The results of a small phase 1 clinical trial of a non-invasive tinnitus therapy where the patient listens to sounds through headphones claims that compared to placebo, the treatment reduced tinnitus loudness and annoyance within 12 weeks in 7 out of 10 patients. Experts who welcomed the news say they now want to see the results repeated in a much bigger phase 2 trial.
The trial was led by Professor Peter Tass at Jülich Research Centre in Germany, who with his colleagues tested a treatment called Acoustic Coordinated Reset (CR) Neuromodulation. They write about their findings in the 13 March online issue of the journal Restorative Neurology and Neuroscience.
Tinnitus is a condition where people perceive they are hearing sound, but there is no corresponding external sound. It is not a disease, but a neurological symptom generated within the auditory pathways in the brain. The precise cause of tinnitus is not fully understood.
Some treatments tend to mask symptoms of tinnitus, but Acoustic CR Neuromodulation targets the neurological causes. The researchers suggest it reduces tinnitus loudness by reducing the overactivity of auditory nerve cells in the part of the brain responsible for hearing.
The patient wears a set of headphones that emit a series of tones designed to match the frequency of his or her own tinnitus “sounds”.
The idea is that hearing these tones disrupts the rhythmic tinnitus firing patterns in the nerve cells, thereby “inducing an unlearning of pathological synaptic connectivity and neuronal synchrony,” write the authors.
The treatment stems from therapies that stimulate neurons with probes that have to be positioned deep inside the brain. One example is the invasive Deep Brain Stimulation to treat Parkinson’s disease.
But Acoustic CR Neuromodulation is non-invasive and only requires patients to wear a set of headphones for a few hours every day.
For the prospective study, Tass and colleagues randomized 63 patients with chronic tonal tinnitus and up to 50 dB hearing loss to receive either Acoustic CR Neuromodulation or a placebo.
They measured visual analogue scale and tinnitus questionnaire (TQ) scores and spontaneous EEG (electrical activity in the brain).
They write that the results showed that the treatment was safe, well-tolerated and “caused a significant decrease of tinnitus loudness and symptoms”, whereas placebo treatment did not lead to any significant changes.
“Effects gained in 12 weeks of treatment persisted through a preplanned 4-week therapy pause and showed sustained long-term effects after 10 months of therapy, ” they write.
There was a reduction of at least 7 TQ points in 75% of patients who received the treatment, with an average TQ reductions of 50%; and the treatment also significantly “lowered tinnitus frequency and reversed the tinnitus related EEG alterations”, they add.
The researchers conclude that:
“The CR-induced reduction of tinnitus and underlying neuronal characteristics indicates a new non-invasive therapy which might also be applicable to other conditions with neuronal hypersynchrony.”
A spokesman for the British Tinnitus Association said they found the trial results interesting and encouraging. But:
“The findings now need to be replicated by an independent research group. A randomised-controlled trial is required to assess whether this new intervention is a viable and effective treatment for tinnitus patients. We look forward to seeing the results of the planned larger scale Phase 2 Trial.”
Written by Catharine Paddock PhD