Brain injury

Also known as Acquired Brain Injury (ABI)

Key points about brain injury

  • A brain injury is damage to brain tissue. It differs from congenital disorders that you were born with.
  • A brain injury can be the result of trauma, eg, a blow to the head or impact that causes your brain to shake within your skull.
  • It can also result from a medical problem, eg, a stroke, brain tumour, lack of oxygen or infection, or by substance abuse or poisoning.
  • The effects of brain injury depend on which parts of your brain were injured and how seriously.
  • A brain injury can have a dramatic impact on your family, job, social and community life – support is available. 
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Need urgent medical help?

If someone is unconscious or unable to move all or some of their limbs or is complaining of neck pain call 111 immediately.

Don’t move the person (unless it’s dangerous to leave them where they are). 

Get immediate medical help if you or someone you are caring for:

  • has received a hard bang on the head (say, from a major fall)
  • appears dazed or loses consciousness, even momentarily
  • seems unwell or vomits after the injury or shows any of the warning signs of a brain injury below:

• Complaints of neck pain 
• Increasing confusion or irritability 
• Repeated vomiting 
• Seizure (fit) or convulsion 
• Double or blurred vision 
• Sleep difficulties 
• Lightheaded and dizziness 

• Muscle weakness, tingling or burning in arms or legs 
• Fatigue or tiredness
• Deteriorating conscious state 
• Severe or increasing headache 
• Unusual behaviour change 
• Difficulty remembering things.

See also: ACC SportSmart National Concussion Guidelines(external link)

Note that not every sign and symptom will be present in every person. 

Read more about concussion and head injury

Brain injury is damage caused to brain tissue that occurs after birth and is not related to a congenital disorder (a problem you are born with). A brain injury can be the result of trauma (known as a traumatic brain injury) or a medical problem.

Traumatic brain injury (TBI)

A TBI is caused when an impact (bump or blow) to your head or body causes your brain to shake inside your skull.  

In New Zealand, the most common causes of TBI are:(external link)(external link) 

Medical brain injury

Brain injury can also be caused by medical problems, such as:

  • brain tumours
  • bleeding in your brain
  • stroke
  • infection
  • lack of oxygen.

Ongoing alcohol and drug abuse can also cause brain injury, as can poisoning with toxic substances such as pesticides, gases and solvents. 

A concussion is a type of mild traumatic brain injury (mTBI). It occurs when a bump, blow or shake to your head or body causes your brain to shake inside your skull, causing your brain to be bruised in a similar way to other parts of your body. 

You don't have to get a blow directly to your head itself – impact anywhere on your body that causes your head to shake violently can lead to a concussion. You also don't have to be knocked out to get a concussion. In fact, loss of consciousness only happens with 10% of concussions. 

Older people

The most common cause of brain injury in older people is a fall. If you or someone you care for has experienced a fall, see a doctor as soon as possible to check for the possibility of a brain injury. A brain injury can be possible even if you have a low-level or a same-level fall. 

The consequences of a brain injury in older people can be serious and long term. This can include:

  • greater risk of cognitive decline
  • longer recovery
  • worse consequences, eg, fractures (broken bones). 

More than two-thirds of older adults with mild brain injury recover fully. Older people who are most at risk of poor recovery from a mild brain injury include those who:

  • are frail
  • have been diagnosed with dementia
  • have a history of cancer
  • are taking or have taken blood-thinning medicines in the past.

The two Rs – recognise and refer is the principle. 


Recognise and be aware of the signs and symptoms of a brain injury (see above).  


If you or someone you care for has experienced a fall, see a doctor as soon as possible to check for the possibility of a brain injury. You can also call Healthline free on 0800 611 116 if you are unsure what to do.

To assess the impact an injury has had on your brain, your doctor will use the Glasgow Coma Scale (GCS) to measure physical, verbal and eye-opening responses. Read more about the Glasgow Coma Scale(external link)(external link)

Brain injuries can range from mild to severe as determined by the GCS, with mild being GCS 14–15, moderate 9–13, and severe 8 or below.

Concussion is on the mild end of the traumatic brain injury spectrum.

The effects of brain injury are different for everyone. How you react depends on which parts of your brain were injured and how seriously.

