Abstracts

Rationale: It remains unclear whether seizures occurring in the setting of sleep deprivation should be considered provoked. The International League Against Epilepsy guidelines for epidemiologic studies on epilepsy do not appear to regard such seizures as provoked but supporting data is limited. This may be clarified by examining the influence of sleep deprivation on seizure recurrence in patients with first-ever seizure. Methods: Adult patients with first-ever seizure seen at three teaching hospitals in Western Australia were prospectively evaluated between 1999 and 2007. Patients with remote symptomatic seizures were excluded. The clinical features and prognosis of patients with idiopathic first-ever seizure occurring with and without sleep deprivation were compared. A comparison was also made with patients satisfying ILAE criteria for a provoked first-ever seizure. Results: Of 554 patients with idiopathic first-ever seizure, 131 were associated with sleep deprivation. The clinical and radiologic features were similar between the sleep deprived and non-sleep deprived patients. The likelihood of seizure recurrence at two years in sleep deprived patients was 46% [95% CI:36-56] and was 53% [95% CI:48-59] in non-sleep deprived patients. The likelihood of seizure recurrence at two years following a provoked seizure without sleep deprivation was 33% [95% CI:26-41]. The cumulative probability of further seizures did not significantly differ between sleep deprived and non-sleep deprived patients, but was significantly lower in patients with provoked seizures (log rank p-=<0001). Patients who had an idiopathic first-ever seizure following sleep deprivation were less likely to receive anti-epileptic medication (8% vs 18%, p=0.004), but treatment did not alter seizure recurrence rate in either group. Conclusions: The prognosis of a first-ever seizure is not significantly influenced by the presence of sleep deprivation. Our findings support the ILAE recommendation that seizures occurring in the setting of sleep deprivation should not be regarded as provoked.