Eric Thornburgh, Wyatt Damon, Dinuka Ranasinghe, & Dr. Brian Rasnow
We constructed a radically inexpensive ($25) bimodal neuromodulator to treat tinnitus.
Tinnitus, a phantom perception of sound occurring in the absence of external sound, affects 10-15% of people and is a serious problem for 1-2% of the population. There are few effective treatments, in part because tinnitus is not a single condition with a single cause. A clinical trial in 2020 demonstrated a novel form of treatment called bimodal neuromodulation. Combining an electrical stimulator placed on the tongue in conjunction with headphones simultaneously producing simple sounds, the device commercialized by Lanire resulted in a sustained reduction in tinnitus for a majority of users. This treatment is expensive ($3-4k), available through a few audiologists, and not covered by insurance. Our alternative bimodal neuromodulator uses a ~$20 commercial transcutaneous electrical nerve stimulator (TENS) as a co-modality with acoustic stimulation. We designed and implemented a simple low-cost electronic circuit that detects the TENS current and transduces it to sound played on a speaker or headphones.
We believe our system and Lenire’s work via classical (Pavlovian) conditioning. Bimodal stimulation creates a novel correlation, just as Pavlov did by ringing a bell correlated with feeding his dogs. Repeating the correlation rewires brain circuits – “neurons that fire together wire together”. Our working hypothesis is that hearing loss results in the brain amplifying a sensory expectation that no longer cancels auditory input. Novel bimodal neuromodulation activates latent synaptic plasticity in the affected circuits, so they learn to predict the bimodal correlation. Concurrently, the auditory system also learns or adapts to the absent or reduced high-frequency auditory input, changing the expectation signal and reducing the perceived ringing.
We will demonstrate our novel bimodal neuromodulator and explain our rationale for why we expect it to be effective in reducing tinnitus.