Abstracts

Rationale: Some studies have claimed that epilepsy patients feel fatigue more frequently than general population. Likewise, other studies have proved that the patients complain of sleep disturbance more than controls, and they whine about daytime drowsiness more than neurology patients without epilepsy. Although the sleep-associated problems and fatigue may be closely correlated, little study has been explored systematically the association between them in epilepsy patients. We investigated the predictors of the fatigue of epilepsy patients by a stepwise multiple regression with diverse variables including sleep-associated problems.Methods: Consecutive epilepsy patients under antiepileptic medication for at least 1 year were enrolled. All subjects were asked to complete Korean versions of self-report questionnaires. The questionnaires were fatigue severity scale (FSS), Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), Generalized Anxiety Disorder-7 (GAD-7), Epworth sleepiness scale (ESS), and Patient-Reported Outcomes Measurement Information System (PROMISTM): PROMISTM-Sleep Disturbance (PROMIS-SD); PROMISTM-Sleep-Related Impairment (PROMIS-SRI). Patients younger than 19 years old and older than 70 years old, those with severe neurological, psychiatric or other disorders were excluded. 270 patients were recruited after the exclusions. We also enrolled 200 age- and sex-matched healthy controls and applied NDDI-E, GAD-7, and FSS for them. Data about patient-related, epilepsy-related, and psychosocial variables of the patients were gathered from medical records. We performed a stepwise multiple regression to identify the best combination of predictors for high scores of FSS in epilepsy patients. We set statistical significance at a p-value of 0.01.Results: The frequency of fatigue was 44.1% and 31.5% in the epilepsy patients and controls respectively. All scores of the questionnaire were significantly different between the patients with fatigue and those without fatigue. The QOLIE-10 total score was 66.5 ± 21.5 (mean ± standard deviation) and 82.6 ± 15.4, the NDDI-E score was 12.0 ± 4.9 and 8.6 ± 3.5, the GAD-7 score was 7.1 ± 6.0 and 2.8 ± 3.8, the ESS score was 7.3 ± 4.7 and 4.2 ± 3.6, the FSS score was 4.5 ± 1.0 and 2.0 ± 0.6, the t-score of PROMIS-SD was 53.7 ± 9.9 and 44.6 ± 8.9, and the t-score of PROMIS-SRI was 54.4 ± 8.4 and 43.5 ± 8.3 respectively. In all patients with epilepsy, the stepwise multiple regression analysis produced a model with two variables explaining 45.1% of the variance. The strongest predictor of the FSS score was the PROMIS-SRI t-score (β = 0.526) and followed by the NDDI-E score (β = 0.234).Conclusions: Fatigue may be more frequent in epilepsy patients than others, and it aggravate the quality of life in the patients. It is evident from this study that sleep-related impairment and depression are much stronger, as predictors of the fatigue of epilepsy patients, than the other factors including seizure-related factors. We may reduce fatigue of epilepsy patients by improving sleep hygiene and reducing depression. That may lead to improvement of quality of life in epilepsy patients.