The meaning of cognitive impairment in the elderly.

In order to determine the meaning of cognitive impairment in community dwelling elderly, 3,481 adults were interviewed in their homes using the Mini-Mental State Examination. Ninety-six per cent of the population aged 18-64 scored 23 or higher, whereas 80 per cent of the population 65 and over scored 23 or higher. Individuals with low scores were suffering from a variety of psychiatric disorders including dementia. Thirty-three per cent of the elderly population scoring in the range of 0-23 had no diagnosable DSM-III condition. Prevalence of dementia from all causes was 6.1 per cent of the population over age 65. Two per cent of the population over age 65 were diagnosed as having Alzheimer's disease.