructed to keep their eyes open, avoid speaking, breathe normally without controlling their breathing, and limit movement or fall asleep. The breathing rate of each participant will not be controlled (i.e., spontaneous breathing patterns). HRV data processing. HRV recordings will be exported from the EliteHRV© app as text files and then imported into Kubios HRV Standard 4.1.0 software( 48 ) where heart rate and inter-beat interval sequences (i.e., RR intervals) are extracted and analysed. An experienced evaluator will manually select RR interval series from the basal and recovery period and visually inspect artefacts. A threshold-based beat correction algorithm with a medium filter will be applied to discriminate and remove artifacts, replacing detected artifacts with interpolated values using cubic spline interpolation( 49 ). In milliseconds, the time-domain-based RMSSD (root mean square of successive differences between adjacent R–R intervals) will be used to measure vagally mediated HRV. We will use RMSSD based on the last five-minute basal and recovery period, corresponding to resting HRV and recovery HRV, respectively. The RMSSD reflects vagally mediated HRV and is relatively free of respiratory influences compared to high-frequency parameters( 44 ). Statistical considerations. All statistical analyses for the HRV measurement will be performed using R Software (version 4.1.3; R Foundation for Statistical Computing, Vienna, Austria). Demographic data [age, height, weight, and body mass index (BMI)] will be presented as means ± standard deviation. The normality of RMSSD values will be tested using Shapiro–Wilk test and visual inspection of histograms. In non-normal distribution, resting and recovery HRV variables will be logarithmically transformed before subsequent analyses( 44 ). Depending on the data distribution, statistical differences in HRV across all sessions (measurement period T1-T6) will be examined by analysis of variance (ANOVA) or Friedman test for repeated measures, analysing the effect of NET on vagal cardiac activity. The effects of NET will also be evaluated by comparing changes in HRV parameters before and after exposure. Two indexes will be created to assess vagal cardiac reactivity. First, we will create an index of vagal cardiac reactivity consisting of the difference in HRV at post-exposure (T6) minus pre-exposure (T1), divided by pre-exposure. In addition to the planned analyses, an interesting and reliable measure of heart rate variability (HRV) is the "rest condition," which could be compared pre- and post-exposure session to further explore the effects of NET. The null hypothesis (H0) for this comparison would be that there is no change in HRV during the resting condition from pre-test to post-exposure session, while the alternative hypothesis (H1) posits that HRV during the resting condition will be higher at post- compared to pre-exposure session. Second, an index will capture the HRV change from baseline (first session) to the last exposure session of each participant. Raw RMSSD (without log transformation) will be applied to these indexes. Additionally, the Spearman correlation test will be performed to determine whether each cluster of post-traumatic symptoms is correlated with either of the vagal indexes. Given the feasibility nature of this study, the primary objective is to evaluate the feasibility of the methodological approach and to obtain preliminary data on HRV changes associated with the course of narrative exposure. In feasibility studies, the emphasis is usually on viability, descriptive statistics, and preliminary estimations of effect rather than hypothesis testing with inferential statistics (e.g. ANOVA). Accordingly, any inferential analysis will be conducted in an exploratory manner to identify potential trends and guide the design of future, larger-scale studies. It is important to acknowledge that the limited sample size inherently reduces the statistical power of the study, particularly in the context of HRV data, which are known to exhibit considerable inter- and intra-individual variability( 44 ) Psychometric data analysis For the measuring the effect of NET based on the instruments described in Psychometric Data, SPSS version 29 will be used to conduct the statistical analyses to perform: (I) Descriptive Statistics to summarize the data including means, standard deviations, and frequencies for demographic and baseline characteristics; (II) Paired Sample t-tests to compare pre- and post-test scores for each instrument. This test will help determine if there are statistically significant changes in the participants' scores after the intervention; (III) Repeated Measures ANOVA to assess changes over time and determine if the intervention has a lasting effect. The expected limitations are: I) Reduced statistical power to detect significant effects or differences between pre- and post-test measurements; II) Impact on the results making it difficult to generalize findings to a broader population due the reduced sample, and III) Increase the risk of Type II errors, where true effects may not be detected due to insufficient data. The reliability and validity of the conclusions drawn can be affected as the sample may not adequately represent the diversity and complexity of the target population. Qualitative data analysis This study protocol integrates qualitative analysis of narratives produced during NET with the collection of HRV to gain a comprehensive understanding of the therapeutic process in individuals undergoing narrative exposure. The qualitative analysis will explore the content, structure, and underlying themes of the participants narratives, emphasizing patterns of emotional expression, cognitive processing, and trauma integration using thematic analysis( 36 , 37 ). Concurrently, HRV data collected during therapy sessions to monitor physiological markers of autonomic nervous system activity, reflecting the individual's stress response and emotional regulation in real-time, will contribute to provide a better understanding of the therapeutic process. Further, the biological biomarkers in what concerns the specific content of the sessions and the arousal of the participant through the HRV, can be compared when embedded with the qualitative analysis. By combining these methodologies, the study aims to provide a multidimensional understanding on how trauma is processed an integrated during NET, potentially facilitating the development of more tailored and effective therapeutic interventions( 50 , 51 ). Discussion The integration of HRV monitoring with NET sessions presents several expected strengths, as highlighted in recent peer-reviewed articles( 52 , 53 ). Firstly, combining HRV with NET allows for a comprehensive understanding of the course of emotional regulation across NET sessions. HRV serves as a physiological marker of autonomic nervous system activity, providing real-time insights into the emotional and stress responses of individuals undergoing therapy. This integration can enhance the therapeutic process by offering objective data that complements the subjective narrative accounts, potentially leading to more tailored and effective interventions( 23 , 54 ). Moreover, multidisciplinary collaboration involving psychology, physiology, and narrative studies can provide robust insights into trauma therapy and its physiological correlates. Such collaboration fosters a holistic approach to understanding trauma, bridging the gap between psychological experiences and physiological responses. This synergy can lead to innovative therapeutic strategies and deepen our understanding of how trauma affects both mind and body( 55 ). Feasibility results from studies integrating HRV with NET can additionally inform future larger studies by providing preliminary data on feasibility, participant retention, and data quality. These initial findings are crucial for refining methodologies and ensuring that subsequent research is grounded in practical insights gained from early trials( 56 , 57 ). There are potential challenges that must be addressed. Language barriers can pose significant obstacles, particularly in diverse populations where NET is often applied( 16 ). Ensuring that narratives are accurately captured and understood across different languages is essential for the therapy's effectiveness. Consequently, ethical approval was sought and obtained to facilitate sessions in the presence of an interpreter. Additionally, small sample sizes in feasibility studies may limit the generalizability of findings, necessitating careful consideration in the design of future research( 20 , 58 ). Feasibility considerations include the acceptability of wearable HRV devices among participants and ensuring minimal disruption of the therapeutic process. Wearable technology must be user-friendly and unobtrusive to maintain the integrity of the therapy sessions. Furthermore, technical issues related to data collection and analysis must be addressed to ensure reliable and valid results( 44 , 48 ). By generating preliminary data on feasibility, participant retention, and data quality, this study can inform the methodology of future randomized controlled trials. Understanding the practical aspects of integrating HRV with NET will enable researchers to design studies that are both scientifically rigorous and clinically relevant. This groundwork is essential for advancing trauma therapy, potentially leading to more effective interventions and improved outcomes for individuals affected by complex trauma( 59 ). Feasibility Study Status The project originally had two primary investigators: one responsible for the clinical aspect of the study, and the other, with a background in the field of art, serving as the general responsible and responsible to a component of the study not connected to this protocol. The Regional Committees for Medical and Health Research Ethics (REK) demanded changes, and the investigator responsible for the clinical part