Decreased Verbal Memory Associated with Anticholinergic Treatment in Parkinson's Disease Patients

Abstract

The effects of chronic administration of the anticholinergic agent, benztropine mesylate (Cogentin^TM), on specific verbal memory were investigated as part of a placebo-controlled randomized double-blind crossover study to determine the clinical efficiency of Cogentin^TM as an adjuvant therapy with Sinemet^TM in Parkinson's disease. Twenty-nine males with clinically definite idiopathic Parkinson's disease participated in the trial. They were tested for acquisition of new word lists, and on four other cognitive tests before, during, between, and after two 10-week trial periods when they received either increasing doses of Cogentin^TM (maximum 2 mg) or placebo while on a maintenance dose of Sinemet^TM. Patients showed a statistically significant decrease (5-10%) in word list acquisition while on Cogentin^TM. The anticholinergic memory effect was unrelated to the degree of improvec clinical efficacy of Cogentin^TM for Parkinsonism, and to initial word list acquisition ability. Verbal memory findings indicate that chronic administration of an anticholinergic in even low therapeutic dosage may play an important role in memory function.