Hemispheric lateralization of voice onset time (VOT) comparison between depth and scalp EEG recordings.
Auditory-evoked potential (AEP)s elicited to French-language voiced stop consonant (/ba/) and voiceless stop consonant (/pa/) were studied in non-language-impaired epileptic patients and non-epileptic volunteers. First, depth AEPs recorded from the primary auditory cortex during pre-surgical exploration and scalp AEPs recordings using high resolution EEG (HR EEG-64 channels scalp EEG) were compared in the same patients. Both methods indicated that the processing of voiced and voiceless consonants was based on a temporal auditory coding. /Ba/ elicited a first complex (N1) at the onset of voicing and a second component [release component (RC)] time-locked to release. This processing took place specifically in the left primary auditory cortex. Source modeling of the RC showed that a left-greater-than-right amplitude of source probes (SP) both in epileptic patients with left-hemispheric language dominance [established by means of invasive tests (WADA test) and/or clinical data] and right-handed non-epileptic subjects. Our data suggest that the processing of VOT is related to hemispheric dominance for language and that scalp-recorded AEPs may represent an effective, non-invasive method to establish hemispheric dominance for language in clinical settings. This procedure could complement existing methods and could help to detect the dissociation between receptive and expressive language sometimes observed in patients with epilepsy.
Trébuchon-Da Fonseca
Agnés
A
Laboratoire de Neurophysiologie et Neuropsychologie, INSERM EMI 9926, Faculte de Medecine, Universite de la Mediterranee, 13385 Marseille Cedex 5, France. Agnes.Trebuchon@medecine.univ-mrs.fr
Giraud
Kimberly
K
Badier
Jean-Michel
JM
Chauvel
Patrick
P
Liégeois-Chauvel
Catherine
C
D000161:Acoustic Stimulation; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D004351:Drug Resistance; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004827:Epilepsy / Q000188:drug therapy / Q000503:physiopathology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D013067:Speech Perception / Q000502:physiology; D014831:Voice
D000927:Anticonvulsants