THE NEUROPSYCHOLOGICAL DIFFERENTIATION OF PATIENTS WITH VERY MILD ALZHEIMERS-DISEASE AND OR MAJOR DEPRESSION/

OBJECTIVE: To evaluate the usefulness of standardized neuropsychologic al tests in the psychometric differentiation of patients with very mil d or mild Alzheimer's Disease (AD) and/or major depression presenting in a tertiary clinic with memory/attention complaints. DESIGN: Control led prospective clinicoexperimental design. SETTING: Multidisciplinary Memory Clinic at Addenbrooke's Hospital, Cambridge, England. PARTICIP ANTS: Twenty-four patients with a clinical diagnosis of Alzheimer's di sease (12 with major depression and 12 without), 12 patients with majo r depressive illness but without AD, and 12 healthy control subjects, all matched for age, sex, education levels, and estimates of premorbid intellectual potential.MEASUREMENTS: Mini-Mental State Examination (M MSE), Wechsler's Logical Memory (WLM) and Visual Reproduction (WVR), i mmediate and delayed reproduction, Wechsler's paired Associate Learnin g (WPAL), including the Easy and Hard subsets. Warrington's Recognitio n Memory for Faces (WRMF), Kendrick's Object Learning (KOLT) and Digit Copying (KDCT)Tests. OUTCOME MEASURES: Minimum 2-year follow-up diagn osis. RESULTS: Statistically, patients with very mild AD were distingu ished clearly from those without AD on most tests of memory functions. Psychometrically, only KOLT and an index of retention on WLM and WVR were specific enough to avoid false positives, a requirement for secon d-stage tools. They also proved sensitive enough to suggest their role as first-stage instruments when screening for primary dementia in hig h-functioning patients scoring above the cut-point on MMSE. CONCLUSION S: As efforts intensify to develop more powerful means to identify pat ients with Alzheimer's disease in its earliest stages, inclusion of sp ecialist tests posing greater cognitive challenge than standard mental status scales has been one strategy. Our study explored how some of t hese neuropsychological tools behave psychometrically when analyzed on a single-case basis, and the results suggest a few are sensitive enou gh to boost detection above base rates alone while also being specific enough to reduce false alarms. Retention on Wechsler's Logical Memory and Visual Reproduction tasks and scores on Kendrick's Object Learnin g Test helped decrease the degree of ambiguity when cognitive profiles were used to distinguish depressed patients with Alzheimer disease fr om these without.