Effects of a Brain Injury

Every brain injury is different. The effects of a brain injury will vary from person to person.  The kind of difficulties experienced also depend on which part of the brain is injured. This page will give you some idea of the possible consequences. Not everyone will experience all these effects.

The brain is so complex and is responsible for so many things that the effects of a brain injury can be far reaching and impact our abilities in so many ways, including effects on our body and senses, our communication abilities, our thinking skills, our emotions and behaviour.

We have broken down the possible effects by section.  Click on each section to expand.

Effects of a Brain Injury on the Body and Senses


Many people experience extreme tiredness (fatigue) following a brain injury.

Disturbed Sleep

A large proportion of people with a brain injury experience sleep difficulties. Disturbed sleep at night can also lead to drowsiness during the day.

Headaches and/or Pain

Headaches and pain are quite common after a brain injury. They can vary in severity and frequency.

Right or Left-sided Weakness

The right side of the brain controls the left side of the body, while the left side of the brain controls the right side of the body. Depending on which part of the brain is injured, the person may have a physical weakness mainly on one side of the body. This is a common problem for people after a stroke.

Balance and Coordination

Difficulties with balance can make it more difficult to walk unaided. The person affected may also have difficulties with coordinating their movements – particularly fine motor movements, such as tying shoelaces or buttoning a jacket.

Sight, Visual Perception and Sensory Difficulties

Difficulties with sight and/or visual perception can include problems with seeing things far away, judging distances, reading maps, doing puzzles and recognising things. Visual Perception is the mental process of recognising and interpreting things we see.
The senses of smell, taste or touch can also be affected. Some people may have difficulties with hearing; for example, experiencing ringing or buzzing noises (Tinnitus) or become very sensitive to noise.


Seizures are common after a traumatic brain injury but they can also occur following other types of brain injury.

Seizures and Epilepsy

Cells in the brain communicate using electrical messages. When these electrical messages are suddenly disrupted, the person can have a seizure.

A seizure may cause a loss of consciousness, involuntary movements, a change in behaviour or a combination of all these. If someone has more than one seizure, they may be diagnosed as having Epilepsy.


A brain injury can affect a person’s ability to control their bowel or bladder.

Swallowing Difficulties

A difficulty with swallowing is called Dysphagia. Dysphagia is common after a stroke. It is caused by damage to the nerve cells that control the muscles used for chewing and swallowing.

Effects of a Brain Injury on Communication and Thinking Skills


This is the sending and receiving of information between two or more people. After a brain injury, some people have trouble communicating. Common communication difficulties are:

  • Dysarthria is a condition where the person affected may speak quickly, slowly, quietly or with a slur. After a brain injury, this can happen due to weakness in the muscles of the face, tongue, voice box and/or the muscles used for breathing.
  • Aphasia is any impairment of language.
    • Receptive Aphasia is when someone has difficulty understanding written language and what people are saying.
    • Expressive Aphasia is when someone has difficulty talking and expressing ideas. They may also find writing difficult.
  • Apraxia of Speech is when someone has difficulty coordinating the muscles they use to speak. The messages from the brain to the mouth are disrupted. The muscles are not weak but the person cannot move them in the way needed to make the correct sounds.


It is very common to have difficulties with memory after a brain injury. These can include problems with remembering skills we had mastered, conversations, appointments or even important events in our lives.

Attention and Concentration

It is also common to have difficulties with concentration after a brain injury (the words ‘concentration’ and ‘attention’ are interchangeable). The person affected may become easily distracted, have trouble keeping track of what is being said or done, experience information ‘overload’ or have difficulty doing more than one task at a time.

Information ‘Overload’

Many people have difficulty taking in, or processing, larger amounts of information following a brain injury. They may also be slower at processing the information. These difficulties can result in the person feeling overwhelmed, frustrated or excluded. They may find it helpful to have information broken down into smaller points and to have extra time to respond.

Planning, Reasoning and Making Decisions

Executive Functions are a group of very important skills. We use these skills for things such as solving problems, planning, making decisions and controlling our behaviour. If the frontal lobes of the brain are injured, these skills can be affected.

Effects of a Brain Injury on Emotions and Behaviour

Irritability and Anger

Some people may experience increased irritability and anger following their brain injury. There are a number of reasons for this: for example, damage to the frontal lobes or a reduced ability to cope with frustration.

Some people find they become more easily overwhelmed in crowded or busy situations. Other causes of anger include the person misinterpreting why someone did or said something. Irritability and anger may result in the person affected doing things such as swearing, breaking things or acting inappropriately.

Reduced Awareness (Reduced Insight and Lack of Insight)

Sometimes after a brain injury, a person may not be aware of their difficulties. This is often referred to as having ‘Reduced Insight’ or ‘Lack of Insight’. Changes in insight are often as a direct result of the brain injury.

Depression, Anxiety or Loss of confidence

Some people experience difficulties with their mood after a brain injury. There are a number of reasons for this, including chemical and physical changes in the brain as a result of their injury. Changes in someone’s mood can also emerge as they begin to come to terms with the impact of their brain injury. This can lead to a loss of confidence, lowered self-esteem and sometimes depression.

