Even though the origin and nature of nocturnal paroxysmal dystonia (NPD) remains unclear, it has been considered as a manifestation of the nocturnal frontal lobe epilepsy. We report a 17-year-old man with abnormal stereotyped movement during sleep. Video-EEG monitoring, ictal SPECT and night polysomnography did not show any evidence of epilepsy. However, the partial response to large dose of carbamazepine and the scoring according to the frontal lobe epilepsy and parasomnias (FLEP) scale suggest his events could be classified as epilepsy. Therefore we think the FLEP scale might be a useful tool for differential diagnosis in a patient presenting NPD.

Background: The intermittent delta activity in electroencephalographies (EEGs) of patients with focal brain lesions has been reported to be a marker of an epileptogenic focus. This study investigated the concordance between the current source distribution (CSD) of the interictal epileptiform discharges (IEDs) and that of the background delta frequency bands (DFBs) of the scalp EEG. Methods: We collected scalp EEGs of 13 patients with focal epilepsy that contained uniregional IEDs and unilateral delta to theta slow waves. We applied a distributed source model using LORETA? to determine the CSD of the peak points of the IEDs and the DFBs of the background activity. Results: The CSDs of the DFBs were ipsilateral to the CSDs of the peak point of the averaged IEDs in ten patients, and bilateral with ipsilateral predominance in three patients. In the cases with an ipsilateral CSD of the DFB, 8 of 10 patients had concordance of the CSD localization between the averaged IED and the DFB. In the cases with bilateral CSD of the DFB, 2 of 3 patients had concordance of the CSD localization between the averaged IED and the DFB. Conclusions: The CSD localization and lateralization appear to be concordant between the IEDs and the DFB of background activity in epileptic patients. Therefore, the CSD of the DFB in EEGs with visually observable slow activities may predict those of IEDs.

Periodic lateralized epileptiform discharges (PLEDs) had been debated whether it is ictal or non-ictal phenomenon. As mostof PLEDs occur in patients with acute structural lesions, some epileptologists prefer PLEDS as a non-ictal phenomenon,rather an obscure epiphenomenon of etiological diseases. But, almost half of the patients with PLEDs do not have acutestructural lesions in the brain and metabolic disorders or old CNS lesions may cause PLEDs and even more, no brain lesionwas identified in some patients. There are many data supporting PLEDs as ictal phenomena. Occurrence of PLEDs usuallyaccompanied by decreased mentality and is improved as PLEDs disappeared. Current SPECT study showed marked hyperperfusionin the lesion side of PLEDs, that is striking evidence of PLEDs as ictal phenomena. Also careful review of EEGwith PLEDs revealed it is a dynamic process rather than a static state. Despite of these evidences, as PLEDs are an end-stageof animal status epilepticus models, it may be a transition of ictal to interictal state.