Excessive daytime sleepiness and subjective sleep quality in patients with nocturnal frontal lobe epilepsy: a case-control study

Abstract

Purpose: Nocturnal frontal lobe epilepsy (NFLE) may be associated with sleep fragmentation and reduced sleep efficiency. Daytime sleepiness and disturbed sleep quality have been reported in some patients. We investigated the occurrence of daytime sleepiness-related symptoms and subjective sleep quality in patients with NFLE in comparison with matched controls.

Methods: Patients with NFLE at a single epilepsy center and matched controls randomly selected from the general population self-administered questionnaires on daytime sleepiness-related symptoms and subjective sleep quality [Epworth sleepiness scale (ESS), Bologna questionnaire on sleepiness-related symptoms (BQS), Berlin questionnaire].

Results: Thirty-three patients with NFLE and 27 controls were enrolled. "Tiredness after awakening" and "spontaneous mid-sleep awakenings" were more frequent in NFLE patients than in controls (36.4% versus 11.1%, p = 0.04, and 50.0% versus 22.2%, p = 0.03). The frequency of excessive daytime sleepiness (EDS) did not differ between groups. Posthoc analysis showed that patients with a complaint of "midsleep awakenings" had higher ESS and BQS scores than those without (7.3 versus 4.3, p = 0.004, and 5.0 versus 2.2, p = 0.001, respectively) and more frequent "tiredness after awakening" (56.3% versus 18.8%, p = 0.03).

Conclusions: Patients with NFLE have no pathological level of EDS with respect to controls. However, daytime sleepiness-related symptoms could be more frequent in a subgroup of patients with subjective disturbed sleep quality, irrespective of the perceived frequency of seizures.