Are Reemergence of Sleep Spindles and Cessation of Hypsarrhythmia Prognostic Factors for Neurodevelopmental Outcome in Adults with a History of West Syndrome in Infancy?

Background/Purpose: West syndrome (WS) is associated with a high risk for developmental delay. There is no prognostic biomarker for neurodevelopment in these patients. Hypsarrhythmia is the characteristic EEG-pattern in WS and mostly leads to disturbed physiological sleep architecture, for example, absence of sleep spindles. There is growing evidence that sleep spindles participate in memory formation and learning. We postulated that resolution of hypsarrhythmia and an early reappearance of sleep spindles could be used as positive prognostic factors for long-term outcome in WS.

Methods: Retrospective analysis of all children with WS treated at the University Hospital Muenster, Germany between 1980 and 1989: 31/88 children (35%) were deceased at the time of follow-up (2014–2015), 6 (7%) were lost to follow-up, 44/51 (86%) participated. 448 sleep EEGs were reassessed. Outcome was measured by the functional independence measurement score reflecting the ability to cope with everyday life situations and highest level of education. Statistical analyses were done by exact Fisher test and Kruskal–Wallis H test.

Results: No significant correlations between the time to cessation of hypsarrhythmia and long-term outcome as well as between re-emergence of sleep spindles and long-term outcome were found. Patients who developed sleep spindles in the first two years of life had a slightly more favorable outcome than those who did not. However, this result did not reach statistical significance.

Conclusion: In WS, there is no significant correlation between long-term outcome and the reemergence of sleep spindles and the time to cessation of hypsarrhythmia after initiation of treatment.