Objectives. To review studies that have reported on the prevalence of memory complaints and the relationship between memory complaints and impairment or decline (dementia) in elderly individuals Data sources and study selection. All publications in the English language relating to memory complaints, memory impairment, cognitive disorder and dementia in MEDLINE, PSYCHLIT and EMBASE computerized databases, together with a search of relevant citations. Data synthesis. The prevalence of memory complaints, defined as everyday memory problems, shows a large variation of approximately 25 – 50%. A high age, female gender and a low level of education are generally associated with a high prevalence of memory complaints. In community‐based samples of elderly subjects an association has been found between memory complaints and memory impairment, after adjustment for depressive symptomatology. Memory complaints predict dementia after a follow‐up of at least 2 years, in particular in those with mild cognitive impairment, defined as Mini Mental State Examination (MMSE) > 23. Memory complaints in highly educated elderly subjects may be predictive of dementia even when there is no indication of cognitive impairment on short cognitive screen tests. The shift in methodology which is noticeable in the recently published major studies is discussed as a possible explanation for the established association between memory complaints and decline in memory (or dementia) in elderly subjects. Three methodological factors, in particular, are responsible for the results: community‐based sampling, longitudinal design and the treatment of variables such as depression, cognitive impairment and level of education. Conclusion. Memory complaints in elderly people should no longer be considered merely as an innocent age‐related phenomenon or a symptom of depression. Instead, these complaints deserve to be taken seriously, at least as a possible early sign of dementia. Copyright © 2000 John Wiley & Sons, Ltd.

The EURO-D scale should permit valid comparison of risk-factor associations between centres, even if between-centre variation remains difficult to attribute.

Feeling lonely rather than being alone is associated with an increased risk of clinical dementia in later life and can be considered a major risk factor that, independently of vascular disease, depression and other confounding factors, deserves clinical attention. Feelings of loneliness may signal a prodromal stage of dementia. A better understanding of the background of feeling lonely may help us to identify vulnerable persons and develop interventions to improve outcome in older persons at risk of dementia.

To obtain age- and gender-specific estimates of the prevalence of dementia in Europe and to study differences in prevalence across countries, we pooled and re-analysed original data of prevalence studies of dementia carried out in some European countries between 1980 and 1990. The study followed these steps: census of existing datasets, collection of data in a standardized format, selection of datasets suitable for comparison, comparison of age and gender patterns. From the 23 datasets of European surveys considered, 12 were selected for comparison. Only population-based studies in which dementia was defined by DSM-III or equivalent criteria and in which all subjects were examined personally were included. Studies in which institutionalized subjects were not investigated were excluded. Age- and gender-specific prevalences were compared within and across studies and overall prevalences were computed. Although prevalence estimates differed across studies, the general age- and gender-distribution was similar for all studies. The overall European prevalences for the five-year age groups from 60 to 94 years, were 1.0, 1.4, 4.1, 5.7, 13.0, 21.6 and 32.2%, respectively. In subjects under 75 years the prevalence of dementia was slightly higher in men than in women; in those aged 75 years or over the prevalence was higher in women. The prevalence figures nearly doubled with every five years of increase in age.

Previous studies showed circadian rhythm disturbances in patients with Alzheimer's disease. Rest-activity rhythm disturbances manifest themselves through a fragmentation of the rhythm, a weak coupling with Zeitgebers, and high levels of activity during the night. The aim of the present study was to investigate which factors contribute to the presence of these disturbances. Therefore, several rest-activity rhythm, constitutional, and environmental variables were assessed in a heterogeneous group of 34 patients with Alzheimer's disease, including presenile and senile patients living at home or in a nursing home, as well as in 11 healthy controls. Circadian rest-activity rhythm disturbances were most prominent in institutionalized patients. Regression analyses showed the involvement of the following variables. First stability of the rest-activity rhythm is associated with high levels of daytime activity and high levels of environmental light resulting from seasonal effects as well as from indoor illumination. Presenile onset contributed to instability of the rhythm. Second, fragmentation of periods of activity and rest is associated with low levels of daytime activity, and is most prominent in moderately severe dementia. Third, night-time activity level is higher during the times of the year when the days are getting shorter and lower when the days are growing longer. These findings indicate that rest-activity rhythm disturbances may improve by increasing environmental light and daytime activity, an assumption for which empirical evidence has recently been published.