ACCURACY OF NEUROPSYCHOLOGICAL TESTS IN PATIENTS WITH BIOLOGICAL DIAGNOSIS OF ALZHEIMER’S DISEASE

Abstract

Background: Neuropsychological tests are important tools for the diagnosis of mild cognitive impairment or dementia due to Alzheimer’s disease (AD). Objective: To investigate the accuracy of common neuropsychological tests used in the clinical setting for AD diagnosis. Methods: Forty two patients with diagnosis of AD continuum [A+T+/-(N)+/-] and 32 non-AD [A-T+/-(N)+/-]. All participants were submitted to a thorough neuropsychological assessment with the following instruments: Mattis Dementia Rating Scale (DRS), Rey’s Auditory Verbal Learning Test (RAVLT), Boston naming-Consortium to Establish a Registry for Alzheimer’s Disease, a reduced version of the CERAD, Digit Span Forward (DSF), Digit Span Backward (DSB) and Cubes from The Wechsler Adult Intelligence Scale (WAIS), verbal fluency – animals (VF-A), and FAS. Results: Memory (MEM) and Initiation/Perseveration (I/P) subscales of the DRS, FAS, Digit Span Backward (DSB) and Boston naming displayed good discrimination between AD and non-AD patients. The MEM subscale of the DRS, RAVLT A6 and FAS presented high sensitivity (90% or more) for AD diagnosis, while DSF displayed high specificity. Non-AD patients had greater difficulty in FAS, DSB and in Boston naming. Conclusion: Performance of patients with biological diagnosis of AD on MEM and I/P of DRS, and RAVLT A7 was significantly different from that of non-AD subjects.