PREVALENCE OF AGE-ASSOCIATED MEMORY IMPAIRMENT AND DEMENTIA IN A RURAL-COMMUNITY

To obtain accurate estimates of the prevalence of age-associated memor y impairment, dementia, and Alzheimer's disease, a population study wa s carried out in Turegano, a rural community of 1011 inhabitants in th e Segovia province of Spain. The study was divided into two phases: a door to door survey of the entire population aged 40 years and over (5 03 persons), followed by a clinical examination of suspected cases for positive and differential diagnosis of dementia and cognitive impairm ent. The prevalence of age-associated memory impairment was 3.6% in in dividuals of 40 years and over and 7.1% in individuals of 65 years and over, whereas dementia was found in 2.6% and 5-2%, respectively. The prevalence rates of both clinical conditions increased with age. The m ost prevalent clinical category of dementia was dementia of Alzheimer type, which represented 1.8% and 3-8% of these two age groups. The cor responding figures for vascular dementia were 0.4% and 0.9% and for se condary dementia 0.4% and 0.5%. Age-associated memory impairment is an age-dependent disorder with a high prevalence among the elderly; some of these patients may represent an early stage of Alzheimer's disease , suggesting that the prevalence of this disorder may be higher than p reviously estimated.