Abstracts

Rationale:
Hemimegalencephaly (HME) is a rare congenital malformation of the brain characterised by the over-growth of one hemisphere. HME is usually associated with severe seizures and developmental delay. Hemispherectomy is an effective treatment option to control seizures, though little is known about its outcomes with respect to cognition and language. The objective of the current study was to delineate cognitive and language outcome of children with HME who underwent a hemispherectomy.
Method:
Data came from the Global Pediatric Epilepsy Surgery Registry, a patient-driven web-based registry which allows parents and guardians of children with epilepsy to report on outcomes after epilepsy surgery. Parents across the world are recruited via email and socialmedia. The registry is hosted on REDCap and collects information on demographics, clinical characteristics, surgery, seizure outcomes, and comorbidities. The parents and guardians of 120 children who had undergone a hemispherectomy participated. For this report, we focus children with hemimegalencephaly (HME) and reported on cognitive and speech outcomes after hemispherectomy.
Results:
Parents of 44 children (50% female) with HME who had undergone a hemispherectomy participated. The average age at seizure onset was 2.7 months (standard deviation [SD]: 6.7, range 0 – 33.5). Prior to the first surgery, 93% of children had several seizures per hour or per day, and the majority underwent one surgery (49%); 33% had two surgeries, 15% had three surgeries, and 3% had 4 or more surgeries. The average age at first and last surgery was 10.6 months (SD: 13.2, range: 1.1 months – 5.5 years) and 2.2 years (SD 2.3, 1.1 months – 8.1 years), respectively. The average age at follow-up was 8.2 years (SD: 5.12, range: 4.2 months – 18.0 years). At follow-up, 6.4 years after last surgery (SD 4.6), 74% were seizure free and an additional 16% had several seizures per year. The children’s current cognitive ability was described by their parents as average (7%), mildly impaired (32%), moderately impaired (29%), or significantly impaired (32%). Of the children old enough to speak at follow-up (n=40), 68% could speak – 23% could speak age appropriately and clearly, 38% speak, but not clearly or age appropriately, and 8% speak but use few words. With respect to the acquisition of speech, among the children old enough 55% and 76% first began to babble by the age of 11 months and 1.5 years, respectively; 44% and 76% spoke their first words by the age of 2 and 4.5 years, respectively; and 51% started speaking sentences of 3 or more words by the age of 5 years.
Conclusion:
We report on cognitive and language outcomes of a large cohort of children with HME who underwent hemispherectomy. The results highlight that hemispherectomy in very young children with HME is very effective in controlling seizures. Nearly two thirds of children present with moderate-severe cognitive impairment at follow-up, however two thirds are also able to speak.
Funding:
:None.