Abstracts

Video EEG-polysomnography is the reference standard in the differential diagnosis between nocturnal frontal lobe seizures (NFLS) and non-epileptic paroxysmal sleep disorders. Nevertheless it is expensive and useful only in case of frequent attacks. On the other hand, the diagnostic accuracy of clinical history, that could be useful in patients with rare events, is unknown. The aim of this study is to measure the diagnostic accuracy of clinical history in distinguishing NFLS from non-epileptic paroxysmal sleep disorders., Three categories of subjects were eligible for this study: 1) patients with NFLS; 2) patients with parasomnias; 3) patients with other sleep disorders confounding for NFLS. Clinical, neuroradiological and interictal and ictal video-polysomnographic recordings from the database of the Sleep Center of the Department of Neurological Sciences, University of Bologna, were retrospectively reviewed. Eligible subjects were classified as having [ldquo]NFLS[rdquo] or [ldquo]NOT-NFLS[rdquo] by sleep medicine and epilepsy experts. Moreover, 5 major and 13 minor anamnestic criteria were selected to be tested in the diagnosis of NFLS. On the basis of these criteria a questionnaire was devised and administered by telephone to 103 patients by a young newly qualified doctor blinded to the aim of the study and the final diagnosis of patients. The diagnostic parameters (i.e. sensitivity, specificity, likelihood ratios, diagnostic odds ratio - DOR) were calculated for each criterion., Forty-four subjects had documented NFLS; 59 subjects were classified as [ldquo]NOT-NFLS[rdquo]. Generally, sensitivity appeared to be moderate (range 0.2-0.6) and specificity was high (0.9-1) for most of the possible criteria associations. The higher diagnostic accuracy, measured by the DOR, was obtained combining the first criterion (defining the semeiology of the epileptic event) with one of the following features (in decreasing order): 1. presence of vocalization (DOR 76.5), 2. less than 2 minutes[apos] duration (42.8), 3. aura preceding motor behaviour (38.9), 4.positive personal history of tonic-clonic seizures during sleep (25.5), 5. stereotypy of motor phenomena (20.9); 6. recurrence of seizures every night for at least one month (20.4)., From this preliminary study we selected one major and six minor clinical criteria for the anamnestic diagnosis of NFLS. The diagnostic accuracy of these criteria appeared to have moderate sensitivity and high specificity. A further prospective validation is needed.,