What is an acquired brain injury?

 An acquired brain injury (ABI) is an injury to the brain that has occurred after birth. Brain injury commonly results in life-long challenges, including changes to behaviour, emotions and physical function.

ABIs may be traumatic, caused by a sudden blow or jolt to the brain. These injuries are usually serious and often occur as a result of falls, assaults and road traffic accidents. ABIs may also be non-traumatic, brought about because something happens within the body like stroke, brain haemorrhage or a viral infection.

Every brain is different, so every brain injury is unique to each individual affected.

Brain injury is often described as an ‘invisible disability’ because its effects are often hidden, despite the fact that 19,000 individuals in Ireland acquire a brain injury every year – that’s 52 people every day.

Causes of brain injury

Concussion is among the most common forms of brain injury

Impacts of brain injury

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Those with brain injury may not be as strong, they may tire more easily. Eyesight and hearing may also be affected.

Talking in a group

Brain injury survivors may find it harder to keep up and stay in the conversation where there is more than one person speaking at the same time.

Organising your life

Day-to-day organisation may be harder for those with brain injury. Their abilities to plan and problem-solve in many different areas may not be as good as they previously were.


Those with brain injury may have problems learning new information, remembering details of recent events or recalling day-to-day things to do – even if they have no difficulty remembering events that happened long ago.

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Making decisions

Weighing up information and working out the best decision may be harder for brain injury survivors. They may find themselves more rigid or more impulsive or may be unable to make decisions, especially under pressure.

Speech and language

Those with brain injury may have problems speaking as fast as before. They may find it difficult to say what they are thinking, or they might not be able to put the words in order. It may be harder to start or join in a conversation or understand what others are saying. They may find themselves getting off topic easily, and might need to ask questions to understand a situation that before would have been clear before the injury.


Concentration may be affected by brain injury. It may be harder to pay attention to more than one thing or for long periods of time. It may be common to become easily distracted and this can also lead to feeling restless. Poor concentration can result in difficulty finishing a project or working on more than one thing at a time.


Thinking, listening and talking may tire those with brain injury much more easily.

The brain and how it works


The brain is responsible for everything we do. It controls all movements, sensations, speech, thoughts and emotions. Surprisingly, for such an important organ, the brain is very soft, almost the consistency of firm gelatin.

The brain would easily be injured if it was not contained by the skull. The brain is made up of two halves – the right and left hemispheres. The right hemisphere controls the left side of the brain and the left hemisphere controls the right side of the brain.

Each half of the brain is made up of sections called lobes. There are 4 lobes and each one has a special function.

  1. The frontal lobe – controls executive functions like emotion regulation, planning, reasoning and problem solving
  2. The parietal lobe – controls sensory information including touch, temperature, pressure and pain
  3. The temporal lobe – controls processing information including recognising language, forming memories and hearing information
  4. The occipital lobe – controls the visual processing including distance, identity of objects, surroundings

The brain also has the cerebellum which controls coordination and the brain stem which controls life sustaining functions like heart rate and breathing. It’s useful to understand the functions of the brain in order to understand the type of deficits that can occur when a particular part of the brain is injured. Download our useful leaflet here.

Rehabilitation and recovery

The recovery and rehabilitation journey is unique for each brain injury survivor.

The type of injury sustained, one’s age, social support network and outlook on life are all factors that can affect recovery. The length of time symptoms remain also has a lot to do with how severe the brain injury was.

Often the most rapid recovery occurs in the first six months after brain injury. In milder cases many individuals with acquired brain injury find that their symptoms disappear or are greatly reduced within a year.

If you suffer a severe brain injury, recovery can take several years. As time progresses, improvements may be more gradual.

Regardless of your age, circumstance or the nature of your brain injury, early access to neuro-rehabilitation services can play a vital role in rebuilding your life and maximising your full potential. This includes the establishment of a meaningful everyday routine, getting enough rest, and gradually introducing some exercise, social activities and family responsibilities.