To the Editor: I read the article by Bruce E. Wexler, M.D., and colleagues R1589CIHFCIGA with much interest. The authors studied the effect of cognitive exercises on verbal and nonverbal memory performance in eight patients with schizophrenia. Three patients exhibited improved performance after training on a verbal memory task (but not on a nonverbal memory test). In these patients, verbal memory gains were associated with an increase in activation of the left frontal cortex on functional magnetic resonance imaging. The authors concluded that verbal memory deficits can be ameliorated by memory exercises in some patients with schizophrenia.

In my opinion, the authors’ conclusion should be treated with some caution. It is possible that the patients showed improved verbal memory performance merely because of repeated testing. My colleagues and I recently conducted a study of the effect of repeated testing on cognitive functioning in psychiatric patients R1589CIHIBHGI and found substantial gains in the patients’ cognitive performance as a result of repeated testing. Had Dr. Wexler and colleagues used a control group consisting of schizophrenic patients who were not undergoing a training program and reported that none of the control patients showed improved performance in verbal memory tasks, it would have been convincing evidence for an effect of memory exercises on memory function in patients with schizophrenia.