MRI Study of Noninvasive Transcranial Electrical Stimulation in Tinnitus
Condition: Tinnitus, Subjective
MeSH terms: Tinnitus
Study type: Interventional
Phase: Early Phase 1

Summary: 
      The purpose of this research is to understand how a neuromodulation technique, transcranial
      electrical stimulation (tES), affects brain function in adults with chronic tinnitus measured
      with functional magnetic resonance imaging (fMRI). We hypothesize that multiple sessions of
      tES (5 consecutive days) will modulate:

        1. Overall activity and local connectivity within brain regions near tES electrodes, and

        2. Functional connectivity within brain networks associated with brain regions near tES
           electrodes.

      In exploratory analyses, we also measure the extent to which the hypothesized changes listed
      above a related to changes in tinnitus symptoms after tES.
    

Detailed description: 
      Chronic subjective tinnitus is a common and sometimes disabling condition, with few effective
      treatments and no cure. Tinnitus is thought to involve dysfunction in central brain networks
      subsequent to peripheral injury or interference; thus, neurostimulation therapies that
      directly target central circuits are receiving growing interest. Of these, noninvasive
      transcranial electrical stimulation (tES) is an attractive option, due to its relative
      affordability, mobility, and favorable safety profile. A growing number of studies have
      demonstrated that tES of temporal/auditory cortex is effective at transiently reducing
      tinnitus symptoms, including tinnitus loudness and tinnitus distress. However, the results of
      previous clinical trials are variable, and a mechanistic understanding of tES and its
      therapeutic effects remains elusive. The main goal of this research is to lay the groundwork
      for improved, patient-centered approaches to noninvasive neurostimulation therapy for chronic
      tinnitus. To accomplish this long-term goal, this study will determine how the intrinsic
      activity and connectivity of auditory networks are affected during simultaneous tES-fMRI of
      auditory cortex, specifically in those patients who experience reduced tinnitus symptoms
      after 5 consecutive days of tES. Though the primary goal of the proposed research is to
      optimize tES for the treatment of tinnitus, these studies will also provide a wealth of
      information regarding tinnitus pathophysiology and the mechanisms of tES more generally,
      which is being investigated for the treatment of a wide variety of brain disorders and
      injuries.
    

Intervention name(s): Transcranial electrical stimulation (tES)
Intervention type(s): Device
Intervention description(s): In tES, a mild electrical current is passed between two or more electrodes placed on the volunteer's head (scalp). In this study, a mild unvarying (constant) electrical 2mA current is passed between two rubber electrodes placed on the head over auditory cortex for 20 minutes per session for 5 consecutive days. Because the electrical current direction (positive/negative) and current amplitude (2mA) does not vary or change during stimulation, this type of tES is also called transcranial "direct current" stimulation, or tDCS.
Other intervention name(s): Transcranial direct current stimulation (tDCS)
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Eligible volunteers will be randomly assigned to receive either 5 consecutive days of active tES or 5 consecutive days of sham/inactive tES. This part of the study is optional. All eligible volunteers will receive active and sham/inactive tES during MRI.
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: transcranial direct current stimulation (tDCS); functional magnetic resonance imaging (MRI)