Preservation of spatial cognitive functioning in depressed patients treated with bilateral electroconvulsive therapy

Abstract

Background: Electroconvulsive therapy (ECT) is associated with memory and non-memory, verbal and nonverbal cognitive deficits. This study was conducted to test the expectation that the Tactual Performance Test (TPT) is uniquely sensitive to perturbation by ECT. Importantly, this study included a non-ECT disease control group.

Methods: Inpatients (n = 35) referred for ECT for the treatment of a major depressive episode were assessed 1-2 days before and after a course of ECT using a logical memory test, the digit span test, the block design test, and the TPT. A comparison cohort was formed from antidepressant-treated inpatients (n = 35); these patients were similarly assessed at admission and discharge. All treatment in both cohorts was naturalistic. Because patients had not been randomized to their respective treatments, the design was quasi-experimental.

Results: At baseline, ECT-treated patients were more severely ill than control patients. ECT patients received a mean of 7.5 treatments in addition to necessary pharmacotherapy. Almost all ECT was bilateral. Because of illness severity, baseline cognitive assessments were possible in only 15 (43%) ECT and 31 (89%) control patients (P < 0.001). At endpoint, 15% vs 0% of patients in the ECT vs control groups, respectively, had remitted. Endpoint cognitive assessments were conducted in all patients. The ECT and antidepressant cohorts did not differ on any cognitive test or subtest at endpoint; the only exception was that ECT patients performed more poorly on the TPT shapes subtest at both baseline and endpoint, but were more improved (at endpoint) than control patients on this outcome (effect size, 0.84 vs 0.60).

Conclusion: Depressed patients treated naturalistically with a mean of 7.5 bilateral ECTs did not show detectable memory and non-memory, verbal and nonverbal cognitive deficits on the 4 tests at the end of a treatment course relative to depressed patients treated with antidepressants alone. The TPT is not sensitive to perturbation by ECT.

Keywords: Antidepressant drugs; Electroconvulsive therapy; Memory; Non-memory cognitive deficits; Nonverbal cognitive deficits; Spatial cognitive deficits; Tactual performance test.