overtook the whole study; this demanded accommodations and caused delays. In addition, due to necessary changes in the study concerning language barriers the use of a government certified interpreter was needed, and the study had to resubmit to the ethical committee (REK and Norwegian Agency for Shared Services in Education and Research – SIKT). These necessary changes led to a backlog and the extension of the study for another year. Hence, even though the recruitment of participants started on October 16th, 2023, it did not end until December 31st, 2024. In addition, to comply with Norwegian GDPR rules, the procedure for the analysis of HRV data had to be changed and the final approval from REK was received November 18th, 2024. The first participant received the first NET-session on December 5th, 2023. Last treatments of NET and post-screenings are still ongoing as of submission, May 29th, 2025. Abbreviations REK Regional Committees for Medical and Health Research Ethics SIKT Norwegian Agency for Shared Services in Education and Research PTSD Posttraumatic Stress Disorder DSM 5 – TR –Diagnostic and Statistical Manual of Mental Disorders, 5th Ed., Text Revision NET Narrative Exposure Therapy HRV Heart Rate Variability RCT Randomized Control Trial PSSI 5 –Posttraumatic Stress Disorder Symptom Scale Interview for DSM–5 THL Threats to Human Life Scale LEC 5 –Life Events Checklist for DSM–5 PHQ 9 –Patient Health Questionnaire–9 Shut D –Shutdown Dissociation Scale AAS Appetitive Aggression Scale RMSSD Root Mean Square of Successive Differences BMI Body mass index ANOVA Analysis of variance Declarations Ethical Approval and Consent to Participate The study complies with ethical guidelines for research involving human participants, including obtaining informed consent and implementing measures to safeguard confidentiality. The study has received ethical approval from both the Regional Committees for Medical and Health Research Ethics (REK) under the reference number 588073 and in the Norwegian Agency for Shared Services in Education and Research (SIKT) under the reference number 662949. Consent for Publication All participants taken in the study consented voluntarily and consented through informed consent forms approved by REK and SIKT. The participants consented: I) to fill out questionnaires at the start and at the end of the study, which will measure demographic data, level of depression, anxiety, trauma exposure, PTSD, somatic problems, impairments of living and grief; II) to receive NET – if applicable; III) to have their HRV measured during the individual NET – applicable if offered NET; IV) that the data from the questionnaires and HRV can be used anonymously in research and publication(s); V) for the use of an interpreter in Ukrainian/Russian during the study – applicable if needed by the participant. The consent form is available in the documents attached. Availability of Data and Materials Anonymised psychometric datasets and data connected to biofeedback will be available from the corresponding author on reasonable request with justification and submission of a valuable research questions. The requests will be taken to the internal ethical committee of the Kristiania University of Applied Sciences. Raw qualitative data will remain unavailable due to confidentiality and ethical legislation applicable to research with vulnerable populations in Norway. Competing Interests Not applicable. Funding Kristiania University of Applied Sciences through incentives [insentivmidler] and interdisciplinary funds [tverrfaglige midler]. Authors’ Contributions Vanessa Nolasco Ferreira (VNF) conceived the study, participated in its design, and coordinated the drafting of the manuscript. She is the primary investigator and contributed to the development of the study protocol and the acquisition of funding. Ashley Rebecca Bell-Mizori (ARB) contributed to the design of the study and the development of the study protocol. She is the project coordinator and participated in the drafting and critical revision of the manuscript. Signe Alexandra Domogalla (SAD) is co-responsible for the conception of the qualitative embedded method. She contributed to the design of the study and participated in the drafting and critical revision of the manuscript. Fernanda Serpeloni (FS) contributed to the design of the study, in what concerns the use of biofeedback in NET, and the development of the intervention. She also participated in the drafting and critical revision of the manuscript. Miroslava Tokovska (MT) participated in the design of the study and the development of the study protocol, especially in the design of the embedded qualitative method. She also contributed to the drafting and critical revision of the manuscript. Anke Köbach (AK) participated in the design of the study and the development of the study protocol, guiding and supervising the main research team due to her expertise and knowledge in NET. She also contributed to the drafting and critical revision of the manuscript. Liliana Abreu (LA) participated in the design of the study and the development of the study protocol. She was involved in the statistical analysis plan and contributed to the drafting and critical revision of the manuscript. Nayara Cristina dos Santos Oliveira (NCSO) participated in the design of the study and the development of the study protocol. She also contributed to the drafting and critical revision of the manuscript. She was involved in the statistical analysis plan and is the co-responsible for the biofeedback (HRV) framework and analysis plan. Acknowledgements Not applicable. Authors’ Information Vanessa Nolasco Ferreira, Associate Professor, Kristiania University of Applied Sciences, School of Health Sciences, Department of Psychology, Pedagogy and Law, Bergen, Norway – ORCID number: https://orcid.org/0000-0003-4243-0466 Ashley Rebecca Bell-Mizori, Associate Professor, Kristiania University of Applied Sciences, School of Health Sciences, Department of Psychology, Pedagogy and Law, Oslo, Norway – ORCID number: https://orcid.org/0000-0002-3303-9994 Signe Alexandra Domogalla, Associate Professor, Kristiania University of Applied Sciences, School of Art, Design and Media, Department of Performing Arts, Film and Media, Oslo, Norway Fernanda Serpelloni, Visiting Researcher in the Department of Studies About Violence and Health Jorge Careli (ENSP/Fiocruz), Oswaldo Cruz Foundation, Rio de Janeiro Brazil. ORCID: https://orcid.org/0000-0001-6222-0162 Miroslava Tokovska, Kristiania University of Applied Sciences, School of Health Sciences, Department of Health and Exercise, Oslo, Norway, ORCID: https://orcid.org/0000-0002-8279-3168 Anke Köbac, Department of Politics and Public Administration, University of Konstanz, Konstanz, Germany. ORCID: https://orcid.org/0000-0002-8666-9586 Liliana Abreu, Department of Politics and Public Administration, University of Konstanz, Konstanz, Germany. ORCID: https://orcid.org/0000-0003-1110-6508 Nayara Cristina dos Santos Oliveira, Genomic Research Institute, State University of the Central West, Paraná, Brazil. ORCID: https://orcid.org/0000-0002-9714-9025 References UNHCR. The Operational Data Portal 2025 [cited 2025 22.05]. UNHCR webpage ]. Available from: https://data.unhcr.org/en/situations/ukraine. Bilewicz M, Maria B, and Gromova A. 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Qualitative Research in Psychology. 2025;22(2):399-438. Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Frontiers in Public Health. 2017;Volume 5 - 2017. May R, McBerty V, Zaky A, Gianotti M. Vigorous physical activity predicts higher heart rate variability among younger adults. Journal of Physiological Anthropology. 2017;36(1):24. Quintana DS, Guastella AJ, McGregor IS, Hickie IB, Kemp AH. Moderate alcohol intake is related to increased heart rate variability in young adults: Implications for health and well-being. Psychophysiology. 2013;50(12):1202-8. Quintana DS, McGregor IS, Guastella AJ, Malhi GS, Kemp AH. A Meta-Analysis on the Impact of Alcohol Dependence on Short-Term Resting-State Heart Rate Variability: Implications for Cardiovascular Risk. Alcoholism: Clinical and Experimental Research. 2013;37(s1):E23-E9. Guo Q-n, Wang J, Liu H-y, Wu D, Liao S-x. Nicotine Ingestion Reduces Heart Rate Variability in Young Healthy Adults. BioMed Research International. 2022;2022(1):4286621. Catai AM, Pastre CM, Godoy MFd, Silva Ed, Takahashi ACdM, Vanderlei LCM. Heart rate variability: are you using it properly? Standardisation checklist of procedures. Brazilian Journal of Physical Therapy. 2020;24(2):91-102. Laborde S, Mosley E, Thayer JF. Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research – Recommendations for Experiment Planning, Data Analysis, and Data Reporting. Frontiers in Psychology. 2017;Volume 8 - 2017. Zimmermann-Viehoff F, Julian T, Julian K, Christian H, S. WC, and Deter H-C. Short-term effects of espresso coffee on heart rate variability and blood pressure in habitual and non-habitual coffee consumers – A randomized crossover study. Nutritional Neuroscience. 2016;19(4):169-75. Himariotis AT, Coffey KF, Noel SE, Cornell DJ. Validity of a Smartphone Application in Calculating Measures of Heart Rate Variability. Sensors. 2022;22(24):9883. Schaffarczyk M, Rogers B, Reer R, Gronwald T. Validity of the Polar H10 Sensor for Heart Rate Variability Analysis during Resting State and Incremental Exercise in Recreational Men and Women. Sensors. 2022;22(17):6536. Tarvainen MP, Niskanen J-P, Lipponen JA, Ranta-aho PO, Karjalainen PA. Kubios HRV – Heart rate variability analysis software. Computer Methods and Programs in Biomedicine. 2014;113(1):210-20. Alcantara JMA, Plaza-Florido A, Amaro-Gahete FJ, Acosta FM, Migueles JH, Molina-Garcia P, et al. Impact of Using Different Levels of Threshold-Based Artefact Correction on the Quantification of Heart Rate Variability in Three Independent Human Cohorts. Journal of Clinical Medicine. 