Neuropsychological and behavioural outcomes in epilepsy involving the insula: A scoping review

Objective: In patients with epilepsy, the insula has been increasingly recognized as a common site of seizures. There is growing interest in understanding the cognitive and psychological consequences of insular epilepsy to help provide clinical recommendations to support patient's cognitive and psychosocial functioning, and to help identify candidates for epilepsy resective surgery. The aim of this scoping review was to describe the cognitive and behavioural characteristics associated with insular epilepsy in children and adults. Method: A systematic search was completed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis -Extension for Scoping Reviews guidelines. Eligible studies reported on a neuropsychological or behavioural outcome, using standardized or research-based psychological measures, in individuals with insular epilepsy, (i.e. the seizure focus and/or surgical resection included the insula), and a comparison group. After duplicates were removed, 2,423 citations were identified from the search, and 39 studies were included in the scoping review. Results: Across the included studies, intellectual/global cognitive functioning and language were most often evaluated. Lower functioning was found across multiple cognitive and behavioural processes in pediatric and adult patients with insular epilepsy. Following resective surgery involving the insula, behavioural and cognitive outcomes are general stable. Conclusions: The results of this scoping review further neuropsychologists' knowledge of the cognitive and behavioural outcomes of insular seizures prior to and following surgical treatment. These results can aid in counselling patients of the potential cognitive dysfunctions, and aid with treatment planning.