title: Intensity, Duration, and Location of High-Definition Transcranial Direct Current Stimulation for Tinnitus Relief.
abstract: OBJECTIVE
  Tinnitus is the perception of a phantom sound. The aim of this study was to compare current intensity (center anode 1 mA and 2 mA), duration (10 minutes and 20 minutes), and location (left temporoparietal area [LTA] and dorsolateral prefrontal cortex [DLPFC]) using 4 × 1 high-definition transcranial direct current stimulation (HD-tDCS) for tinnitus reduction.
  
  
  METHODS
  Twenty-seven participants with chronic tinnitus (>2 years) and mean age of 53.5 years underwent 2 sessions of HD-tDCS of the LTA and DLPFC in a randomized order with a 1 week gap between site of stimulation. During each session, a combination of 4 different settings were used in increasing dose (1 mA, 10 minutes; 1 mA, 20 minutes; 2 mA, 10 minutes; and 2 mA, 20 minutes). The impact of different settings on tinnitus loudness and annoyance was documented.
  
  
  RESULTS
  Twenty-one participants (77.78%) reported a minimum of 1 point reduction on tinnitus loudness or annoyance scales. There were significant changes in loudness and annoyance for duration of stimulation,F(1, 26) = 10.08,P< .005, and current intensity,F(1, 26) = 14.24,P= .001. There was no interaction between the location, intensity, and duration of stimulation. Higher intensity (2 mA) and longer duration (20 minutes) of stimulation were more effective.
  
  
  CONCLUSIONS
  A current intensity of 2 mA for 20-minute duration was the most effective setting used for tinnitus relief. The stimulation of the LTA and DLPFC were equally effective for suppressing tinnitus loudness and annoyance.
authors.affiliation: University of Auckland, New Zealand.
authors.forename: Giriraj Singh
authors.initials: GS
authors.lastname: Shekhawat
authors.affiliation: University of Auckland, New Zealand.
authors.forename: Frederick
authors.initials: F
authors.lastname: Sundram
authors.affiliation: City College of New York, New York, NY, USA.
authors.forename: Marom
authors.initials: M
authors.lastname: Bikson
authors.affiliation: City College of New York, New York, NY, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Truong
authors.affiliation: Dunedin School of Medicine, University of Otago, Dunedin, New Zealand Tinnitus Research Initiative, Regensburg, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.affiliation: University of Auckland, New Zealand.
authors.forename: Cathy M
authors.initials: CM
authors.lastname: Stinear
authors.affiliation: University of Auckland, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Welch
authors.affiliation: University of Auckland, New Zealand Tinnitus Research Initiative, Regensburg, Germany g.searchfield@auckland.ac.nz.
authors.forename: Grant D
authors.initials: GD
authors.lastname: Searchfield
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010296:Parietal Lobe; D017397:Prefrontal Cortex; D013702:Temporal Lobe; D014012:Tinnitus / Q000628:therapy*; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
keywords: high-definition transcranial direct current stimulation; neuromodulation; noninvasive brain stimulation; tinnitus; treatment