INTRODUCTION:
Hearing impairment is the most common sensory disability found among human beings. (1) After aging, noise exposure either occupational or recreational is the leading cause. Noise induced hearing loss (NIHL) once established, is irreversible, only partly manageable though totally preventable. (2) WHO estimated that 1.1 billion young people (12-35 years) are at risk of hearing loss due to recreational noise exposure. (3)
Leisure time noise exposure has become a great concern of public health. Occupational noise hazards have been evidently defined and protective measures are adopted globally. But no such preventive methods are clearly devised for the protection of dreadful effects of recreational noise. (4) Noise induced acoustic trauma has been conventionally described to effect high tone frequencies when assessed by Pure Tone Audiometry (PTA). This high tone frequency loss is graphical representation of response of hair cells in cochlear base. Based on the guidelines of Health and Safety Executive it was proposed that the frequency where notch appears in a pure tone audiogram suggests the specific type of noise to which one was exposed. Intense low frequency noise can cause maximal loss at lower frequencies while intense high frequency sound can predominantly affect higher frequencies. (5)
Hearing difficulty not only hinders the functional capacity of an individual but also affects the intellectual health of a potential mind. A large population-based study discovered that low frequency hearing loss (0.25-0.5kHz) among young and middle age people(6) while generalized hearing loss among elderly population considerably affect mental health and quality of life.(7)