Sensorineural hearing loss(SNHL) is a type of hearing loss in which damage occurs to an individual’s inner ear (cochlea) or neural areas of the auditory system. Sometimes it is difficult to determine and it also damaged by excessive noise. This type of hearing loss can be genetic or cause due to natural aging process. In some case, a person can lose their hearing ability due to head injuries. In this person lost their ability to understand sounds clearly. Medical treatments such as Hearing Aids, Cochlear Implants and Hybrid Cochlear Implants help in reducing sensorineural hearing loss.
As stated by National Institute on Deafness and Other Communication Disorders (NIDCD), one in eight American over 12 years of age is suffering from the hearing loss in both the ears. From the three types of hearing loss, more than 90 percent are suffering from sensorineural hearing loss. Some people with this hearing loss have reported that they can hear but unable to understand the speech, especially with the presence of background noise. Which is somehow very frustrating.
In the sensorineural hearing loss, the hair cells or the nerve pathway (leads from the inner ear to brain) are damaged. In most of the cases, it is age-related but there may be other factors also.
Causes of Sensorineural hearing loss
This hearing loss is categorized into two types: congenital and acquired sensorineural hearing disorder.
Congenital sensorineural hearing loss
The occurrence of this type of hearing loss is while childbirth. Following are the causes responsible for congenital sensorineural hearing loss:
- Happens due to premature birth.
- Due to maternal diabetes
- Due to deficiency of oxygen during birth.
- The diseases that inherited from mother to child such as rubella.
Acquired sensorineural hearing loss
The occurrence of his type of hearing loss generally happens later in life. Following are the causes responsible for Acquired sensorineural hearing loss:
- Noice – The data from NIDCD shows that almost 15% of Americans of age bracket 20 to 69 are suffering from Noise-Induced hearing loss (NIHL). The main cause of this is exposure to a one-time loud noise, like explosion or sound above 85 decibels over a prolonged period of time. If you feel a ringing sound in your ear after attending a concert or ballgame, then your hearing is at risk.
- Aging – This is one of the most common causes of the sensorineural hearing loss also known as Presbycusis or age-related hearing loss. This cause affects one in three American between the ages of 65-74 and 1 in 7 people of age 65. It is really difficult to notice this loss as it happens gradually over time, typically in both the ears. It is due to high pitched sounds.
- Disease and Infection – There are many viral infections that can cause sensorineural hearing loss, such as measles, meningitis, and mumps. These infections can even lead to permanent hearing loss or varying degrees in the cochlea.
- Tumors – Tumors can be a major cause of sensorineural hearing loss. Common types of tumors include Acoustic Neuroma, a benign tumor affecting the auditory system and cholesteatoma which is an abnormal skin growth in the middle ear. It typically affects high-pitched hearing in one ear. You can also associate this with tinnitus and imbalance.
- Head or acoustic Trauma – The hearing loss can also be due to a blow in the head or exposure to extremely loud noise, such as an explosion. It can damage the inner ear. The hearing nerve or cochlea can also be due to fracture of the skull. People who spent most of their time around firearms, artillery and jet engines also suffer from the sensorineural hearing loss.
- Medications – There are more than 200 medications or chemical which are ototoxic for the hearing health, as stated by American Speech-Language-Hearing Association (ASHA). There are many of them which cause permanent damage to the hearing. These include certain antibiotics, anti-inflammatory medications, and cancer chemotherapy drugs such as cisplatin and carboplatin.
- Malformation of the inner ear – There are approximately 20% of children with congenital sensorineural hearing loss who have reported about the occurrence of cochlear malformation or inner ear malformation. Basically, there are two types of malformation: Membranous malformations and Bony malformations.
- Otosclerosis – It is a type of hereditary/genetic disorder. In this, a bony growth get develop around the small bone in the middle ear. This growth prevents it from vibrating freely when stimulated by the sound. This leads to hearing loss, ringing in ear or tinnitus, and even vertigo in some of the cases.
- Ear Surgery – Ear Surgeries with them carry a high risk of hearing loss. This is due to the trauma undergone by inner ear due to the surgical instruments.
- Meniere’s disease – The pressure in the inner ear due to the build-up of excess fluid in any of the ear directly affects the hearing and balance organs. Initially it affects one ear, but later on, involves both the ears. It causes a low pitched hearing loss, that may fluctuate with time. It may cause tinnitus or vertigo in addition to the hearing difficulty.
- Autoimmune inner ear disease – This is the condition in which immune system of the body misdirects the defenses against the inner ear structure. It will cause the damage to this part of the body
Sensorineural hearing loss treatment
Most of the times sensorineural hearing loss can be permanent hearing damage. It can be treated by using hearing aids so firstly you should take the hearing test so according to that doctor will suggest a hearing machine that suits your ear or it can be treated by surgery. By those in severe condition or with irreversible sensorineural hearing loss may need the cochlear implant which is an electronic hearing device. This device is surgically implanted into the inner ear directly with an external portion to wear behind the ear.
Hearing loss with different causes responds to different treatments in a varied manner.
- Sensorineural hearing loss due to acoustic trauma may respond to medical therapies. These therapies include corticosteroids to reduce cochlear hair cell swelling and inflammation. This will help to improve healing of the injured inner ear structure.
- If the hearing loss occurs due to any head trauma or any abrupt air pressure change i.e. airplane descent. It will lead to rupture or leakage from inner ear fluid compartment and it can be toxic to the inner ear. And if this condition happens, emergency ear surgery can be done, having variable success. But if the condition is sudden then it may be of viral origin. Then the treatment will be with Corticosteroids considering it an otologic emergency.
- In case of tumors, if hearing loss is mild with small tumor then it is possible to save hearing. Especially for 50% of those undergoing the surgical procedure of tumor removal for hearing preservation. But if the tumor is of balance nerve which is adjacent to the hearing nerve, then it can’t reverse with the surgery.
- If a bilateral progressive hearing loss has persisted over some months, also diagnosed with autoimmune inner ear disease. Then this condition is managed medically with the help of corticosteroids and drug therapy.
The first step for the healthy hearing is a thorough hearing examination from a hearing healthcare professional. They will determine the cause and extent of the hearing difficulty. After this, an individual plan for treatment is developed for you.