Wechsler Intelligence Scale profiles, the cholinergic system, and Alzheimer's disease

Forty-one patients with putative Alzheimer's Disease (AD) were evaluated to determine the diagnostic utility of a profile of Wechsler Adult Intelligence Scale (WAIS) subtests which has been proposed by Fuld (1984) to identify cholinergic dysfunction. Only nine (21.9%) of these patients had positive Wechsler profiles. Half (n = 21) of the AD patients had been given the WAIS, and the other half (n = 20) the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Positive profiles occurred more often in the AD subgroup given the WAIS-R, but this difference was not statistically significant. Specificity of the formula was evaluated using Wechsler results of 42 older normals and 30 patients who were being evaluated for dementia but who did not have AD. One of the 42 normals (2.4%) and five of the patient controls (16.7%) showed a positive Wechsler profile. Because of the Fuld formula's low sensitivity, a negative Wechsler profile cannot be used to help rule out AD. Although specificity of the formula is high, the diagnostic value of a positive Wechsler profile is modest even under the most favorable AD baserate conditions.