Low Motivation (Apathy)

Difficulties with motivation are commonly seen after damage to the frontal lobes of the brain. The person affected may have a lack of motivation to do activities, to set goals or to work towards achieving goals.

Inability to Control Emotions (Lability)

Sometimes after a brain injury a person can no longer control how they express their emotions. This is known as Emotional Lability. They may move quickly from one strong emotion to another, often in ways that may seem inappropriate; for example, they may laugh in a situation that is actually sad.

Impulsivity and Inappropriate Behaviour

Some people may become disinhibited after their brain injury. This means they may have less control over their behaviour, they may be more impulsive or say and do things without considering the consequences; for example, they may blurt out a hurtful remark that they did not intend.


After a brain injury, some people may lose their ability to be flexible in different situations. This problem may make them seem difficult or unreasonable.

Difficulties with Empathy

Some people, due to their brain injury, find it more difficult to identify with other people’s feelings. This lack of empathy may make them seem self-centred. This can be difficult for family members and friends.

Sexual Difficulties

Sexual difficulties are common after a brain injury. This can be due to many reasons including pain or changes in movement, touch or communication. The person affected may experience difficulty enjoying, or having,  sexual activity. Some medications can also lower sex-drive. In addition, many people experience depression, anxiety or changes in how they feel about themselves and/or their body after their brain injury.

How exactly each person is affected, will depend on factors such as which parts of their brain were injured and how severely. Naturally, the person’s intimate relationship with their partner will also be influenced by what it was like before the injury.

Effects of a brain injury to the various lobes of the brain

Some Effects of an Injury to the Frontal Lobes

The frontal lobes are particularly vulnerable to injury because they are large and are at the front of the brain. An injury to the frontal lobes can lead to a number of changes including:

  • Changes in personality.
  • Difficulties with attention and taking in information.
  • Emotional responses may be reduced.
  • Difficulties with motivation (Apathy) or getting things started (Initiation).
  • Changes in the ability to control behaviour (Disinhibition). This means that the person may be more impulsive. They may say or do things without considering the consequences.
  • Reduced self-awareness (Anosagnosia).
  • Poor judgment and decision-making.
  • Difficulty planning things and meeting goals.
  • ‘Black and white’ thinking (Concrete Thinking).
  • Irritability and less tolerance of frustration.

Some Effects of an Injury to the Temporal Lobes

  • Difficulty in recognising faces, things or places.
  • Difficulty understanding or remembering what people say.
  • Difficulty reading.
  • Difficulty recognising objects.
  • Short-term memory difficulties.
  • Changes in sexual behaviour.
  • Increased aggression.

Some Effects of an Injury to the Parietal Lobes

  • Difficulty naming objects (Anomia).
  • Difficulty in distinguishing left from right.
  • Difficulties with hand-eye coordination.
  • Difficulty making sense of what we see even if we do not have a visual impairment (Visual Perceptual difficulty).
  • Difficulty knowing the function of an object.
  • Problems with reading (Alexia), writing (Agraphia) or maths (Dyscalculia).
  • Difficulty knowing where things are in relation to our own bodies; for example, how close an object is to us (Spatial Awareness Difficulties).
  • Reduced self-awareness (Anosognosia).
  • Visual Neglect (see the box below).
Visual neglect is an attention disorder which may be caused by a brain injury.

It prevents the person aff ected from noticing things, or people, that are to one side of them. This is most often on their left-hand side – for example, during a meal the person may eat all the food on the right half of their plate but leave the left half untouched.

Some Effects of an Injury to the Occipital Lobes

  • Sight defects (known as Visual Field Cuts).
  • Blurred vision or sight loss.
  • Visual hallucinations and distortions.
  • Difficulty with identifying colours (Colour agnosia).
  • Difficulty recognising words.
  • Difficulty recognising when people, or things, are moving (Motion blindness or Akinetopsia).

The Brain’s Ability to Adapt (Neuroplasticity)


This is the brain’s unique ability to reorganise, change and adapt. One way that neuroplasticity works is by forming new pathways and connections between brain cells. This happens when, for example, we learn new skills or experience different situations. So, while neuroplasticity is a normal part of our everyday lives, the processes involved complex and not yet fully understood.

However, it is known that neuroplasticity is significant in recovering from a brain injury because it allows our brains to reorganise and re-learn. Therefore, it is the basis of many rehabilitation programmes. Part of the goal of these programmes is to try to build new connections between brain cells.

There are limits to how much our brains can recover, however. Neuroplasticity enables the brain to adapt to an injury but sometimes an area is so extensively damaged that its ability to reorganise is not sufficient to regain the lost function

Brain Injury – the Hidden Disability

Many of the effects of brain injury are not visible to a casual observer. Headway’s “I see beyond” campaign on the invisible effects of brain injury was an attempt to start a conversation about how we could all become more tolerant of the invisible effects of brain injury and similar conditions.

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