Baris Baklan

Automatic detection of epileptiform events in EEG by a three-stage procedure based on artificial neural networks

This paper introduces a three-stage procedure based on artificial neural networks for the automatic detection of epileptiform events (EVs) in a multichannel electroencephalogram (EEG) signal. In the first stage, two discrete perceptrons fed by six features are used to classify EEG peaks into three subgroups: 1) definite epileptiform transients (ETs); 2) definite non-ETs; and 3) possible ETs and possible non-ETs. The pre-classification done in the first stage not only reduces the computation time but also increases the overall detection performance of the procedure. In the second stage, the peaks falling into the third group are aimed to be separated from each other by a nonlinear artificial neural network that would function as a postclassifier whose input is a vector of 41 consecutive sample values obtained from each peak. Different networks, i.e., a backpropagation multilayer perceptron and two radial basis function networks trained by a hybrid method and a support vector method, respectively, are constructed as the postclassifier and then compared in terms of their classification performances. In the third stage, multichannel information is integrated into the system for contributing to the process of identifying an EV by the electroencephalographers (EEGers). After the integration of multichannel information, the overall performance of the system is determined with respect to EVs. Visual evaluation, by two EEGers, of 19 channel EEG records of 10 epileptic patients showed that the best performance is obtained with a radial basis support vector machine providing an average sensitivity of 89.1%, an average selectivity of 85.9%, and a false detection rate (per hour) of 7.5.

Childhood and juvenile onset multiple sclerosis: clinical and paraclinical features

It is well known that multiple sclerosis (MS) is a demyelinating disease of the central nervous system that mostly starts in the second to third decade. In the present study, we reviewed our own observations of the clinical and paraclinical features in the 36 of 890 (4.04%) MS patients whose symptoms started before 16 years of age. The average age at onset of the disease in these 36 patients was 12.9 years. In 18 patients, the disease onset was monosymptomatic. Diplopia and sensory disturbances were the most common initial manifestations and occurred in 27.7% of cases. Twenty-one patients (59%) had a relapsing and 11 patients (30.5%) had a secondary progressive course. On the last evaluation, the EDSS score was above 5 in 11 patients and it was below 5 in 21 patients. As a result of this study, we concluded that childhood onset MS does not significantly differ from that it has been typically seen in adults in terms of major clinical manifestations and course of disease.

Motor cortical thresholds and cortical silent periods in epilepsy.

We studied motor cortical thresholds (TIs) and cortical silent periods (SPs) evoked by transcranial magnetic stimulation (TMS) in 110 epileptic patients. Sixty-two had primary generalised, 48 had partial type seizures. Fifteen out 110 patients were analysed both before and after anticonvulsant medication. Our aims were to evaluate the TI levels and the duration of SPs in patients with epilepsy and to determine the reliability of TMS in patients with epilepsy. There was no negative effect of TMS on the clinical status and EEG findings in patients with epilepsy. TIs obtained from patients with partial epilepsy were higher than those obtained from both controls and primary epileptics. The duration of SP in patients with primary epileptics was more prolonged than those obtained from controls. There was no correlation between EEG lateralisation and both SP duration and TI values. In de novo patient group, SP duration was significantly prolonged after anticonvulsant medication. We concluded that TMS is a reliable electrophysiological investigation in patients with epilepsy. The analysis of SP duration may be an appropriate investigation in monitoring the effect of anticonvulsant medication on the cortical inhibitory activity.

Headache in Sleep Apnea Syndrome

Objective.—To find out whether there is a relationship between the headache characteristics and polysomnographic findings in patients with prediagnosis of the sleep apnea syndrome (SAS) and, if there is, to search for its possible cause.

MRI follow-up of basal ganglia involvement in subacute sclerosing panencephalitis

A 12-year-old male with subacute sclerosing panencephalitis is presented. Magnetic resonance imaging revealed basal ganglia involvement without white matter changes for several months. Basal ganglia changes are not infrequent in subacute sclerosing panencephalitis, but they tend to appear in advanced clinical stages. Prominent basal ganglia involvement may occur very rarely in subacute sclerosing panencephalitis. In our patient, serial magnetic resonance imaging demonstrated the involvement of white matter after 2 years of magnetic resonance imaging follow-up. In contrast with the neuroradiologic progression, our patients clinical status remained stable.

