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Electrophysiological Sequelae of Hemispherotomy in Ipsilateral Human Cortex
Ammar H Hawasli1, Ravi Chacko2, Nicholas P Szrama2
1Department of Neurological Surgery, Washington University School of MedicineSaint Louis, MO, USA.
Frontiers in Human Neuroscience
|April 21, 2017
Summary
Hemispherotomy, a surgery for epilepsy, alters brain activity differently in peri-stroke versus dysplastic cortex. It reduces brain signal power in peri-stroke areas but increases it in dysplastic areas, affecting information transfer and connectivity.
Area of Science:
- Neurosurgery
- Epileptology
- Neurophysiology
Background:
- Hemispherotomy is a surgical treatment for medically refractory epilepsy.
- It involves disconnecting a cerebral hemisphere, primarily for diffuse hemispheric diseases.
- The electrophysiological impact on the ipsilateral hemisphere is not well understood.
Purpose of the Study:
- To evaluate the electrophysiological effects of hemispherotomy.
- To compare effects in peri-stroke cortex versus dysplastic cortex.
Main Methods:
- Intraoperative electrocorticography (ECoG) was recorded from 5 epilepsy patients.
- ECoG data were analyzed for power spectral density, mutual information, and phase-amplitude coupling.
- Analysis was performed before and after hemispherotomy.
Main Results:
- Hemispherotomy reduced broad-band power in peri-stroke cortex but increased low/high-frequency power in dysplastic cortex.
- Functional connectivity increased in lower frequencies in peri-stroke tissue; no change in dysplastic tissue.
- Phase-amplitude coupling decreased in peri-stroke cortex but was unaffected in dysplastic cortex.
Conclusions:
- Hemispherotomy attenuates oscillations and information transfer in peri-stroke cortex.
- It reduces heterogeneity in peri-stroke cortex but impairs phase-amplitude coupling.
- Dysplastic cortex exhibits different network dysfunction, leading to distinct responses to hemispherotomy.
