Cognitive Outcome after Hemispherotomy – An Analysis of 75 Children and Adolescents

Objective: Hemispherotomies are epilepsy surgeries in which an entire hemisphere is disconnected. These interventions are mainly performed in children with hemispheric, therapy-refractory epilepsies and account about 16% of all epilepsy surgeries performed in children. The main goal of these procedures is seizure freedom, but another important aim is the postoperative stabilization of cognitive development (1, 2). In this study we evaluated the pre- as well as postsurgical cognitive outcome of a large number of paediatric patients and looked for influencing factors.

Methods: In this retrospective cohort study, we included presurgical and 6 months postsurgical developmental and cognitive data of 75 children and adolescents (age range: 0.87 – 19.78 years) who underwent hemispherotomies at the Epilepsy Center Vogtareuth, Germany between 1999 and 2016. The whole sample was divided into two groups: a ‘Severely Impaired Group’ in which cognitive functioning was described and analysed in terms of developmental speed and quotients, and a ‘Not Severely Impaired Group’ in which cognitive functioning was reported and analysed by IQ scores.

Results: In the Severely Impaired Group (n = 40), 30 patients showed further development after surgery, 9 patients showed stagnancy, and one patient a regression. Longer duration of presurgical epilepsy was significantly related to a lower presurgical developmental level, and seizure freedom was significantly related to a better postoperative development. In the Not Severely Impaired Group (n = 31), the postoperative cognitive level of 22 patients was similar to the presurgical level. Two patients showed a significant postoperative IQ gain (≥ +15 points), 5 patients tended to a postoperative IQ improvement (≥ +8 IQ points), and two patients tended to deterioration (-8 IQ points). Over all patients, early age at seizure onset and early lesion timing predicted poorer presurgical cognitive development, and presurgical cognitive levels were strongly related to postoperative levels.

Discussion: Although a hemisphere was disconnected, the vast majority of patients showed stabilization in postoperative cognitive development; deterioration was rare (here: 3/75 patients) and was never severe. Thus, as a result, (apparently epilepsy-related) stagnant and regressive developmental processes could be stopped in most patients from both groups. Patients with early seizure onsets and early ‘lesion-timing’ displayed a higher risk for severely impaired development. Especially severely impaired patients can benefit from the earliest possible epilepsy surgery.

References

1. Ramantani G, Kadish NE, Brandt A, et al. Seizure control and developmental trajectories after hemispherotomy for refractory epilepsy in childhood and adolescence. Epilepsia 2013;54(6):1046–1055

2. Van Schooneveld et al. Epileptic Disord 2011;13(1):47–55

No conflict of interest has been declared by the author(s).