D-CYCLOSERINE ENHANCES IMPLICIT MEMORY IN ALZHEIMER PATIENTS

We tested the ability of d-cycloserine, a partial glycine agonist acti ng at the N-methyl-D-aspartate (NMDA) receptor complex, to improve imp licit memory in Alzheimer patients in a parallel-group, placebo-contro lled, double-blind study. One-hundred eight patients with probable Alz heimer's disease of mild to moderate severity received d-cycloserine ( 5, 15, or 50 mg) or placebo twice daily for 10 weeks. We then evaluate d their ability to identify perceptually degraded words, some of which were repeated over multiple trials across 3 days. Implicit memory per formance of words repeated across trials was significantly enhanced fo r the patients who received 15 mg d-cycloserine compared with those wh o received placebo. These findings support development of NMDA recepto r-mediated glutamatergic interventions for the treatment of Alzheimer- related memory disorders.