title: Clinical impact of intraoperative CCEP monitoring in evaluating the dorsal language white matter pathway.
abstract: In order to preserve postoperative language function, we recently proposed a new intraoperative method to monitor the integrity of the dorsal language pathway (arcuate fasciculus; AF) using cortico-cortical evoked potentials (CCEPs). Based on further investigations (20 patients, 21 CCEP investigations), including patients who were not suitable for awake surgery (five CCEP investigations) or those without preoperative neuroimaging data (eight CCEP investigations including four with untraceable tractography due to brain edema), we attempted to clarify the clinical impact of this new intraoperative method. We monitored the integrity of AF by stimulating the anterior perisylvian language area (AL) by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. After tumor resection, single-pulse electrical stimuli were also applied to the floor of the removal cavity to record subcortico-cortical evoked potentials (SCEPs) at AL and PL in 12 patients (12 SCEP investigations). We demonstrated that (1) intraoperative dorsal language network monitoring was feasible even when patients were not suitable for awake surgery or without preoperative neuroimaging studies, (2) CCEP is a dynamic marker of functional connectivity or integrity of AF, and CCEP N1 amplitude could even become larger after reduction of brain edema, (3) a 50% CCEP N1 amplitude decline might be a cut-off value to prevent permanent language dysfunction due to impairment of AF, (4) a correspondence (<2.0 ms difference) of N1 onset latencies between CCEP and the sum of SCEPs indicates close proximity of the subcortical stimulus site to AF (<3.0 mm). Hum Brain Mapp 38:1977-1991, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yamao
authors.affiliation: Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.|Department of Neurosurgery, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Kunieda
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Riki
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Arakawa
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Nakae
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Sei
authors.initials: S
authors.lastname: Nishida
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Inano
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Sumiya
authors.initials: S
authors.lastname: Shibata
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shimotake
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.|Department of Human Health Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Sawamoto
authors.affiliation: Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mikuni
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery; D002540:Cerebral Cortex / Q000503:physiopathology*; D004558:Electric Stimulation; D000069280:Electrocorticography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011930:Reaction Time; D012189:Retrospective Studies; D014851:Wakefulness; D066127:White Matter / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: awake craniotomy; cortico-cortical evoked potential; dorsal language pathway; electrical stimulation; subcortico-cortical evoked potential