Recovering from Mild Traumatic Brain Injury: The Important Role of Brain Filters

NB the below in entirely (NB also, I have not asked for permission yet!!) from the link https://www.brainline.org/article/recovering-mild-traumatic-brain-injury  from 2009 – which I will follow up!

Much of the brain’s energy is used to filter out irrelevant or unnecessary information. Just imagine what it would be like with no filter on your brain. All the sounds, smells, images, and feelings would come crashing in at the same time. The overstimulation would probably paralyze you and prevent you from taking any action.

After sustaining MTBI, most of the brain’s energy is diverted to basic functioning, and little is left over for filtering or censoring. Trivial or insignificant thoughts may often have the same weight in your mind as important ones. This can make decisions difficult. You may find that your brain gets stuck on an idea or phrase that keeps replaying, and this uses a great deal of brain energy.

New sensitivities can be very challenging and baffling for the injured person and their loved ones. Going into a restaurant or store where there are fluorescent lights, background music, or a great deal of visual stimuli may cause the brain to shut down. Most people say that they want to get into a quiet place and rest their brain after that experience. That is why it is so important to plan your social activities when fewer people are around and when there is less commotion.

Hearing Problems and Hypersensitivity to Sound

As mentioned above, a common symptom of traumatic brain injury is hypersensitivity to sound. This is called hyperacusis. The auditory system becomes very sensitive to environmental noise, and you may discover that you have great difficulty going to restaurants, the grocery store, or social gatherings.

Many individuals report staying at home to avoid the assault and feelings of being overwhelmed in these noisy situations, or they may go out only at times when places are less crowded and less noisy. Any noise can assault and overwhelm a person with MTBI, including a vibrating refrigerator, heating system, or humming fan, etc.

An excellent accommodation for hyperacusis is ear filters. The actual name is ER 15/25 noise-dampening ear filters. These are custom-fitted earplugs, originally made for musicians, but they now have been adapted for individuals with traumatic brain injuries. Consult an audiologist at a speech and hearing clinic to obtain filters. Current studies show that filters can reduce overstimulation to the auditory system and allow you to participate in social situations without becoming overwhelmed. An advantage of using ear filters is that you can put them in for brief periods of time and take them out when you don’t need them. They can be made with clear materials and are therefore less visible. The ear molds for these filters are made by an audiologist, or a specialist trained in testing hearing and treating hearing problems.

The ear is susceptible to blast injuries. Unique patterns of injury occur with bombs and explosions that are seldom seen outside of combat. The eardrum or tympanic membrane may be perforated in the blast and should be evaluated with an otologic evaluation and audiometry (hearing evaluation) to determine whether there is an injury to the ear.

Eardrums can be replaced, but observational studies over the years have shown a high rate of spontaneous healing of ruptured eardrums following blast injuries. Whether a perforated eardrum heals spontaneously depends on the size and placement of the perforation.

Two types of hearing loss are associated with blast-induced injuries. One type is called conductive hearing loss, and the second type is sensorineural hearing loss. The high-frequency sounds are more likely to be affected in blast injuries. Many individuals complain of tinnitus or ringing in the ears, and it is common to have balance problems, dizziness and/or vertigo associated with perforated eardrums. It is very important to keep the ear canal dry until the eardrum has healed.

Vision Problems and Sensitivity to Light

You may notice that your eyes don’t seem to be working in the same way that they did before your brain injury. Some eye doctors specialize in vision problems resulting from an acquired brain injury. They can help diagnose visual problems related to the injury and provide exercises or special glasses to help with recovery.

Because the visual changes are sometimes subtle, you may pass them off as being related to fatigue or brain fog. Aiming and focusing the eyes are linked, and that is why objects may appear to move, be seen as double, or blur in and out. Some individuals also complain that it is difficult to focus quickly from near to far or far to near.

Vision problems and cognitive deficits may compound one another. The most common complaints related to visual problems associated with brain injuries include light sensitivity, headaches, double vision, fatigue, dizziness, difficulty reading, or loss of peripheral visual fields. You may feel a heightened sensitivity to light and may even need to wear your sunglasses inside. You may have to request that fluorescent lights be turned off. Computer and reading tasks may take longer than usual, and tend to be more confusing and tiring.

A behavioral optometrist or a doctor who belongs to the Neuro-Optometric Rehabilitation Association can perform a comprehensive vision evaluation and help you determine the best course of action. Some individuals with visual deficits can benefit from specific lenses or prisms in their glasses and/or from vision therapy.

If you have vision problems associated with MTBI, this may deplete your energy and decrease your ability to perform daily living tasks. It is unrealistic to return to work
until vision problems are addressed. If your job requires a great deal of reading or moving your eyes between the desk and a computer screen, you may find that your errors increase because of difficulty tracking. It is very important to address visual problems, as they can increase the recovery time.

Dizziness and Vertigo

Feelings of dizziness and nausea are common after a head injury. You may notice that these symptoms come and go depending on the activity you are doing. Dizziness may refer to distinct symptoms, one of them being vertigo. This is when you feel as though you are spinning, and sometimes you feel nauseated or like you may lose your balance. Researchers have discovered various causes for this symptom, such as problems with your inner ear, impairments in eye movements, clenching and grinding your teeth, tightness in the neck muscles, etc.

Dizziness may also originate from cervical neck injuries. The primary symptoms with this type of dizziness include feeling off balance, lightheadedness, and the sensation of floating. If you have what is called benign paroxysmal positional vertigo (BPPV), you may notice that you have a sudden attack of spinning when you turn over in bed, change your head position quickly, or reach for an item above your head. This usually lasts for less than a minute, but you may be left with feelings of nausea and dizziness for a longer time.

The Mayo Clinic developed a technique called canalith repositioning (1994). where the head is maneuvered in various positions to help eliminate the dizziness. This is accomplished by moving the calciumcrystals in the inner ear. Medications that can help dizziness are also available. Be sure to consult with your doctor to see if you need a referral to an ear doctor who specializes in traumatic dizziness and/or an eye doctor who specializes in traumatic vision syndrome.

Changes in Energy Reserve After Injury

Healing takes a tremendous amount of energy. The diagram in Figure 1 illustrates functioning before and after the injury. It shows how the uninjured brain can perform many activities that are physical, cognitive, and emotional throughout the day, and still have a reserve of energy. After a brain injury, it takes more energy to deal with cognitive and emotional issues, leaving little or no reserve.

The brain uses more energy than any other organ in the body. Before you were injured, you had a pool of reserve energy available when you overextended yourself. Following your injury, nearly all of your energy is required to perform the most basic functions just to get through the day. If you are continuing to work, you may find that when you get home, you must rest and not engage in other activities as before.

Your energy reserves at this point are almost nonexistent. When you push too much you may reach overload, and the extreme fatigue may cause your brain and body to shut down. This exhaustion can also amplify all of your symptoms, and cause an emotional reaction.

Almost Immediately after an injury it becomes clear that you don’t have the same amount of energy that you previously did. It is important to emphasize the need for rest and conserving energy. For a while you may be unable to do as much as you used to and may need to take time out for rest — Brain Rest. Lay down during the day for naps. Even if you don’t sleep, resting your head and lying down may make a significant difference in your recovery.

Posted on BrainLine November 20, 2009. Reviewed July 26, 2018.

From Recovering from Mild Traumatic Brain Injury: A handbook of hope for our military warriors and their families by Mary Ann Keatley, PhD, CCC and Lauar L. Whittemore. Copyright © 2009 the Brain Injury Hope Foundation. Reprinted with permission. www.braininjuryhopefoundation.org.