INTRODUCTION: Epilepsy is one of the most common neurological diseases and has many detrimental effects on the patients' well-being as well as sleep quality. The aim of this study was to assess the subjective quality of sleep and influencing factors on subjective sleep quality in patients with partial epilepsy using a combined retrospective and prospective study design.
METHODS: We conducted a combined retrospective and prospective study in patients with partial epilepsy and analyzed subjective ratings of sleep quality in 32 patients (17 female, 15 male; mean age: 40.41 ± 12.67 years, range: 20-64) with partial epilepsy (mean duration of epilepsy diagnosis: 18.31 ± 13.26 years) and 32 healthy gender-matched and age-matched controls. All patients filled out a seizure diary for 90 days, which included the number, duration, and type (partial vs. secondary generalized) of epileptic seizures and intake of antiepileptic and sleep medications. At baseline, all participants completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Beck's Depression Inventory (BDI), and Beck Anxiety Inventory (BAI). Poor sleepers were defined by a PSQI score of ≥ 5.
RESULTS: Twenty-three patients (72%) reported 15.17 ± 25.54 seizures in the previous three months, and nine (28%) patients reported being seizure-free. During the 90-day diary period, twenty-two patients (69%) documented a total of 319 epileptic seizures, while ten patients (31%) reported that they were seizure-free. The mean PSQI score of all patients was 4.88 ± 2.92 (range: 1-14) and the mean ESS score was 5.25 ± 2.98 (range: 0-10). The mean PSQI score of the control group was 3.25 ± 1.57 (range: 1-6), and their mean ESS score was 6.72 ± 3.48 (range: 0-14). The comparison of the two groups showed a significantly higher PSQI score in the patient group (t = 2.778, p = 0.008), but no statistically significant difference regarding their ESS score (t = -1.811, p = 0.075). Sixteen (50%) patients were poor sleepers. Good sleepers showed a significantly lower PSQI (2.69 ± 1.08 vs. 7.06 ± 2.49; p < 0.001) and BDI scores (2.38 ± 2.50 vs. 9.63 ± 7.63; p < 0.002) than poor sleepers. Linear regression analysis showed that the BDI score was the significant predictor for the PSQI score (estimate: 0.2019; p = 0.00819) and for the ESS score (estimate: 0.2251; p = 0.0321).
CONCLUSION: In patients with partial epilepsy, a higher depression score was the best predictor for a poor subjective sleep quality and increased daytime sleepiness.
