Correlational analysis of five commonly used measures of mental status/functional abilities in patients with Alzheimer disease.

There are multiple assessment techniques to help clinicians diagnose, stage, and measure the rate of progression in Alzheimer disease (AD). We analyzed retrospectively the relationship between scores on commonly used scales and tests (Mini-Mental State, the Blessed Information-Memory-Concentration Test, the Alzheimer's Disease Assessment Scale--cognitive portion, the Activities of Daily Living Scale, and the Global Deterioration Scale) of 100 successive admissions to a memory clinic. Patients were included in the study if they were diagnosed subsequently with probable AD and if all five measures were administered in the same day. Regression analysis yielded 20 linear equations that allowed for conversion between test scores on any two instruments. With the exception of the Activities of Daily Living Scale (intercorrelation range with the other four instruments, r = 0.56-0.66), intercorrelations were generally high (r = 0.81-0.87). The results of this study should provide a clinically useful tool for converting test scores on five commonly used dementia screening/rating instruments.