Neurocognitive effects after brief pulse and ultrabrief pulse unilateral electroconvulsive therapy for major depression: a review

BackgroundNeurocognitive functioning is well known to be affected after ECT. However quantified data about the severity of the cognitive impairment after ultrabrief pulse and brief pulse ECT are limited, which makes it hard to judge its clinical relevance.MethodsTo review all prospective studies using right unilateral (ultra) brief pulse index electroconvulsive therapy published up until February 2011 which used at least one instrument for cognitive assessment before and after ECT. The severity and persistence of neurocognitive side effects immediately (one to seven days post ECT), between one and six months and after six months post ECT were assessed by calculating effect sizes using Cohen's d.ResultsTen studies fulfilled the inclusion criteria and provided detailed information to compute effect sizes. The results indicate loss of autobiographical memory and impairment of verbal fluency, anterograde verbal and non-verbal memory immediately after brief pulse RUL ECT. To a lesser extent impairment of working memory and reduced speed of processing is found. Autobiographical memory is the only domain still being impaired between one and six months post ECT, but improved in this period. Verbal fluency normalized to baseline performance between one and six months post ECT whereas anterograde verbal and non-verbal memory normalized or even improved. Speed of processing improved within six months after ECT. Long-term data on these cognitive domains were not available. Based on two of the ten included studies the results suggest that ultrabrief pulse RUL ECT causes less decline in autobiographical and anterograde memory after ECT than brief pulse RUL ECT.LimitationsThis review may be limited because of the small number of included studies and due to unreliable effect sizes. Furthermore, few data were available for non-memory domains and cognitive functioning after six months.ConclusionsLoss of autobiographical memory is still present between one and six months after unilateral brief pulse ECT. Ultrabrief pulse RUL ECT shows less decline in autobiographical memory. Other neurocognitive impairments after brief pulse RUL ECT seem to be transient.