Underdiagnosis of cognitive impairment in a rehabilitation setting.

Of 100 patients consecutively admitted to a rehabilitation hospital, 25 were cognitively impaired. On two brief tests of intellectual function, they scored below the criteria selected by the originators of those tests for clinically significant mental impairment. Nineteen of the 25 had vascular disease of the heart, brain, or peripheral vessels; two had cardiac valvular disease; three had head trauma; and one was mentally retarded. Mental impairment appears to be relatively common among the hospitalized elderly who do not carry the primary diagnosis of "dementia" or "organic brain syndrome." It appears to be particularly common among those with cardiovascular disease, even without frank stroke. Brief mental status examinations should be part of the routine evaluation of such patients.