Abstracts

OSA commonly coexists with epilepsy, and its treatment may improve seizure control and daytime sleepiness. The frequency of OSA in epilepsy may be as high as 33% (Malow et al., [italic]Neurology [/italic]1997), which is higher than that reported for the general population. The mechanisms whereby OSA exacerbates seizures are unclear. Processes that fragment sleep may facilitate nocturnal (sleep-related) seizures. The purpose of this study was to determine if patients with sleep-related seizures are at higher risk for OSA. Adult patients with epilepsy completed a survey about their sleep and seizures. The survey included the Epworth Sleepiness Scale (ESS) and the Sleep Apnea Scale of the Sleep Disorders Questionnaire (SA-SDQ), which has been validated as a screening instrument for OSA in epilepsy patients (Weatherwax et al., [italic]Sleep Medicine[/italic] 2003). Surveys were completed during a visit to the adult neurology clinic or during long-term monitoring in the epilepsy laboratory at the University of Michigan. Patients were divided into two groups: those with sleep-related seizures (SRS) or awake seizures. Sleep-related seizures were defined by subject report that at least half of their seizures occur during sleep. T-tests were used to compare age, body mass index (BMI), ESS, seizure frequency and SA-SDQ scores between the two groups. Logistic regression was used to examine whether the occurrence of SRS was predicted by the frequency of OSA symptoms and by SA-SDQ scores. Significance was set at p [lt] 0.05. The survey was completed by 1256 patients, including 562 men (44.7%) and 694 (55.3%) women (Table 1). Thirty percent of the patients had SRS. Symptoms of OSA that predicted SRS included loud snoring (p= 0.019); witnessed apnea (p= 0.0001); awakening gasping for breath (p= 0.005) and overall SA-SDQ score (p= 0.03). ESS score was not associated with having SRS ([italic]p[/italic]=0.111). Epilepsy patients at high risk for OSA, as reflected by loud snoring, witnessed apnea and higher SA-SDQ scores are more likely than other patients to have seizures predominantly during sleep. As SRS tend to occur in lighter stages of sleep (Minecan et al., [italic]Sleep[/italic] 2002), pathological events that facilitate arousals with shifting to a lighter sleep stage, such as obstructive apneas, potentially play an important role in exacerbating SRS in patients with epilepsy. Patients with SRS may merit special consideration in screening for obstructive sleep apnea.[table1] (Supported by NINDS RO1 NS 042698 (BAM) and NINDS KO2 NS2099 (BAM) and GCRC grant RR00042 (University of Michigan).)