Pediatric patients with epilepsy with myoclonic atonic seizures (EMAS) were found to have structural brain changes to the frontal lobes and cerebellum, according to study findings published in Epilepsy Research.
EMAS is a rare form of epilepsy and has been associated with intellectual disability, however, brain imaging at EMAS onset has not identified structural changes which may be responsible for subnormal development. The objective of the current study was to assess the brain morphometry of pediatric patients with EMAS and compare it with healthy individuals several years after epilepsy onset, and correlate it to epilepsy severity and cognitive findings.
In order to assess whether longer-term structural changes may be occurring, children (n=14) with EMAS were recruited at the Lausanne University Hospital and Geneva Children’s Hospital in Switzerland. Patients and healthy control individuals (n=14) underwent a neuropsychological assessment and magnetic resonance imaging.
Patients were aged median 10.5 (range, 5-15) years, 10 were boys, and seizures onset at a median of age 36.5 (range, 22-62) months. The control cohort was aged median 10.0 (range, 5-13) years and 10 were boys.
The patients with EMAS were found to have significantly reduced whole-brain cortical volume (t, -2.32; P =.029), cortical thickness (t, -2.12; P =.044), and local gyrification index (t, -2.19; P =.038) compared with healthy individuals.
In specific brain regions, patients with EMAS had reduced cortical volumes of the frontal (t, -4.06; P <.001), temporal (t, 3.28; P =.009), parietal (t, -2.71; P =.024) lobes, cingulate gyrus (t, -2.27; P =.046), and cerebellum (t, -2.74; P =.011). In addition, the patients had decreased cortical thickness (t, -3.00; P =.006) and local gyrification index (t, -2.27; P =.032) in the frontal lobe.
Age of onset was observed to correlate with frontal (F[1,5], 15.04; P =.012), temporal (F[1,5], 10.05; P =.025), and cingulate (F[1,5], 7.10; P =.045) cortical volumes as well as frontal (F[1,5], 8.64; P =.032), temporal (F[1,5], 13.79; P =.014), and cingulate (F[1,5], 14.91; P =.012) local gyrification indices.
Patients were stratified into good (n=6), intermediate (n=3), and poor (n=5) cohorts on the basis of intellectual quotient (IQ) scores. IQ groups were correlated with frontal (F[1,5], 8.55; P =.033) and temporal (F[1,5], 11.77; P =.019) local gyrification indices.
The number of antiseizure medications was observed to correlate with cingulate cortical thickness (F[1,5], 7.40; P =.042).
This study was likely limited by the inclusion of participants with heterogeneous age, severity, treatments, and disease durations.
The study authors concluded that patients with EMAS had significant cortical changes compared with their non-elliptic counterparts. These changes correlated with patient IQ. However, the researchers cautioned, “whether these anatomical changes reflect genetically determined abnormal neuronal networks or a consequence of sustained epilepsy remains to be solved with prospective longitudinal studies.”
Denervaud S, Korff C, Fluss J, et al. Structural brain abnormalities in epilepsy with myoclonic atonic seizures. Epilepsy Res. Published online September 21, 2021. doi:10.1016/j.eplepsyres.2021.106771