Can brain stimulation treatments reduce tinnitus? A Cochrane review protocol

What is it about?

Tinnitus is the persistent perception of sound, such as ringing or buzzing, with no external source, and for many people it causes significant distress, cognitive difficulties and reduced quality of life. One theoretical explanation is that tinnitus arises from abnormal synchronised neural activity in the brain's auditory system, and a range of neuromodulation techniques have been developed to disrupt this pathological synchrony. This Cochrane protocol, registered with the Cochrane Ear, Nose and Throat Disorders Group in 2015, set out the methods for a planned systematic review of these desynchronisation approaches, including transcranial direct current stimulation, transcranial alternating current stimulation, vagus nerve stimulation, acoustic neuromodulation and paired stimulation therapies. The protocol specified the objectives, inclusion criteria, search strategy and analytical methods that would be used to evaluate the effectiveness of these interventions in reducing tinnitus loudness, distress, and associated symptoms including emotional distress and impaired quality of life, and to document physiological changes and adverse events.

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Why is it important?

There is currently no treatment that reliably and directly reduces or eliminates tinnitus as a perceptual experience, making it one of the most persistent unmet needs in audiology and neuroscience. Neuromodulation approaches that target the underlying neural mechanisms have generated considerable research interest, but the quality and consistency of the evidence base was poorly characterised at the time this protocol was developed. Registering the review with Cochrane established a transparent, pre-specified methodology designed to minimise bias in synthesising that evidence. The work initiated here was eventually completed as an independent systematic review published in Brain Sciences (2024), which included 24 randomised controlled trials.