Noise-induced hearing loss is one of the most common occupational diseases. Approximately 30 million workers in the USA alone are exposed to hazardous noise at work. There is no effective treatment for permanent hearing loss resulting from excessive noise exposure. Furthermore, the condition can be easily prevented using preventative measures such as personal hearing protection devices or hearing protectors. This book summarises the evidence for the effectiveness and safety of different types of hearing protective devises among workers exposed to noise in the workplace. Furthermore, sensori-neural hearing loss is a frequent complication of radiotherapy of head and neck tumours, when the auditory pathways have been included in the radiation field. This book focuses on reviewing three aspects of radiation-induced SNHL which have significant impact on modern-day medicine. Otoacoustic emissions (OAEs) are a promising technique for the early detection of mild hearing loss. The authors of this book re-evaluate recently published OAE data and its role in hearing loss evaluation. Other chapters provide new insights into our understanding of the influence of chronic sublethal hypoxia on functional integrity of the auditory system, interventions in hearing impairment due to peri-natal asphyxia and the effects of clinical studies using rTMS in tinnitus patients.