Notched sound therapy

Notched sound therapy is an experimental, research-stage approach studied for tinnitus, the perception of sound (often a ringing, buzzing, or hissing) with no external source. The idea is to take music or noise and remove a narrow band of frequencies centred on the pitch a person hears as their tinnitus, using a notch filter (a filter that removes a narrow band of frequencies while leaving the rest of the sound intact). The remaining audio is then listened to over many sessions. Because the band is matched to each person's tinnitus pitch, the approach is sometimes described as tailor-made or personalised; one studied form is called tailor-made notched music training. See Wikipedia: Tinnitus, which describes music notched at the tinnitus frequency and notes that such methods are poorly supported by evidence.

The proposed reasoning rests on lateral inhibition (the way neighbouring nerve cells in the hearing pathway can damp down each other's activity). By reducing the sound input at the tinnitus pitch, the approach is hypothesised to lower the related neural activity over time, an effect sometimes linked to tonotopic reorganisation (gradual change in how the auditory brain maps different frequencies). This is a hypothesis under investigation, not an established fact. Controlled trials have produced mixed and limited results: in a randomised, controlled trial of notched music therapy, the authors found no statistically significant difference between the notched-music and ordinary-music groups on its primary outcome measures (the Tinnitus Handicap Inventory and visual analogue scales), and concluded that more research is needed to draw firm conclusions about its benefits and cost-effectiveness. See A Randomized, Controlled Trial of Notched Music Therapy for Tinnitus Patients, Journal of International Advanced Otology (2021), PMC9450089. Notched sound therapy is therefore not an established cure or guaranteed treatment for tinnitus.

As described in audiology, the approach works like this: a clinician first estimates the person's tinnitus pitch, then a notch filter removes a narrow band of frequencies around that pitch from music or noise, leaving the rest of the sound unchanged. The person listens to this notched audio over repeated sessions. The hypothesis, via lateral inhibition (neighbouring nerve cells in the hearing pathway damping each other's activity), is that reducing the input at the tinnitus pitch lowers the neural activity tied to that pitch over time. This mechanism is plausible and actively studied, but it remains a hypothesis rather than a proven pathway.

The honest evidence verdict is that the research is limited and mixed. Some small studies report modest changes; a randomised, controlled trial found no statistically significant difference between notched and ordinary music on its primary outcome measures and called for more research before firm conclusions about benefits or cost-effectiveness can be drawn (see A Randomized, Controlled Trial of Notched Music Therapy for Tinnitus Patients, Journal of International Advanced Otology, 2021 (PMC9450089)). Notched sound therapy is not a cure and is not a guaranteed way to relieve tinnitus.

Tinnitus is a recognised medical condition, and a sudden, one-sided, or distressing change in what you hear should be assessed by a professional. If you are considering an approach like this, consult a qualified audiologist or your doctor, who can assess your situation and discuss the current evidence. Sonora is a general wellbeing and sound app; it is not a medical device, it does not diagnose or treat tinnitus, and it does not provide notched sound therapy. For context, see the tinnitus retraining therapy glossary term, the sound and tinnitus guide, and the sound healing pillar.