IDENTIFICATION OF DRUG-RELATED COGNITIVE IMPAIRMENT IN OLDER INDIVIDUALS - CHALLENGE STUDIES WITH DIPHENHYDRAMINE

The authors tested the use of repeated cognitive measures to identify those older individuals who experience cognitive decline after adminis tration of a centrally acting medication. Subjects were 30 medically s table, older volunteers, mean age 71.4. Administration was a double-bl ind, placebo-controlled, crossover ''challenge'' from baseline to plac ebo, 50 mg, or 75 mg of diphenhydramine. More patients exhibited signi ficant cognitive decrements after 75 mg of diphenhydramine than after placebo on the Buschke Selective Reminding Test Total Recall and the T rials B test. Data were consistent with models based on prediction int ervals. Quantitative algorithms using prediction equations can charact erize the normal limits of within-subject variability and define exces sive cognitive change in elderly subjects, showing promise for use in monitoring patients to identify those who experience mild cognitive to xicity from prescribed medications.