Abstracts

Abnormal paroxysmal events in sleep may be parasomnias or epileptic seizures. In the case of nocturnal frontal lobe epilepsy (NFLE) the unusual seizure semiology often leads to an incorrect diagnosis of parasomnias. Despite this, the clinical presentation of these conditions is different, and it should usually be possible to differentiate them on the basis of the clinical history. We have developed the Frontal Lobe Epilepsy and Parasomnias (FLEP) scale as a clinical tool to distinguish these conditions based on relevant features of the patient[rsquo]s history. 1) Scale development. The FLEP scale, consisting of specific questions reflecting the diagnostic features of NFLE and parasomnias, was developed by an expert panel following review of the literature. The scale weightings were adjusted by unblinded application to a sample of cases. 2) Pilot validation 11 subjects with NFLE and 6 with parasomnias were enrolled. All patients had been reviewed by at least two neurologists or sleep physicians, and 14 of the 17 subjects had undergone diagnostic video EEG monitoring. A 15 minute telephone interview was conducted by a blinded researcher in each case; this involved both the patient and a witness to the patient[rsquo]s events. A diagnosis was made on the basis of their FLEP score. 3) Validation study. Sixty subjects using the same methodology are currently being assessed. NFLE was correctly diagnosed from the FLEP score in 11 out of 11 patients giving a sensitivity of 1.0 (95% CI: 0.81, 1.0). The specificity of a diagnosis of NFLE was 0.8 (95% CI: 0.37, 0.8). The diagnosis of NFLE from the FLEP scale had a positive predictive value of 0.92 (95% CI 0.74, 0.92) and a negative predictive value of 1.0 (95% CI 0.47, 1.0). The FLEP scale appears to be a sensitive, specific and easily administered clinical instrument for the differentiation of Nocturnal Frontal Lobe Epilepsy from parasomnias on the basis of the clinical history. (Supported by The Brockhoff Foundation, Australia)