Swallowing Difficulty Is Common After Head Trauma

Complex brain signals are required to chew and swallow

Unrecognizable person holding nachos with guacamole
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Parts of the brain responsible for producing speech and controlling the mouth and throat muscles can be damaged during head trauma. This damage then affects how the muscles and their associated nerves respond to messages from the brain or from pressure and reflex triggers in the throat. When the chewing and swallowing system doesn’t work right, it can lead to numerous complications including pneumonia.

Eating and swallowing difficulties may be a lack of coordination between the brain and the responsible muscles, although there may also be underlying tissue damage that contributes to the problem.

The Brain and Swallowing

There are 26 different muscles in the mouth, neck, throat and esophagus that the brain controls when food or fluid is consumed. The nerves that control these muscles receive signals from the brain so they can work in a coordinated manner. When the brain has suffered an injury from head trauma, the signals to these 26 muscles may become uncoordinated.

Functional MRI and PET scans of the brain show that swallowing is a complex process and that there are differences between swallowing on purpose versus swallowing by reflex when the back of the throat is triggered by fluid or a ball of food. Swallowing correctly isn’t limited to one specific area of the brain but involves numerous areas of the brain.

Damage to the brain from head trauma and associated bleeding, swelling and nerve cell death can prevent the swallow signals from moving from the brain to the mouth and throat, and back again.

Dysphagia from Brain Injury

The following terms are used to describe the complications that result from inadequate control over the tongue, mouth, throat and esophagus.

  • Dysphagia: difficulty swallowing
  • Dysarthria: difficulty vocalizing speech

There are four steps, or stages, that need to be followed when swallowing. They are called the oral preparatory phase, oral phase, pharyngeal phase and esophageal phase.  Dysfunction can occur in any one of these based on the location of brain injury

  • Oral preparatory phase: the food is introduced to the mouth, but there is difficulty chewing it correctly, mixing it with saliva and making it into a ball of food ready to be swallowed. This is often seen when there is subcortical brain injury.
  • Oral dysphagia: difficulty controlling the ball of food once it has been formed, and inability to get it to the right place for swallowing. Researchers believe the trigeminal nucleus and reticular formation may control this phase.
  • Pharyngeal phase dysphagia: the ball of food has made it to the back of the mouth and the top of the pharynx. The appropriate trigger doesn't happen so the food slowly glides down the back of the throat. This can result in the food getting into the lungs. Damage to the nucleus tractus solitaries may be involved in this swallowing issue.
  • Esophageal stage dysphagia: the food has made it past the throat and into the esophagus, but it gets stuck. The food can also travel backward and get into the lungs. Signals to the esophagus that trigger pushing the food down to the stomach are required during this phase, and once again the nucleus tractus solitaries is believed to be responsible, in addition to the nucleus ambiguus and dorsal motor nucleus.

Researchers are still studying the complex mechanisms responsible for controlling swallowing.

What to Look For

Some of the initial warning signs of a swallowing problem include:

  • Eating or drinking causes immediate coughing
  • Coughing right after swallowing
  • Choking when trying to swallow
  • Uncoordinated chewing or swallowing
  • Pocketing of food between the cheek or gum
  • Leakage of food or liquid through the nose
  • Drooling/leakage of liquid or food from the mouth while eating or drinking
  • Eating very slowly
  • Visible grimacing or difficulty swallowing
  • Not eating or drinking enough
  • A wet gurgling cough
  • Complaints that if feels like food is getting stuck in the throat
  • Pain behind the sternum after eating

Since it is essential to be able to speak, cough and swallow, anyone with difficulty in these areas needs to see a speech language therapist. Specific testing can help determine the underlying problem behind losing one’s control over this essential function.

The Role of the Speech Language Therapist After Head Trauma

You might not think that a speech-language therapist  can help someone who has difficulty swallowing. However, this type of therapy addresses a number of issues that often go together such as controlling the lips, tongue and jaw, which are essential for both speech and swallowing.

A swallow therapist may start with an interview, then examine the mouth and then provide food and fluids at varying levels of thickness to determine how a person responds.

There are numerous, more invasive tests that may be used when it’s necessary to understand exactly which phase of swallowing isn’t working correctly.

