{'fraction_non_alphanumeric': 0.036191536748329624, 'fraction_numerical': 0.024498886414253896, 'mean_word_length': 4.815533980582524, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Association of the apolipoprotein E genotype with memory performance and executive functioning in cognitively intact elderly.

OBJECTIVE
To test for a possible effect of the apolipoprotein E epsilon 4 (APOE ε4) allele on memory performance and executive functioning (EF) in cognitively intact elderly.


METHOD
The authors studied 202 randomly selected and cognitively intact older adults (65+ years) of the Leipzig Research Center for Civilization Diseases Health Care Study. Intact global cognitive functioning was defined using a Mini-Mental Status Examination (MMSE) score ≥ 28. Performance in memory was assessed with the CERAD Word List and Constructional Praxis Recall, performance in EF with the Trail Making Test Part B (TMT-B). Multivariable linear regressions were used to evaluate the association between cognitive performance and APOE status, controlled for covariates.


RESULTS
Among the cognitively intact older adults, 21.3% (n = 43) were carriers of the APOE ε4 allele. Carriers did not differ significantly from noncarriers in terms of age, gender, intelligence level, or performance in memory but showed a significantly lower TMT-B performance as a measure of EF (TMT-B M time/SD = 105.6/36.2 vs. 91.9/32.7 s; Mann-Whitney U = 4,313.000; p = .009). The association between lower TMT-B performance and APOE ε4 genotype remained significant in multivariable linear regression analysis. Similar findings were found for the subsample of those 78 elderly, who reached a perfect MMSE-score of 30.


CONCLUSIONS
A lower EF performance in cognitively intact older APOE ε4 allele carriers might be related to an early Alzheimer's dementia (AD) prodrome. In this case, a stronger focus on first subtle changes in EF may help to improve early AD detection in those being at genetic risk.