Twenty seven studies were included in the review (n was unclear, but more than 1,063 participants).
The results of studies that used tests of global cognitive functioning were mixed: five studies reported improvements in Mini Mental State Examination and Mattis Dementia Rating Scale scores after electroconvulsive therapy; four studies reported no change. Limitations to these studies were reported. Evidence of arousal and orientation from the included studies suggested that unilateral rather than bilateral electrode placement during a course of electroconvulsive therapy may reduce the risk of interictal disorientation. No difference in information processing speed or changes in language (general word knowledge and object naming) were detected when comparing pre- and post-treatment levels. No treatment-related changes on working memory, executive function or visuospatial skills were found.