ECoG Gamma-band Modulations Induced by Cognitive-linguistic Tasks during Awake Craniotomy
Poster No:
1048
Submission Type:
Abstract Submission
Authors:
Sujit Prabhu1, Israt Tasnim2, Priscella Asman1, Matthew Hall2, Chandra Prakash Swamy3, Giuseppe Pellizzer4, Kyle Noll1, Sudhakar Tummala1, Nuri Firat Ince3
Institutions:
1The University of Texas MD Anderson Cancer Center, Houston, TX, 2University of Houston, Houston, TX, 3Mayo Clinic, Rochester, MN, 4University of Minnesota, Minneapolis, MN
First Author:
Co-Author(s):
Introduction:
Intraoperative functional language mapping using Direct Cortical Stimulation (DCS), the gold standard for defining eloquent language areas, has uncertainty in predicting language functions and post-surgical outcomes [1]. Moreover, DCS mapping can potentially induce seizure with prolonged usage. Here, we study the feasibility of intraoperative functional mapping using gamma-band modulations of electrocorticogram (ECoG) induced by linguistic tasks having different complexity levels during awake craniotomy.
Methods:
Seven subjects with left temporal lobe glioma underwent resection surgeries involving awake language mapping using a 4x8 ECoG electrode grid (2.3mm contact exposure and 10mm pitch). A MATLAB/Simulink based real-time software system running on a portable laptop computer was used to map task-induced gamma-band modulations as 2D heat maps (Fig. 1) [2]. Tasks included verbally responding to individual words versus tones categorization, picture naming (object/nouns, action/verbs), written descriptive and auditory naming (AN) respectively [3]. Auditory stimuli were provided during word versus tone categorization (duration 300~500ms) and auditory naming tasks (> 1s). Other naming tasks provided visual stimuli (line drawings or written phrases). Bipolar DCS (2/4/6 mA, 60Hz, 2s) was applied at different electrode pairs while repeating the naming tasks.
Results:
The electrodes having strongest gamma-band modulations (ERS power> 2dB for >=200ms) were distinct for different tasks across subjects (Fig. 2). Cortical regions activated by word stimuli and the AN task were similar; superior and middle temporal gyri (STG, MTG). Gamma band modulations with tone stimuli were observed early (<200ms post stimuli onset) in the STG. Whereas with word and AN stimuli additional late activated (>200ms) contacts were observed. Visual naming tasks modulated posterior MTG (pMTG), written naming induced additional long latency activations (>500ms) around STG, indicating STG involvement in higher level cognitive-linguistic processing. DCS induced reproducible speech arrests occurred during different naming tasks while stimulating specific electrode pairs, responsive electrodes were not necessarily those with strong task-specific gamma-band activations. Considerable inter-personal variability of language areas identified with DCS was observed, despite the similarity of task-specific gamma-band modulated regions across subjects.
Conclusions:
Intraoperative language mapping guided by gamma-band ECoG modulations induced by simple word versus tone categorization task exhibited similar patterns to more complex naming tasks, suggesting this task may be a viable approach to localize functional cortex, especially in patients unable to reliably perform more difficult paradigms. With this task-based activations in conjunction with DCS mapping guided by visual naming tasks, eloquent cortical language areas may be better preserved, thereby reducing post-operative language deficits.
Language:
Language Comprehension and Semantics 2
Speech Perception 1
Keywords:
Cortex
ELECTROCORTICOGRAPHY
Language
1|2Indicates the priority used for review
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2. Tasnim, Israt, Priscella Asman, Chandra Prakash Swamy, Sudhakar Tummala, Sujit Prabhu, and Nuri Firat Ince. "Microcontroller-Based Low Latency Audio System to Study Cortical Auditory Evoked Potentials: Applications with Intraoperative Language Mapping." In 2023 11th International IEEE/EMBS Conference on Neural Engineering (NER), pp. 01-04. IEEE, 2023.
3. Israt Tasnim, Nuri Ince, Sujit Prabhu, Kyle Noll, Chandra Swamy, Katherine Connelly, Priscella Asman, Tummala Sudhakar, Sarah Prinsloo, Chibawanye Ene, Roxana Grasu, Ho-Ling Liu, Matthew Muir, Shreyas Bhavsar, Vinodh Kumar, NIMG-64. INTRAOPERATIVE LANGUAGE MAPPING USING GAMMA-BAND MODULATIONS OF ELECTROCORTICOGRAM (ECOG) INDUCED BY WORD/SOUND CATEGORIZATION TASK: VALIDATION WITH REPRODUCIBLE SPEECH ARRESTS DURING LINGUISTIC TASKS, Neuro-Oncology, Volume 24, Issue Supplement_7, November 2022, Pages vii178–vii179,