2020;9(2):325. Meiser-Stedman R, McKinnon A, Dixon C, Boyle A, Smith P, Dalgleish T. A core role for cognitive processes in the acute onset and maintenance of post-traumatic stress in children and adolescents. Journal of Child Psychology and Psychiatry. 2019;60(8):875-84. Porges SW. The polyvagal perspective. Biological Psychology. 2007;74(2):116-43. Dos Santos Oliveira NC, Fernanda S, and Gonçalves de Assis S. The interplay between DNA methylation and cardiac autonomic system functioning: a systematic review. International Journal of Environmental Health Research. 2023;33(1):54-70. dos Santos Oliveira NC, Seyma K, Gonçalves dAS, K. SA, and Serpeloni F. Community and domestic violence are associated with DNA methylation GrimAge acceleration and heart rate variability in adolescents. European Journal of Psychotraumatology. 2023;14(2):2202054. Thayer JF, Lane RD. Claude Bernard and the heart–brain connection: Further elaboration of a model of neurovisceral integration. Neuroscience & Biobehavioral Reviews. 2009;33(2):81-8. Beck JG, Grant DM, Clapp JD, Palyo SA. Understanding the interpersonal impact of trauma: Contributions of PTSD and depression. Journal of Anxiety Disorders. 2009;23(4):443-50. Im B, Keum J, Kim T, Lee K-i, Koo K-i. Utilizing Real-Time Heart Rate Variability during Psychological Intervention Program for Complex Post-Traumatic Stress Disorder: A Case Study. Applied Sciences. 2024;14(1):4. Mensinger JL, Weissinger GM, Cantrell MA, Baskin R, George C. A Pilot Feasibility Evaluation of a Heart Rate Variability Biofeedback App to Improve Self-Care in COVID-19 Healthcare Workers. Applied Psychophysiology and Biofeedback. 2024;49(2):241-59. Neuner F, Onyut, P. L., Ertl, V., Odenwald, M., Schauer, E., & Elbert, T. Treatment of posttraumatic stress disorder by trained lay counselors in an African refugee settlement: A randomized controlled trial. Journal of Consulting and Clinical Psychology. 2008;76(4):686–94. Riva G, Wiederhold BK, Mantovani F. Neuroscience of Virtual Reality: From Virtual Exposure to Embodied Medicine. Cyberpsychol Behav Soc Netw. 2019;22(1):82-96. 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09:17:10","extension":"html","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":154642,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-6779026/v1/fae2e497050e911e09e77e95.html"},{"id":92932846,"identity":"bd7db362-253d-4203-98d5-750a54d7fb04","added_by":"auto","created_at":"2025-10-07 09:25:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":816057,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6779026/v1/c86a203b-e4f7-4ef3-89eb-ad414b3f034f.pdf"}],"financialInterests":"","formattedTitle":"Assessing autonomic nervous system via heart rate variability to measure responses during trauma-focused Narrative Exposure Therapy sessions: Protocol of a pretest-posttest quasi-experimental feasibility study","fulltext":[{"header":"Background","content":"\u003cp\u003eOn February 24th, 2022, Russia invaded Ukraine, and this aggression has resulted in the displacement of 6.9\u0026nbsp;million individuals, and by March 3rd, 2025, approximately 80 thousand have sought refuge in Norway(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). These individuals are experiencing psychological difficulties, including Posttraumatic Stress Disorder (PTSD)(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). This crisis unfolded while European health systems were already strained by the ongoing recovery from the COVID-19 pandemic (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Norway responded to the influx of Ukrainian refugees through measures such as a special asylum scheme established by the Norwegian Directorate of Immigration and initiatives by the Ministry of Education to integrate students and university personnel from Ukraine into Norwegian institutions(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). While studies and reports have examined the mental health status of Ukrainians refugees residing in Norway(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e), this current study aims to contribute to the field by evaluating the effectives of receiving evidence-based trauma-focused treatment on Ukrainian refugees in Norway. As a response to the ongoing crisis, Kristiania University of Applied Sciences in Norway collaborates with the University of Konstanz in Germany to offer trauma-focused treatment to Ukrainian refugees. The aim it to assess the effectiveness of Narrative Exposure Therapy (NET) in the reduction of PTSD and its comorbidities using Heart Rate Variability (HRV) as an outcome measure (biomarker for NET) to build further plans for larger scale interventions.\u003c/p\u003e\u003cp\u003eThe prevalence of mental disorders\u0026mdash;including depression, anxiety, PTSD, bipolar disorder, and schizophrenia\u0026mdash;was estimated to be 22.1% at any given time among populations affected by conflict(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). In what concerns PTSD, approximately 70% of individuals worldwide will encounter a potentially traumatic event at some point in their lives(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e); 5.6% will develop PTSD as a result (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). The probability of developing PTSD differs based on the nature of the traumatic event. For instance, individuals exposed to violent conflict or war have PTSD rates that are over three times higher (15.3%) the general population(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003ePTSD is defined(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e) as a mental health condition caused by exposure to actual or threatened death, serious injury, or sexual violence. The exposure can occur through direct experience, witnessing the event, learning that the event occurred to a close family member or friend, or repeated or extreme exposure to aversive details of the event, arising from a complex interaction of genetic, social, and psychological factors. The diagnostic criteria for PTSD include intrusion symptoms, avoidance, negative alterations in cognitions and mood and alterations in arousal and reactivity. These symptom clusters must persist for more than one month. The DSM-5-TR also includes specifiers for PTSD, such as \"with dissociative symptoms\" (depersonalization or derealization) and \"with delayed expression\" if the full criteria are not met until at least six months after the event(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Research indicates that repeated exposure to traumatic events significantly increases the likelihood of developing PTSD, a phenomenon known as the cumulative or \"building block\" effect(\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Populations affected by armed conflicts consistently show higher prevalence rates of PTSD and depression compared to non-conflict populations(\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eNET is a psychotherapeutic intervention recommended for the prevention and treatment of PTSD(\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). NET has demonstrated efficacy in reducing symptom severity across diverse cultural and clinical contexts(\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). In NET the client supported by the therapist reconstructs a coherent chronological life narrative. With the chronological and detailed processing of traumatic experiences, the contextualisation of fragmented autobiographical memories allows for and reduction of symptoms(\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). Given that PTSD is associated with autonomic nervous system dysregulation(\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), physiological monitoring during NET may offer valuable insights into individuals\u0026rsquo; internal regulatory responses during trauma processing.\u003c/p\u003e\u003cp\u003eHRV is a well-established, non-invasive biomarker of autonomic nervous system function and reflects an individual's capacity for emotional and physiological regulation(\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). Notably, individuals with PTSD consistently exhibit lower HRV, particularly in both low-frequency and high-frequency components, indicating a reduced ability to modulate stress responses and maintain autonomic flexibility(\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). Although previous research has established that individuals with PTSD exhibit reduced HRV compared to healthy controls(\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), and that psychological interventions targeting stress and anxiety can lead to modest improvements in HRV over time(\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e), there remains a significant gap in research directly evaluating HRV changes in the context of structured trauma-focused psychotherapies. While few investigations have systematically examined HRV in relation to therapeutic processes, to our knowledge, none have yet applied continuous HRV monitoring specifically within NET, despite its widespread application in populations exposed to cumulative trauma(\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). This study contributes to the research field by integrating continuous HRV monitoring within NET sessions delivered to Ukrainian refugees, providing a naturalistic assessment of autonomic function in relation to therapeutic engagement and outcome.\u003c/p\u003e\u003cp\u003eEmotional activation is a core mechanism within NET, as trauma narration inherently evokes significant physiological arousal(\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). The integration of HRV monitoring into NET sessions provides a unique opportunity to track autonomic shifts in real time, offering a physiological link to the unfolding therapeutic process. Previous research has demonstrated that changes in HRV can correlate with moments of heightened emotional arousal or therapeutic breakthroughs within the narrative(\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e). This intersection between narrative-based psychotherapy and real-time physiological assessment opens promising avenues for optimizing treatment delivery and deepening our understanding of the embodied dimensions of trauma recovery.