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Understanding the Side Effects of Traumatic Brain Injury: A Comprehensive List

doctor explaining the effects of traumatic brain injury to patient

TBI can cause a variety of side effects, some more severe than others. Because no two brain injuries are identical, however, every TBI patient can experience slightly different symptoms.

To make matters more difficult, some TBI side effects do not develop until several months after the initial injury. Therefore, it is important for patients to understand the potential effects of traumatic brain injury, so that they can recognize the early signs.

This article contains a comprehensive guide to the most common effects of TBI. We also briefly discuss treatment options for specific side effects at the end of each section.

Before diving into specific symptoms though, it will help to understand the causes of TBI symptoms.

What Causes TBI Side Effects?

TBIs occur after a bump or blow to the head. If this blow to the head is strong enough, it can cause the brain tissue to swell and push up against the inside of the skull. When this occurs, blood circulation is cut off from those parts of the brain, causing oxygen deprivation and tissue death.

In addition, some injuries cause the brain to twist or shake. As the brain twists, brain tissue slides back and forth until the long connecting fibers in the brain (axons) tear. This is known as axonal shearing.

This tearing disrupts the messages that neurons send, resulting in loss of function, which causes the different effects of brain injury covered on this page.

Symptoms of brain injury will vary depending on where the damage occurred. For example, an injury to the frontal lobe will cause different side effects compared to damage to the parietal lobe.

In the following sections, we will take a look at some of the most common TBI side effects.

Part 1: Physical Effects of Traumatic Brain Injury

therapist teaching woman to walk again using parallel bars

The primary motor cortex controls most intentional physical movements. Therefore, some of the most common effects of traumatic brain injury are movement disorders.

Some physical skills that a brain injury can affect include:

  • Balance
  • Movement
  • Muscle strength and control

Below are some examples of the physical complications of traumatic brain injury:

Tremors are an uncontrollable, rhythmic shaking of certain parts of the body, usually the hands.

Tremors are sometimes classified by their appearance and origin. The most frequent type of tremors to develop after a head injury are known as cerebellar tremors. With these tremors, the shaking only occurs at the end of a purposeful movement.

As the name suggests, cerebellar tremors are caused by damage to the cerebellum or its neural pathways.

Learn more about tremors after brain injury »

Dystonia refers to sustained, involuntary muscle contractions that force people into abnormal positions. The most common areas that dystonia affects include the neck, jaw, mouth, and arms.

With all types of dystonia, the side of your body opposite the brain-injured side is the one affected. For example, if you suffered a left-side brain injury, your right side would experience dystonia.

Learn more about dystonia after brain injury »

Sometimes, the neural connections between the brain and muscles are completely severed after a TBI. This leads to paralysis on one side of the body, also known as hemiplegia.

Treatment for hemiplegia should involve passive exercises to prevent contractures and rewire the brain through neuroplasticity.

Learn more about brain injury paralysis »

Spasticity is a condition in which your muscles become stiff and tight. It occurs after damage to the part of the brain that controls voluntary movement. This damage leads to an imbalance of signals between the brain and the muscles.

Normally, your brain sends messages through the spinal cord to tell your muscles when to contract or relax. This helps your body maintain a comfortable muscle tone.

However, after a brain injury, this message flow can be interrupted, and your muscles no longer know whether they are supposed to tighten or relax. As a result, the muscles stay in a constant state of flexion, also known as spasticity.

Learn more about spasticity after TBI »

Contractures occur when muscle fibers shorten, causing a decrease in range and function. They typically arise if spasticity is left untreated.

You can treat contractures with a combination of splints, stretching, and passive range of motion exercises.

Learn more about contractures after brain injury »

Fatigue is one of the most common effects of traumatic brain injury. Because the body and brain use a significant amount of energy to fuel the healing process, there is not much energy left over to perform other activities. This can lead to extreme cognitive fatigue and drowsiness, also known as hypersomnia.

Learn more about post-traumatic hypersomnia »

Probably the most frequently reported physical effects of traumatic brain injury are headaches and migraines. These can occur for several reasons, such as:

  • Surgical pain
  • Small collections of blood on the brain
  • Muscle tension
  • Inflammation
  • Nerve damage

In addition, genetics can play a role in migraines after brain injury. For example, if you were prone to migraines before your injury, you will most likely experience more afterwards.

Learn more about headaches after TBI »

Foot drop, sometimes called drop foot, occurs when a person struggles with dorsiflexion: the movement of lifting the front part of their foot up towards their shin.

