Hemispheric Dominance for Language and Side Effects in Mapping the Inferior Frontal Junction Area with Transcranial Magnetic Stimulation.
Adult
Brain Mapping
/ methods
Dominance, Cerebral
Female
Frontal Lobe
/ diagnostic imaging
Humans
Language
Male
Movement Disorders
/ etiology
Muscle Contraction
Neuronavigation
Oculomotor Muscles
/ physiology
Patient Comfort
Psychomotor Performance
Transcranial Magnetic Stimulation
/ adverse effects
Young Adult
Journal
Journal of neurological surgery. Part A, Central European neurosurgery
ISSN: 2193-6323
Titre abrégé: J Neurol Surg A Cent Eur Neurosurg
Pays: Germany
ID NLM: 101580767
Informations de publication
Date de publication:
Mar 2020
Mar 2020
Historique:
pubmed:
12
2
2020
medline:
12
9
2020
entrez:
12
2
2020
Statut:
ppublish
Résumé
Language mapping by navigated transcranial magnetic stimulation (TMS) is commonly applied over the left language-dominant hemisphere to indicate the language-related cortex. Detailed language mapping of Broca's region including stimulation targets in the immediate vicinity to the premotor cortex may raise concern about confounding unspecific motor effects. We performed interhemispheric comparisons to delineate such possible unspecific effects from true TMS-induced language inhibition. Fifteen healthy German speakers named object pictures during navigated TMS over a left- and right-hemispheric target array covering the left inferior frontal junction area. Six mapping repetitions were conducted per hemisphere. Order of stimulation side was randomized between participants. Self-rating of discomfort was assessed after each stimulation; language errors and motor side effects were evaluated offline. Naming errors were observed significantly more frequently during left- than right-hemispheric stimulation. The same pattern was found for the most frequent error category of performance errors. Hierarchical cluster analyses of normalized ratings of error severity revealed a clear focus of TMS susceptibility for language inhibition in object naming at the dorsoposterior target sites only in the left hemisphere. We found no statistical difference in discomfort ratings between both hemispheres and also no interhemispheric difference in motor side effects, but we observed significantly stronger muscle contractions of the eyes as compared with the mouth. Our results of (1) unspecific pre-/motor effects similarly induced in both hemispheres, and (2) a specific focus of TMS susceptibility in the language-dominant hemisphere render any substantial contribution of nonlanguage-specific effects in TMS language mapping of the inferior frontal junction area highly unlikely.
Sections du résumé
BACKGROUND AND STUDY AIMS
OBJECTIVE
Language mapping by navigated transcranial magnetic stimulation (TMS) is commonly applied over the left language-dominant hemisphere to indicate the language-related cortex. Detailed language mapping of Broca's region including stimulation targets in the immediate vicinity to the premotor cortex may raise concern about confounding unspecific motor effects. We performed interhemispheric comparisons to delineate such possible unspecific effects from true TMS-induced language inhibition.
MATERIAL AND METHODS
METHODS
Fifteen healthy German speakers named object pictures during navigated TMS over a left- and right-hemispheric target array covering the left inferior frontal junction area. Six mapping repetitions were conducted per hemisphere. Order of stimulation side was randomized between participants. Self-rating of discomfort was assessed after each stimulation; language errors and motor side effects were evaluated offline.
RESULTS
RESULTS
Naming errors were observed significantly more frequently during left- than right-hemispheric stimulation. The same pattern was found for the most frequent error category of performance errors. Hierarchical cluster analyses of normalized ratings of error severity revealed a clear focus of TMS susceptibility for language inhibition in object naming at the dorsoposterior target sites only in the left hemisphere. We found no statistical difference in discomfort ratings between both hemispheres and also no interhemispheric difference in motor side effects, but we observed significantly stronger muscle contractions of the eyes as compared with the mouth.
CONCLUSION
CONCLUSIONS
Our results of (1) unspecific pre-/motor effects similarly induced in both hemispheres, and (2) a specific focus of TMS susceptibility in the language-dominant hemisphere render any substantial contribution of nonlanguage-specific effects in TMS language mapping of the inferior frontal junction area highly unlikely.
Identifiants
pubmed: 32045945
doi: 10.1055/s-0040-1701236
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
130-137Informations de copyright
Georg Thieme Verlag KG Stuttgart · New York.
Déclaration de conflit d'intérêts
None declared.