Quantitative Assessments of Finger Individuation with an Instrumented Glove

Background: In clinical and research settings, hand dexterity is often assessed as finger individuation, or the ability to move one finger at a time. Despite its clinical importance, there is currently no standardized, sufficiently sensitive, or fully objective platform for these evaluations. Methods: Here we developed two novel individuation scores and tested them against a previously developed score (1) using a commercially available instrumented glove and data collected from 20 healthy adults. Participants performed individuation for each finger of each hand as well as whole hand open-close at two study visits separated by several weeks. Using the three individuation scores, intra-class correlation coefficients (ICC’s) and minimal detectable changes (MDC) were calculated. Individuation scores were further correlated with subjective assessments to assess validity. Results: We found that each score emphasizes different aspects of individuation performance while generating scores on the same scale (0 [poor] to 1 [ideal]). These scores are repeatable, but the quality of these metrics vary by both equation and finger of interest. For example, index finger intra-class correlation coefficients (ICC’s) were 0.90 (< 0.0001), 0.77 ([< 0.001), and 0.83 (p < 0.0001), while pinky finger ICC’s were 0.96 (p < 0.0001), 0.88 (p < 0.0001), and 0.81 (p < 0.001) for each score. Similarly, MDCs also vary by both finger and equation. In particular, thumb MDCs were 0.068, 0.14, and 0.045, while index MDCs were 0.041, 0.066, and 0.078. Furthermore, objective measurements correlated with subjective assessments of finger individuation quality for all three equations (ρ=-0.45, p < 0.0001; ρ=-0.53, p < 0.0001; ρ=-0.40, p < 0.0001). Conclusions: Here we evaluate the nuances of each objective scoring system and discuss ideal translational applications into motor physiology and rehabilitations labs, orthopedic hand and neurosurgery clinics, and even operating rooms for real-time objective scoring during peripheral nerve and awake brain operations for each equation. This work represents the first healthy participant data set for this translatable and objective measurement and scoring platform.