The apolipoprotein E (ApoE) ε4 allele is a definite risk factor for sporadic Alzheimer's disease (AD), while its possible influence on cognitive performance in early stages of AD is less clearly defined. This study was aimed at investigating the influence of the ApoE ε4 allele on neuropsychological features at onset and disease progression in patients with AD. Thirty-five de novo patients with probable AD were examined twice, at baseline (early assessment, soon after the clinical diagnosis) and about 1 year later (follow-up). All patients underwent ApoE genotyping and various neuropsychological tasks, such as the Mini-Mental State Examination (MMSE) and an extended version of the Mental Deterioration Battery (EMDB), including tasks of short-term memory, verbal episodic long-term memory, selective attention, abstract reasoning, verbal fluency, and executive functions. Fifteen AD patients were defined as fast decliners (FD), as they showed a >25% decline on both the MMSE and three or more tests of the EMDB; 20 patients who did not meet this criterion were defined as slow decliners (SD). The scores obtained on the neuropsychological tasks at baseline by patients with one or two ε4 allele(s) (ε4 carriers) were compared with the scores of ε4 non-carriers by means of a one-way MANOVA. No significant difference was found between the two groups (ε4 carriers versus non- carriers) in educational level and the age and disease duration at baseline. The results of the MANOVA showed a trend towards a significant difference between the ε4 carriers versus ε4 non-carriers as to the scores obtained on neuropsycological tests at baseline (P = 0.055). Post-hoc comparisons showed that ε4 carriers performed significantly worse (P = 0.006) on a test of verbal episodic memory (recognition subtest of the Rey's Auditory Verbal Learning Test, RAVLT). Moreover, on the immediate recall subtest of RAVLT, ε4 carriers showed a significantly larger 'recency effect" than ε4 non-carriers (P = 0.02). As to the possible influence of the ε4 allele on disease progression, there was a statistical trend towards a greater frequency of FD among ε4 carriers than among ε4 non-carriers (P = 0.055). These findings suggest that in early stages of AD the presence of the ε4 allele may result in a greater impairment in performing verbal episodic memory tasks and could be associated with a faster decline of cognitive performance.
|Issue number||4 SUPPL.|
|Publication status||Published - 2000|
ASJC Scopus subject areas
- Clinical Neurology