\u003c/p\u003e"},{"header":"Method","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Setting and Design\u003c/h2\u003e\u003cp\u003eThis feasibility study has a pretest-posttest quasi-experimental design and will be conducted at Kristiania University of Applied Sciences in Norway in collaboration with University of Konstanz. Physiological data, specifically HRV, will be continuously recorded throughout individual NET sessions particularly during the exposure sessions of events symbolized by stones, flowers, candles or sticks(\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). The treatment sessions will take place in a dedicated room designed to minimize external distractions, featuring sound proofing, controlled lightning, and maintained ambient temperatures between 21\u0026ndash;24\u0026deg;C.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eObjectives\u003c/h3\u003e\n\u003cp\u003eThe overall aim of the study is to assess the effectiveness of NET by examining biological biomarkers through measurement of HRV. The study is structured around two primary and one secondary objective:\u003c/p\u003e\u003cp\u003e\u003cb\u003ePrimary objectives\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003col style=\"list-style-type:upper-roman;\"\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eCompare pre- and post-treatment screening results to measure the effectiveness of NET in reducing symptoms of PTSD, depression, and dissociation six months post conclusion of the therapy amongst Ukrainian refugees in Norway.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eUtilize biofeedback as an outcome measure to assess therapy functioning during exposure sessions in Narrative Exposure Therapy.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\n\u003ch3\u003eSecondary Objective\u003c/h3\u003e\n\u003cp\u003e\u003col style=\"list-style-type:upper-roman;\"\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eDevelop a comprehensive plan for providing mental health support to refugees arriving in Norway, aiming to mitigate trauma triggered by the consequences of the exposure to the Russian invasion.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\n\u003ch3\u003ePopulation and Recruitment\u003c/h3\u003e\n\u003cp\u003eThe study plans to recruit between 5\u0026ndash;20 Ukrainian refugees currently residing in Norway, who arrived after Russia\u0026acute;s invasion of Ukraine in February 2022. Participants are planned to be recruited through a public call published on the Kristiania University of Applied Sciences website. Additionally, a research assistant originally from Ukraine, is already employed in the project and will help to facilitate the recruitment by connecting the project team with the Ukrainian refugee communities in and around Oslo, Norway.\u003c/p\u003e\u003cp\u003eThe small sample size is understandable considering that this is a pilot feasibility study, which carries limitations for generalizing the results and detecting clinically significant statistical power in heart rate variability (HRV), known for its high intra- and inter-individual variability. Therefore, it is important to emphasize that any inferential statistics derived from this study are exploratory in nature and are intended to inform the design and implementation of a future larger randomized controlled trial (RCT).\u003c/p\u003e\n\u003ch3\u003eInclusion criteria\u003c/h3\u003e\n\u003cp\u003eTo be eligible for participation in the study, participants must fulfil the following criteria:\u003c/p\u003e\u003cp\u003e\u003col style=\"list-style-type:upper-roman;\"\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eUkrainian nationality currently holding refugee status under collective protection in Norway having arrived after February 2022.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eAged between 18\u0026ndash;55 years (age group in which it is mandatory to take the \u0026lsquo;Introduction Program\u0026rsquo; directed to immigrants and refugees in Norway).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eEnrolment in an introductory program designed for refugees, or participation in other educational activities, configurating being a student in addition to the refugee status.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eFluent comprehension of English, Russian or Ukrainian. In case of Russian or Ukrainian language, sessions will be facilitated using a government certified interpreter.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eA diagnosis of PTSD, according to DSM-5-TR criteria, confirmed by the Posttraumatic Stress Disorder Symptom Scale Interview for DSM-5 (PSSI-5), or significant trauma-related or comorbid symptoms as identified by a screening battery that includes the Threats to Human Life Scale (THL), Life Events Checklist for DSM-5 (LEC-5), Patient Health Questionnaire-9 (PHQ-9), and Shutdown Dissociation Scale (Shut-D). In case the participant was enrolled directly in combat the Appetitive Aggression Scale (AAS) will be administrated.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e Willingness to participate in NET and physiological monitoring indicated by signing the consent form.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eExclusion criteria\u003c/h2\u003e\u003cp\u003eIndividuals will be excluded if they meet any of the following conditions:\u003c/p\u003e\u003cp\u003e\u003col style=\"list-style-type:upper-roman;\"\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eIndividuals younger than 18 years or older than 55 years.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eRisk of developing severe mental health problems.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eSevere cardiovascular conditions that can potentially interfere with accurate HRV measurements.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eCurrent psychiatric instability contraindicating trauma-focused therapy or diagnosis of neurological disorder(s).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eInability to speak and understand English, Russian or Ukrainian\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eData Collection\u003c/h3\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003eIntervention\u003c/h2\u003e\u003cp\u003e Participants meeting inclusion criteria will undergo six to eight individual NET sessions lasting between 60 and 120 minutes each, delivered by trained NET therapists. HRV will be continuously monitored during each therapy session, with specific trauma \u0026ldquo;hot spots\u0026rdquo; identified and time-stamped for detailed physiological responses. During NET the client supported by the therapist will chronologically reconstruct the most important life events of the clients with a focus on fragmented trauma memories. By creating a chronological life story, individuals engage in meaning-making and cognitive restructuring, which aids in identity reconstruction and empowerment. This process, supported by validation and social support from the therapist, has been shown to effectively reduce PTSD symptoms by addressing avoidance behaviours and intrusive memories (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003ePhysiological data\u003c/h2\u003e\u003cp\u003eHRV metrics will be recorded using wearable devices (Polar H10 heart rate monitor). Analysis of synchronization will examine coherence between HRV patterns before, during, and after exposure to trauma narratives.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003ePsychometric data\u003c/h2\u003e\u003cp\u003eParticipants will complete standardized psychometric assessments pre and post intervention using PTSD, life event checks and scales to measure depression and dissociation. The instruments that will be used for screening and evaluation include:\u003c/p\u003e\u003cp\u003e\u003col style=\"list-style-type:upper-roman;\"\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003ePTSD Symptom Scale \u0026ndash; Interview for DSM-5 (PSS-I-5(\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eThreats to Human Life Scale (THL(\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eLife Events Checklist for DSM-5 Standard Version (LEC-5 (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003ePatient Health Questionnaire (PHQ-9 (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eThe Shutdown Dissociation Scale (Shut-D (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eOnly in case the participant was enrolled in combat situation(s): Appetitive Aggression Scale (AAS (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e))\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eQualitative data\u003c/h2\u003e\u003cp\u003eThe narratives constructed alongside the NET process will be qualitatively analysed(\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e) aiming to shed light on different aspects of the perceptions and experiences of the refugees taken into the project.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003ePost-test data\u003c/h2\u003e\u003cp\u003eParticipants will repeat the psychometric questionnaires listed above under psychometric data, excluding THL, LEC-5 and AAS, six months post-NET treatment to assess the long-term effect of the treatment intervention. During the semi-structured diagnostic interviews participants subjective experiences of NET and HRV monitoring will also be collected.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003eStudy Procedure on Data Processing and Statistical Analysis\u003c/h2\u003e\u003cdiv id=\"Sec16\" class=\"Section3\"\u003e\u003ch2\u003ePhysiological data analysis\u003c/h2\u003e\u003cp\u003e\u003cb\u003eHRV procedure.