- As an Invisible Condition, Hearing Loss Often Goes Ignored - October 17, 2022
- All About Assistive Listening Devices & More - October 1, 2022
- Tired of Loud Restaurants? Time for a Hearing Test! - September 17, 2022
In the United States alone, there are over 1 million hospitalizations per year as a result of traumatic brain injury (TBI). It’s estimated that if we include incidents of TBI that do not result in hospitalization, the number climbs to around 3 million. It’s the leading cause of death or disability in the US. Injuries to the brain from blunt force trauma or rapid acceleration or deceleration can have a multiplicity of effects on a person. Since every sensation involves the brain in some way, brain injuries can affect all five senses, as well as memory and other cognitive abilities.
Head trauma can affect not only the brain but any of the organs of the head, including the ears. When hearing loss occurs after head trauma, it could be the result of damage to the ears, the brain, or both. Even some catastrophically loud sounds can cause hearing loss as a result of brain injury, as opposed to ear injury. Even mild concussions can cause hearing loss. TBI has been little-understood, but knowledge is growing; and it has been in the news more often in recent years as statistics are compiled regarding the long-term effects of repeated, minor head traumas on the brains of American football players.
The most likely events resulting in TBI are car accidents, explosions and sports accidents. Head traumas are categorized as mild, moderate or severe, and all levels can cause hearing loss. The population most at risk for head injuries in males age 15-35 – the group that demonstrates the most risk-taking behavior.
Trauma-Related Ear Damage
Head trauma has a wide range of potential effects, based on what part of the head, how hard, and by what type of material the trauma was induced. Setting aside the hearing-related effects that head trauma can have on the brain, there are a number of things that can go wrong directly with the ear. Some ear injuries may heal or be cured with currently available surgeries, while others are permanent.
Head trauma can rupture the eardrum or cause the ossicles (three tiny bones) in the middle ear to break or dislocate. These are both examples of conductive hearing loss. These are frequent injuries when head trauma occurs as these parts of the ear are close to the outside of the head, and often in harm’s way when trauma occurs. Head trauma can also damage the tissues and membranes of the inner ear, or reduce the flow of blood to the cochlea. These events would be considered examples of sensorineural hearing loss.
In some cases, trauma can cause damage to the myelin sheaths around the auditory nerve, which transports sonic information in the form of electricity from the inner ear to the brain. This causes this transport process to be less efficient, effectively “leaking” auditory information as it travels. This usually results from repeated minor head trauma, and creates a form of hearing loss that we call “hidden hearing loss.” A person with hidden hearing loss will be considered to have “normal” hearing by the standards of a hearing test, but once they are out in the world with a multitude of sounds around them, they’ll be unable to distinguish between sounds as only a portion of each sonic thread is making its way to their brain.
Hearing Loss as a Result of TBI
TBI causes a shearing and stretching of brain tissues. When the position of this finely-tuned neural network is changed, the parts relate to one another differently. Common hearing-related complaints of the recently concussed include tinnitus, aural fullness, sensitivity to loudness, hearing loss, distorted hearing, earache and dizziness. It can be difficult to locate where sounds are coming from. As the brain struggles to regain its bearings – its sense of where its elements are in relation to one another – the senses will frequently seem distorted.
For treatment of hearing loss related to head injury or TBI to be effective, the patient should be in frequent contact with a hearing healthcare practitioner. Since “head trauma” can cause so many types of specific injuries anywhere along the auditory pathway, from the eardrum to the brain itself, and because it is common for more than one part of the pathway to be damaged as the result of a single trauma, it can take some time to identify what treatments are needed.