Feasibility, content and construct validity of the Patient Specific Functional Scale for chronic stroke survivors.

PURPOSE: To establish the feasibility, content, and construct validity of the Patient Specific Functional Scale (PSFS) for chronic stroke survivors using the COSMIN standards. To identify functional predictors of PSFS completion and evaluate their predictive accuracy. METHODS: Sixty-six stroke survivors (81 years old, 76 months from onset; median) were participated. Feasibility was assessed via completion rate and ceiling/floor effects. Predictive ability was analyzed using receiver operating characteristic (ROC) curves. Content validity was established through linking activities to the International Classification of Functioning, Disability and Health (ICF). Construct validity was confirmed with hypothesis testing for correlations between the PSFS and standardized functional measurements. RESULTS: Fifty-six participants (85%) were PSFS completers; non-completers reported no perceived difficulties. No ceiling/floor effects were observed. Hemiparesis was a significant independent predictor of PSFS completion, with adequate predictive accuracy (AUC= 0.864). Content validity was supported by 90.5% of activities linking to the ICF "Activity and Participation" component. Adequate construct validity was demonstrated by significant relationships with functional measurements, with 85.7% of hypotheses were confirmed. CONCLUSION: The PSFS is a feasible, valid instrument to capture the patient-identified difficulties in stroke survivors. Notably, it shows better applicability for those with hemiparesis.