Excessive Daytime Sleepiness, Inflammation, and Platelet Energy Metabolism in Chronic Stroke Survivors: A Pilot Study.

Abstract

Excessive daytime sleepiness is a prevalent and sustained symptom that contributes to untoward physiologic and psychologic outcomes among stroke survivors. Mechanisms of excessive daytime sleepiness post-stroke are not fully understood. Chronic systemic inflammation may contribute to impaired mitochondrial functioning and thereby reduce cellular energy metabolism which may contribute to symptoms of excessive daytime sleepiness in stroke survivors. This pilot study aimed to assess the relationship between systemic inflammation and cellular energy metabolism to post-stroke excessive daytime sleepiness. This descriptive pilot study explored the relationship between excessive daytime sleepiness, systemic inflammation, and aerobic energy metabolism of platelets in 22 chronic stroke survivors. The Epworth Sleepiness Scale was used to measure excessive daytime sleepiness. Systemic inflammation was measured by assessing pro-inflammatory cytokines IL-6, IL-1β and TNF-α and the inflammatory marker C-reactive protein. Aerobic energy metabolism was measured by assessing oxygen consumption rates of platelets. Simple linear regression was used to test the influence of oxygen consumption rates and inflammation on excessive daytime sleepiness. Correlations were analyzed using Spearman rho correlation coefficients. Excessive daytime sleepiness was recognized in 27.3% of the sample. Systemic inflammation was associated with excessive daytime sleepiness in women but not men. We found no significant relationship between excessive daytime sleepiness and energy metabolism of platelets. However, all oxygen consumption rates were numerically higher in persons with excessive daytime sleepiness. Systemic inflammation may be related to excessive daytime sleepiness symptoms with a notable effect among women. Future larger studies are needed to further explore the sexually dimorphic relationship of post-stroke excessive daytime sleepiness to systemic inflammation. Numerically higher platelet oxygen consumption rates may indicate higher energy demands for stroke survivors with excessive daytime sleepiness.