OP20 – 2281: Pre-Emptive EEG and synchronization analysis strategy for West syndrome

Abstract

Objective To explore surrogate markers for early detection of West syndrome in patients with Down syndrome (DS) and to evaluate the correlation between the EEG phase synchrony (R index) and its spatial complexity, during developmental electric brain function in children with DS. Methods Retrospective analyses of sequential scalp EEG and clinical records of children with DS with early seizure disorders, with or without the EEG pattern of hypsarrhythmia, at the Hospital for Sick Children (Toronto, Ontario, Canada), from 1990 to 2012. Scalp EEG recordings were performed with the International 10–20 system of electrode placement. We extracted 10 second artifact-free epochs with 19 electrode EEG data (n=10) during stage II non-rapid eye movement (NREM) sleep for each patient. The R Index of the EEG synchronization was calculated using the Laplacian estimate followed by the Hilbert Transform. The spatial complexity of the R index was then calculated. Both measures were ascertained at 3, 6, 11 and 15 Hz. Results Children with DS, infantile spasms and hypsarrhythmia on their EEGs, showed higher R index of synchronization at all bandwidths (p Conclusion There was higher R index of EEG synchronization in patients with DS with hypsarrhythmia and also higher spatial complexity at 3Hz in DS without hypsarrhythmia. These data indicate that further synchronization and complexity analyses could be valuable in longitudinal EEG follow up to monitor earlier the evolution of hypsarrhythmia in children with DS. A prospective pre-emptive EEG strategy with R index of synchronization analyses is warranted, for earlier pharmacological treatments of patients with DS. The R index of EEG synchronization appears to be a useful surrogate marker before the final diagnosis of West syndrome.