Tanakan was found to decrease the intensity of tympanitis and improve speech and hearing in aged patients, giving rise to the idea of recommending treatment with it to elderly patients with presbycusis or normal tonal hearing. AM-111, an otoprotective peptide, was shown in a chinchilla study to rescue and protect against hearing loss following impulse noise trauma. AM-111 acts as a cell-permeable inhibitor of JNK-mediated apoptosis. IP injections or local injections into membrane of the round window were given, and permanent threshold shifts (PTS) were measured three weeks after impulse noise exposure. AM-111 animals had significantly lower PTS, implicating AM-111 as a possible protective agent against JNK-mediated cochlear cell death and against permanent hearing deficits after noise trauma. The anti-inflammatory, anti-oxidant substance Ebselen was observed to reduce hearing loss in a study done in 2007. It has been previously shown that noise trauma correlates with decreases in glutathione peroxidase (GPx) activity, which has been linked to loss of the outer hair cells. GPx1, an isoform of GPx, is predominantly expressed in stria vascularis, cochlea, spiral ligament, organ of Corti, and spiral ganglion cells. The stria vascularis displayed significant decreases in GPx1 immunoreactivity and increased swelling following noise exposure in rats. There was also significant outer hair cell loss in the cochlea within five hours of noise exposure. Administration of Ebselen before and after the noise stimulus reduced stria vascularis swelling as well as cochlear outer hair cell loss. This implicates Ebselen as a supplement for GPx1 in the outer hair cell degradation mechanism of hearing loss.
Presbycusis (also spelled presbyacusis, from Greek πρέσβυς presbys "old" + ἄκουσις akousis "hearing"), or age-related hearing loss, is the cumulative effect of aging on hearing. It is a progressive and irreversible bilateral symmetrical age-related sensorineural hearing loss resulting from degeneration of the cochlea or associated structures of the inner ear or auditory nerves. The hearing loss is most marked at higher frequencies. Hearing loss that accumulates with age but is caused by factors other than normal aging (nosocusis and sociocusis) is not presbycusis, although differentiating the individual effects of distinct causes of hearing loss can be difficult. The cause of presbycusis is a combination of genetics, cumulative environmental exposures and pathophysiological changes related to aging. At present there are no preventive measures known; treatment is by hearing aid or surgical implant. Presbycusis is the most common cause of hearing loss, affecting one out of three persons by age 65, and one out of two by age 75. Presbycusis is the second most common illness next to arthritis in aged people. Many vertebrates such as fish, birds and amphibians do not experience presbycusis in old age as they are able to regenerate their cochlear sensory cells, whereas mammals including humans have genetically lost this regenerative ability.