Evaluation of electroencephalographic changes in patients with the new onset suspicious seizure movements

Background: Abnormal EEG is a predictor of seizure relapse. Obtaining data related to the diagnosis and outcome of the first seizures is necessary for improving care for these patients, whereas data for these studies is scarce and is limited to a few a few centres. The aim was evaluation of the EEG changes in patients with first suspicious movements of seizure.Methods: All of the patients with first suspicious movements of seizure referred to Alavi hospital of Ardabil from March 2019 to March 2020 enrolled in this study. Data including age, gender, etiology of the seizure, seizure type and EEG changes gathered. Collected data were analyzed by statistical methods in SPSS version 21.Results: 71 patients were studied. Based on the seizure type, 50 (70.4%) patients had motor, 10 (14.1%) patients had nonmotor and 11 (15.5%) patients had focal seizures type impaired awareness. EEG findings were normal in 46 patients (64.8%). There were slowing waves and epileptic discharge in 12 (16.9%) and 13 (18.3%) patients, respectively. Abnormal EEGs recorded in routine modality in 16 patients (64%), H. V. modality in 2 patients (8%), Ph. S. modality in 2 patients (8%) and both routine and excitatory modalities in 5 (20%) patients.Conclusions: There was not a significant relationship between EEG findings and age, gender, seizure etiology and seizure type. Also there was not a significant relationship between abnormal waves in different modalities and type and etiology of the seizures.

Reduction of spike generation frequency by cooling in brain slices from rats and from patients with epilepsy

This study aimed to understand the mechanism by which brain cooling terminates epileptic discharge. Cortical slices were prepared from rat brains (n = 19) and samples from patients with intractable epilepsy that had undergone temporal lobectomy (n = 7). We performed whole cell current clamp recordings at approximately physiological brain temperature (35℃) and at cooler temperatures (25℃ and 15℃). The firing threshold in human neurons was lower at 25℃ (−32.6 mV) than at 35℃ (−27.0 mV). The resting potential and spike frequency were similar at 25℃ and 35℃. Cooling from 25℃ to 15℃ did not change the firing threshold, but the resting potential increased from −65.5 to −54.0 mV and the waveform broadened from 1.85 to 6.55 ms, due to delayed repolarization. These changes enhanced the initial spike appearance and reduced spike frequency; moreover, spike frequency was insensitive to increased levels of current injections. Similar results were obtained in rat brain studies. We concluded that the reduction in spike frequency at 15℃, due to delayed repolarization, might be a key mechanism by which brain cooling terminates epileptic discharge. On the other hand, spike frequency was not influenced by the reduced firing threshold or the elevated resting potential caused by cooling.