Brain stimulation for the treatment of tinnitus?
Imagine sitting at your desk, working in silence, when suddenly you hear a constant beep, murmur or static noise that is absent to your colleagues. Imagine going to bed every night and hearing that same, persisting noise again, preventing you from falling asleep.
Tinnitus, the perception of sound in the absence of any external acoustic stimulation, is a common yet poorly understood disorder. For most patients, subjective tinnitus manifests as a ringing in the ear which may lead to sleep deprivation, concentration disorders, and considerable distress. In periods of stress, the ringing often amplifies to an almost intolerable level.
This subjective phantom noise affects approximately 10-15% of the general population (to a greater or lesser extent) and, as of yet, its pathology is still inadequately understood. Evidence states that central mechanisms like sensitization, neural reorganization or pathological synchronization of neural activity may be involved in the production of tinnitus. Pharmacological interventions and behavioral interventions involving a combination of sound treatment, counseling, stress reduction, education and coping are commonly used but show low strength of evidence. To date, there is no one-treatment-fits-all solution for tinnitus.
In recent years, transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, has been proposed as a potential tinnitus-relieving treatment strategy. A recent study by Jacquemin and colleagues (2018) investigated the effects of tDCS and high-definition (HD) tDCS in 78 persons with tinnitus and found significant improvements in one-third of all subjects, both for the “conventional” and HD tDCS. Another study by Abtahi and colleagues (2018) found similar improvements following the application of conventional tDCS.
These preliminary results are promising and encouraging for persons suffering from tinnitus, as tDCS devices are non-invasive, safe and easy to administer. Future studies aim to assess the long-term effects of tDCS on tinnitus and develop systematic protocols to be used in clinical contexts.
Mahyar Firouzi
is a junior Ph.D. researcher at the Vrije Universiteit Brussel. As a member of the Brain, Body & Cognition and the Rehabilitation Research groups, his research focuses on improving implicit sequence learning in persons with Parkinson’s disease by using transcranial direct current stimulation.
References and further reading:
[1] Jacquemin L, Shekhawat GS, Van de Heyning P, et al. Effects of electrical stimulation in tinnitus patients: conventional versus high-definition tDCS. Neurorehabil. Neural Repair. 2018;32:714–723.
[2] Pattyn T, Van Den Eede F, Vanneste S, et al. Tinnitus and anxiety disorders: A review. Hear. Res. [Internet]. 2016;333:255–265. Available from: http://www.sciencedirect.com/science/article/pii/S0378595515001811.
[3] Pichora-Fuller MK, Santaguida P, Hammill A, et al. Evaluation and Treatment of Tinnitus: Comparative Effectiveness [Internet]. Agency for Healthcare Research and Quality (US), Rockville (MD); 2013. Available from: http://europepmc.org/books/NBK158963.
[4] Wang T-C, Tyler RS, Chang T-Y, et al. Effect of transcranial direct current stimulation in patients with tinnitus: a meta-analysis and systematic review. Ann. Otol. Rhinol. Laryngol. 2018;127:79–88.