scholarly journals Unilateral Blinking: Insights from Stereo-EEG and Tractography

2021 ◽  
Author(s):  
Elisabeth Kaufmann ◽  
Joanna Bartkiewicz ◽  
Nicholas Fearns ◽  
Katharina Ernst ◽  
Christian Vollmar ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Focal Epilepsy ◽  
Contextual Information ◽  
Temporal Region ◽  
Direct Electrical Stimulation ◽  
Probabilistic Tractography ◽  
Drug Resistant ◽  
Presurgical Evaluation ◽  
Ct Data ◽  
Epilepsy Monitoring

AbstractTo study the neuroanatomical correlate of involuntary unilateral blinking in humans, using the example of patients with focal epilepsy. Patients with drug resistant focal epilepsy undergoing presurgical evaluation with stereotactically implanted EEG-electrodes (sEEG) were recruited from the local epilepsy monitoring unit. Only patients showing ictal unilateral blinking or unilateral blinking elicited by direct electrical stimulation were included (n = 16). MRI and CT data were used for visualization of the electrode positions. In two patients, probabilistic tractography with seeding from the respective electrodes was additionally performed. Three main findings were made: (1) involuntary unilateral blinking was associated with activation of the anterior temporal region, (2) tractography showed widespread projections to the ipsilateral frontal, pericentral, occipital, limbic and cerebellar regions and (3) blinking was observed predominantly in female patients with temporal lobe epilepsies. Unilateral blinking was found to be associated with an ipsilateral activation of the anterior temporal region. We suggest that the identified network is not part of the primary blinking control but might have modulating influence on ipsilateral blinking by integrating contextual information.

scholarly journals Ictal Asystole in Drug-Resistant Focal Epilepsy: Two Decades of Experience from an Epilepsy Monitoring Unit

2020 ◽  
Vol 10 (7) ◽  
pp. 443
Author(s):  
Sara Casciato ◽  
Pier Paolo Quarato ◽  
Addolorata Mascia ◽  
Alfredo D’Aniello ◽  
Vincenzo Esposito ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Rare Event ◽  
Cardiac Risk ◽  
Loss Of Consciousness ◽  
Drug Resistant ◽  
Seizure Onset ◽  
Presurgical Evaluation ◽  
History Of ◽  
Epilepsy Monitoring ◽  
Video Eeg

Background: Ictal asystole (IA) is a rare event observed in people with epilepsy (PwE). Clinical and IA video-electroencephalographic findings may be helpful in screening for high-risk subjects. Methods: From all PwE undergoing video-EEG for presurgical evaluation between 2000 and 2019, we retrospectively selected those with at least one IA (R–R interval of ≥3 s during a seizure). Results: IA was detected in eight out of 1088 (0.73%) subjects (mean age: 30 years; mean epilepsy duration: 9.6 years). Four out of them had a history of atonic falls. No patients had cardiac risk factors or cardiovascular diseases. Seizure onset was temporal (n = 5), temporo-parietal (n = 1) or frontal (n = 2), left-sided and right-sided in five and two patients, respectively. In one case a bilateral temporal independent seizure onset was recorded. IA was recorded in 11 out of 18 seizures. Mean IA duration was 13 s while mean IA latency from seizure onset was 26.7 s. Symptoms related to IA were observed in all seizures. Conclusion: IA is a rare and self-limiting event often observed during video-EG in patients with a history of atonic loss of consciousness and/or tardive falls in the course of a typical seizure.

scholarly journals Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation (SEEG-Guided RF-TC) in Patients with Drug-Resistant Focal Epilepsy

2017 ◽  
Vol 3 (1) ◽  
pp. 40-47
Author(s):  
Chengwei Xu ◽  
Wenjing Zhou
Keyword(s):  
Radio Frequency ◽  
Surgical Resection ◽  
Seizure Frequency ◽  
Palliative Treatment ◽  
Focal Epilepsy ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Functional Area ◽  
Presurgical Evaluation ◽  
Epileptic Patients

For some patients with drug-resistant focal epilepsy, we usually select conventional surgical resection, which has brought better outcomes. However, others are not eligible for a conventional open surgical resection of the epileptogenic zone because of the proximity of a functional area or the implication of a larger epileptogenic network. Initially, stereoelectroencephalography (SEEG) exploration was a method of electroencephalography recording that was used in the presurgical evaluation of epileptic patients with complex epilepsy. Later, intracerebral electrodes used for SEEG were applied to produce radio frequency thermocoagulation (RF-TC) in epileptic patients. SEEG-guided RF-TC has produced some promising results, especially in the last dacade. Now, it has become popular as a palliative treatment to reduce seizure frequency in patients with drug-resistant focal epilepsy. This article presents a review of SEEG-guided RF-TC.

