Reza Basiri1, Aidin Shariatzadeh2, Samuel Wiebe2, Yahya Aghakhani3. 1. Department of Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. 2. Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. 3. Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. Electronic address: yahya.aghakhani@vch.ca.
Abstract
OBJECTIVE: Interictal epileptiform discharges (IEDs) are important to identify the epileptogenic zone and to define epileptic syndromes. However, not all patients show IEDs on scalp EEG. We evaluate the likelihood of not findings spikes on prolonged Video-EEG Monitoring (VEM) in patients with focal epilepsy, and explore clinical correlates. METHODS: We retrospectively reviewed the VEM reports for all the patients admitted to the seizure monitoring unit in the Calgary Epilepsy Program between July'10 and August'17. Adult focal epilepsy patients, using the diagnostic criteria of the International League Against Epilepsy, who had at least three consecutive VEM days and one recorded seizure were included. Patients were categorized as spikers or non-spikers if any or no spikes were seen on VEM. We compared demographic, neuroimaging, epilepsy risk factor and seizure data. RESULTS: Of 933 patients, 345 fulfilled our eligibility criteria, 17% [55% males] non-spikers and 83% [53% males] spikers. There were no statistically significant differences between non-spikers and spikers in the studied clinical variables at our epilepsy centre. Average age and average duration of epilepsy were 39 and 13 years for non-spikers and 38 and 16 years for spikers. The average duration of VEM was 8-9 days in both groups. The most frequent seizure focus was in the temporal lobe in both groups (53% in non-spikers vs. 64% in spikers, p = 0.06). An epileptogenic lesion on MRI was identified in 26 (46%) of non-spikers and 158 (57%) of spikers (p = 0.16). SIGNIFICANCE: Approximately one out of six patients with focal epilepsy showed no IEDs despite prolonged VEM. There was no significant difference among the investigated clinical variables between these two groups of patients in our epilepsy centre. We hypothesise that patients without IEDs on scalp EEG may have smaller, deeper generators with lower levels of neuronal synchrony, which precludes the expression of high amplitude spikes detectable on scalp EEG.
OBJECTIVE: Interictal epileptiform discharges (IEDs) are important to identify the epileptogenic zone and to define epileptic syndromes. However, not all patients show IEDs on scalp EEG. We evaluate the likelihood of not findings spikes on prolonged Video-EEG Monitoring (VEM) in patients with focal epilepsy, and explore clinical correlates. METHODS: We retrospectively reviewed the VEM reports for all the patients admitted to the seizure monitoring unit in the Calgary Epilepsy Program between July'10 and August'17. Adult focal epilepsypatients, using the diagnostic criteria of the International League Against Epilepsy, who had at least three consecutive VEM days and one recorded seizure were included. Patients were categorized as spikers or non-spikers if any or no spikes were seen on VEM. We compared demographic, neuroimaging, epilepsy risk factor and seizure data. RESULTS: Of 933 patients, 345 fulfilled our eligibility criteria, 17% [55% males] non-spikers and 83% [53% males] spikers. There were no statistically significant differences between non-spikers and spikers in the studied clinical variables at our epilepsy centre. Average age and average duration of epilepsy were 39 and 13 years for non-spikers and 38 and 16 years for spikers. The average duration of VEM was 8-9 days in both groups. The most frequent seizure focus was in the temporal lobe in both groups (53% in non-spikers vs. 64% in spikers, p = 0.06). An epileptogenic lesion on MRI was identified in 26 (46%) of non-spikers and 158 (57%) of spikers (p = 0.16). SIGNIFICANCE: Approximately one out of six patients with focal epilepsy showed no IEDs despite prolonged VEM. There was no significant difference among the investigated clinical variables between these two groups of patients in our epilepsy centre. We hypothesise that patients without IEDs on scalp EEG may have smaller, deeper generators with lower levels of neuronal synchrony, which precludes the expression of high amplitude spikes detectable on scalp EEG.
Authors: Mustafa Aykut Kural; Jin Jing; Franz Fürbass; Hannes Perko; Erisela Qerama; Birger Johnsen; Steffen Fuchs; M Brandon Westover; Sándor Beniczky Journal: Epilepsia Date: 2022-03-07 Impact factor: 6.740
Authors: Zachary Fitzgerald; Marcia Morita-Sherman; Olivia Hogue; Boney Joseph; Marina K M Alvim; Clarissa L Yasuda; Deborah Vegh; Dileep Nair; Richard Burgess; William Bingaman; Imad Najm; Michael W Kattan; Ingmar Blumcke; Gregory Worrell; Benjamin H Brinkmann; Fernando Cendes; Lara Jehi Journal: Epilepsia Date: 2021-08-02 Impact factor: 6.740