Stjepana Kovac1, Catherine A Scott2, Vesela Maglajlija2, Nathan Toms2, Roman Rodionov3, Anna Miserocchi3, Andrew W McEvoy3, Beate Diehl4. 1. Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Department of Neurology, University of Muenster, Muenster, Germany. 2. Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. 3. Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. 4. Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. Electronic address: b.diehl@ucl.ac.uk.
Abstract
OBJECTIVE: Extraoperative cortical stimulation (CS) for mapping of eloquent cortex in patients prior to epilepsy surgery is not standardized across centres. Two different techniques are in use, referred to as bipolar and monopolar CS. We compared the ability of bipolar versus monopolar CS to identify eloquent cortex and their safety profile in patients undergoing subdural EEG recordings. METHODS: Five patients undergoing intracranial EEG recordings and extraoperative CS. Systematic comparison of stimulus parameters, clinical signs and afterdischarges of bipolar versus monopolar CS. RESULTS: Bipolar CS requires less stimulation current but is more time consuming and more likely to produce afterdischarges when compared to monopolar CS. None of the stimulations elicited seizures. The area defined as eloquent by either bipolar or monopolar CS reveals only minor discordances, involving mainly the outer row and edge of the electrode array producing clinical signs with monopolar CS only. Qualitatively, bi- and monopolar CS reproduced similar movements and types of muscle contractions. CONCLUSIONS: Bipolar and monopolar CS are safe procedures identifying similar cortical areas as eloquent, although monopolar cortical stimulation is less time consuming. SIGNIFICANCE: Findings advocate the use of monopolar CS in a clinical setting.
OBJECTIVE: Extraoperative cortical stimulation (CS) for mapping of eloquent cortex in patients prior to epilepsy surgery is not standardized across centres. Two different techniques are in use, referred to as bipolar and monopolar CS. We compared the ability of bipolar versus monopolar CS to identify eloquent cortex and their safety profile in patients undergoing subdural EEG recordings. METHODS: Five patients undergoing intracranial EEG recordings and extraoperative CS. Systematic comparison of stimulus parameters, clinical signs and afterdischarges of bipolar versus monopolar CS. RESULTS: Bipolar CS requires less stimulation current but is more time consuming and more likely to produce afterdischarges when compared to monopolar CS. None of the stimulations elicited seizures. The area defined as eloquent by either bipolar or monopolar CS reveals only minor discordances, involving mainly the outer row and edge of the electrode array producing clinical signs with monopolar CS only. Qualitatively, bi- and monopolar CS reproduced similar movements and types of muscle contractions. CONCLUSIONS: Bipolar and monopolar CS are safe procedures identifying similar cortical areas as eloquent, although monopolar cortical stimulation is less time consuming. SIGNIFICANCE: Findings advocate the use of monopolar CS in a clinical setting.
Authors: Elena Roca; Johan Pallud; Francesco Guerrini; Pier Paolo Panciani; Marco Fontanella; Giannantonio Spena Journal: Neurosurg Rev Date: 2019-12-03 Impact factor: 3.042
Authors: Imran H Quraishi; Christopher F Benjamin; Dennis D Spencer; Hal Blumenfeld; Rafeed Alkawadri Journal: Epilepsy Behav Case Rep Date: 2017-09-29
Authors: Gianluca Trevisi; Simon B Eickhoff; Fahmida Chowdhury; Ashwani Jha; Roman Rodionov; Mark Nowell; Anna Miserocchi; Andrew W McEvoy; Parashkev Nachev; Beate Diehl Journal: Cortex Date: 2018-07-06 Impact factor: 4.027