Excessive daytime sleepiness in patients with epilepsy: contributing factors and impact on quality of life

Abstract

Excessive daytime sleepiness (EDS) is common complaint in patients with epilepsy (PWE). Generally, antiepileptic drug (AED) is regarded as the cause of EDS. In recent studies, however, prevalence of EDS in PWE was similar to that in healthy subjects. And comorbid sleep disorders with epilepsy were more related to EDS than AEDs. The purposes of this study were (1) to evaluate EDS in PWE compared with healthy control, (2) to explore the potential factors contributing to EDS, (3) and to determine the impact of EDS on quality of life (QoL) in PWE. PWE were recruited unselectively from university hospital in Korea. Patients who agreed to participate were asked to complete the following questionnaires: (1) for detecting sleep problems, Epworth Sleepiness Scale (ESS), Medical Outcomes Study Sleep Scale (MOS-SS), Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ), four questions by International Restless legs Syndrome Study Group, questions for insomnia, and Sleep Hygiene Index (SHI), (2) for depression, Hospital Anxiety and Depression Scale (HADS), (3) for measure QoL, Quality of Life in Epilepsy survey (QOLIE-10). EDS was defined as ESS >= 11. Healthy subjects were recruited unselectively. Demographic and clinical information were obtained by neurologists. A total of 165 PWE and 149 controls subjects were enrolled in the study. (1) Patient and control groups did not differ in age and gender. There was no difference in degree of sleepiness between epilepsy and control groups. Mean raw ESS scores in both groups did not differ. The proportion of EDS was somewhat higher in epilepsy (24.2%) than in control group (17.4%), but it was not statistically significant ( p = 0.088). (2) EDS in PWE was significantly associated with the number of AEDs ( p = 0.033), MOS-SS Problem Index-2 ( p = 0.004), and a subscale of MOS-SS ¡®Shortness of Breath¡ ¯ ( p = 0.029). Logistic linear regression showed that the number of AEDs and MOS–SS Problem Index-2 remained significantly associated with EDS. (3) QoL in PWE was significantly associated with MOS-SS Problem Index-2 and sleep hygiene, but not with EDS and the number of AEDs based on multiple regression analysis. EDS in PWE was significantly associated with the number of AEDs and poor sleep quality. QoL of PWE was related to their overall poor sleep quality and bad sleep hygiene, but not related to their EDS. The authors have no financial conflicts of interest.