Ototoxic is a word not seen or read very often unless one works at Praedicat. The latter part is familiar-toxic, so what is “oto”? It is a medical term used for the ear. Ototoxic is defined as being toxic to the organs or nerves of the ear. Damage to the ear, which can be irreversible, can result in hearing loss and balance issues.
It is widely known that loud noise can damage ear function. However, chemicals can also lead to hearing loss. Examples of ototoxic substances Praedicat monitors are cobalt, ethylbenzene, styrene, and toluene. Exposure to these can occur in an occupational environment. Out of these four, styrene is predicted from our analysis to have the highest ototoxic risk. Ototoxicity is also a side effect of prescription drugs. Praedicat maintains a profile on sildenafil, better recognized by its propriety name Viagra, which can result in hearing loss. So how do ototoxic chemicals result in ear damage? When a person is exposed to an ototoxic chemical, it is absorbed into the blood stream and causes damage to the inner ear. It is the inner ear that transfers sound as a mechanical signal to a chemical signal. Ototoxic chemicals can also damage the vestibulocochlear nerve which relays the chemical signal of sound from the ear to the brain. Damage to the inner ear and/or the vestibulocochlear nerve results in the brain receiving faulty information to distinguish sounds. In contrast, loud noise affects hearing by damaging the middle ear which “amplifies” sounds as a mechanical signal.
There are different types of hearing tests to determine where in the hearing process (from middle ear amplification of sound to inner ear processing of sounds to vestibulocochlear nerve transmission of sound to the brain) is broken. Since it can be ascertained where in the process hearing is damaged, it can be hypothesized how the damage may have occurred. So if a person experiences hearing loss that can be determined to be due to an inner ear dysfunction, exposure to an ototoxic substance can be hypothesized as the reason for the hearing loss. For Praedicat’s liability risk analytics, this ability to distinguish hearing loss from toxic substances from that caused by loud noise means that the “specific liability risk” is higher for ototoxic chemicals and hearing loss.
In an occupational environment, protection against loud noise is monitored. However, where there is loud noise, a solvent like styrene may also be present. The combination of these two hazards, each resulting a specific damage in the hearing process, is extremely harmful to sense of sound.
Research has shown that exposure to certain chemicals in the workplace may also negatively affect how the ear functions, potentially causing hearing loss or balance problems, regardless of noise exposure.