salicylates and Presbycusis

Numerous techniques have been tested to attempt to prevent the onset or progression of age-related hearing loss (ARHL): raising the animals in an augmented acoustic environment (used successfully in mouse and rat models), enhancing the antioxidant defenses with exogenous antioxidant treatments (used with mixed results in mouse and rat models), raising the animals with a calorie restricted diet (used successfully in mouse and rat models), restoring lost endocochlear potential voltage with exogenous electrical stimulation (used successfully in the Mongolian gerbil model), and hypothetical enhancement of outer hair cell electromotility with salicylate therapy. Studies of human ARHL have revealed a set of unique hearing loss configurations with unique underlying pathologies. Animal research has developed models for the different forms of age-related peripheral pathology. Using the animal models, different techniques for prevention of ARHL have been developed and tested. The current review discusses ARHL patterns in humans and animal models, followed by discussions of the different prevention techniques.

Topics: Acoustic Stimulation; Age Factors; Aging; Animals; Antioxidants; Auditory Pathways; Auditory Threshold; Caloric Restriction; Cochlea; Disease Models, Animal; Electric Stimulation Therapy; Humans; Mice; Presbycusis; Rats; Salicylates

The interaction of noise with a variety of other agents and with some physical characteristics of the individual to produce noise-induced hearing loss is reviewed critically. The review is restricted, for the most part, to publications since 1970. Other agents interacting with steady-state noise that are reviewed here include: (1) ototoxic drugs (kanamycin, neomycin, ethacrynic acid, furosemide, and salicylates), (2) impulse noise, and (3) whole-body vibration. Physical characteristics of the individual that are reviewed are: (1) age, (2) presence of previous hearing loss from prior noise exposure, (3) eye color, and (4) race. Suggestions for future research in this general area are also made. Some of these suggestions are as follows: (1) to extend studies of the interaction of steady-state noise with impulse noise, salicylates, and whole-body vibration to encompass a broader range of exposure conditions, including exposure conditions typically encountered by the worker, (2) to develop an animal model of presbycusis to explore the interactions of noise-induced hearing loss and presbycusis, and (3) to explore the potential interactions resulting from concurrent exposure to multiple agents, such as impulse noise and ototoxic drugs, in younger, more susceptible animals.

Topics: Acoustic Stimulation; Age Factors; Animals; Ethacrynic Acid; Eye Color; Furosemide; Hearing Loss, Noise-Induced; Hearing Loss, Sensorineural; Humans; Kanamycin; Melanins; Neomycin; Presbycusis; Risk; Salicylates; Vibration