The Role of Baseline Cognitive Function in the Neurocognitive Effects of Electroconvulsive Therapy in Depressed Elderly Patients

Abstract

Objective: Electroconvulsive therapy (ECT) is an effective biological treatment option for severely depressed elderly patients; however, it can cause cognitive side effects, including anterograde and retrograde amnesia. Elderly patients with “cognitive impairment no dementia” (CIND) are reported as being more vulnerable to the cognitive side effects of ECT compared with patients with “no cognitive impairment” (NCI). The few studies that have reached this conclusion can be criticized for using insensitive outcome measures. Method: The present study investigated cognitive side effects using standard neuropsychological tests before and after twice-weekly ECT. Patients were assessed at baseline (T1) and within one week after a course of ECT (consisting of a mean of 10 treatments) (T2), and were followed up for three months after T2 (T3). The sample included 54 patients with NCI (n = 36) or CIND (n = 18). For a control group, we recruited 17 healthy elderly persons. Tests of anterograde memory, information-processing speed, executive function, and retrograde memory were administered. We computed reliable change indices using simple regression methods. Results: Short-term side effects were detected at T2 in a large minority of patients, with no significant differences between NCI and CIND patients. Considerable improvement in global cognitive function from T1 to T3 was observed in 44% of the CIND patients. At the group level, information-processing speed improved significantly in CIND vs. NCI patients. Conclusions: CIND patients were not more vulnerable to amnesia than were NCI patients. Long-term cognitive side effects of ECT were not detected.

Keywords:

• Cognitive impairment
• Depression
• Electroconvulsive therapy (ECT)
• Memory
• Reliable decline.

Acknowledgments

We are thankful for the valuable supervision of Ivar Reinvang, Professor in Neuropsychology, in the planning of the study. We would like to thank the staff at the Department of Geriatric Psychiatry for their persistent support and engagement in the study, particularly Torfinn Lødøen Gaarden, MD, who recruited and assessed patients, and registered nurse Marianne Larsen, who carried out neuropsychological testing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Norwegian Extra Foundation for Health and Rehabilitation through the Norwegian Council for Mental Health [grant number 2011/2/0009].