Detecting Subclinical Change in Cognitive Functioning in Older Adults: Part II: Initial Validation of the Method.

Repeated measures of cognitive functioning may provide a clinically feasible supplement to standard operational criteria for the diagnosis of delirium or toxic or metabolic encephalopathies in older adults. This research reports on the feasibility of detecting change in cognitive functioning through repeated assessments. The findings demonstrate that the method of identifying excessive cognitive changes through repeated assessments is not compromised by fatigue or practice effects. Further, a controlled drug trial validated this method for detecting change in a situation in which investigators would expect mild cognitive change to occur. Significant change in memory functioning was detected after administration of 50 mg of diphenhydramine. The results suggest that repeated monitoring of cognitive functioning may be an objective tool for measuring cognitive change that may facilitate the identification of subclinical toxic and metabolic encephalopathies.