Leeftijd: een belangrijke factor voor cognitieve profielen van de ziekte van Alzheimer

Abstract

Alzheimer’s disease (AD) in younger patients is associated with a higher prevalence of atypical symptoms. We examined neuropsychological performance according to age-at-onset. We assessed cognition in 172 patients with AD (81 early and 91 late onset) in five cognitive domains (memory, language, visuospatial functioning, executive functioning, attention). Dementia severity was assessed using MMSE and global cognitive decline using CAMCOG. Analyses of variance were performed with age-at-onset as between-subjects factor, and sex and education as covariates. Analysis was repeated after stratification for dementia severity (based on median MMSE). In early onset AD, age (mean±SD) was 60±4 years, 44 (54%) were female. In late onset AD, age was 72±5 years, 47 (52%) were female. Dementia severity and global cognitive decline did not differ between groups (early onset: MMSE: 20±5, CAMCOG: 69±15, late onset: MMSE: 21±5, CAMCOG: 70±15; p > 0.05). Early onset patients performed worse than late onset patients on visuospatial functioning (p < 0.01), executive functioning (p < 0.001) and attention (p < 0.01). Late onset patients performed worse on memory, although not significantly (p = 0.11). Stratification for dementia severity showed that in mildly demented early onset patients, memory function was remarkably preserved compared to late onset patients (p < 0.01). In moderate AD, differences in memory function disappeared, but early onset patients performed worse on visuospatial functioning (p < 0.01), executive functioning (p < 0.001) and attention (p < 0.01) than late onset patients. Adjustment for APOE left results unchanged. In conclusion, early onset AD presents with a different cognitive profile and the disease course seems differently. Relative sparing of memory function in early stages stresses the need to adequately test other cognitive domains.