\u003c/b\u003e Participants will be instructed to follow specific recommendation prior to HRV measurement sessions to ensure high-quality data. Specifically, participants will be advised to have adequate sleep the night before the measurement(\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e), avoid strenuous aerobic physical training(\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e), and refrain from alcohol(\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e), nicotine(\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e), and, whenever possible, medications both the day before and on the day of the measurement. For those who regularly take medications, details including medication names, dosage, and time of administration will be documented(\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e). Additionally, participants will be asked to abstain from consuming caffeine-containing foods and drinks and to consume only a light meal approximately two hours before the assessment(\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eHRV data will be continuously collected using the Polar H10 heart rate monitor with a chest strap (Polar Electro Oy, Kempele, Finland). Before data collection, the heart rate sensor will be moistened and attached just below the participant's chest, following Polar\u0026rsquo;s guidelines. The sensor will be paired via Bluetooth to the EliteHRV\u0026copy; app (Elite HRV, Ashville, NC, USA) on a smartphone. Once the device connection is confirmed, data recording will be initiated by selecting the \u0026ldquo;open reading\u0026rdquo; option on the EliteHRV\u0026copy; app. Previous studies have validated HRV parameters obtained by the Polar H10 chest strap monitors via EliteHRV\u0026copy; app as comparable to electrocardiogram-derived data(\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAfter the HRV device has been properly placed, participants will rest for 10 minutes before the session starts and for 5 minutes after its completion. During these baseline and recovery recordings, participants will be instructed to keep their eyes open, avoid speaking, breathe normally without controlling their breathing, and limit movement or fall asleep. The breathing rate of each participant will not be controlled (i.e., spontaneous breathing patterns).\u003c/p\u003e\u003cp\u003e\u003cb\u003eHRV data processing.\u003c/b\u003e HRV recordings will be exported from the EliteHRV\u0026copy; app as text files and then imported into Kubios HRV Standard 4.1.0 software(\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e) where heart rate and inter-beat interval sequences (i.e., RR intervals) are extracted and analysed. An experienced evaluator will manually select RR interval series from the basal and recovery period and visually inspect artefacts. A threshold-based beat correction algorithm with a medium filter will be applied to discriminate and remove artifacts, replacing detected artifacts with interpolated values using cubic spline interpolation(\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e). In milliseconds, the time-domain-based RMSSD (root mean square of successive differences between adjacent R\u0026ndash;R intervals) will be used to measure vagally mediated HRV. We will use RMSSD based on the last five-minute basal and recovery period, corresponding to resting HRV and recovery HRV, respectively. The RMSSD reflects vagally mediated HRV and is relatively free of respiratory influences compared to high-frequency parameters(\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical considerations.\u003c/b\u003e All statistical analyses for the HRV measurement will be performed using R Software (version 4.1.3; R Foundation for Statistical Computing, Vienna, Austria). Demographic data [age, height, weight, and body mass index (BMI)] will be presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. The normality of RMSSD values will be tested using Shapiro\u0026ndash;Wilk test and visual inspection of histograms. In non-normal distribution, resting and recovery HRV variables will be logarithmically transformed before subsequent analyses(\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e). Depending on the data distribution, statistical differences in HRV across all sessions (measurement period T1-T6) will be examined by analysis of variance (ANOVA) or Friedman test for repeated measures, analysing the effect of NET on vagal cardiac activity.\u003c/p\u003e\u003cp\u003eThe effects of NET will also be evaluated by comparing changes in HRV parameters before and after exposure. Two indexes will be created to assess vagal cardiac reactivity. First, we will create an index of vagal cardiac reactivity consisting of the difference in HRV at post-exposure (T6) minus pre-exposure (T1), divided by pre-exposure. In addition to the planned analyses, an interesting and reliable measure of heart rate variability (HRV) is the \"rest condition,\" which could be compared pre- and post-exposure session to further explore the effects of NET. The null hypothesis (H0) for this comparison would be that there is no change in HRV during the resting condition from pre-test to post-exposure session, while the alternative hypothesis (H1) posits that HRV during the resting condition will be higher at post- compared to pre-exposure session. Second, an index will capture the HRV change from baseline (first session) to the last exposure session of each participant. Raw RMSSD (without log transformation) will be applied to these indexes. Additionally, the Spearman correlation test will be performed to determine whether each cluster of post-traumatic symptoms is correlated with either of the vagal indexes.\u003c/p\u003e\u003cp\u003eGiven the feasibility nature of this study, the primary objective is to evaluate the feasibility of the methodological approach and to obtain preliminary data on HRV changes associated with the course of narrative exposure. In feasibility studies, the emphasis is usually on viability, descriptive statistics, and preliminary estimations of effect rather than hypothesis testing with inferential statistics (e.g. ANOVA). Accordingly, any inferential analysis will be conducted in an exploratory manner to identify potential trends and guide the design of future, larger-scale studies. It is important to acknowledge that the limited sample size inherently reduces the statistical power of the study, particularly in the context of HRV data, which are known to exhibit considerable inter- and intra-individual variability(\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003ePsychometric data analysis\u003c/h2\u003e\u003cp\u003eFor the measuring the effect of NET based on the instruments described in Psychometric Data, SPSS version 29 will be used to conduct the statistical analyses to perform: (I) Descriptive Statistics to summarize the data including means, standard deviations, and frequencies for demographic and baseline characteristics; (II) Paired Sample t-tests to compare pre- and post-test scores for each instrument. This test will help determine if there are statistically significant changes in the participants' scores after the intervention; (III) Repeated Measures ANOVA to assess changes over time and determine if the intervention has a lasting effect.\u003c/p\u003e\u003cp\u003eThe expected limitations are: I) Reduced statistical power to detect significant effects or differences between pre- and post-test measurements; II) Impact on the results making it difficult to generalize findings to a broader population due the reduced sample, and III) Increase the risk of Type II errors, where true effects may not be detected due to insufficient data. The reliability and validity of the conclusions drawn can be affected as the sample may not adequately represent the diversity and complexity of the target population.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003eQualitative data analysis\u003c/h2\u003e\u003cp\u003eThis study protocol integrates qualitative analysis of narratives produced during NET with the collection of HRV to gain a comprehensive understanding of the therapeutic process in individuals undergoing narrative exposure. The qualitative analysis will explore the content, structure, and underlying themes of the participants narratives, emphasizing patterns of emotional expression, cognitive processing, and trauma integration using thematic analysis(\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e). Concurrently, HRV data collected during therapy sessions to monitor physiological markers of autonomic nervous system activity, reflecting the individual's stress response and emotional regulation in real-time, will contribute to provide a better understanding of the therapeutic process. Further, the biological biomarkers in what concerns the specific content of the sessions and the arousal of the participant through the HRV, can be compared when embedded with the qualitative analysis. By combining these methodologies, the study aims to provide a multidimensional understanding on how trauma is processed an integrated during NET, potentially facilitating the development of more tailored and effective therapeutic interventions(\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe integration of HRV monitoring with NET sessions presents several expected strengths, as highlighted in recent peer-reviewed articles(\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e). Firstly, combining HRV with NET allows for a comprehensive understanding of the course of emotional regulation across NET sessions. HRV serves as a physiological marker of autonomic nervous system activity, providing real-time insights into the emotional and stress responses of individuals undergoing therapy. This integration can enhance the therapeutic process by offering objective data that complements the subjective narrative accounts, potentially leading to more tailored and effective interventions(\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e). Moreover, multidisciplinary collaboration involving psychology, physiology, and narrative studies can provide robust insights into trauma therapy