A review on medicinal plants used for treating ototoxicity and acoustic trauma induced hearing loss

Hearing loss induced by chemotherapy and acoustic trauma is mainly associated with two factors, free radical formation and apoptosis pathway activation. Despite numerous efforts on reducing the effects of these factors, no definite strategy is still determined to interfere with and control these processes. In recent studies, various protective agents, including antioxidants have been used on animal models, to inhibit the formation of free radicals thus improving hearing loss.In this review article we will discuss the role of traditional herbal medicine in treatment of noise/drug induced hearing loss, focusing on medicinal plants' active substances,as well as their mechanisms of action in reducing or preventing the formation of free radicals thus increasing the rate of survival of cochlea cells. Data have been gathered since year 2000, from scientific publications including the following keywords: deafness, drug toxicity, acute trauma, medicinal herbs and oxidative stress. The study includes all herbs and medicinal plants that have been experimentally used in studies on animal models and clinical trials. The results from these studies indicate the effectiveness of most of these herbs and their active substances through their antioxidative properties. Medicinal plants reported in this review can thus be considered as effective remedies intreating noise/drug induced hearing loss,yet further studies need to be done.

[The Königsteiner Empfehlung of 2012 - essential alterations and modifications]. / Die Königsteiner Empfehlung von 2012 - Wesentliche Neuerungen und Änderungen.

BACKGROUND: Since 1974, the recommendation for assessment of hearing impairment caused by noise - formerly known as "Königsteiner Merkblatt" (now: "Königsteiner Empfehlung") - has been representing the state of the art for the assessment of the occupational disease BK-No. 2301. It was updated several times, the last time in 2012. It provides a summary of the current medical knowledge. A new measurement for the entire working life - the Effective Noise Dose by Liedtke - was introduced. Otoacoustic emissions (OAE) are now the crucial tests in order to detect a hair cell dysfunction. As from now the tinnitus has to be put under a more comprehensive examination. On the strength of post experience the previous speech audiometry (Freiburger Test) is reliable, it was retrained. In future the indication for hearing aids will be oriented towards the aid guidelines of the legal health insurance. The questionnaire for the expert opinion was revised and the fee was adapted.

Latent cochlear damage in personal stereo users: a study based on click-evoked otoacoustic emissions.

OBJECTIVE: To assess the effects of use of personal stereo systems (PS) on hearing by means of the objective measure of transient-evoked otoacoustic emissions. PARTICIPANTS AND SETTING: People aged between 10 and 59 years who had otoacoustic emissions recorded by the National Acoustic Laboratories between 1989 and 1997 were eligible for inclusion. Recordings from participants with hereditary disorders or any form of aural disease (e.g., otitis media, otosclerosis, fluctuant hearing loss, Meniere's syndrome, or exposure to ototoxic substances) were excluded. METHODS: Transient-evoked otoacoustic emission (TEOAE) records were obtained with a standard 260 repetitions of an 80 dB train of clicks used for recording outer hair cell activity. The measure of otoacoustic emission strength was the Otodynamics ILO88 variable Waverepro%. For each participant, all the key factors relating to their hearing history were assessed from patient referral information or from demographic information obtained in writing at the time of recording either in the form of a detailed questionnaire or verbal assessment. Otoacoustic emission data were analysed according to age, industrial noise exposure and personal stereo use. RESULTS: Usable otoacoustic emission records were obtained from 1724 people (1066 males and 658 females). Otoacoustic emission strength declined with age, and was significantly lower in males than females, lower in people exposed to industrial noise than those not exposed, and significantly lower in users of personal stereo systems than non-users. People with both kinds of noise exposure had values which were significantly lower again, indicating an additive effect. CONCLUSIONS: As only 39 people with PS exposure admitted any hearing problems, decline in otoacoustic emission strength forewarns premature hearing loss in personal stereo users.

Support for Corso's hearing loss model. Relating aging and noise exposure.

A brief review is provided of the variable ratio model [Corso, Audiology 1980;19:221-232] for partitioning the effects of age and noise exposure in cases of occupational hearing loss. Data are presented from Rosenhall, Pedersen, and Svanborg [Ear Hear 1990;11:257-263] which support the variable-ratio model. Suggestions are offered for the application of the model in medico-legal cases of permanent hearing damage due to excessive noise exposure.