Validity and reliability assessment of a Japanese version of the Snaith-Hamilton pleasure scale

Anhedonia is one of the main non-motor symptoms in Parkinson's disease (PD); it is assessed using the Snaith-Hamilton pleasure scale (SHAPS). To assess anhedonia in the Japanese population, we prepared a Japanese language version of SHAPS (SHAPS-J), and evaluated its validity and reliability in 8 neurological centers. Seventy subjects (48 patients with PD and 22 healthy subjects) were enrolled in this study.

The validity of the test was assessed by the correlation between SHAPS-J and the apathy scale, based on the fact that anhedonia is considered a symptom of apathy syndrome. Test-retest reliability and internal consistency were assessed by Cohen's kappa and Cronbach's alpha coefficients, respectively.

In the evaluation of validity, the total scores obtained on SHAPS-J during the test and retest significantly correlated with scores on Item 4 in Part 1 of the unified Parkinson's disease rating scale (p<0.0008 and p<0.0036, respectively). Cohen's kappa coefficient was >0.3 on all items (p<0.0005 on all items). Cronbach's alpha coefficient was 0.90 at the baseline and 0.88 at the retest.

These results indicate that SHAPS-J has good validity, test-retest reliability, and internal consistency, thus establishing an available measure of anhedonia in Japanese.