and its physiological correlates. Such collaboration fosters a holistic approach to understanding trauma, bridging the gap between psychological experiences and physiological responses. This synergy can lead to innovative therapeutic strategies and deepen our understanding of how trauma affects both mind and body(\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e). Feasibility results from studies integrating HRV with NET can additionally inform future larger studies by providing preliminary data on feasibility, participant retention, and data quality. These initial findings are crucial for refining methodologies and ensuring that subsequent research is grounded in practical insights gained from early trials(\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThere are potential challenges that must be addressed. Language barriers can pose significant obstacles, particularly in diverse populations where NET is often applied(\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Ensuring that narratives are accurately captured and understood across different languages is essential for the therapy's effectiveness. Consequently, ethical approval was sought and obtained to facilitate sessions in the presence of an interpreter. Additionally, small sample sizes in feasibility studies may limit the generalizability of findings, necessitating careful consideration in the design of future research(\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e). Feasibility considerations include the acceptability of wearable HRV devices among participants and ensuring minimal disruption of the therapeutic process. Wearable technology must be user-friendly and unobtrusive to maintain the integrity of the therapy sessions. Furthermore, technical issues related to data collection and analysis must be addressed to ensure reliable and valid results(\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eBy generating preliminary data on feasibility, participant retention, and data quality, this study can inform the methodology of future randomized controlled trials. Understanding the practical aspects of integrating HRV with NET will enable researchers to design studies that are both scientifically rigorous and clinically relevant. This groundwork is essential for advancing trauma therapy, potentially leading to more effective interventions and improved outcomes for individuals affected by complex trauma(\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e).\u003c/p\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003eFeasibility Study Status\u003c/h2\u003e\u003cp\u003eThe project originally had two primary investigators: one responsible for the clinical aspect of the study, and the other, with a background in the field of art, serving as the general responsible and responsible to a component of the study not connected to this protocol. The Regional Committees for Medical and Health Research Ethics (REK) demanded changes, and the investigator responsible for the clinical part overtook the whole study; this demanded accommodations and caused delays. In addition, due to necessary changes in the study concerning language barriers the use of a government certified interpreter was needed, and the study had to resubmit to the ethical committee (REK and Norwegian Agency for Shared Services in Education and Research \u0026ndash; SIKT). These necessary changes led to a backlog and the extension of the study for another year. Hence, even though the recruitment of participants started on October 16th, 2023, it did not end until December 31st, 2024. In addition, to comply with Norwegian GDPR rules, the procedure for the analysis of HRV data had to be changed and the final approval from REK was received November 18th, 2024. The first participant received the first NET-session on December 5th, 2023. Last treatments of NET and post-screenings are still ongoing as of submission, May 29th, 2025.\u003c/p\u003e\u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eREK\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRegional Committees for Medical and Health Research Ethics\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eSIKT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eNorwegian Agency for Shared Services in Education and Research\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePTSD\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePosttraumatic Stress Disorder\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDSM\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003e\u003cb\u003e5\u003c/b\u003e\u0026ndash;\u003cb\u003eTR\u003c/b\u003e\u0026ndash;Diagnostic and Statistical Manual of Mental Disorders, 5th Ed., Text Revision\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eNET\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eNarrative Exposure Therapy\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHRV\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHeart Rate Variability\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRCT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRandomized Control Trial\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePSSI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003e\u003cb\u003e5\u003c/b\u003e\u0026ndash;Posttraumatic Stress Disorder Symptom Scale Interview for DSM\u0026ndash;5\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTHL\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eThreats to Human Life Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eLEC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003e\u003cb\u003e5\u003c/b\u003e\u0026ndash;Life Events Checklist for DSM\u0026ndash;5\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePHQ\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003e\u003cb\u003e9\u003c/b\u003e\u0026ndash;Patient Health Questionnaire\u0026ndash;9\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eShut\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003e\u003cb\u003eD\u003c/b\u003e\u0026ndash;Shutdown Dissociation Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eAAS\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAppetitive Aggression Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRMSSD\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRoot Mean Square of Successive Differences\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBody mass index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eANOVA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAnalysis of variance\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval and Consent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study complies with ethical guidelines for research involving human participants, including obtaining informed consent and implementing measures to safeguard confidentiality. The study has received ethical approval from both the Regional Committees for Medical and Health Research Ethics (REK) under the reference number 588073 and in the Norwegian Agency for Shared Services in Education and Research (SIKT) under the reference number 662949. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll participants taken in the study consented voluntarily and consented through informed consent forms approved by REK and SIKT. The participants consented: I) to fill out questionnaires at the start and at the end of the study, which will measure demographic data, level of depression, anxiety, trauma exposure, PTSD, somatic problems, impairments of living and grief; II) to receive NET \u0026ndash; if applicable; III) to have their HRV measured during the individual NET \u0026ndash; applicable if offered NET; IV) that the data from the questionnaires and HRV can be used anonymously in research and publication(s); V) for the use of an interpreter in Ukrainian/Russian during the study \u0026ndash; applicable if needed by the participant. The consent form is available in the documents attached. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data and Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnonymised psychometric datasets and data connected to biofeedback will be available from the corresponding author on reasonable request with justification and submission of a valuable research questions. The requests will be taken to the internal ethical committee of the Kristiania University of Applied Sciences. Raw qualitative data will remain unavailable due to confidentiality and ethical legislation applicable to research with vulnerable populations in Norway. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKristiania University of Applied Sciences through incentives [insentivmidler] and interdisciplinary funds [tverrfaglige midler].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eVanessa Nolasco Ferreira (VNF) \u003c/em\u003econceived the study, participated in its design, and coordinated the drafting of the manuscript. She is the primary investigator and contributed to the development of the study protocol and the acquisition of funding.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAshley Rebecca Bell-Mizori (ARB)\u003c/em\u003e contributed to the design of the study and the development of the study protocol. She is the project coordinator and participated in the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSigne Alexandra Domogalla (SAD)\u003c/em\u003e is co-responsible for the conception of the qualitative embedded method. She contributed to the design of the study and participated in the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFernanda Serpeloni (FS)\u003c/em\u003e contributed to the design of the study, in what concerns the use of biofeedback in NET, and the development of the intervention. She also participated in the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMiroslava Tokovska (MT)\u003c/em\u003e participated in the design of the study and the development of the study protocol, especially in the design of the embedded qualitative method. She also contributed to the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAnke K\u0026ouml;bach (AK)\u003c/em\u003e participated in the design of the study and the development of the study protocol, guiding and supervising the main research team due to her expertise and knowledge in NET. She also contributed to the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eLiliana Abreu (LA)\u003c/em\u003e participated in the design of the study and the development of the study protocol. She was involved in the statistical analysis plan and contributed to the drafting and critical revision of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNayara Cristina dos Santos Oliveira (NCSO)\u003c/em\u003e participated in the design of the study and the development of the study protocol. She also contributed to the drafting and critical revision of the manuscript. She was involved in the statistical analysis plan and is the co-responsible for the biofeedback (HRV) framework and analysis plan. