Daytime sleepiness is not increased in mild to moderate multiple sclerosis: a pupillographic study

Abstract Background Daytime sleepiness has been described in multiple sclerosis (MS); a combination of MS and narcolepsy has also been observed in a few case reports. In this study, we investigated daytime sleepiness in a general sample of MS patients compared to healthy controls with the pupillographic sleepiness test (PST) and the Epworth and Stanford sleepiness scales (ESS, SSS). Methods A PST was performed in consecutive MS patients and controls. Additionally, a questionnaire including the ESS and the SSS was applied. Results Sixty-one MS patients (29 men and 32 women, age 34.5±8.3 years, mean disease duration 7.4±6.6 years, expanded disability status scale (EDSS) 1.7±1.2 (mean ± sd)) and 42 age-matched controls (13 men and 29 women, age 36.9±12.9 years) participated in this study. In the MS group, the pupillary unrest index (PUI) was 5.0±2.0, the ESS 7.4±3.5 and the SSS 2.4±1.2, whereas in the control group, the PUI was 4.7±1.8, the ESS 8.4±4.0 and the SSS 2.4±1.2 (mean ± sd). These differences were not significant. No correlation was found between PUI and the ESS or the SSS. Furthermore, no correlation was found between EDSS and sleepiness measured by PUI, ESS and SSS. Conclusion In a general sample of MS patients with mild to moderate disease, there was no evidence for overall increased daytime sleepiness compared to healthy controls.