Characterization of a unique patient cohort with spike-wave activation in sleep without cognitive decline or increased seizure burden: Considerations for a more conservative treatment approach

Abstract

Objective

The goal of this study is to better characterize a unique subset of patients who present with so-called “isolated SWAS” (Spike Wave Activation in Sleep) by analyzing electrographic and neuropsychological data.

Methods

We evaluated our institution's population of patients with SWAS, defined as >/= 50 % spike-wave index potentiated during slow-wave sleep. Of this group, 26 patients were identified with no worsening cognitive performance or seizure burden at the time of diagnosis, deemed “isolated SWAS”, in comparison to patients with Developmental and/or Epileptic Encephalopathy (D/EE)-SWAS. Paraclinical studies of this cohort were analyzed, including high-frequency oscillations, specifically on scalp electroencephalogram as well as comprehensive behavioral and neuropsychologic data at one-year follow-up.

Results

We found that 80 % (n=21) of the cohort was started on a unique treatment for SWAS at the time of diagnosis, with the most common treatment being clobazam (n=12; 57 %) followed by valproic acid (n=9; 43 %). The cognitive performance of patients who received treatment and those who did not receive treatment was not statistically significant, and after one year of follow-up the patients who did not receive treatment for SWAS had no cognitive decline. Furthermore, the treatment group reported more medication side effects (n=14/21; 67 %). Seven patients (27 %) of the cohort continued to have SWAS at follow-up, and 11 patients (42 %) had ongoing seizures. The presence of ripples did not correlate with cognitive outcomes.

Significance

This study suggests that if patients have “isolated-SWAS” at the time of diagnosis a more conservation approach may be considered.