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003cbr\u003e\u003c/strong\u003eNot applicable. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Information\u003c/strong\u003e\u003c/p\u003e\n\u003col style=\"list-style-type: upper-roman;\"\u003e\n\u003cli\u003eVanessa Nolasco Ferreira, Associate Professor, Kristiania University of Applied Sciences, School of Health Sciences, Department of Psychology, Pedagogy and Law, Bergen, Norway \u0026ndash; ORCID number: https://orcid.org/0000-0003-4243-0466 \u003c/li\u003e\n\u003cli\u003eAshley Rebecca Bell-Mizori, Associate Professor, Kristiania University of Applied Sciences, School of Health Sciences, Department of Psychology, Pedagogy and Law, Oslo, Norway \u0026ndash; ORCID number: https://orcid.org/0000-0002-3303-9994 \u003c/li\u003e\n\u003cli\u003eSigne Alexandra Domogalla, Associate Professor, Kristiania University of Applied Sciences, School of Art, Design and Media, Department of Performing Arts, Film and Media, Oslo, Norway\u003c/li\u003e\n\u003cli\u003eFernanda Serpelloni, Visiting Researcher in the Department of Studies About Violence and Health Jorge Careli (ENSP/Fiocruz), Oswaldo Cruz Foundation, Rio de Janeiro Brazil. ORCID: https://orcid.org/0000-0001-6222-0162 \u003c/li\u003e\n\u003cli\u003eMiroslava Tokovska, Kristiania University of Applied Sciences, School of Health Sciences, Department of Health and Exercise, Oslo, Norway, ORCID: https://orcid.org/0000-0002-8279-3168 \u003c/li\u003e\n\u003cli\u003eAnke K\u0026ouml;bac, Department of Politics and Public Administration, University of Konstanz, Konstanz, Germany. ORCID: https://orcid.org/0000-0002-8666-9586 \u003c/li\u003e\n\u003cli\u003eLiliana Abreu, Department of Politics and Public Administration, University of Konstanz, Konstanz, Germany. ORCID: https://orcid.org/0000-0003-1110-6508 \u003c/li\u003e\n\u003cli\u003eNayara Cristina dos Santos Oliveira, Genomic Research Institute, State University of the Central West, Paran\u0026aacute;, Brazil. ORCID: https://orcid.org/0000-0002-9714-9025 \u003c/li\u003e\n\u003c/ol\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eUNHCR. The Operational Data Portal 2025 [cited 2025 22.05]. UNHCR webpage ]. Available from: https://data.unhcr.org/en/situations/ukraine.\u003c/li\u003e\n\u003cli\u003eBilewicz M, Maria B, and Gromova A. High rates of probable PTSD among Ukrainian war refugees: the role of intolerance of uncertainty, loss of control and subsequent discrimination. European Journal of Psychotraumatology. 2024;15(1):2394296.\u003c/li\u003e\n\u003cli\u003eLeon DA, Jdanov D, Gerry CJ, Grigoriev P, Jasilionis D, McKee M, et al. The Russian invasion of Ukraine and its public health consequences. The Lancet Regional Health - Europe. 2022;15:100358.\u003c/li\u003e\n\u003cli\u003eUDI. Information for people fleeing the war in Ukraine 2025 [cited 2025 22.05]. Available from: https://www.udi.no/en/information-ukraine-and-russia/ukraine/.\u003c/li\u003e\n\u003cli\u003eHansen TM, Skogheim TS, Helland Y. Health \u0026amp;amp; healthcare needs among refugees from Ukraine arriving in Norway during 2022. European Journal of Public Health. 2023;33(Supplement_2).\u003c/li\u003e\n\u003cli\u003eLabberton AS, Ozeryansky L, Helland Y, Skogheim TS, Hansen TM. Trends in the health status of Ukrainian refugees in Norway according to month of arrival during 2022. BMC Public Health. 2024;24(1):3127.\u003c/li\u003e\n\u003cli\u003eCharlson F, van Ommeren M, Flaxman A, Cornett J, Whiteford H, Saxena S. New WHO prevalence estimates of mental disorders in conflict settings: a systematic review and meta-analysis. The Lancet. 2019;394(10194):240-8.\u003c/li\u003e\n\u003cli\u003eKessler RC, Sergio A-G, Jordi A, Corina B, J. BE, Gra\u0026ccedil;a C, et al. Trauma and PTSD in the WHO World Mental Health Surveys. European Journal of Psychotraumatology. 2017;8(sup5):1353383.\u003c/li\u003e\n\u003cli\u003eKoenen KC, Ratanatharathorn A, Ng L, McLaughlin KA, Bromet EJ, Stein DJ, et al. Posttraumatic stress disorder in the World Mental Health Surveys. Psychol Med. 2017;47(13):2260-74.\u003c/li\u003e\n\u003cli\u003eAssociation AP. Diagnostic and statistical manual of mental disorders (5th ed., text rev.): American Psychiatric Publishing; 2022.\u003c/li\u003e\n\u003cli\u003eSchauer M, Neuner F, Karunakara U, Klaschik C, Robert C, Elbert T. PTSD and the building block effect of psychological trauma among West Nile Africans. 2003.\u003c/li\u003e\n\u003cli\u003eKolassa IT, Kolassa S, Ertl V, Papassotiropoulos A, De Quervain DJ. The risk of posttraumatic stress disorder after trauma depends on traumatic load and the catechol-o-methyltransferase Val(158)Met polymorphism. Biol Psychiatry. 2010;67(4):304-8.\u003c/li\u003e\n\u003cli\u003eWilker S, Anett P, Stephan K, Daniela K, Thomas E, and Kolassa I-T. How to quantify exposure to traumatic stress? Reliability and predictive validity of measures for cumulative trauma exposure in a post-conflict population. European Journal of Psychotraumatology. 2015;6(1):28306.\u003c/li\u003e\n\u003cli\u003eTol WA, Barbui C, Galappatti A, Silove D, Betancourt TS, Souza R, et al. Mental health and psychosocial support in humanitarian settings: linking practice and research. Lancet. 2011;378(9802):1581-91.\u003c/li\u003e\n\u003cli\u003eSchauer M, Elbert T, Neuner F. Narrative exposure therapy : a short-term treatment for traumatic stress disorders. Cambridge, Massachusetts: Hogrefe; 2011.\u003c/li\u003e\n\u003cli\u003eSchauer M, Neuner F, Elbert T. Narrative Exposure Therapy (NET) For Survivors of Traumatic Stress. 3 ed: Hogrefe Publishing; 2025.\u003c/li\u003e\n\u003cli\u003eKaltenbach E, Hermenau K, Schauer M, Dohrmann K, Elbert T, Schalinski I. Trajectories of posttraumatic stress symptoms during and after Narrative Exposure Therapy (NET) in refugees. BMC Psychiatry. 2020;20(1):312.\u003c/li\u003e\n\u003cli\u003eLely JCG, June THFJ, Mirjam M, W. KJ, and Kleber RJ. 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Psychophysiology. 2023;60(2):e14167.\u003c/li\u003e\n\u003cli\u003eSchneider M, Schwerdtfeger A. Autonomic dysfunction in posttraumatic stress disorder indexed by heart rate variability: a meta-analysis. Psychological Medicine. 2020;50(12):1937-48.\u003c/li\u003e\n\u003cli\u003eKim H-G, Cheon E-J, Bai D-S, Lee YH, Koo B-H. Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature. Psychiatry Investig. 2018;15(3):235-45.\u003c/li\u003e\n\u003cli\u003eReena Tiwari RK, Sujata Malik, Tilak Raj and Punit Kumar*. Analysis of Heart Rate Variability and Implication of Different Factors on Heart Rate Variability. Current Cardiology Reviews. 2021;17(5):10.\u003c/li\u003e\n\u003cli\u003eSlavish DC, Ruggero CJ, Schuler K, Schwartz JE, Luft B, Kotov R. Effects of Daily Posttraumatic Stress Disorder Symptoms on Heart Rate Variability. Biopsychosocial Science and Medicine. 2024;86(1).\u003c/li\u003e\n\u003cli\u003eGoreis A, Prillinger K, Bedus C, Lipp R, Mayer A, Nater UM, et al. Physiological stress reactivity and self-harm: A meta-analysis. Psychoneuroendocrinology. 2023;158:106406.\u003c/li\u003e\n\u003cli\u003eSack M, Hopper JW, Lamprecht F. Low respiratory sinus arrhythmia and prolonged psychophysiological arousal in posttraumatic stress disorder: heart rate dynamics and individual differences in arousal regulation. Biological Psychiatry. 2004;55(3):284-90.\u003c/li\u003e\n\u003cli\u003eSiehl S, Katy R, and Crombach A. Systematic review and meta-analyses of the long-term efficacy of narrative exposure therapy for adults, children and perpetrators. Psychotherapy Research. 2021;31(6):695-710.\u003c/li\u003e\n\u003cli\u003eFoa EB, McLean CP, Zang Y, Zhong J, Rauch S, Porter K, et al. Psychometric properties of the Posttraumatic Stress Disorder Symptom Scale Interview for DSM-5 (PSSI-5). Psychol Assess. 2016;28(10):1159-65.\u003c/li\u003e\n\u003cli\u003eKoebach A, Elbert, T., \u0026amp; Schauer, M. Checklist for Threats to Human Life (THL). 2016.\u003c/li\u003e\n\u003cli\u003eGray MJ, Litz BT, Hsu JL, Lombardo TW. Psychometric properties of the life events checklist. Assessment. 2004;11(4):330-41.\u003c/li\u003e\n\u003cli\u003eWeathers FW, Blake, D.D., Schnurr, P.P., Kaloupek, D.G., Marx, B.P., \u0026amp; Keane, T.M. The Life Events Checklist for DSM-5 (LEC-5) 2013 [Available from: www.ptsd.va.gov.\u003c/li\u003e\n\u003cli\u003eKroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16(9):606-13.\u003c/li\u003e\n\u003cli\u003eSchalinski I, Maggie S, and Elbert T. The Shutdown Dissociation Scale (Shut-D). European Journal of Psychotraumatology. 2015;6(1):25652.\u003c/li\u003e\n\u003cli\u003eWeierstall R, and Elbert T. The Appetitive Aggression Scale\u0026mdash;development of an instrument for the assessment of human\u0026apos;s attraction to violence. European Journal of Psychotraumatology. 2011;2(1):8430.\u003c/li\u003e\n\u003cli\u003eBraun V, and Clarke V. Using thematic analysis in psychology. Qualitative Research in Psychology. 2006;3(2):77-101.\u003c/li\u003e\n\u003cli\u003eBraun V, and Clarke V. Reporting guidelines for qualitative research: a values-based approach. Qualitative Research in Psychology. 