Psychometric Properties of Jebsen Taylor Hand Function Test in an Italian Population with Parkinson’s Disease

Background: Assessment of upper limb function is critical in the rehabilitation process of people with Parkinson's Disease (PD), and universally validated outcome measures are needed to allow comparisons across the practice. Moreover, the study of psychometric properties of the same tool on different clinical populations guarantees the possibility of reliably evaluating the same rehabilitation treatment in people with different clinical conditions. Aim of the study: The aim of this research was to evaluate the psychometric characteristics of the Italian adaptation of the Jebsen Taylor Hand Function Test (JTHFT) in individuals with PD. Methods: The reliability and validity of the test were assessed in accordance with international standards. Internal consistency was measured using Cronbach's alpha, and test-retest reliability was determined via the intraclass correlation coefficient (ICC). The construct validity and cross-cultural validity of the test were evaluated using Pearson's correlation coefficient with three assessment tools on upper limb function, independence, and quality of life, with hand grip power measured by a dynamometer and an Italian pangram. Finally, responsiveness after a one month of rehabilitation treatment was measured using the Wilcoxon rank test. Results: Fifty-two Italian people with PD were recruited. Cronbach's alpha values ranged from 0.556 (non-dominant hand) to 0.668 (dominant hand); ICC values ranged from 0.754 to 0.988. Construct validity showed that several statistically significant correlations were detected. Wilcoxon's test showed that the assessment tool can detect a change in this population after treatment. Conclusions: The JTHFT is a reliable, valid, and respondent tool to evaluate the upper limb and hand functionalities in PD patients. It should be added to the toolkit for measuring upper limb performance in this population, adding value to clinical evaluation and ensuring comparable results for different clinical populations and different countries.