The topographical distribution of epileptic spikes in juvenile myoclonic epilepsy with and without photosensitivity

Publication date: Available online 14 November 2016
Source:Clinical Neurophysiology
Author(s): P.R. Bauer, K. Gorgels, W. Spetgens, N.E.C. van Klink, F.S.S. Leijten, J.W. Sander, G.H. Visser, M. Zijlmans
[Objective]Up to 30% of people with juvenile myoclonic epilepsy (JME) have photoparoxysmal responses (PPR). Recent studies report on structural and pathophysiological differences between people with JME with (JME+PPR) and without PPR (JME-PPR). We investigated whether electrophysiological features outside photic stimulation differ between these subtypes.[Methods]We analysed EEG recordings of people with JME at a tertiary epilepsy centre and an academic hospital. Photosensitivity was assessed in a drug-naïve condition. We compared the occurrence and involvement of posterior electrodes for focal abnormalities and generalised spike-wave activity in the EEG outside photic stimulation between JME+PPR and JME-PPR.[Results]We included EEG recordings of 18 people with JME+PPR and 21 with JME-PPR. People with JME-PPR had less focal abnormalities in the posterior brain regions than people with JME+PPR (19% vs 55%, p<0.05). There was no difference in the distribution of generalised spike-wave activity between people with JME+PPR and JME-PPR.[Conclusion]This study demonstrates electrophysiological correlates of the previously described structural and physiological differences between JME+PPR and JME-PPR.[Significance]Findings support the hypothesis that posterior interictal EEG abnormalities reflect localised cortical hyperexcitability, which makes patients with JME more sensitive to photic stimuli.



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