Comparison of Unilateral and Bilateral ECT: Evidence for Selective Memory Impairment

Abstract

SummaryReview of studies from the past 16 years employing quantitative measurement of memory functions before and after ECT revealed the following trends: impairment of non-verbal memory functions after less than five unilateral non-dominant ECTs; improvement of non-verbal memory functions after five or more unilateral non-dominant ECTs; no change or improvement of verbal memory functions with unilateral non-dominant ECT; consistent impairment of verbal functions with unilateral dominant ECT, and impairment of both verbal and nonverbal functions with bilateral ECT. The relative lack of impairment in memory functions with unilateral non-dominant ECT is consistent with the theory of asymmetrical hemispheric disorganization in affective disorders, and supports the choice of unilateral non-dominant ECT over bilateral or unilateral dominant ECT in the treatment of depression.