Reliability and validity of the Japanese version of the GBS scale

The Japanese version of the GBS Scale (GBSS-J) was administered to 246 elderly patients with dementia in a geriatric hospital to test the inter-rater reliability and validity of the items and the subscales of the GBSS-J. The inter-rater reliability of the 26 items was tested by rating 20 patients. After the raters conferred with each other how to rate the items of the scale, the items were rated independently. Pearson's correlation coefficients indicating the agreement between the rates were as good as more than. 660 except for the items of impaired wakefulness and confusion. The validity of the 28 items was examined by comparing them with the stages of Functional Assessment Staging (FAST). Hasegawa's dementia scale (HDS) was employed as an external standard to test the items of the subscale of intellectual functions. Physical disability was checked by using the Rapid Disability Rating Scale (RDRS). Mean scores of the 20 items except for the 6 items included in the subscale of different symptoms common in dementia significantly increased as the FAST stage advanced. These results indicated that the 20 items of the GBSS-J measured the severity of dementia with sufficient validity. In addition, according to the results of analysis of variance and covariance, the items of motor insufficiency in taking food, impaired physical activity, impaired wakefulness and irritability were related to the severity of physical disability rather than that of dementia. Also, the 10 items of the subscale of intellectual functions showed significant correlations with the scores of HDS, while the item of impaired wakefulness showed a significant, although fairly low correlation.(ABSTRACT TRUNCATED AT 250 WORDS)