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• An approach for analysis of task-related high-gamma modulation in stereo-EEG using distribution of power differential clusters is described. • Stereo-EEG high-gamma language mapping effectively localized reference neuroanatomy (Neurosynth). • Stereo-EEG high-gamma language mapping also adequately classified electrical stimulation mapping speech/language sites. A novel analytic approach for task-related high-gamma modulation (HGM) in stereo-electroencephalography (SEEG) was developed and evaluated for language mapping. SEEG signals, acquired from drug-resistant epilepsy patients during a visual naming task, were analyzed to find clusters of 50–150 Hz power modulations in time–frequency domain. Classifier models to identify electrode contacts within the reference neuroanatomy and electrical stimulation mapping (ESM) speech/language sites were developed and validated. In 21 patients (9 females), aged 4.8–21.2 years, SEEG HGM model predicted electrode locations within Neurosynth language parcels with high diagnostic odds ratio (DOR 10.9, p < 0.0001), high specificity (0.85), and fair sensitivity (0.66). Another SEEG HGM model classified ESM speech/language sites with significant DOR (5.0, p < 0.0001), high specificity (0.74), but insufficient sensitivity. Time to largest power change reliably localized electrodes within Neurosynth language parcels, while, time to center-of-mass power change identified ESM sites. SEEG HGM mapping can accurately localize neuroanatomic and ESM language sites. Predictive modelling incorporating time, frequency, and magnitude of power change is a useful methodology for task-related HGM, which offers insights into discrepancies between HGM language maps and neuroanatomy or ESM. [ABSTRACT FROM AUTHOR]

Summary: Objective: This prospective study compared the topography of high‐gamma modulation (HGM) during a story‐listening task requiring negligible patient cooperation, with the conventional electrical stimulation mapping (ESM) using a picture‐naming task, for presurgical language localization in pediatric drug‐resistant epilepsy. Methods: Patients undergoing extraoperative monitoring with subdural electrodes were included. Electrocorticographic signals were recorded during quiet baseline and a story‐listening task. The likelihood of 70‐ to 150‐Hz power modulation during the listening task relative to the baseline was estimated for each electrode and plotted on a cortical surface model. Sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) were estimated compared to ESM, using a meta‐analytic framework. Results: Nineteen patients (10 with left hemisphere electrodes) aged 4‐19 years were analyzed. HGM during story listening was observed in bilateral posterior superior temporal, angular, supramarginal, and inferior frontal gyri, along with anatomically defined language association areas. Compared to either cognitive or both cognitive and orofacial sensorimotor interference with naming during ESM, left hemisphere HGM showed high specificity (0.82‐0.84), good accuracy (0.66‐0.70), and DOR of 2.23 and 3.24, respectively. HGM was a better classifier of ESM language sites in the left temporoparietal cortex compared to the frontal lobe. Incorporating visual naming with the story‐listening task substantially improved the accuracy (0.80) and DOR (13.61) of HGM mapping, while the high specificity (0.85) was retained. In the right hemisphere, no ESM sites for aphasia were seen, and the results of HGM and ESM comparisons were not significant. Significance: HGM associated with story listening is a specific determinant of left hemisphere ESM language sites. It can be used for presurgical language mapping in children who cannot cooperate with conventional language tasks requiring active engagement. Incorporation of additional language tasks, if feasible, can further improve the diagnostic accuracy of language localization with HGM. [ABSTRACT FROM AUTHOR]

• Stereo-EEG sensorimotor mapping was prospectively compared with reference neuroanatomy. • Electrical stimulation mapping localized anatomic sensorimotor parcels with high accuracy. • Sensorimotor thresholds below after-discharge thresholds suggest safety of stereo-EEG ESM. We evaluated stereo-EEG electrical stimulation mapping (ESM) for localization of anatomic sensorimotor parcels in pediatric patients with drug-resistant epilepsy. We also analyzed sensorimotor and after-discharge thresholds, and the somatotopy of sensorimotor responses. ESM was performed with 50 Hz, biphasic, 2–3 s trains, using 1–9 mA current. Pre- and post-implant neuroimaging was co-registered and intersected with Neurosynth reference, to classify each electrode contact as lying within/outside an anatomic sensorimotor parcel. Indices of diagnostic performance were computed. Sensorimotor and after-discharge thresholds were analyzed using multivariable linear mixed models. In 15 patients (6 females), aged 5.5–21.2 years, ESM showed high accuracy (0.80), high specificity (0.86), and diagnostic odds ratio (11.4, p < 0.0001) for localization of sensorimotor parcels. Mean sensorimotor threshold (3.4 mA) was below mean after-discharge threshold (4.2 mA, p = 0.0004). Sensorimotor and after-discharge thresholds showed a significant decrease with increasing intelligence quotient. Somatotopy of sensorimotor responses was mapped to standardized brain parcels. We provide evidence for diagnostic validity and safety of stereo-EEG sensorimotor ESM. The somatotopy of sensorimotor responses elicited with electrical stimulation provide new insights into mechanisms of motor control and sensory perception. [ABSTRACT FROM AUTHOR]