Sleep disordered breathing in patients with epilepsy

Background:Sleep has long been known to affect epilepsy. Little has been documented regarding the epidemiology of sleep disordered breathing (SDB) in patients with epilepsy from India. Methods:Between April 2009 and September 2011, in the first stage of the study, 452 consecutive patients with epilepsy (cases) and 500 age- and gender-matched normal control subjects were screened using Epworth’s Sleepiness Scale (ESS). Of these, 98 (23%) had an ESS score of 10 or more, suggestive of excessive day time sleepiness (EDS). Of these, 30 patients (mean age was 35.8±13.1; 26 males) were taken up for the second stage of the study, underwent detailed evaluation and overnight in-hospital polysomnography (PSG) in the sleep laboratory. Results: Their mean age was 35.8 ±13.1; 26 males); Of these, 13 (43.3%)(all males) had evidence of OSAS on PSG: 9 had mild OSAS [apnoea-hypopnoea index (AHI) 5-15]; 3 had moderate OSAS (AHI 15-30) and one patient had severe OSAS (AHI >30). On univariate analysis, a higher proportion of patients with nocturnal seizures had OSAS compared with those with diurnal seizures and combined periodicity (7/8 vs 6/16; p=0.009). Patients with uncontrolled seizures had a higher prevalence of OSAS (p=0.045). Conclusions: Our observations suggest that EDS is an important symptom being six times more common in patients with epilepsy compared to healthy control subjects. Furthermore, PSG study indicated that 43.3% of epilepsy patients with EDS have OSAS. Thus, SDB appears to be an underdiagnosed disease in patients with epilepsy from India.