Sensorineural Hearing Loss.
About Sensorineural Hearing Loss
Your ear is made up of three parts— the outer, the middle, and the inner ear. Sensorineural hearing loss, or SNHL, happens after inner ear damage. Problems with the nerve pathways from your inner ear to your brain can also cause SNHL. Soft sounds may be hard to hear. Even louder sounds may be unclear or may sound muffled. This is the most common type of permanent hearing loss. Most of the time, medicine or surgery cannot fix SNHL. Hearing aids may help you hear.
The incidence of sensorineural hearing loss varies in different countries. In the United States, sudden SNHL affects between 5-27 per 100,000 people each year, with approximately 66,000 new annual cases.[6] Due to different studies using varying thresholds when classifying hearing loss, there is little consensus in the literature regarding the epidemiology of age-related hearing known as presbycusis. In presbycusis, hearing loss prevalence doubles every decade of life from the second through to the seventh decade, and is nearly universal past the eighth decade of life.[7] Another important cause of hearing loss in the adult population is noise-induced hearing loss (NIHL). It has been estimated that 16% of adults worldwide disabling hearing loss is occupational noise related.[8] This remains a common occupational disease despite legislation in place in most developed countries to prevent NIHL. Congenital hearing loss is nearly always sensorineural in nature, and can have various etiologies. In patients with robust prenatal care, congenital infectious causes such as cytomegalovirus are rare and the most common causes are genetic. There are many genetic syndromes with hearing loss as a component, and SNHL developing in childhood warrants a thorough workup.[9]
Causes of Sensorineural Hearing Loss
- Illnesses.
- Drugs that are toxic to hearing.
- Hearing loss that runs in the family.
- Aging.
- A blow to the head.
- A problem in the way the inner ear is formed.
- Listening to loud noises or explosions.