Journal of evaluation in clinical practice
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Reliability and validity of the SF-36 Health Survey Questionnaire was assessed in older rehabilitation patients, comparing cognitively impaired with cognitively normal subjects. The SF-36 was administered by face-to-face interview to 314 patients (58-93 years) in the day hospital and rehabilitation wards of a department of medicine for the elderly. Reliability was measured using Cronbach's alpha (for internal consistency) on the main sample and intraclass correlation coefficients on a test-retest sample; correlations with functional independence measure (FIM) were examined to assess validity. ⋯ Only the physical function dimension in the cognitively normal group attained the criterion level (r > 0.4) for construct validity when correlated with the FIM. In this group of older physically disabled patients, levels of reliability and validity previously reported for the SF-36 in younger subjects were not attained, even on face-to-face testing. Patients with coexistent cognitive impairment performed worse than those who were cognitively normal.