Phe 84 deletion of the PMP22 gene associated with hereditary motor and sensory neuropathy HMSN III with multiple cranial neuropathy: clinical, neurophysiological and magnetic resonance imaging findings

Abstracts Hereditary motor and sensory neuropathy (HMSN) is a heterogeneous group of peripheral neuropathies which are diagnosed on the basis of clinical, electrophysiological and neuropathological findings. Among the hypertrophic demyelinating neuropathies, HMSN III is the most severe. It is often associated with de novo mutations in the genes encoding for peripheral myelin proteins. While peripheral nerve hypertrophy is an expected finding in HMSN III, cranial nerve hypertrophy is exceptional. Here we describe a mutation in the PMP22 gene in a 19-year-old man with infantile onset of sensory motor polyneuropathy without family history and multiple cranial nerve hypertrophy shown by cranial magnetic resonance imaging.

Thyroxine-induced hypermotor seizure

Thyroxine-induced epilepsy is a very rare condition occurring in epileptic patients. Here we report a boy with thyroxine-induced hypermotor seizure (HMS) following thyroxine administration for his central hypothyroidism secondary to surgery and cranial radiation for his brain tumor. After 3 years seizure-free period, he had repeated HMS, seven to eight attacks per day, after initiation L-thyroxine treatment. Following reduction of the daily thyroxine dose, his seizures decreased in frequency. To our knowledge, this is the first reported case of HMS associated with L-thyroxine administration.

Determinants of felt stigma in epilepsy.

The present study aimed to determine the level of felt stigma, overprotection, concealment, and concerns related to epilepsy in different life domains by using culturally-specific scales for Turkish individuals with epilepsy. Also, it aimed to detect relations among the study variables and to determine the variables which predict felt stigma. For this purpose, felt stigma scale, overprotection scale, concealment of epilepsy scale, and concerns of epilepsy scale were administered to two hundred adult persons with epilepsy (PWE). The results showed that almost half of the participants reported felt stigma, overprotection, concealment of epilepsy, concerns related to future occupation, and concerns related to social life. Almost all the study variables show correlations with each other. Concealment of epilepsy, concerns related to social life, and concerns related to future occupation were found as the predictors of felt stigma.

A case report of surgically treated drug resistant epilepsy associated with subependymal nodular heterotopia

Subependymal nodular heterotopia (SNH) is a cortical development malformation that is commonly associated with medically resistant epilepsy. Cases of SNH are challenging to treat surgically because there are typically multiple nodules, which may be involved in epileptogenesis. Moreover, dual pathology may exist in these patients. Here, we present a case with unilateral subependymal heterotopic nodules associated with ipsilateral hippocampal atrophy. Invasive and non-invasive work-ups revealed that the hippocampus was the actual ictal onset zone and that the SNH was not involved. An anterior temporal lobectomy was carried out, and postoperative seizure outcome was class Ia at the end of 2 years. The case demonstrates that SNH may not play a major role in patients with dual pathology. However, direct electroencephalography (EEG) recording from areas of SNH and other possible epileptogenic regions is indispensable in defining the ictal onset zone and avoiding poor surgical outcomes.

Mesencephalic cavernoma causing reversible nuclear third nerve palsy and obstructive hydrocephalus

We present a case of mesencephalic cavernoma, which caused various interesting clinical symptoms. A 58-year-old man was admitted to the emergency unit with a history of sudden, bilateral ptosis. Neurological examination revealed bilateral ptosis-limited elevation of both eyes, limited depression and adduction of the left eye, and a monocular abducting nystagmus in the right eye. Computed tomography showed a small hematoma in the mesencephalon and magnetic resonance imaging revealed a cavernoma with a hemorrhage. The patient was treated conservatively. Three months later, his bilateral ptosis had resolved and both the depression and the adduction of the left eye had improved. A year later, ocular motility had normalized. He subsequently presented with obstructive hydrocephalus, which was resolved with endoscopic third ventriculostomy.