In a double-blind clinical trial with 21 subjects, University of Michigan Medical School professor Susan Shore, Ph.D. (1987 and 1992–95 ERG) and team showed an experimental device could help people with tinnitus (hearing ringing or buzzing in the absence of an external sound source). Fusiform cells, the main neurons in the brainstem’s dorsal cochlear nucleus region, help the brain focus on where sounds are coming from, and help tune out sensations that result from the movement of our own head and neck (known as somatosensory inputs). The team’s previous work in animals showed that loud noise can trigger a change in the nerve cells’ activity—altering its timing so that the cells fire off synchronized signals spontaneously instead of waiting for an actual sound from the environment.
This phantom signal is transmitted into other centers where perception occurs. To stop the signal, the device uses “bimodal auditory-somatosensory stimulation,” which plays a sound into the ears, alternating it with precisely timed, mild electrical pulses delivered to the cheek or neck. Both are aimed at pushing the damaged nerve cells back to typical activity. In the trial, whose results were published in Science Translational Medicine on September 2018, participants using a sham treatment experienced no effect, but those who used the device daily for four weeks reported a decrease in tinnitus and an improved quality of life. —University of Michigan
