Clinical Neuroscience

The yield of electroencephalography in syncope

NALBANTOGLU Mecbure1, TAN Ozturk Ozlem2

MARCH 30, 2019

Clinical Neuroscience - 2019;72(03-04)


Introduction - Syncope is defined as a brief transient loss of consciousness due to cerebral hypoperfusion. Although the diagnosis of syncope is based on a thorough history and examination, electroencaphalography (EEG) is also an important investigational tool in the differential diagnosis in this group of patients. In this study we aimed to identify the diagnostic value of EEG in patients with syncope. Methods - We retrospectively examined EEG recordings of 288 patients with the diagnosis of syncope referred to the Cankiri State Hospital EEG laboratory, from January 2014 to January 2016. The EEG findings were classified into 6 groups as normal, epileptiform discharges (spike and sharp waves), generalized background slowing, focal slowing, hemispherical asymmetries, and low amplitude EEG tracing. The EEGs were separated according to gender and age. Results - Total of 288 patients were included in this study, 148 were females (51.4%) and 140 (48.6%) were males. Among all the EEG reports, 203 (70.5%) were normal, 8 of them (2.8%) showed generalized background slowing and 7 (2.4%) demonstrated focal slow waves. Epileptiform discharges occured among 13 patients (4.5%). Hemispherical asymmetries were detected in 10 patients (3.5%) and low amplitude EEG tracing in 47 patients (16.3%). There was no significant difference between age groups in EEG findings (p=0.3). Also no significant difference was detected in EEG results by gender (p=0.2). Discussion - Although the diagnosis of syncope, epilepsy and non-epileptic seizures is clinical diagnosis, EEG still remains additional method


  1. Istanbul Bilim University Medical Faculty, Neurology Department, Istanbul, Turkey
  2. Ankara Numune Training and Research Hospital, Neurology Department, Ankara, Turkey



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[Sturge Weber syndrome is the third most common neurocutaneous syndrome after neurofibromatosis and tuberous sclerosis. Three distinct types were identified. Type 3 with leptomeningeal involvement alone is the rarest among other types. The reported case is a 21-years-old female patient without any known chronic disease. She admitted to the emergency department after visual symptoms and headache, followed by generalized tonic clonic seizure. EEG of the patient showed left occipital seizure activity. The contrast enhanced magnetic resonance imaging (MRI) showed left occipital leptomeningeal angioma. Digital substraction angiography (DSA) revealed minimal blushed contrast enhancement on late venous phase and lack of superficial cortical veins. Her focal seizures were under control with levatiracetam and lacosamide treatment. The reported case is unique because of the late onset presentation with focal seizure without mental retardation.]

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Objective - to investigate the neurophysiological basis of secondary generalization of partial epileptic seizures. Patients and methods - inter-ictal, resting-state EEG functional connectivity (EEGfC) was evaluated and compared: patients with exclusively simple partial seizures (sp group) were compared to patients with simple partial and secondary generalized seizures (spsg group); patients with exclusively complex partial seizures (cp group) were compared to patients with cp and secondary generalized seizures (cpsg group); the collapsed sp+cp group (spcp) was compared to those who had exclusively secondary generalized seizures (sg group). EEGfC was computed from 21-channel waking EEG. 3 minutes of waking EEG background activity was analyzed by the LORETA Source Correlation (LSC) software. Current source density time series were computed for 23 pre-defined cortical regions (ROI) in each hemisphere, for the 1-25 Hz very narrow bands (1 Hz bandwidth). Thereafter Pearson correlation coefficients were calculated between all pairs of ROI time series in the same hemisphere. Z-scored correlation coefficients were compared at the group level (t-tests and correction for multiple comparisons by local false discovery rate, FDR). Results - Statistically significant (corrected p<0.05) EEGfC differences emerged at specific frequencies (spsg > sg; cpsg > cp), and at many frequencies (sg > spcp). The findings indicated increased coupling between motor cortices and several non-motor areas in patients with partial and sg seizures as compared to patients with partial seizures and no sg seizures. Further findings suggested increased coupling between medial parietal-occipital areas (structural core of the cortex) and lateral hemispheric areas. Conclusion - increased inter-ictal EEGfC is associated with habitual occurrence of secondary generalized seizures.

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Clinical Neuroscience

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