Subjective sleep quality in epilepsy patients with sleep-related seizures

Abstract

Sleep quality is expected to be poor in epilepsy patients with sleep-related seizures as a consequence of the disruptive effect of seizures themselves on sleep patterns, a potentially heightened pre sleep emotional arousal due to patient’s worries about having seizures during sleep and associated sleep comorbidities. This study is aimed at investigating subjective sleep quality and features in adult patients with seizures occurring exclusively or predominantly during sleep. Patients affected with Nocturnal Frontal Lobe Epilepsy were not included. Fifty-seven subjects ( 18–72 years of age; 27 males), 27 (47.3%) diagnosed with sleep related undetermined epilepsy and 30 (52.7%) with focal epilepsy based on clinical, awake/sleep EEG and brain MRI findings, were investigated. Most of the patients (94%) had <1 seizure per month, with the seizures being in most cases generalized convulsive seizures during sleep. All the patients were given Pittsburgh questionnaire (PQ), Morningness – Eveningness Questionnaire (MEC), STAI 1 and 2, Beck Depression inventory (BDI). Patients reporting snoring and/or witnessed apneas during sleep underwent a nocturnal polysomnographic screening for obstructive sleep apnea (OSA). At the time of the questionnaire compiling the patients had had at least 1 seizure during the previous month (seizures recency) in 19% of the cases and they all were on antiepileptic drugs at bed time, with valproate, levetiracetam and carbamazepine, alone (89.5%) or in combination (10.5%) being the most frequently used drugs. Fifty-seven healthy subjects matched for age and sex served as controls. Univariate analyses were preliminary performed in comparing categorical (chi square test) and continuous variables ( T -test) between patients and controls and patients with PSQI >5 and those with PSQI <5. Neither PSQI total score (5.2 ± 3.6 in patients and 5.3 ± 3.4 in controls) nor its components differ significantly between patients and controls. PSQI >5 patients (39%) and PSQI <5 patients (61%) do not differ significantly for age (47.1 ± 15.0 vs. 43.9 ± 15.0 years), sex (41% vs. 50% males), STAI 1 ( 46.2 ± 13.2 vs. 37.9 ± 9.6) and STAI2 scores (44.2 ± 10.5 vs. 39 ± 10.7), BDI (12.8 ± 8.0 vs. 9.1 ± 9.0), MEQ chronotype, OSA prevalence (15.8% vs. 7.1%). As for illness-related parameters, PSQI >5 patients proved to have a significantly longer illness duration than PSQI <5 patients (17.5 ± 18.2 years vs 8.2 ± 0.3 years; p = 0.035) and a higher rate of seizures recency (54.5% vs. 15.4%; p = 0.04). Our data indicate that subjective sleep quality in adult patients with seizures occurring exclusively or predominantly during sleep is not poorer than in healthy controls. Patients’ sleep quality is influenced by some illness related parameters, with poor sleep quality being associated with longer disease duration and seizure recency. The relatively low frequency of seizures along with a blunting effect of antiepileptic treatment on arousal instability during sleep may explain the finding of a substantially good sleep quality in our patients series. However also epilepsy patients’ life style and their good compliance to sleep hygiene rules may account for a preserved sleep quality. The Authors wish to thank the technogists Valter Rustioni, Daniele Marchese, Laura Spelta, Federica Camasso for their technical support.