A long-term longitudinal follow-up of depressed patients treated with ECT with special focus on development of dementia.

BACKGROUND: In this study, the long term effects of ECT on patients with depression were investigated through repeated rCBF and EEG measures as well as clinical characteristics over several years. The aim of the investigation was to establish an association with the eventual development of dementia.

METHOD: A cohort of forty-nine patients (21 men and 28 women) with a mean age of 61 years underwent ECT. A subsequent evaluation from medical records and three rating-scales for diagnosis of Alzheimer´s disease (AD), fronto-temporal dementia (FTD), and for vascular dementia (VaD), revealed that 17 patients (8 men and 9 women), had developed dementia. These cases were compared to the 32 patients (13 men and 19 women), who had not developed dementia.

RESULT: Initially, the dementia group, compared to those without dementia, showed a lower hemispheric CBF (left side; p=.029, right side; p=.033), and a lower mean occipital EEG frequency (p=.048). After the first ECT-series, an increase in general disorientation (p=.015), personal disorientation (p=.009), and subsequently, spatial disorientation (p=.021), were seen in the dementia group. There were no differences in the clinical response or remissions after treatment in the groups.

LIMITATIONS: The small sample-size, which did not allow for the comparison of characteristics between different dementias.

CONCLUSION: Depressed older patients who later developed dementia showed lower hemispheric mean level of CBF and EEG mean frequency before ECT and higher personal and spatial disorientation following ECT.