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SUMMARYObjective: Automatic detection of generalized tonic-clonic seizures (GTCS) will facilitate patient monitoring and early intervention to prevent comorbidities, recurrent seizures, or death. Brain Sentinel (San Antonio, Texas, USA) developed a seizure-detection algorithm evaluating surface electromyography (sEMG) signals during GTCS. This study aims to validate the seizure-detection algorithm using inpatient video-electroencephalography (EEG) monitoring. Methods: sEMG was recorded unilaterally from the biceps/triceps muscles in 33 patients (17white/16 male) with a mean age of 40 (range 14-64) years who were admitted for video-EEG monitoring. Maximum voluntary biceps contraction was measured in each patient to set up the baseline physiologic muscle threshold. The raw EMG signal was recorded using conventional amplifiers, sampling at 1,024 Hz and filtered with a 60 Hz noise detection algorithm before it was processed with three band-pass filters at pass frequencies of 3-40, 130-240, and 300-400 Hz. A seizure-detection algorithm utilizing Hotelling's T-squared power analysis of compound muscle action potentials was used to identify GTCS and correlated with video-EEG recordings. Results: In 1,399 h of continuous recording, there were 196 epileptic seizures (21 GTCS, 96 myoclonic, 28 tonic, 12 absence, and 42 focal seizures with or without loss of awareness) and 4 nonepileptic spells. During retrospective, offline evaluation of sEMG from the biceps alone, the algorithm detected 20 GTCS (95%) in 11 patients, averaging within 20 s of electroclinical onset of generalized tonic activity, as identified by video-EEG monitoring. Only one false-positive detection occurred during the postictal period following a GTCS, but false alarms were not triggered by other seizure types or spells. Significance: Brain Sentinel's seizure detection algorithm demonstrated excellent sensitivity and specificity for identifying GTCS recorded in an epilepsy monitoring unit. Further studies are needed in larger patient groups, including children, especially in the outpatient setting.

Summary:Purpose: Focal cerebral cooling has been shown to reduce epileptiform activity in animals. There are, however, few reports of this phenomenon in humans.Methods: Electrocorticography was performed before resection of a right frontal tumor in a patient with partial seizures. Cold saline was applied to the interictal spike focus, and its effect on the epileptiform discharges was observed.Results: Application of cold saline to the spike focus resulted in a transient, complete cessation of spiking. This effect was reproduced with a second application of cold saline. The motor threshold for electrical stimulation remained unchanged during the application of saline.Conclusions: In this patient with tumor-related epilepsy, focal cooling of the cortex reproducibly abolished interictal epileptiform discharges without changing the motor threshold to electrical stimulation.

Summary:Purpose: We evaluated visual patterns and source localization of ictal magnetoencephalography (MEG) in patients with intractable temporal lobe epilepsy (TLE) and extratemporal epilepsy (ETE).Methods: We performed spike and seizure recording simultaneously with EEG and MEG on two patients with TLE and five patients with ETE. Scalp EEG was recorded from 21 channels (10-20 international system), whereas MEG was recorded from two 37-channel sensors. We compared ictal EEG and MEG onset, frequency, and evolution and performed MEG dipole source localization of interictal spikes and early ictal discharges and coregistered dipoles to brain magnetic resonance imaging (MRI). We correlated dipole characteristics with intracranial EEG, surgical resection, and outcome.Results: Ictal MEG lateralized seizure onset in both TLE patients and demonstrated ictal onset, frequency, and evolution in accordance with EEG. Ictal MEG source analysis revealed tangential vertical dipoles in the anterolateral angle in one patient, and anterior dipoles with anteroposterior orientation in the other. Intracranial EEG revealed regional entorhinal seizure onset in the first patient. Both patients became seizure free after temporal lobectomy. In ETE, ictal MEG demonstrated visual patterns similar to ictal EEG and had concordant localization with interictal MEG in all five patients. Two patients underwent surgery. Ictal MEG localization was concordant with intracranial EEG in both cases. One patient had successful outcome after surgery. The second patient did not improve after limited resection and multiple subpial transections.Conclusions: Ictal MEG can demonstrate ictal onset frequency and evolution and provide useful localizing information before epilepsy surgery. Key Words: MEG-IctalTemporal-Extratemporal-Epilepsy.Source-localization techniques of EEG and magnetoencephalography (MEG) in epilepsy have been useful in providing noninvasive localizing information in evaluating intractable temporal lobe epilepsy (TLE) and extratemporal epilepsy (ETE) for epilepsy surgery (1). Many studies have demonstrated the value of MEG source localization of interictal spikes in determining the seizure focus in TLE (2-17) and ETE (13-18). Ictal rhythms, however, are believed to have more localizing value than do interictal spikes (19,20). Ictal MEG recording is rare because many MEG studies have been performed on epilepsy outpatients with therapeutic anticonvulsant (AED) levels and because of the logistic difficulty with prolonged patient recording in the MEG laboratory (1). Thus only limited reports exist of ictal MEG recordings of seizures in intractable TLE and ETE (21-25).Sutherling et al. (21) with TLE and two other patients with ETE and concluded that ictal MEG and EEG discharges have a similar frequency. Stefan et al. (22) reported on interictal and ictal MEG recording from three patients, of whom two patients had TLE, and one patient had frontal lobe epilepsy. The source localization by MEG was concordant with electrocorticography and imaging stu...

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Precise control of neuronal migration is essential for proper function of the brain. Taking a forward genetic screen, we isolated a mutant mouse with defects in interneuron migration. By genetic mapping, we identified a frame shift mutation in the pericentrin (Pcnt) gene. The Pcnt gene encodes a large centrosomal coiled-coil protein that has been implicated in schizophrenia. Recently, frame shift and premature termination mutations in the pericentrin (PCNT) gene were identified in individuals with Seckel syndrome and microcephalic osteodysplastic primordial dwarfism (MOPD II), both of which are characterized by greatly reduced body and brain sizes. The mouse Pcnt mutant shares features with the human syndromes in its overall growth retardation and reduced brain size. We found that dorsal lateral ganglionic eminence (dLGE)-derived olfactory bulb interneurons are severely affected and distributed abnormally in the rostral forebrain in the mutant. Furthermore, mutant interneurons exhibit abnormal migration behavior and RNA interference knockdown of Pcnt impairs cell migration along the rostal migratory stream (RMS) into the olfactory bulb. These findings indicate that pericentrin is required for proper migration of olfactory bulb interneurons and provide a developmental basis for association of pericentrin function with interneuron defects in human schizophrenia.

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