Brief cognitive screening in a field survey of the oldest old

A nationally representative survey of living conditions among persons aged 77 to 98 years included a short instrument for cognitive impairment consisting of items from the Mini-Mental State Examination (MMSE). Because of the wide range of social, health, and economic domains included in the survey, it was necessary that the instrument could be administered in a short time by interviewers without experience in neuropsychological testing. Because of the age of the subjects, the instrument must be relatively independent of sensory or motor disabilities, and be acceptable to both interviewers and older adults. There were very few problems with the use of the instrument and very little missing data. A cut-off point for cognitive impairment was ascertained for the items included in this instrument using other data sets where diagnostic confirmation was available. Being able to identify subjects who are probably cognitively impaired is helpful in a multipurpose survey study of the oldest old, both in documenting the cognitive status of the sample and in evaluating the quality of other information being collected in the study.