Abstracts

Although the incidence of new-onset seizures is much higher in older adults than in any other age group, the etiology remains unknown in about 45% (Epilepsia, 34(3): 453-68, 1993). One possible etiological factor is untreated obstructive sleep apnea (OSA), which can lead to sleep fragmentation and chronic sleep deprivation, potentially facilitating seizures in susceptible individuals (Neurology, 48(5):1389-94, 1997)., To determine whether OSA is more common in individuals with later-onset seizures or worsening of seizure control in later life, we performed a cross-sectional study of adults 50 years or older presenting to a tertiary center epilepsy clinic. Patients with provoked seizures, associated neurological disease, or unreliable seizure histories were excluded. An epilepsy specialist blinded to the study results classified each subject into one of two groups.
[underline]Group 1[/underline]:
-Seizure-onset before age 50 with stable or improved seizure frequency at or after age 50
[underline]Group 2[/underline]:
-Seizure-onset before age 50 with increased seizure frequency at or after age 50 [italic]OR[/italic]
-Seizure-onset at age 50 or older
Each subject underwent one-night polysomnography. The studies were reviewed by a sleep specialist blinded to the epilepsy histories. The number of apneas and hypopneas per hour of sleep (apnea-hypopnea index; AHI) was calculated., Of 290 patients screened, 135 met inclusion criteria, and 21 consented to participate. Epilepsy syndromes included partial epilepsy of temporal lobe (15) or frontal lobe (3) origin, idiopathic generalized (2), and unspecified (1).[table1]The two groups were similar in age, BMI, number of AEDs currently used, and frequency of nocturnal seizures. Group 2 had more men and a higher neck circumference. Group 2 had significantly higher AHIs, as well as higher scores on Epworth Sleepiness Scale (ESS) and Sleep Apnea section of the Sleep Disorders Questionnaire (SA-SDQ).[figure1], The AHI was higher in the group with either new seizures or increased seizures, suggesting that OSA may play a role in facilitating seizures in this older population., (Supported by Epilepsy Foundation of America Clinical Research and Training Fellowship Program through the Roger F. and Edna F. Evans Fund.)