title: Early onset Alzheimer's disease is associated with a distinct neuropsychological profile.
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, visuo-spatial functioning, executive functioning, attention). Dementia severity was assessed using the Mini-Mental State Examination (MMSE) and global cognitive decline using Cambridge Cognitive Examination (CAMCOG). Analyses of variance were performed with age-at-onset as between-subjects factor, and gender 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 visuo-spatial 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 visuo-spatial 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 different. Relative sparing of memory function in early stages stresses the need to adequately test other cognitive domains.
authors.affiliation: Alzheimer Center and Department of Neurology, VU University Medical Center, Amsterdam, the Netherlands. l.smits@vumc.nl
authors.forename: Lieke L
authors.initials: LL
authors.lastname: Smits
authors.forename: Yolande A L
authors.initials: YA
authors.lastname: Pijnenburg
authors.forename: Esther L G E
authors.initials: EL
authors.lastname: Koedam
authors.forename: Annelies E
authors.initials: AE
authors.lastname: van der Vlies
authors.forename: Ilona E W
authors.initials: IE
authors.lastname: Reuling
authors.forename: Teddy
authors.initials: T
authors.lastname: Koene
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Teunissen
authors.forename: Philip
authors.initials: P
authors.lastname: Scheltens
authors.forename: Wiesje M
authors.initials: WM
authors.lastname: van der Flier
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000453:epidemiology / Q000235:genetics / Q000523:psychology*; D001057:Apolipoproteins E / Q000235:genetics; D001288:Attention / Q000502:physiology; D003072:Cognition Disorders / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D003704:Dementia / Q000453:epidemiology; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008568:Memory / Q000502:physiology; D008609:Mental Status Schedule; D009154:Mutation / Q000235:genetics; D009483:Neuropsychological Tests; D053764:Presenilin-1 / Q000235:genetics; D012189:Retrospective Studies; D013028:Space Perception / Q000502:physiology
chemical_list: D001057:Apolipoproteins E; C508853:PSEN1 protein, human; D053764:Presenilin-1