New U of M Study Offers Promise in Developing Therapy for Tinnitus
She explains that in tinnitus, some of the input to the brain from the ear’s cochlea is reduced, while signals from the somatosensory nerves of the face and neck, related to touch, are excessively amplified.
“It’s as if the signals are compensating for the lost auditory input, but they overcompensate and end up making everything noisy,” says Shore.
The new findings illuminate the relationship between tinnitus, hearing loss and sensory input and help explain why many tinnitus sufferers can change the volume and pitch of their tinnitus’s sound by clenching their jaw, or moving their head and neck.
But it’s not just the combination of loud noise and overactive somatosensory signals that are involved in tinnitus, the researchers report.
It’s the precise timing of these signals in relation to one another that prompt the changes in the nervous system’s plasticity mechanisms, which may lead to the symptoms known to tinnitus sufferers.
This research has implications for treatment:
Shore is now working with other students and postdoctoral fellows to develop a device that uses the new knowledge about the importance of signal timing to alleviate tinnitus. The device will combine sound and electrical stimulation of the face and neck in order to return to normal the neural activity in the auditory pathway.
“If we get the timing right, we believe we can decrease the firing rates of neurons at the tinnitus frequency, and target those with hyperactivity,” says Shore. She and her colleagues are also working to develop pharmacological manipulations that could enhance stimulus timed plasticity by changing specific molecular targets.