Foot drop after TBI is usually a result of damage to the neural pathways responsible for activating the anterior (front) muscles of the leg. The brain injury disrupts the central nervous system’s ability to send signals to these muscles, making it difficult if not impossible to control dorsiflexion.

Learn more about foot drop after brain injury »

Dysphagia is a common side effect of traumatic brain injury that makes it difficult to swallow. It often affects people in the early stages of TBI recovery.

To treat dysphagia, TBI patients will work with a speech therapist, who will teach you exercises to strengthen your swallowing muscles.

Learn more about dysphagia after head injury »

Traumatic brain injury can also lead to severe balance issues. This most often occurs after damage to the cerebellum.

After a brain injury, you might have trouble holding yourself upright when sitting or standing. You also can feel a strong sense of dizziness.

Learn more about balance issues after head injury »

To treat these physical effects of traumatic brain injury, patients are strongly encouraged to take part in outpatient physical therapy.

Physical therapists can help you engage your brain’s natural healing mechanism to repair lost neural connections and restore functional movement.

While physical therapy is helpful, brain injury also causes cognitive and sensory issues that must be addressed by other treatment methods. We’ll look at these symptoms next.

Part 2: Cognitive Effects of Traumatic Brain Injury

close up of man's hands holding 3D hologram image of human brain

There are multiple possible cognitive side effects of TBI. These most often occur after a frontal lobe injury, which affects a person’s ability to process information.

The following are the most common cognitive effects of traumatic brain injury:

Traumatic brain injuries don’t usually damage a person’s personal memories. However, they do frequently impair a person’s short-term and working memory. Doctors call this type of memory loss anterograde amnesia.

These types of memory are what the brain uses to hold on to information it just received. That is how you can know what the person talking to you just said, for example.

Learn more about amnesia after head injury »

Conversation requires a joint effort from multiple areas of the brain. If any of these regions sustain damage, you can lose your ability to speak to and understand others.

The most common language difficulties are:

  • Receptive aphasia (problems understanding spoken words)
  • Expressive aphasia (problems producing the right words)
  • Dysphagia (slurred speech)

Learn more about aphasia after TBI »

Agnosia is a rare cognitive disorder that causes problems with recognition. In other words, a person with agnosia would see a pencil, but would not recognize it as a pencil. If you asked them what it was, they could not tell you.

One common type of agnosia is prosopagnosia. Also known as face-blindness, this type of agnosia makes it impossible for a person to recognize familiar faces. For someone with prosopagnosia, staring at the face of their spouse would feel like staring at a stranger.

Learn more about agnosia after head injury »

This cognitive effect of brain injury makes it difficult to focus on one activity for long periods. It also makes it harder for a person to complete whatever they are doing.

Concentration problems are partly a result of memory problems since the person often can’t remember what they were doing and loses focus. But it’s also a symptom of executive dysfunction after brain injury, which is caused by damage to the frontal lobe.

Learn more about attention problems after brain injury »

Patients with this TBI side effect have a hard time initiating an activity and finding internal motivation.

This disorder can look to others a lot like laziness, but in fact, it is not. Rather, the person’s brain can no longer sort out the steps needed to start something new.

For example, a person might want to continue their therapy exercises at home. But the mental effort required to plan that activity overwhelms them, and they end up preferring to watch TV again.

Learn more about low motivation after traumatic brain injury »

Some cognitive effects of traumatic brain injury cause a person to fixate on a certain topic. Psychologists refer to this as perseveration.

Perseveration is a thought disorder that causes prolonged repetition of a word, phrase, or gesture after they have ceased being appropriate. It also involves the inability to shift goals or tasks when required.

This disorder can unfortunately make it much more difficult for people with brain injuries to interact with peers socially.

Learn more about perseveration after brain injury »

Traumatic brain injuries can also impair a person’s insight or self-awareness. In mild cases, TBI patients might struggle to recognize their own limitations. This can contribute to impulsive behavior.

In severe cases, on the other hand, self-awareness can be so diminished that the person does not even know they have an injury. Doctors call this condition anosognosia.

Learn more about lack of insight after TBI »

The frontal lobe plays a crucial lobe in a person’s ability to empathize. For example, the orbitofrontal cortex helps us react appropriately to another person’s feelings.

Therefore, if any of these brain regions become damaged after brain injury, a lack of empathy can occur. This can cause TBI patients to display self-centered or even childish behavior.

Learn more about lack of empathy after brain injury »

Because brain injury often affects a person’s self-awareness, it can often impact a person’s social skills.

