Scientists have found a cancer treatment drug for humans, dabrafenib, helps treat hearing loss in mice. It seems to work for cisplatin chemotherapy and noise-induced hearing loss. This is good news. But noise-induced hearing loss is more than decreased hearing thresholds from inner ear or cochlear damage.
Harmful noise >70 dB snaps connections or synapses between the inner ears and hearing nerves. This is followed by progressive hearing nerve deterioration. This is likely similar to spinal cord injuries from synapse and nerve damage. If noise exposure is repeated over time, measurable sensory hearing loss develops. Early noise-induced neural damage is called hidden hearing loss, because the person can have sound distortion and speech understanding disorders despite hearing thresholds within the normal range.
There is no way to test speech understanding in mice. When this drug reaches clinical trials for hearing loss treatment, I hope they use available measures sensitive to neural and sensory hearing system function. This means checking hearing acuity in the standard and extended high frequency ranges as well as measures of auditory neuropathy or central auditory processing disorders. It will also be important to find out if this type of drug can help people with noise-induced tinnitus or decreased sound tolerance with or without related hearing loss.
There are cases where a noise-induced hearing loss prevention drug could be very useful. This includes chemotherapy related or military noise exposure. Otherwise, environmental and community noise control is the best approach to protect speech communication, music appreciation, and hearing health. A pharmaceutical approach is not the answer for preventable noise from transit, road-rail-air traffic, consumer products, construction activities, and other harmful sources.
Feature Photo by Naassom Azevedo on Unsplash