Hearing loss can be caused by a variety of conditions. Hearing loss occurs when different parts of the auditory pathway are affected, and the resulting hearing loss is classified as either conductive, neural or mixed, depending on which part of the pathway is affected. Conductive hearing loss occurs before the sound reaches the sensory organs of the inner ear. It may involve the outer ear canal, the eardrum, and the middle ear conduction chain. Neurogenic hearing loss occurs when sound reaches the inner ear but is not converted into nerve impulses (sensory loss) or when nerve impulses are not transmitted to the brain. Mixed hearing loss includes both conduction and sensory loss. Overall, the most common causes of generation are as follows, 1. Cerumen blockage of the outer ear canal: the accumulation of earwax is the most common cause of treatable hearing loss, especially in the elderly. 2. Noise: Noise can cause sudden or progressive neurological hearing loss. Exposure to a single, extreme noise sound (such as a nearby gunshot or explosion) can produce sudden hearing loss. It may also produce tinnitus, which usually disappears within a day. However, prolonged exposure to noise is the cause of most noise-induced hearing damage. Noise greater than 85 decibels (dB) may cause hearing loss if exposure to noise is prolonged. Although people vary in their sensitivity to noise-induced hearing loss, almost everyone will suffer some degree of hearing loss if exposed to sufficiently loud noise for long periods of time 3. Ear infections: Ear infections are a common cause of mild to moderate transient hearing loss, most often occurring in children. Hearing loss is more common in children who have frequent ear infections. 4. Aging or hearing system function decline: the human body will appear a series of aging phenomenon. Age-related hearing loss is caused by the auditory system aging triggered hearing dysfunction. According to audiological studies, men begin to experience hearing loss after the age of 45, women slightly later. As the human life expectancy extends, the elderly population increases, and the incidence of deafness in the elderly also increases. According to statistics, one third of people over the age of 65 have hearing loss of varying degrees and 50% of people over the age of 75 have hearing loss of varying degrees.