Severe Impairment Rating Scale: A Useful and Brief Cognitive Assessment Tool for Advanced Dementia for Nursing Home Residents.

To investigate the utility of the Severe Impairment Rating Scale (SIRS) as a cognitive assessment tool among nursing home residents with advanced dementia, we conducted a cross-sectional study of 96 residents in 3 nursing homes with Functional Assessment Staging Test (FAST) stage 6a and above. We compared the discriminatory ability of SIRS with the Chinese version of Mini-Mental State Examination, Abbreviated Mental Test, and Clock Drawing Test. Among the cognitive tests, SIRS showed the least "floor" effect and had the best capacity to distinguish very severe (FAST stages 7d-f) dementia (area under the curve 0.80 vs 0.46-0.76 for the other tools). The SIRS had the best correlation with FAST staging (r = -.59, P < .01) and, unlike the other 3 tools, exhibited only minimal change in correlation when adjusted for education and ethnicity. Our results support the utility of SIRS as a brief cognitive assessment tool for advanced dementia in the nursing home setting.