Nonhabitual Seizures in Patients with Implanted Subdural Electrodes

Fountas, Kostas N.; King, Donald W.; Jenkins, Patrick; Smith, Joseph R.

doi:10.1159/000081881

Cited by 22 publications

(13 citation statements)

References 48 publications

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“…Our finding has been previously reported in a smaller clinical series and explanations as to the possible pathophysiologic mechanisms implicated in the pathogenesis of this finding have been explored [3] . Malow et al [34] have reported a case of recording nonhabitual seizures in a patient with a SDH caused by a subdural grid implantation.…”

Section: Discussionsupporting

confidence: 79%

Subdural Electrode-Associated Complications: A 20-Year Experience

Fountas

Smith

2007

Stereotact Funct Neurosurg

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Background: Implantation of subdural strip and grid electrodes is a common methodology in the invasive evaluation of patients with medically refractory epilepsy. Although their implantation is safe, the occurrence of implantation-associated complications can occasionally be troublesome. Methods: In our current retrospective study, 185 patients undergoing subdural grid/strip implantation for invasive monitoring were examined. Their ages ranged between 16 and 48 years (mean 23.6). AdTech (Racine, Wisc., USA) strip and grid electrodes were implanted under general endotracheal anesthesia in all our cases. Duration of electroencephalographic monitoring ranged from 2 to 25 days (mean 10.8). The follow-up period ranged from 24 to 60 months (mean 44.6 months). Results: The most common complication in our series was the development of postoperative epidural hematoma in 3 patients (1.6%), while 2 patients (1.1%) suffered a subdural hematoma. Two patients (1.1%) developed significant brain edema postoperatively, 2 others (1.1%) developed an infection, while 2 patients (1.1%) experienced transient aphasia. Two patients (1.1%) had fatal outcomes in our series. Interestingly, in 5 patients (2.7%) nonhabitual seizures were recorded. Conclusion: Thorough understanding, early identification and prompt management of potential complications can minimize the risks associated with the implantation of subdural electrodes.

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Section: Discussionsupporting

confidence: 79%

Subdural Electrode-Associated Complications: A 20-Year Experience

Fountas

Smith

2007

Stereotact Funct Neurosurg

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“…Acute implantation can induce interictal epileptiform activity and seizures that do not accurately represent a patient’s underlying disorder 43,44 . This may be a result of direct effects, such as of trauma, electrode contact with the cortical tissue, or complications of electrode placement such as hemorrhage, fluid collections or cerebral edema 44 .…”

Section: Discussionmentioning

confidence: 99%

Intracranial EEG fluctuates over months after implanting electrodes in human brain

et al. 2017

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Objective Implanting subdural and penetrating electrodes in the brain cause acute trauma and inflammation that affect intracranial electroencephalographic (iEEG) recordings. This behavior and its potential impact on clinical decision-making and algorithms for implanted devices have not been assessed in detail. In this study we aim to characterize the temporal and spatial variability in continuous, prolonged human iEEG recordings. Approach Intracranial electroencephalography from 15 patients with drug-refractory epilepsy, each implanted with 16 subdural electrodes and continuously monitored for an average of 18 months, was included in this study. Time and spectral domain features were computed each day for each channel for the duration of each patient’s recording. Metrics to capture post-implantation feature changes and inflexion points were computed on group and individual levels. A linear mixed model was used to characterize transient group-level changes in feature values post-implantation and independent linear models were used to describe individual variability. Main Results A significant decline in features important to seizure detection and prediction algorithms (mean line length, energy, and half-wave), as well as mean power in the Berger and high gamma bands, was observed in many patients over 100 days following implantation. In addition, spatial variability across electrodes declines post-implantation following a similar timeframe. All selected features decreased by 14–50% in the initial 75 days of recording on the group level, and at least one feature demonstrated this pattern in 13 of the 15 patients. Our findings demonstrate that iEEG signal features demonstrate increased variability following implantation, most notably in the weeks immediately post-implant. Significance These findings suggest that conclusions drawn from iEEG, both clinically and for research, should account for signal variability and that properly assessing the iEEG in patients, depending upon the application, may require extended monitoring.

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“…If present before resection, these symptoms are transient. New seizure patterns can develop due to cortical compression or contusion and if not properly identified lead to mis-localization of the epileptogenic focus; this may be related to subdural hematoma under the plates [42,43].…”

Section: Complicationsmentioning

confidence: 99%