Common Swallow Tests

  • Barium Swallow: Barium is a type of contrast that shows up on x-rays. A patient is given fluid or a pill coated with barium and then x-ray is used to see how the system functions, and if the pill can pass from the mouth to the stomach.  
  • Dynamic Swallow Study: Food is coated with the barium contrast and consumed. The chewing process is visualized on x-ray, including the ability to form food into a ball, move it to the back of the throat and swallow it. It’s possible to see if food is getting into the lungs.
  • Endoscopy/Fiber-Optic Swallow Evaluation: A tube is threaded down into the throat and pictures of the esophageal and tracheal muscles are taken while swallowing.
  • Manometry: A small tube is inserted into the throat to measure pressure while swallowing. This may be one way to determine if weak muscles strength is contributing to the poor movement of foods.

Recovery Milestones After Head Trauma

A couple key milestones need to be met from the brain injury perspective when determining how well someone will be able to swallow and how likely it is that rehabilitation will bring this function back.

  • There needs to be consistent improvement in the level of consciousness. Appropriate responses to a variety of physical, verbal and visual stimuli are necessary. As independence increases and responses become more appropriate, it is more likely that the brain will also respond appropriately to the introduction of food and fluids.
  • The ability to stay focused on activities and reduce confusion is also important. Participating in swallow therapy, and getting through an entire meal without any problems, requires concentration.

There are a number of specific swallow exercises that therapists perform with head trauma patients, and that families can also help the head trauma survivor practice.

Signs That Swallowing Will Return After Head Trauma

Some signs that the rehab team looks for to indicate control over swallowing is coming back include:

  • Staying focused and understanding what is going on in the environment
  • Correcting mistakes when trying to do any type of activity
  • The problems with swallow are primarily in the chewing and creation of the food ball, not in controlling the muscles of the throat
  • If food goes down the wrong way, there is a strong cough to protect the airway
  • The ability to take deep breaths and breathe effectively is present
  • The ability to consume enough calories and nutrition by eating

What Can You Eat?

In the beginning it may be necessary for food and fluids to have a consistent texture. The swallow therapist determines which type of texture works best for a patient’s specific swallowing difficulty. Textures include:

  • Pureed: Selected when there is mouth and tongue weakness, with related difficulty chewing and clearing the mouth when swallowing. A pureed diet reduces the chance that a larger piece of food will get stuck and block the airway
  • Mechanical soft: these foods are ground or cut up into small pieces. They are for individuals who have graduated from a pureed diet, but are still at risk of choking on larger pieces.
  • Soft: this diet is for individuals with mouth muscle weakness who have difficulty adequately chewing foods with a regular texture. Foods such as bagels or steak that require strong chewing and preparation for swallowing are avoided.
  • Soft cut-up: is often used for head trauma survivors who have additional difficulties such as determining the right side of food to be placed in the mouth, or who have upper extremity weakness which makes it difficult for them to cut their own food.
  • Regular: A regular diet has no restrictions.

Artificial Feedings

Sometimes the body’s ability to swallow does not return. In these cases, it becomes necessary to start artificial feedings.

  • IV Feeding: A short-term solution may be to provide nutrition through the IV. This might be used if there was damage to the digestive system that prevented consumption of nutrition through a normal route.
  • Nasogastric Tube: This is a temporary type of artificial feeding. The tube goes in through the nose and down to the stomach. It can be used right after head trauma while someone is still on a ventilator, or has other limitations preventing them from swallowing regular food.
  • PEG Tube: PEG stands for Percutaneous Endoscopic Gastrostomy. A feeding tube is surgically placed through the abdominal wall into the stomach. This is a long-term approach to artificial feeding.

Head Trauma Recovery and Swallowing

Recovering from head trauma can be a slow process. There may be numerous challenges to overcome, with swallowing just being one of them. Since nutrition is such an important element for muscles, nerves and tissues to heal, swallowing will be an early issue addressed by the head trauma team.

Sources

American Speech, Language and Hearing Association (2016) Traumatic Brain Injury. http://www.asha.org/public/speech/disorders/TBI/

Hamdy, S. (2006) Role of cerebral cortex in the control of swallowing, GI Motility online doi:10.1038/gimo8

Lang, I. (2009) Brain stem control of the phases of swallowing. Dysphagia. 24(3):333-48. doi: 10.1007/s00455-009-9211-6

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