The Sensible Senseless Person: a theoretical framework for clinical assessment of proprioception

Abstract Proprioception, the sense of body position and motion, is essential for all motor activities. Position-matching is a common task used to assess proprioceptive acuity. This assessment is limited due to reliance on self-report, and biased performance measures. To support this statement, we introduce the concept of a “sensible senseless person” (SSP), a theoretical construct that lacks sensory perception but is capable of logical inference. This framework allows for critical examination of the validity of conventional performance measures used in position-matching tasks. Our analysis reveals that traditional measures are influenced by the structural parameters of the task, strategic responses, and the prior beliefs of the SSP. To address these limitations, we propose a novel performance metric: the Guess Index (GI). Unlike existing measures, the GI is designed to be robust against these confounding factors, ensuring that the SSP would consistently receive the same score. To demonstrate the utility of the GI, we applied a simplified, clinically-oriented version of the position-matching task to healthy individuals and persons with stroke. Our findings show that the GI is more sensitive to group differences than traditional measures and is the only metric capable of correctly classifying persons with stroke above chance level. Competing Interest Statement The authors have declared no competing interest. Funding Statement The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: this research was supported by the Israeli Science Foundation (grant 1244/22 to LS) and the Lillian and David E. Feldman Research fund. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Local Ethical Committee at Adi-Negev Nahalat-Eran Rehabilitation Hospital (ADINEGEV-2023_106), and all participants provided a written informed consent prior to enrollment. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability All data produced in the present study are available upon reasonable request to the authors