A rapid and reliable procedure to localize subdural electrodes in presurgical evaluation of patients with drug-resistant focal epilepsy

2006 ◽  
Vol 117 (2) ◽  
pp. 341-347 ◽  
Author(s):  
F. Sebastiano ◽  
G. Di Gennaro ◽  
V. Esposito ◽  
A. Picardi ◽  
R. Morace ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Drug Resistant ◽  
Presurgical Evaluation ◽  
Subdural Electrodes ◽  
Reliable Procedure

Stereoelectroencephalography in the presurgical evaluation of children with drug-resistant focal epilepsy

2005 ◽  
Vol 103 (4) ◽  
pp. 333-343 ◽  
Author(s):  
Massimo Cossu ◽  
Francesco Cardinale ◽  
Nadia Colombo ◽  
Roberto Mai ◽  
Lino Nobili ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Drug Resistant ◽  
Presurgical Evaluation

Transient hypoxemia induced by cortical electrical stimulation

Neurology ◽  
2020 ◽  
Vol 94 (22) ◽  
pp. e2323-e2336
Author(s):  
Marine Loizon ◽  
Philippe Ryvlin ◽  
Benoit Chatard ◽  
Julien Jung ◽  
Romain Bouet ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Primary Outcome ◽  
Focal Epilepsy ◽  
Direct Electrical Stimulation ◽  
Limbic Structures ◽  
Individual Effects ◽  
Cortical Electrical Stimulation ◽  
Eeg Recordings ◽  
Cortical Regions ◽  
Stimulation Of

ObjectiveTo identify which cortical regions are associated with direct electrical stimulation (DES)–induced alteration of breathing significant enough to impair pulse oximetry (SpO2).MethodsEvolution of SpO2 after 1,352 DES was analyzed in 75 patients with refractory focal epilepsy who underwent stereo-EEG recordings. For each DES, we assessed the change in SpO2 from 30 seconds prior to DES onset to 120 seconds following the end of the DES. The primary outcome was occurrence of stimulation-induced transient hypoxemia as defined by decrease of SpO2 ≥5% within 60 seconds after stimulation onset as compared to pre-DES SpO2 or SpO2 nadir <90% during at least 5 seconds. Localization of the stimulated contacts was defined according to MarsAtlas brain parcellation and Freesurfer segmentation.ResultsA stimulation-induced transient hypoxemia was observed after 16 DES (1.2%) in 10 patients (13%), including 6 in whom SpO2 nadir was <90%. Among these 16 DES, 7 (44%) were localized within the perisylvian cortex. After correction for individual effects and the varying number of DES contributed by each person, significant decrease of SpO2 was significantly associated with the localization of DES (p = 0.019).ConclusionThough rare, a significant decrease of SpO2 could be elicited by cortical direct electrical stimulation outside the temporo-limbic structures, most commonly after stimulation of the perisylvian cortex.

Spatial distribution and hemispheric asymmetry of electrically evoked experiential phenomena in the human brain

2020 ◽  
Vol 133 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Michal M. Andelman-Gur ◽  
Tomer Gazit ◽  
Fani Andelman ◽  
Svetlana Kipervasser ◽  
Uri Kramer ◽  
...  
Keyword(s):  
Neural Networks ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Functional Organization ◽  
Focal Epilepsy ◽  
Drug Resistant ◽  
Visual Hallucinations ◽  
Presurgical Evaluation ◽  
Temporal Lobes ◽  
The Right

