A systematic review of the reliability of screening for cognitive impairment in older adults by use of standardised assessment tools administered via the telephone.

We conducted a systematic review to identify the extent to which the process of screening for cognitive impairment in older adults has been validated for administration by telephone. A search of electronic databases and a handsearch of relevant journals and reference lists were carried out for studies published between 1966 and 2008. The database search identified 411 studies and handsearching found another seven. Fourteen studies were finally identified as relevant to the review: three concerned a modified telephone version of the Mini-Mental State Examination (MMSE); five concerned the Telephone Interview for Cognitive Status; one study tested a telephone-administered Short Portable Mental Status Questionnaire; four studies tested the validity of newly developed tools; and the remaining study considered the Confusion Assessment Method as a means of diagnosing delirium. The quality of the reference standard varied among the papers reviewed. The limited number of high quality studies with suitable reference standards makes it difficult to recommend a specific tool which should be used to assess the cognition of older adults by telephone. In advance of further studies, the 22-item MMSE is simple to administer and was shown to correlate well with the face-to-face MMSE. It appears to be a useful technique for telephone screening for cognitive impairment or delirium, if used in conjunction with the Delirium Symptom Interview.