Abstracts

Rationale: Isolated midline spike (IMS) is an unusual finding in the paediatric electroencephalogram (EEG)1. Its significance in developing epilepsy, therefore needing long term anti-seizure medications, is no fully understood2, 3. We hypothesized that in previously healthy children there could be no need of long term commitment to anti-seizure medications despite the presence of IMS on their EEG.Methods: This is a descriptive, single center, retrospective cohort study of consecutive pediatric patients presented to our neurophysiology laboratory from April 2009 to March 2011 in whose first EEG showed IMS. Neurophysiology database was queried for key words “midline spikes”. We included children (0-17 years) with isolated midline spikes, and EEG recording only during wakefulness to avoid transient waves of sleep. We excluded patients with other epileptiform activity beside isolated midline spikes and those whose EEG showed abnormal background activity.Results: From 1528 EEGs performed during the studied period, 266 EEGs were retrieved for review. 56 patients met inclusion criteria. 44 patients had seizures and 12 had other reasons to request an EEG (i.e. ataxia, ADHD, behavior disorders). 31 patients had normal neurological examination and neuroimaging and 25 did not. Twenty one out of the 31 normal patients had follow up. Only two developed epilepsy. Twenty one of the 25 abnormal patients had follow-up. Seventeen developed epilepsy (RR 8.5; 95% CI 2.2 – 32.3; p = 0.0017).Conclusions: Despite the small sample group, these results suggest that the vast majority of patients with IMS and normal physical examination and neuroimaging, are unlikely to develop epilepsy. These findings support a conservative approach when considering the use of anti-seizure medications in those patients.