OBJECTIVEExperiential phenomena (EP), such as illusions and complex hallucinations, are vivid experiences created in one’s mind. They can occur spontaneously as epileptic auras or can be elicited by electrical brain stimulation (EBS) in patients undergoing presurgical evaluation for drug-resistant epilepsy. Previous work suggests that EP arise from activation of different nodes within interconnected neural networks mainly in the temporal lobes. Yet, the anatomical extent of these neural networks has not been described and the question of lateralization of EP has not been fully addressed. To this end, an extended number of brain regions in which electrical stimulation elicited EP were studied to test whether there is a lateralization propensity to EP phenomena.METHODSA total of 19 drug-resistant focal epilepsy patients who underwent EBS as part of invasive presurgical evaluation and who experienced EP during the stimulation were included. Spatial dispersion of visual and auditory illusions and complex hallucinations in each hemisphere was determined by calculation of Euclidean distances between electrodes and their centroid in common space, based on (x, y, z) Cartesian coordinates of electrode locations.RESULTSIn total, 5857 stimulation epochs were analyzed; 917 stimulations elicited responses, out of which 130 elicited EP. Complex visual hallucinations were found to be widely dispersed in the right hemisphere, while they were tightly clustered in the occipital lobe of the left hemisphere. Visual illusions were elicited mostly in the occipital lobes bilaterally. Auditory illusions and hallucinations were evoked symmetrically in the temporal lobes.CONCLUSIONSThese findings suggest that complex visual hallucinations arise from wider spread in the right compared to the left hemisphere, possibly mirroring the asymmetry in the white matter organization of the two hemispheres. These results offer some insights into lateralized differences in functional organization and connectivity that may be important for functional mapping and planning of surgical resections in patients with epilepsy.

Stereoelectroencephalography in the presurgical evaluation of focal epilepsy in infancy and early childhood

2012 ◽  
Vol 9 (3) ◽  
pp. 290-300 ◽  
Author(s):  
Massimo Cossu ◽  
Marco Schiariti ◽  
Stefano Francione ◽  
Dalila Fuschillo ◽  
Francesca Gozzo ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Brain Mri ◽  
Electrode Placement ◽  
Motor Deficit ◽  
Epileptogenic Zone ◽  
Drug Resistant ◽  
Presurgical Evaluation ◽  
Intracranial Surgery ◽  
Eloquent Areas ◽  
Drug Resistant Epilepsy

Object The authors report on the use of stereoelectroencephalography (stereo-EEG) in the presurgical electroclinical evaluation of infants and very young children with focal drug-resistant epilepsy. Methods Fifteen patients (9 girls and 6 boys, mean age 34.1 ± 7.3 months, range 21–45 months), potentially candidates to receive surgical treatment for their focal drug-resistant epilepsy, were evaluated using stereo-EEG recording for a detailed definition of the epileptogenic zone. Stereoelectroencephalography was indicated because neuroradiological (brain MRI) and video-EEG data failed to adequately localize the epileptogenic zone. Stereotactic placement of multicontact intracerebral electrodes was preceded by the acquisition of all pertinent anatomical information from structural and functional MRI and from brain angiography, enabling the accurate targeting of desired structures through avascular trajectories. Stereoelectroencephalography monitoring attempted to record habitual seizures; electrical stimulations were performed to induce seizures and for the functional mapping of eloquent areas. Stereoelectroencephalography-guided microsurgery, when indicated, pointed to removal of the epileptogenic zone and seizure control. Results Brain MRI revealed an anatomical lesion in 13 patients (lobar in 2 cases, multilobar or hemispheric in 11 cases) and was unremarkable in 2 patients. One patient underwent 2 stereo-EEG studies. The arrangement of the intracerebral electrodes was unilateral in all but 1 case. One patient died the day following electrode placement due to massive brain edema and profound hyponatremia of undetermined cause. In 8 cases intracerebral electrical stimulations allowed mapping of functionally critical areas; in 3 other cases that received purposeful placement of electrodes in presumably eloquent areas, no functional response was obtained. Of the 14 patients who completed stereo-EEG monitoring, 1 was excluded from surgery for multifocality of seizures and 13 underwent operations. Postoperatively, 2 patients exhibited an anticipated, permanent motor deficit, 3 experienced a transient motor deficit, and 2 experienced transient worsening of a preexisting motor deficit. Three patients developed a permanent homonymous hemianopia after posterior resections. Histological analysis revealed cortical malformations in 10 cases. Of the 10 patients with a postoperative follow-up of at least 12 months, 6 (60%) were seizure-free (Engel Class Ia), 2 (20%) experienced a significant reduction of seizures (Engel Class II), and 2 (20%) were unchanged (Engel Class IV). Conclusions The present study indicates that stereo-EEG plays a prominent role in the presurgical evaluation of focal epilepsies also in the first years of life and that it may offer a surgical option in particularly complex cases that would have scarcely benefitted from further medical treatment. Results of stereo-EEG–guided resective surgery were excellent, with 80% of patients exhibiting a substantial improvement in seizures. In consideration of the potentially life-threatening risks of major intracranial surgery in this specific age group, the authors recommend reserving stereo-EEG evaluations for infants with realistic chances of benefiting from surgery.

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