The following are some signs that a person struggles with social communication:

  • They fixate on one topic and try to bring every conversation back to it
  • They give too little or too much information
  • Their responses might not make sense
  • They ramble or repeat themselves

Learn more about improving social skills after brain injury »

For most cognitive problems, the best way to treat them is to work with a speech therapist. Speech therapists are trained to deal with the cognitive effects of brain injury and can teach you effective ways to cope.

Part 3: Emotional Complications of Traumatic Brain Injury

boyfriend comforting upset girlfriend who is struggling with the emotional effects of traumatic brain injury

Besides cognitive side effects, traumatic brain injury can cause a person to experience emotional changes. Some of these are a result of direct damage to the emotional center of the brain. Others are caused by a combination of circumstances related to brain injury.

Below are a few of the most common emotional effects of brain injury:

Extreme mood swings, also known as pseudobulbar affect, occur after damage to areas of the brain that regulate emotions. These brain regions help us control our:

  • Appropriate emotional response  
  • Awareness of our own emotions and others
  • Ability to inhibit emotions

After a frontal lobe injury, patients can lose these skills. As a result, they may experience random bouts of laughter and/or crying.

Learn more about mood swings after brain injury »

An apparent lack of emotion is a common symptom of traumatic brain injury. Most people with this problem do not actually lack emotion. Rather, they cannot show normal signs of emotion with their facial expressions or voice.

This condition is also known as flat affect and is caused by damage to the frontal lobe of the brain. A person with flat affect often has a flat, monotonous voice, causing them to sound almost robotic.

Learn more about lack of emotion after brain injury »

Some of the most distressing effects of brain injury are the personality changes that can occur. For example, a previously good-natured and friendly person might become irritable and impatient after their TBI.

There are multiple reasons why personality changes appear after a brain injury, but they most often occur after damage to the orbitofrontal cortex.

Learn more about personality changes after brain injury »

Unfortunately, brain injury also increases a person’s risk of experiencing chronic depression and anxiety. In fact, according to the Mayo Clinic, the risk of TBI patients developing depression is two to five times higher than the general population.

The ultimate cause of depression and anxiety after brain injury is unknown. However, scientists have identified a few factors that might play a role, such as changes in brain chemistry and emotional struggles.

Learn more about depression after brain injury »

Fortunately, a neuropsychologist can help TBI patients overcome most of these emotional complications. In fact, one of the best treatments for these symptoms is cognitive-behavioral therapy. Talk to a psychologist for more information.

Part 4: Sensory Effects of Traumatic Brain Injury

man plugging ears and squinting in front of blurred, bright, outdoor background

Finally, traumatic brain injury can cause a variety of sensory side effects. These typically occur after damage to the parietal and temporal lobes.

The following are the most common sensory side effects of brain injury:

Some brain injuries can also lead to a decreased sense of smell. Sometimes it can even cause a person to lose their ability to smell entirely. This condition is known as anosmia.

Learn more about anosmia after head trauma »

Damage to the somatosensory cortex can cause patients to experience numbness and tingling sensations. Numbness can also develop after nerve damage, which is a common side effect of traumatic brain injury. For example, damage to the trigeminal nerve in your jaw will lead to numbness in your face.

Learn more about numbness after head injury »

Brain injury can lead to several different types of hearing loss. The most common type of hearing loss due to TBI occurs after damage to the auditory nerve. Other types can result from temporal lobe damage.

Head injuries can also cause a persistent ringing in the ear, known as tinnitus.

Learn more about hearing loss after head injury »

Vision loss after a head injury occurs after damage to the eye structures themselves or damage to the visual pathways. These pathways consist of cells and synapses that carry information from the eye to the visual processing centers in the brain.

There are several different types of visual defects that can arise after a brain injury, such as blurred vision, double vision, and visual field loss.

Learn more about vision loss after head injury »

Spatial neglect, also known as left neglect, is a sensory awareness problem caused by damage to the parietal lobe. In particular, it is associated with lesions on the posterior parietal cortex.

It causes a person to lose all awareness of one side of their body, usually the left side. This means they cannot hear or see anything from the neglected side, for example. They also will rarely move the left side of their body, despite having normal muscle strength.

Learn more about left neglect after brain injury »

Sensory problems can vary in severity and types. Therefore, these issues will require specific, personalized treatments from an occupational therapist. Most treatments will involve learning adaptive tactics to compensate for your lost senses.

Understanding TBI Side Effects

TBI is a serious medical condition that can cause life-changing side effects. However, many of these effects are treatable, especially if you can catch them early. That’s why it is so crucial to educate yourself and others about the possible symptoms that can occur. 

We hope this guide to the most common effects of traumatic brain injury empowers you to overcome the obstacles you may face after your injury.

Featured Image: ©iStock/Drazen Zigic

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