TY - JOUR
T1 - Middle Frontal Gyrus and Area 55b
T2 - Perioperative Mapping and Language Outcomes
AU - Hazem, Sally Rosario
AU - Awan, Mariam
AU - Lavrador, Jose Pedro
AU - Patel, Sabina
AU - Wren, Hilary Margaret
AU - Lucena, Oeslle
AU - Semedo, Carla
AU - Irzan, Hassna
AU - Melbourne, Andrew
AU - Ourselin, Sebastien
AU - Shapey, Jonathan
AU - Kailaya-Vasan, Ahilan
AU - Gullan, Richard
AU - Ashkan, Keyoumars
AU - Bhangoo, Ranjeev
AU - Vergani, Francesco
N1 - Funding Information:
OL was funded by the EPSRC Research Council (EPSRC DTP EP/R513064/1). HI and CS were supported by the EPSRC-funded UCL Centre for Doctoral Training in Medical Imaging (EP/L016478/1).
Publisher Copyright:
© Copyright © 2021 Hazem, Awan, Lavrador, Patel, Wren, Lucena, Semedo, Irzan, Melbourne, Ourselin, Shapey, Kailaya-Vasan, Gullan, Ashkan, Bhangoo and Vergani.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/10
Y1 - 2021/3/10
N2 - Background: The simplistic approaches to language circuits are continuously challenged by new findings in brain structure and connectivity. The posterior middle frontal gyrus and area 55b (pFMG/area55b), in particular, has gained a renewed interest in the overall language network. Methods: This is a retrospective single-center cohort study of patients who have undergone awake craniotomy for tumor resection. Navigated transcranial magnetic simulation (nTMS), tractography, and intraoperative findings were correlated with language outcomes. Results: Sixty-five awake craniotomies were performed between 2012 and 2020, and 24 patients were included. nTMS elicited 42 positive responses, 76.2% in the inferior frontal gyrus (IFG), and hesitation was the most common error (71.4%). In the pMFG/area55b, there were seven positive errors (five hesitations and two phonemic errors). This area had the highest positive predictive value (43.0%), negative predictive value (98.3%), sensitivity (50.0%), and specificity (99.0%) among all the frontal gyri. Intraoperatively, there were 33 cortical positive responses—two (6.0%) in the superior frontal gyrus (SFG), 15 (45.5%) in the MFG, and 16 (48.5%) in the IFG. A total of 29 subcortical positive responses were elicited−21 in the deep IFG–MFG gyri and eight in the deep SFG–MFG gyri. The most common errors identified were speech arrest at the cortical level (20 responses−13 in the IFG and seven in the MFG) and anomia at the subcortical level (nine patients—eight in the deep IFG–MFG and one in the deep MFG–SFG). Moreover, 83.3% of patients had a transitory deterioration of language after surgery, mainly in the expressive component (p = 0.03). An increased number of gyri with intraoperative positive responses were related with better preoperative (p = 0.037) and worse postoperative (p = 0.029) outcomes. The involvement of the SFG–MFG subcortical area was related with worse language outcomes (p = 0.037). Positive nTMS mapping in the IFG was associated with a better preoperative language outcome (p = 0.017), relating to a better performance in the expressive component, while positive mapping in the MFG was related to a worse preoperative receptive component of language (p = 0.031). Conclusion: This case series suggests that the posterior middle frontal gyrus, including area 55b, is an important integration cortical hub for both dorsal and ventral streams of language.
AB - Background: The simplistic approaches to language circuits are continuously challenged by new findings in brain structure and connectivity. The posterior middle frontal gyrus and area 55b (pFMG/area55b), in particular, has gained a renewed interest in the overall language network. Methods: This is a retrospective single-center cohort study of patients who have undergone awake craniotomy for tumor resection. Navigated transcranial magnetic simulation (nTMS), tractography, and intraoperative findings were correlated with language outcomes. Results: Sixty-five awake craniotomies were performed between 2012 and 2020, and 24 patients were included. nTMS elicited 42 positive responses, 76.2% in the inferior frontal gyrus (IFG), and hesitation was the most common error (71.4%). In the pMFG/area55b, there were seven positive errors (five hesitations and two phonemic errors). This area had the highest positive predictive value (43.0%), negative predictive value (98.3%), sensitivity (50.0%), and specificity (99.0%) among all the frontal gyri. Intraoperatively, there were 33 cortical positive responses—two (6.0%) in the superior frontal gyrus (SFG), 15 (45.5%) in the MFG, and 16 (48.5%) in the IFG. A total of 29 subcortical positive responses were elicited−21 in the deep IFG–MFG gyri and eight in the deep SFG–MFG gyri. The most common errors identified were speech arrest at the cortical level (20 responses−13 in the IFG and seven in the MFG) and anomia at the subcortical level (nine patients—eight in the deep IFG–MFG and one in the deep MFG–SFG). Moreover, 83.3% of patients had a transitory deterioration of language after surgery, mainly in the expressive component (p = 0.03). An increased number of gyri with intraoperative positive responses were related with better preoperative (p = 0.037) and worse postoperative (p = 0.029) outcomes. The involvement of the SFG–MFG subcortical area was related with worse language outcomes (p = 0.037). Positive nTMS mapping in the IFG was associated with a better preoperative language outcome (p = 0.017), relating to a better performance in the expressive component, while positive mapping in the MFG was related to a worse preoperative receptive component of language (p = 0.031). Conclusion: This case series suggests that the posterior middle frontal gyrus, including area 55b, is an important integration cortical hub for both dorsal and ventral streams of language.
KW - area 55b
KW - DTI
KW - language mapping
KW - language network
KW - nTMS
KW - perioperative mapping
KW - speech arrest
KW - TMS
UR - http://www.scopus.com/inward/record.url?scp=85103068846&partnerID=8YFLogxK
U2 - 10.3389/fneur.2021.646075
DO - 10.3389/fneur.2021.646075
M3 - Article
C2 - 33776898
AN - SCOPUS:85103068846
SN - 1664-2295
VL - 12
JO - Frontiers in Neurology
JF - Frontiers in Neurology
M1 - 646075
ER -