Utility of the Japanese version of the 9-item Wearing-off Questionnaire

The 9-item Wearing-off Questionnaire (WOQ-9) is a useful tool for screening of wearing-off. We performed a validation study of the Japanese version of the WOQ-9 (JWOQ-9) using a cross-sectional design in Japanese Parkinson's disease (PD) patients diagnosed with sporadic PD and treated with levodopa.

Subjects with severe dementia, uncontrolled psychiatric comorbidities, and previous PD neurosurgery were excluded. The wearing-off phenomenon was detected according to the JWOQ-9, and the results were compared with independent evaluations of wearing-off conducted by PD specialists blinded to the JWOQ-9 results. To validate the JWOQ-9, a sample size of at least 70 patients with wearing-off and 70 patients without wearing-off was required. Therefore, a total of 180 patients (101 patients with wearing-off and 79 patients without wearing-off) were enrolled.

The sensitivity, specificity, positive predictive value, and negative predictive value of the JWOQ-9 were 94.1%, 39.2%, 66.4%, and 83.8%, respectively. Motor symptom questions demonstrated both moderate sensitivity (58.1-87.3%) and specificity (60.4-87.5%). In contrast, non-motor symptom questions demonstrated fair to moderate sensitivity (51.5-64.6%), with high specificity (80.0-94.1%). Like the original WOQ-9, the JWOQ-9 exhibits significant value for detecting possible wearing-off.

The JWOQ-9 is a useful screening tool for detecting wearing-off of both motor and non-motor symptoms.