Authors :
Presenting Author: Juan Toro Perez, MSc – University of Ottawa, Children's Hospital of Eastern Ontario
Erick Sell Marruco, MSc – University of Ottawa, Children's Hospital of Eastern Ontario
Asif Doja, MSc – University of Ottawa, Children's Hospital of Eastern Ontario
Katherine Muir, MSc – University of Ottawa, Children's Hospital of Eastern Ontario
Ana Suller-Marti, PhD – Western University
Sarah Healy, PhD – University of Ottawa, Children's Hospital of Eastern Ontario
Srinivas Buluso, MSc – University of Ottawa, Children's Hospital of Eastern Ontario
Sharon Whiting, PhD – University of Ottawa, Children's Hospital of Eastern Ontario
Roberto Caraballo, PhD – Hospital de Pediatria Prof. Dr. Juan P Garrahan
Rationale:
Generalized epilepsy represents 23-43% of new-onset epilepsy in children and adolescents. These may have focal or asymmetric clinical features. Absence seizures evolving to bilateral tonic-clonic seizure were described as “the double generalization phenomenon” or “a new generalized seizure type”. Digital signal processing by quantitative EEG (QEEG) may evaluate this phenomenon which could represent a propagation of the neuronal network involved.
Methods:
a retrospective chart review of patients admitted to the epilepsy monitoring unit (EMU) between May 2014 and May 2024 with generalized idiopathic epilepsy and normal brain MRI.
Results:
66 patients with generalized epilepsy were reviewed. Seven patients, all females, had a generalized onset seizures with focal evolution (GOFE) and bilateral tonic-clonic progression. Eight seizures were recorded. Three had juvenile absence epilepsy (JAE), two had juvenile myoclonic epilepsy (JME), and two had a generalized genetic epilepsy (GGE) in the context of SLC13A5 and CFTR (Delta F508 & L206W). Average age at seizure onset was 7.5 years (range:1-12, SD ±5.0139), at diagnosis was 8.14 years (range:1-13, SD ± 5.1455). Six had normal background, one mild slowing. Hyperventilation triggered absence seizures in six, one of them evolved to absence status epilepticus. The photic stimulation showed photoparoxysmal response (4/7) and triggered a GOFE at 12 Hz (1/7). QEEG spectrogram with spike detection analysis showed 2.5-3.5 Hz generalized spike and wave followed by focal build up over the lateral frontal (3 right and 1 left), occipital (1 right, 1 left and 1 bilateral) and frontal-central (right frontal and left central) regions before bilateral tonic clonic progression.
Conclusions:
In our cohort of patients, QEEG analysis showed that generalized onset seizures have a focal evolution to the frontal and occipital cortices during the propagation to the cortex through the thalami-cortical network. The right lateral frontal and occipital cortices appear to be the most frequent regions demonstrating the first focal evolution. Funding: Self-funding.