Development of the Cognitive Test for Severe Dementia.

BACKGROUND/AIMS: Existing cognitive measures for moderate-to-severe dementia have shown floor effects and an inability to assess the remaining cognitive function, especially for profound dementia.

METHODS: We constructed the Cognitive Test for Severe Dementia (CTSD), which consists of 13 items covering 7 cognitive domains, and examined its reliability and validity.

RESULTS: Cronbach's α in severe dementia participants was 0.896. Interrater and test-retest reliability were 0.961 and 0.969, respectively. The CTSD showed a significant correlation with 3 other measures of cognitive function (Mini-Mental State Examination, Severe Cognitive Impairment Rating Scale, and Hasegawa Dementia Scale-Revised: r values = 0.870-0.922, p values <0.001). While the other measures showed floor effects, the CTSD did not.

CONCLUSION: The CTSD was able to sensitively capture the remaining cognitive function in severe dementia patients when compared with other cognitive tests.