S2-04-06: Differential decline of memory functions in cognitive aging and early stages of Alzheimer’s disease

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Findings of the MAastricht Aging Study (MAAS), a crosssectional–longitudinal study in almost 2000 Dutch adults (aged 24–81), indicated that nearly 40% of all participants considered themselves forgetful. This prevalence increases with age. Various aspects of objective memory functioning declined differentially. Verbal learning and especially delayed recall of newly learned material was compromised already at age 45 in healthy subjects. A further decline started around 65 years of age. Likewise, information processing speed deteriorated already in the fourth decade, especially for functions where complex cognitive operations had to be performed under time pressure. The age–speed function further declined after age 60. Age–extrinsic factors appeared of major importance in MAAS. Minor biological/medical factors were a major risk factor for memory problems and cognitive deterioration, easpecially after age 60. On the other hand, psychosocial factors such as low education were a risk for cognitive deterioration especially over the age period of 25–60 years and were more potent over that period than age per se. A 3, 6 and 9 year follow–up has been performed over 1800 subjects. An active lifestyle (social activities, cognitive and physical activities) protected against memory decline over a three year period. Impairments on delayed recall function of verbal learning tests were among the strongest predictor of pathological cognitive development and development of dementia. Subjective feelings of decreased memory functioning were not related to objective memory dysfunction, whereas development of dementia was also dependent upon presence of particular affective symptomatology. The MAAS study shows that it is of major importance to evaluate various memory functions and processes on other cognitive domains as well as affective functions at the same time. Biological and psychosocial determinants should be looked into because there are protective and risk factors which are age–extrinsic. Close evaluation of various memory related processes is of major importance for both scientific investigation and clinical assessment of early stages of Alzheimer's disease.