<p><strong>Objectives: </strong>To assess the reliability and validity of the Patient Specific Functional Scale when administered to people living with Parkinson’s Disease.<strong></strong></p> <p><strong>Methods and Materials: </strong>Twenty six people living with Parkinson’s Disease from Hamilton and Burlington were interviewed four times within a four month period. The participants answered the Movement Disorders Sponsored Unified Disease Rating Scale part II, the Parkinson’s Disease Questionnaire 39, and the Patient Specific Functional Scale. Reliability assessment addressed test-retest reliability and reliability of the change scores using Intraclass Correlation Coefficients. Validity assessment focused on convergent construct validity and longitudinal validity by correlating the Patient Specific Functional Scale with the other measures administered.</p> <p><strong>Results: </strong>The<strong> </strong>test retest reliability of the scores yielded by the PSFS was ICCpre= 0.72 (95%CI=0.47-0.86); ICCpost=0.83 (95%CI=0.66-0.92). The reliability of change scores was 0.50. In relation to the validity, no significant correlations were found between the Patient Specific Functional Scale and the other measures. <strong></strong></p> <p><strong>Conclusions: </strong>The PSFS yields reliable scores when it is administered to people living with PD. The Patient Specific Functional Scale does not target the same outcomes as the MDS-UPDRS part II and the PDQ-39. The PSFS does not detect change in functioning in people living with PD within a four month period.</p> / Master of Science (MSc)