title: Polarity-dependent transcranial direct current stimulation effects on central auditory processing.
abstract: Given the polarity dependent effects of transcranial direct current stimulation (tDCS) in facilitating or inhibiting neuronal processing, and tDCS effects on pitch perception, we tested the effects of tDCS on temporal aspects of auditory processing. We aimed to change baseline activity of the auditory cortex using tDCS as to modulate temporal aspects of auditory processing in healthy subjects without hearing impairment. Eleven subjects received 2mA bilateral anodal, cathodal and sham tDCS over auditory cortex in a randomized and counterbalanced order. Subjects were evaluated by the Random Gap Detection Test (RGDT), a test measuring temporal processing abilities in the auditory domain, before and during the stimulation. Statistical analysis revealed a significant interaction effect of time vs. tDCS condition for 4000 Hz and for clicks. Post-hoc tests showed significant differences according to stimulation polarity on RGDT performance: anodal improved 22.5% and cathodal decreased 54.5% subjects' performance, as compared to baseline. For clicks, anodal also increased performance in 29.4% when compared to baseline. tDCS presented polarity-dependent effects on the activity of the auditory cortex, which results in a positive or negative impact in a temporal resolution task performance. These results encourage further studies exploring tDCS in central auditory processing disorders.
authors.affiliation: Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program, Center for Health and Biological Sciences, Mackenzie Presbyterian University, Sao Paulo, Brazil.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ladeira
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
authors.forename: Camila
authors.initials: C
authors.lastname: Campanhã
authors.forename: Cláudia Aparecida
authors.initials: CA
authors.lastname: Valasek
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.forename: André Russwsky
authors.initials: AR
authors.lastname: Brunoni
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Boggio
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001308:Auditory Perceptual Disorders; D004311:Double-Blind Method; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult