Assessment of cognitive status in the elderly using telephone interviews.
OBJECTIVE: To examine the feasibility to assess cognitive status in the elderly using telephone interviews. RESEARCH DESIGN AND METHODS: From January to December 2003, 740 participants of the ongoing Heidelberg longitudinal study (HeiDE) aged 70 years or more were eligible for a telephone interview on cognitive status. Validated instruments to assess cognitive status, including the Telephone Interview of Cognitive Status (TICS) and the East Boston Memory Test (EBMT, immediate and delayed recall), the Verbal Fluency Test, the HAWIE-"Vocabulary Test" and the HAWIE-"General Knowledge", a prospective memory test, and a digit span backwards-test were translated into German, if applicable. RESULTS: Out of 740 participants at the age of 70 or older, 473 participants were interviewed (64.9%). The total score of the TICS (maximum=best: 41) ranged from 21 to 40 (mean 33.5, SD 3.1; median 34.0). The EBMT scores (immediate recall; maximum=best: 12) ranged from 4 to 12 (mean 9.2, SD 1.7; median 9.0). CONCLUSIONS: Cognitive status could be successfully assessed by telephone interview in elderly participants of an ongoing population-based cohort study. Specifically, some of the tests showed pronounced variability allowing cross-sectional analyses whereas others seem more valuable for longitudinal assessment.