Hearing loss affects five percent of the world’s population. This condition has a wide range of people that can be categorized under it due to there being several levels of hearing loss. It is estimated that one in ten Americans suffers from some degree of hearing loss and that one in three senior citizens are affected by hearing loss as well.

There are multiple types of hearing loss, and it is uncommonly diagnosed as a congenital condition. Congenital hearing loss is indicative of an impairment that is present from birth. Before we start looking at causes, symptoms, and treatments for congenital hearing loss, let's first take a look at what hearing loss is and how it is categorized. 

Hearing Loss Is a Disability

A disability is considered any condition that impairs a person’s senses, mobility, or general activities. It can also be defined as anything that impairs your ability to live life. 

While culture and society are growing to be more inclusive and friendly to those with disabilities, these conditions typically pose a serious learning curve for those who have them. Hearing loss is a very dynamic condition. It has five general categories that range from mild hearing loss to severe hearing loss. An example of mild hearing loss would be if you have a hard time hearing a bird sing in an overhead tree. An example of severe hearing loss would be if you have a hard time hearing loud noises like engines. 

Hearing loss can also develop in anyone. It is not a condition that any one person is immune to attaining and is even commonly experienced to some degree as we age. The measurement for hearing loss is based on a threshold of decibels that a person can recognize. As your hearing deteriorates, your threshold will get higher and higher, meaning that any noise that registers below that threshold is unrecognizable.

For people in the United States, financial aid is only available to those with a threshold of sixty decibels or higher. This threshold is categorized as moderately severe hearing loss. Severe hearing loss can be treated with cochlear implant surgery, which also qualifies someone to get financial aid from the government. In some cases, after evaluation by an Ear, Nose and Throat specialist, hearing or partial hearing may be restored by surgery which is generally done as an outpatient.

3 Types of Hearing Loss

When it comes to hearing impairment, there are three kinds that a person can develop. These three types of hearing loss are placed in categories of severity and indicate what kind of treatment will be required. 

The type of hearing loss is based on the ear area that is affected by the condition. Our ears are divided into three general regions: the external, middle, and internal ear. All three regions play an important part in interpreting the sounds around us and can be prone to develop conditions that challenge our ability to hear.

Conductive

Conductive hearing loss is when a physical object blocks or impairs the ear’s ability to receive sound waves. This primarily affects the outer and inner ear as these are the part of the ear most prone to interacting directly with sound waves. 

The blockage can be a variety of things, from a traumatic injury like lodging a foreign object in the ear canal to infection causing a buildup of pus or mucus. Excessive ear wax can also cause conductive hearing loss. Conductive hearing loss can be a result of damage to the eardrum or the bones behind the eardrum called ossicles. This type of hearing loss is often repairable, if not completely, at least partially.

This blockage is considered to be mild and correctable without hearing aids. Loud sounds may present as distant and muted, but it doesn’t impair a person's ability to interact with their surroundings. 

Sensorineural

Sensorineural deals with the neurological aspects of hearing loss. This condition directly affects the nervous system and presents as a defective cochlea which is the nerve bundle of the ear. 

This type of hearing loss is severe and can, in most situations, be improved by hearing aids and cochlear implants. 

Mixed

Mixed hearing loss is self-explanatory and can develop at any time. A person who suffers a conductive hearing loss could have had a traumatic incident that damages their inner ear, and then suffers from conductive and sensorineural hearing loss. 

Mixed hearing loss ranges from mild to severe and can be treated by both hearing aids and reparative surgeries, depending on the severity of the case. 

Causes of Congenital Hearing Loss

A congenital condition is indicative of a health condition or impairment that is present from birth. This means that the condition is not acquired after birth but instead is the result of some kind of development defect. 

In congenital hearing loss, this condition is mostly the result of developmental issues that present at birth in the form of hearing impairment. The level of hearing loss that an infant can experience from congenital hearing loss varies. Early detection of hearing loss and assessment of hearing loss severity may improve an infant's chances of correcting or improving hearing.

