REVIEW OF: Wagenmakers M et al, Am J Geriatr Psychiatry 2021;29(11):1117−1128

TYPE OF STUDY: Naturalistic prospective study

We know that a subset of patients with late-life depression (LLD) who are treated with electroconvulsive therapy (ECT) develop transient cognitive impairment (TCI). Is there any way to predict which patients will experience the most memory loss? Some studies have linked white matter hyperintensities (WMH), which represent brain damage generally associated with small vessel disease, with an increased risk for TCI in ECT patients (Oudega ML et al, Am J Geriatr Psychiatry 2014;22(2):157–166). This latest study sought to replicate this finding. 

In a naturalistic prospective study, 80 elderly patients with severe unipolar depression were followed before and after a course of ECT. All patients started with right unilateral ECT, although approximately one-third required a switch to bilateral ECT due to clinical worsening. Patients had a median age of 73 years and 67.5% were female. All received an MRI, and their cognitive functioning was assessed before and after ECT with the Folstein Mini Mental Status Exam (MMSE). Patients with comorbid psychiatric and neurological illness (including dementia) were excluded and did not differ in baseline cognitive functioning. The goal was to see if there was an association between certain structural brain abnormalities and TCI. 

Although MMSE scores dropped significantly during ECT by an average of two points in all participants, scores improved above baseline post-ECT by two to three points and remained stable six months later, independent of structural brain abnormalities. Patients with severe WMH had lower MMSE scores at all stages compared to patients without severe WMH, but the trajectory was similar for both groups. Regardless of the brain finding—such as WMH, medial temporal atrophy (MTA), or global cortical atrophy (GCA)—there was no significant association with degree of cognitive impairment. 

Carlat Take 

Clinicians often worry about the effects of ECT on cognition, especially in patients with known structural brain abnormalities. This study is encouraging, as cognition returned to baseline levels post-ECT independent of the severity of WMH, MTA, or GCA. As ECT is the most effective treatment for LLD, we can continue to recommend ECT in patients with severe WMH and cognitive impairment.