2025;22(2):399-438.\u003c/li\u003e\n\u003cli\u003eShaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Frontiers in Public Health. 2017;Volume 5 - 2017.\u003c/li\u003e\n\u003cli\u003eMay R, McBerty V, Zaky A, Gianotti M. Vigorous physical activity predicts higher heart rate variability among younger adults. Journal of Physiological Anthropology. 2017;36(1):24.\u003c/li\u003e\n\u003cli\u003eQuintana DS, Guastella AJ, McGregor IS, Hickie IB, Kemp AH. Moderate alcohol intake is related to increased heart rate variability in young adults: Implications for health and well-being. Psychophysiology. 2013;50(12):1202-8.\u003c/li\u003e\n\u003cli\u003eQuintana DS, McGregor IS, Guastella AJ, Malhi GS, Kemp AH. A Meta-Analysis on the Impact of Alcohol Dependence on Short-Term Resting-State Heart Rate Variability: Implications for Cardiovascular Risk. Alcoholism: Clinical and Experimental Research. 2013;37(s1):E23-E9.\u003c/li\u003e\n\u003cli\u003eGuo Q-n, Wang J, Liu H-y, Wu D, Liao S-x. Nicotine Ingestion Reduces Heart Rate Variability in Young Healthy Adults. BioMed Research International. 2022;2022(1):4286621.\u003c/li\u003e\n\u003cli\u003eCatai AM, Pastre CM, Godoy MFd, Silva Ed, Takahashi ACdM, Vanderlei LCM. Heart rate variability: are you using it properly? Standardisation checklist of procedures. Brazilian Journal of Physical Therapy. 2020;24(2):91-102.\u003c/li\u003e\n\u003cli\u003eLaborde S, Mosley E, Thayer JF. Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research \u0026ndash; Recommendations for Experiment Planning, Data Analysis, and Data Reporting. Frontiers in Psychology. 2017;Volume 8 - 2017.\u003c/li\u003e\n\u003cli\u003eZimmermann-Viehoff F, Julian T, Julian K, Christian H, S. WC, and Deter H-C. Short-term effects of espresso coffee on heart rate variability and blood pressure in habitual and non-habitual coffee consumers \u0026ndash; A randomized crossover study. Nutritional Neuroscience. 2016;19(4):169-75.\u003c/li\u003e\n\u003cli\u003eHimariotis AT, Coffey KF, Noel SE, Cornell DJ. Validity of a Smartphone Application in Calculating Measures of Heart Rate Variability. Sensors. 2022;22(24):9883.\u003c/li\u003e\n\u003cli\u003eSchaffarczyk M, Rogers B, Reer R, Gronwald T. Validity of the Polar H10 Sensor for Heart Rate Variability Analysis during Resting State and Incremental Exercise in Recreational Men and Women. Sensors. 2022;22(17):6536.\u003c/li\u003e\n\u003cli\u003eTarvainen MP, Niskanen J-P, Lipponen JA, Ranta-aho PO, Karjalainen PA. Kubios HRV \u0026ndash; Heart rate variability analysis software. Computer Methods and Programs in Biomedicine. 2014;113(1):210-20.\u003c/li\u003e\n\u003cli\u003eAlcantara JMA, Plaza-Florido A, Amaro-Gahete FJ, Acosta FM, Migueles JH, Molina-Garcia P, et al. Impact of Using Different Levels of Threshold-Based Artefact Correction on the Quantification of Heart Rate Variability in Three Independent Human Cohorts. Journal of Clinical Medicine. 2020;9(2):325.\u003c/li\u003e\n\u003cli\u003eMeiser-Stedman R, McKinnon A, Dixon C, Boyle A, Smith P, Dalgleish T. A core role for cognitive processes in the acute onset and maintenance of post-traumatic stress in children and adolescents. Journal of Child Psychology and Psychiatry. 2019;60(8):875-84.\u003c/li\u003e\n\u003cli\u003ePorges SW. The polyvagal perspective. Biological Psychology. 2007;74(2):116-43.\u003c/li\u003e\n\u003cli\u003eDos Santos Oliveira NC, Fernanda S, and Gon\u0026ccedil;alves de Assis S. The interplay between DNA methylation and cardiac autonomic system functioning: a systematic review. International Journal of Environmental Health Research. 2023;33(1):54-70.\u003c/li\u003e\n\u003cli\u003edos Santos Oliveira NC, Seyma K, Gon\u0026ccedil;alves dAS, K. SA, and Serpeloni F. Community and domestic violence are associated with DNA methylation GrimAge acceleration and heart rate variability in adolescents. European Journal of Psychotraumatology. 2023;14(2):2202054.\u003c/li\u003e\n\u003cli\u003eThayer JF, Lane RD. Claude Bernard and the heart\u0026ndash;brain connection: Further elaboration of a model of neurovisceral integration. Neuroscience \u0026amp; Biobehavioral Reviews. 2009;33(2):81-8.\u003c/li\u003e\n\u003cli\u003eBeck JG, Grant DM, Clapp JD, Palyo SA. Understanding the interpersonal impact of trauma: Contributions of PTSD and depression. Journal of Anxiety Disorders. 2009;23(4):443-50.\u003c/li\u003e\n\u003cli\u003eIm B, Keum J, Kim T, Lee K-i, Koo K-i. Utilizing Real-Time Heart Rate Variability during Psychological Intervention Program for Complex Post-Traumatic Stress Disorder: A Case Study. Applied Sciences. 2024;14(1):4.\u003c/li\u003e\n\u003cli\u003eMensinger JL, Weissinger GM, Cantrell MA, Baskin R, George C. A Pilot Feasibility Evaluation of a Heart Rate Variability Biofeedback App to Improve Self-Care in COVID-19 Healthcare Workers. Applied Psychophysiology and Biofeedback. 2024;49(2):241-59.\u003c/li\u003e\n\u003cli\u003eNeuner F, Onyut, P. L., Ertl, V., Odenwald, M., Schauer, E., \u0026amp; Elbert, T. Treatment of posttraumatic stress disorder by trained lay counselors in an African refugee settlement: A randomized controlled trial. Journal of Consulting and Clinical Psychology. 2008;76(4):686\u0026ndash;94.\u003c/li\u003e\n\u003cli\u003eRiva G, Wiederhold BK, Mantovani F. Neuroscience of Virtual Reality: From Virtual Exposure to Embodied Medicine. Cyberpsychol Behav Soc Netw. 2019;22(1):82-96.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pilot-and-feasibility-studies","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pafs","sideBox":"Learn more about [Pilot and Feasibility Studies](http://pilotfeasibilitystudies.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/PAFS/default.aspx","title":"Pilot and Feasibility Studies","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Narrative Exposure Therapy, PTSD, Trauma, War, Autonomic Nervous System, Heart Rate Variability, Cardiovascular System","lastPublishedDoi":"10.21203/rs.3.rs-6779026/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6779026/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eThe Russian invasion of Ukraine has led to repercussions, including the displacement of people, challenges to physical and mental health, and strains on health systems across Europe. Narrative Exposure Therapy as an evidence-based method aims to mitigate Posttraumatic Stress Disorder and its comorbidities; the physiological mechanisms underlying its results remain unexplored. Heart rate variability provides a non-invasive method to examine autonomic responses during therapy, offering insights into therapeutic outcomes and attitudes toward violence. The overall aim of the study is to assess the effectiveness of Narrative Exposure Therapy by examining biological biomarkers.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis study will involve Ukrainian refugees residing in Norway who meet the inclusion criteria. Eligible participants will engage in six to eight individual sessions of Narrative Exposure Therapy. During these therapy sessions, heart rate variability will be continuously monitored using commercially available Polar devices equipped with a chest strap. This data will be gathered to evaluate therapeutic outcomes. Primary objectives of the study are: (I) Compare pre- and post-treatment screening results to measure the effectiveness of Narrative Exposure Therapy in reducing symptoms of Posttraumatic Stress Disorder, depression, and dissociation six months post conclusion of the therapy amongst Ukrainian refugees in Norway; (II) Utilize biofeedback as an outcome measure to assess therapy functioning during exposure sessions in Narrative Exposure Therapy. Secondary objective: (III) Develop a comprehensive plan for providing mental health support to refugees arriving in Norway, aiming to mitigate trauma triggered by the consequences of the exposure to the Russian invasion.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThis pretest-posttest quasi-experimental feasibility study aims to evaluate the use of biological feedback in measuring the effectiveness of narrative exposure therapy. The findings will help determine the feasibility of this approach, potentially informing the design and implementation of future randomized control trials.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e\u003cp\u003e The trial is registered in the Regional Committees for Medical and Health Research Ethics under the reference number 588073, and in the Norwegian Agency for Shared Services in Education and Research under the reference number 662949.\u003c/p\u003e","manuscriptTitle":"Assessing autonomic nervous system via heart rate variability to measure responses during trauma-focused Narrative Exposure Therapy sessions: Protocol of a pretest-posttest quasi-experimental feasibility study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-07 09:17:06","doi":"10.21203/rs.3.rs-6779026/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-02-06T01:14:59+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-24T14:30:54+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-07T07:10:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pilot and Feasibility Studies","date":"2025-06-05T04:02:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pilot-and-feasibility-studies","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pafs","sideBox":"Learn more about [Pilot and Feasibility Studies](http://pilotfeasibilitystudies.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/PAFS/default.aspx","title":"Pilot and Feasibility Studies","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"34be2782-da52-4eff-8fc3-d6a3f185f7b2","owner":[],"postedDate":"October 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-10-07T09:17:06+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-07 09:17:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6779026","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6779026","identity":"rs-6779026","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}