Congenital hearing loss has multiple causes, all of which affect a baby during development. These causes can range from an infection to premature birth, low birth weight, or even maternal diabetes. It is possible in rare cases for the infant to acquire hearing loss as a result of traumatic injury at birth; however, that would not fall under a developmental problem. 

Here are more possible causes for congenital hearing loss:

• Anoxia (lack of proper amounts of oxygen)
• Jaundice 
• Maternal high blood pressure 
• Genetics

According to the American Speech-Language-Hearing Association (ASHA), the main reason for congenital hearing loss is due to genetic abnormalities. If a baby is born with a genetic disposition to having hearing loss, this can appear at birth or develop later in life. 

This condition would be caused by a parent of an infant passing on a gene that impairs the normal development of the hearing system. 

Symptoms of Congenital Hearing Loss

The sensorineural aspect of congenital hearing loss is most often credited to developmental issues at birth. The inner ear houses the cochlea, which contains the nerves that help take all the information from the ear to the brain, where sound is interpreted. 

This means that the symptoms of congenital hearing loss will be moderately severe to severe. However, this is not always the case! 

Treatment of Congenital Hearing Loss

The first step of treatment is diagnosis. This is administered by a series of auditory tests that assess the infant’s level of hearing loss. Once it has been confirmed that the infant has congenital hearing loss, treatment then becomes an option. 

Treatment for congenital hearing loss generally falls under four procedures: hearing aids, cochlear implants, reconstructive surgery, and auditory brainstem implants. 

Hearing Aids

Hearing aids are the most common form of hearing impairment treatment. These devices are simple in concept and are designed to be on or in-ear devices that amplify sound directly to the ear. 

When using hearing aids, it has been noted that the earlier a person implements hearing aids, the better. 

For infants, there are hearing aids that are specifically designed for their small ears, and it is generally recommended that they use the behind-the-ear style (BTE). This method of hearing aids is suggested due to the swallowing hazard risk that normal hearing aids have. 

Cochlear Implants

The inner ear houses the cochlea, and when there are developmental problems, an implant that directly stimulates the inner part of the cochlea known as the spiral ganglion can be applied. This works directly to stimulate your neural activity that helps to recognize sounds. 

Children with sensorineural hearing loss who receive cochlear implants may have hearing improvements. Studies have even shown that infants less than twelve months old who have received cochlear implants have better improvement than infants who receive the same treatment after twelve months of age. 

Auditory Brainstem Implants

This type of implant is one of the most recent forms of treatment and has the least amount of data. This extreme treatment directly integrates with the secondary neural activity, bypassing the cochlear nerve altogether.  

Reconstructive Surgery

In some cases, the child is born with an abnormality of the eardrum, ossicles (bones behind the ear) or the pinna (outside portion of the ear). Often these abnormalities involve some sensorineural hearing loss as well as conductive hearing loss. The conductive hearing loss component can be repaired in many cases, restoring at least a portion of the hearing.

Conclusion

Congenital hearing loss is a serious condition that affects many people. While it can seem overwhelming, rest assured that there are professionals who can help diagnose and treat, and hopefully control the level of hearing impairment an infant may have due to congenital hearing loss.  

“There is a great variety of possibilities and medical conditions which can lead to congenital hearing loss. The most important factors for success are early evaluation, proper examination and diagnostic testing, and planning by an Ear, Nose and Throat specialist.” - Drew Sutton, MD, Board-Certified Otolaryngologist.

 

Source:

Anatomy and Physiology of the Ear | Standrodchildrens.org

Congenital Hearing Loss | Iowa Head and Neck Protocols | medicine.uiowa.edu

Degrees of Hearing Loss | Hearing Health Foundation

Diagnosis and Management of  Congenital Sensorineural Hearing Loss | nih.gov

Hearing Loss: Hearing Aid, Causes,  Symptoms, Treatment & Types | clevelandclinic.org

Deafness and hearing loss fact sheet | WHO

Cochlear implantation in infants below 12 months of age | NCBI