Hearing loss is often associated with old age, tinnitus or balance disorders. However, studies show that anyone can be affected by hearing loss, at any age if exposed to a chemical present in many common household products.

 

Chances are, you take your senses for granted. Associated generally with deterioration in old age, we never assume we will go deaf or blind in our younger years. Nevertheless, approximately 3 million children in the USA suffer from hearing loss and this number is on the rise. (CHC, 2016)

In 2006, a study was released detailing the mysterious premature hearing loss of a collection of employees in a manufacturing site in Taiwan, specialising in adhesive materials. Chang, Chen, Lien, and Sung narrowed the phenomenon that was the loss of the worker’s auditory sense down to the responsibility of one chemical: Toluene.

Chemical-induced hearing loss, also known as “ototoxicity”, can affect anyone of any age and today, there are over 200 known ototoxic medications on the market known to cause damage to the inner ear containing chemicals largely known to induce ototoxicity such as Syrene and Xylene.

However, sold in many high-street shops, you’ll find the biggest player in the cause of ototoxicity: Toluene. Toluene is a major component of paints, varnishes, petroleum, printing inks, degreasers, adhesives, cigarette smoke, glues, thinners, and plastics. Exposure to Toluene, such as inhalation, ingestion or skin contact, is known to cause not only hearing loss, but commonly can be a factor in causing Tinnitus, Dermatitis, and vision impairment. In general, the component can wreak havoc for the central nervous system and prolonged exposure to high concentrations of the colourless liquid may result in loss of consciousness, and may even be fatal.

Wanisiusiow, whose findings were conducted using the RX series’ RX daytona and a Randox creatinine kit stated, “Toluene is undoubtedly one of the most widely used organic solvents in industry.” But how does Toluene do it? Wanisusiow goes on to state, “As far as we know, there are two major mechanisms which might explain toluene-induced hearing loss. Firstly, a poisoning of Deiters and Hensen’s cells, which are both important to maintain the K+ homeostasis in the vicinity of outer hair cells. Secondly, an oxidative cell injury, such as lipid peroxidation.”

An interesting point uncovered in this study is that suffering the severe side-effect of Toluene seems to be species-specific. The original experiment, carried out on rats, displayed expected symptoms of ototoxicity. However, guinea pigs reacted differently. The study speculates: The half-life of toluene is longer in the rat than in the guinea pig. This might be one way to explain the difference in cochlear sensitivity to toluene between rats and guinea pigs but likely not the only one.

So, what is it in the genetic makeup of guinea pigs, that rats do not possess, that could fight the negative effects of Toluene? Could learning what causes guinea pigs immunity be beneficial to our research into hearing loss?

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