Test profile of cholinergic dysfunction and of Alzheimer-type dementia.

A characteristic profile of subtest scores from the Wechsler Adult Intelligence Scale (WAIS) similar to that seen in clinically tested dementia patients was found in 10 of 19 normal young adult subjects with a drug-induced cholinergic deficiency of mental functioning but in only 4 of 22 control subjects. The same subtest profile was then found in test data from two groups of consecutive dementia patients (61 and 77 patients, respectively) with research diagnoses of Alzheimer-type dementia (DAT, senile and presenile), multi-infarct, and other dementias. The profile identified 44% of testable patients with AD and was 96% specific to DAT (only two false positives). A Verbal-Performance IQ discrepancy of 15 or more points was associated with cholinergic dysfunction in the normal drug subjects, but this IQ-score discrepancy did not differentiate AD from multi-infarct dementia patients. It was concluded that the subtest profile could contribute to the differentiation of DAT from other dementias. The association of this profile with drug-induced cholinergic deficiency suggested that the cholinergic deficiency of DAT might be responsible for the intellectual changes seen in this disease.