title: Polarity specific suppression effects of transcranial direct current stimulation for tinnitus.
abstract: Tinnitus is the perception of a sound in the absence of an external auditory stimulus and affects 10-15% of the Western population. Previous studies have demonstrated the therapeutic effect of anodal transcranial direct current stimulation (tDCS) over the left auditory cortex on tinnitus loudness, but the effect of this presumed excitatory stimulation contradicts with the underlying pathophysiological model of tinnitus. Therefore, we included 175 patients with chronic tinnitus to study polarity specific effects of a single tDCS session over the auditory cortex (39 anodal, 136 cathodal). To assess the effect of treatment, we used the numeric rating scale for tinnitus loudness and annoyance. Statistical analysis demonstrated a significant main effect for tinnitus loudness and annoyance, but for tinnitus annoyance anodal stimulation has a significantly more pronounced effect than cathodal stimulation. We hypothesize that the suppressive effect of tDCS on tinnitus loudness may be attributed to a disrupting effect of ongoing neural hyperactivity, independent of the inhibitory or excitatory effects and that the reduction of annoyance may be induced by influencing adjacent or functionally connected brain areas involved in the tinnitus related distress network. Further research is required to explain why only anodal stimulation has a suppressive effect on tinnitus annoyance.
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, 2650 Edegem, Belgium ; Department of Translational Neuroscience, Faculty of Medicine, University of Antwerp, 2650 Edegem, Belgium.
authors.forename: Kathleen
authors.identifier: 0000-0002-5109-0937
authors.initials: K
authors.lastname: Joos
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin 9054, New Zealand ; BRAI N & TRI, Sint Augustinus Hospital, 2610 Wilrijk, Belgium.
authors.forename: Dirk
authors.identifier: 0000-0002-4625-268X
authors.initials: D
authors.lastname: De Ridder
authors.affiliation: Department of Translational Neuroscience, Faculty of Medicine, University of Antwerp, 2650 Edegem, Belgium ; Department of Otorhinolaryngology and Head & Neck Surgery, University Hospital Antwerp, 2650 Edegem, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Van de Heyning
authors.affiliation: Department of Translational Neuroscience, Faculty of Medicine, University of Antwerp, 2650 Edegem, Belgium ; School of Behavioral and Brain Sciences, The University of Texas at Dallas, TX 75235, USA.
authors.forename: Sven
authors.initials: S
authors.lastname: Vanneste
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001303:Auditory Cortex / Q000502:physiology*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004566:Electrodes; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014012:Tinnitus / Q000628:therapy*