Parasomnias, sleep-related movement disorders and physiological sleep variants in focal epilepsy: A polysomnographic study

Purpose: The link existing between epilepsy and sleep is widely recognized. However, little is known about the prevalence and the clinical consequences of the comorbidity between focal epilepsy and sleep disorders, especially those sleep phenomena classified as isolated symptoms or normal variants. Objective of the study was to evaluate the frequency of sleep disorders and physiological sleep variants in a group of adult patients with focal epilepsy as compared to healthy controls by means of nocturnal polysomnography. Methods: We performed a retrospective observational study in the Neurological Clinic of the University of Catania in adult patients with a diagnosis of focal epilepsy and in a group of control subjects. All subjects underwent an overnight polysomnography. The following sleep disorders were considered: NREM-related parasomnias; REM-related parasomnias; sleep-related movement disorders; isolated symptoms or normal variants. Results: 100 patients [mean age 30.3 ± 14.7 years, 40 men] and 62 controls [mean age 36.4 ± 15.9, 20 men] were studied. A significant higher percentage of sleep disorders was recorded in patients as compared to controls (73 % vs 48.4 %; p = 0.002). In particular, we found a higher frequency of periodic limb movements (PLM) (20 % vs 4.8 %; p = 0.007), bruxism (20 % vs 4.8 %; p = 0.007) and neck myoclonus (22 % vs 4.8 %; p = 0.003). Moreover, alternating limb muscle activation was associated with sleep-related hypermotor epilepsy (OR = 7.9; p = 0.01). Conclusion: Sleep disorders and physiological sleep variants are common in adult patients with focal epilepsy.