Better knowledge of the preclinical phase of Alzheimer’s disease would be an important advance to allow earlier treatment of this ominous disease. This prodr omal period was investigated in the Paquid cohort by analysing change in cogniti ve performances at five time points over a 9 year period. Neuropsychological mea sures including global cognitive functioning (Mini-Mental State Examination), v isuo-spatial memory (Benton Visual Retention Test), verbal fluency (Isaacs Set Test) and abstract thinking (Wechsler Similarities Test) were assessed in 215 fu ture Alzheimer’s disease subjects and 1050 individuals without dementia. The resul ts showed that cognitive performances of the pre-morbid subjects at baseline we re already lower than those of individuals without dementia (1.4 points less on the Mini-Mental State Examination; 1.8 points less on the Benton Visual Retenti on Test; 4 points less on the Isaacs Set Test and 0.8 points less on the Wechsle r Similarities Test). For some neuropsychological tests, an acceleration of the decline occurred ～3 years before the diagnosis and, for each test, the course o f decline was modulated by education level. These findings show that abnormally low performances can be evidenced 9 years before the clinical diagnosis of Alzhe imer’s disease in several domains of cognition beyond memory and that cognitive change over time can be influenced by education.
展开▼
