The effects of intelligence and education on the development of dementia

A number of recent epidemiological studies have shown that the prevalence and incidence of dementia are increased in population strata with low compared to high levels of education. This has been explained as a consequence of a greater 'brain reserve capacity' in people with a high level of education. Theoretically, however, brain reserve capacity is better reflected by intelligence than by level of education. Thus, the emergence of dementia will be better predicted by low pre-morbid intelligence than by low education. This prediction was tested in a population based sample of elderly subjects (N = 2063; age range 65-84; Amsterdam Study of the Elderly) who were followed over 4 years. Dementia was diagnosed using the Geriatric Mental State examination (GMS). Pre-morbid intelligence was measured using the Dutch Adult Reading Test (DART), a short reading test which gives a good estimate of verbal intelligence, and is relatively insensitive to brain dysfunction. The effects of age, gender, occupational level, number of diseases affecting the central nervous system and family history of dementia or extreme forgetfulness were also examined. Logistic regression analysis showed that low DART-IQ predicted incident dementia better than low level of education. A high occupational level (having been in charge of subordinates) had a protective effect. This result supports the brain reserve theory. It also indicates that low pre-morbid intelligence is an important risk factor for cognitive decline and dementia. Use of reading ability tests is to be preferred over years of education as estimator of pre-morbid cognitive level in (epidemiological) dementia researc

Association between memory complaints and incident Alzheimer's disease in elderly people with normal baseline cognition

In the community-based Amsterdam Study of the Elderly, a sample of 3,778 nondemented persons, 65-84 yrs old, was divided into 2 cognitive categories: normal, and borderline and impaired. At baseline, the presence or absence of memory complaints was assessed with a single question. At follow-up, incident cases of Alzheimer's disease were diagnosed in a 2-step procedure. After an average of 3.2 yrs, 2,169 persons were reevaluated, of whom 77 had incident Alzheimer's disease. Analyses showed that memory complaints were associated with incident Alzheimer's disease in Ss with normal baseline cognition but not in Ss with impaired baseline cognition. Findings suggest that memory complaints are a relatively strong predictor of incident Alzheimer's disease in older persons in whom cognitive impairment is not yet apparent. Also, they suggest that older persons may be aware of a decline in cognition at a time when mental status tests are still unable to detect a decline from premorbid functioning. (PsycINFO Database Record (c) 2002 APA, all rights reserved

Early detection of Alzheimer's disease using the Cambridge Cognitive Examination (CAMCOG)

Dementia screening instruments, such as the Cambridge Cognitive Examination (CAMCOG), measure a variety of cognitive functions. However, memory impairment generally is the first sign of Alzheimer's disease (AD). It seems logical, therefore, to use only memory-related items for the early detection of AD. We divided the CAMCOG into a memory section and a non-memory section, and tested the hypothesis that the memory section predicts AD better than the non-memory section. We also provide normative data for both sections. Normal subjects (N = 169) and patients with incident AD (i.e. satisfying AD criteria between 1 and 3 years from baseline: N = 25) were participants in the Amsterdam Study of the Elderly (AMSTEL), a population-based longitudinal study on cognitive decline and dementia. Patients with prevalent AD (i.e. satisfying AD criteria at baseline: N = 155) were either recruited in a memory clinic or came from AMSTEL. Normal subjects were cognitively intact at baseline and remained so for at least 3 years. The CAMCOG was administered to all subjects. AD was diagnosed by DSM-III-R criteria. Logistic regression analysis showed that the memory section was related to prevalent AD, whereas in multivariate analysis the non-memory section was not (after correction for the memory score and demographic characteristics). A similar analysis showed that the memory section predicted incident AD, as did a higher score on the non-memory section. The MMSE did not predict incident AD better than age alone. For the early detection of AD it is best to use the memory and non-memory sections separately instead of the total CAMCOG scor

Depressive symptoms and risk of Alzheimer's disease in more highly educated older people

In an earlier study we observed that a depressive syndrome was highly predictive of developing Alzheimer's disease (AD) in older persons with normal baseline cognition and higher levels of education. We interpreted these findings as the depression being an early noncognitive manifestation of AD in persons with more cognitive reserve. The present study examines whether specific symptoms of depression can be identified that predict AD among older subjects with higher levels of education. In the community-based Amsterdam Study of the Elderly (AMSTEL), a sample of 3,147 nondemented persons with normal cognition, 65 to 84 years old, was selected and divided into subjects with >8 years and 8 years and 31 with 8 years of education depressed mood and subjective bradyphrenia were strongly associated with incident AD. No association between depressive symptoms and AD was observed among subjects with <or =8 years of education. Both depressed mood and subjective bradyphrenia seem to indicate subclinical AD in older people with higher levels of education. Clinicians should be alert that in these persons, AD may become apparent within a relatively short period of tim