About 5% of traumatic brain injuries in New Zealand are moderate to severe. If you have a moderate to severe brain injury, you are likely to have some level of physical, cognitive (thinking) or behavioural disability.

Some symptoms may appear right away, whereas others may not be present for days or weeks after the injury. Some symptoms may disappear after a few hours; some may continue for weeks or months.

Because the brain is so complicated, it is difficult to know exactly what the long-term outcome will be. Most people keep getting better slowly over time, but some people never recover to be exactly as they were before the injury.

Some ongoing problems include:

  • cognitive problems, eg, difficulties with thinking clearly, maintaining concentration, problem-solving and completing projects
  • memory problems particularly with learning and remembering new information
  • physical problems, eg, with sense of balance, fatigue causing reduced mental and physical stamina, slower reflexes and headaches
  • sensory problems, eg, lower tolerance to light and noise, or problems with taste, smell and touch
  • communication difficulties making it difficult to express yourself and understand others
  • personality changes, eg, irritability, intolerance, depression, anxiety, socially inappropriate behaviour and mood swings
  • loss of contact with friends and associates.

A brain injury can have a dramatic impact on family, job, social and community life. Brain Injury NZ(external link)(external link) has a range of resources for living with brain injury.

When someone in your family has a brain injury, the whole family/whānau is affected.

This could involve the following: 

  • The initial shock of the initial brain injury. This can include coping with intensive care treatment.
  • Dealing with ACC, hospitals, WINZ and other agencies.
  • Adjusting to the changes in the person with the brain injury and how these may affect other family members and friends.
  • Coping with financial and legal problems.
  • Stress related to caring for the person.

Read about Coping with brain injury for family and friends(external link)(external link) Brain Injury NZ

Maintain core strength and balance

Keeping active and exercising regularly is important for older people to maintain core strength and balance. This helps to keep you steady on your feet and reduce the risk of a fall and prevent a possible brain injury, as well as other consequences such as fractures. Lack of exercise can lead to weak legs, which increases the chances of falling.

Any increased exercise is helpful. Start with 5 minutes a day and build up. 

There are also community group or in-home strength and balance classes that are fun and can help improve strength and coordination. Find a community group strength and balance class near you(external link).

Read more about community group and balance classes(external link) and in-home strength and balance classes(external link).

Make it safer in and around the home

Making your home safer by reducing tripping hazards and clutter, adding hand-rails and improving lighting can help reduce the chances of a fall. Read more about the home safety checklist(external link).  

Reducing traumatic brain injuries(external link) ACC, NZ
Home safety checklist(external link) Live Stronger, NZ



Resources and videos from other organisations that give you more information on brain injury.

Brain Injury NZ(external link)(external link) provides a range of downloadable resources and helpful links for those living with brain injury:

About the brain

Discover more about how your brain works, describing the different parts of the brain and what they do. A clear and easy to understand resource. Download pdf(external link)(external link)

What is brain injury?

Understand the different types of brain injury, their effects and the medical definitions. The symptoms and effects of brain injury are also explored. Download pdf(external link)(external link)

Learning to live with brain injury

This leaflet will help you understand how a brain injury might affect you and what you can do to help. Download pdf(external link)(external link)

Your rehabilitation

Learn how to get the most from your appointments and treatments with this easy to follow resource. Download pdf(external link)(external link)

Cognition – attention, concentration and memory

This resource explores how damage to different parts of your brain can affect your attention, concentration and memory. Download pdf(external link)(external link)

Changes in behaviour

Learn more about how damage to certain parts of the brain can change your personality and behaviour and affect your mood too. Download pdf(external link)(external link)


One of the most common complaints associated with a brain injury, this resource will help you to manage your fatigue levels. Download pdf(external link)(external link)

Coping with brain injury – for family and friends
This leaflet is about how you can help in the recovery of a person who has sustained a brain injury, and how to look after yourself at the same time. Download pdf(external link)(external link)

Alcohol & drugs

Discover how the use of alcohol and drugs will affect you after sustaining a brain injury. Download pdf(external link)(external link)

Work and study
This leaflet will help you start the process of returning to work or study, including what support services you may need, and what to expect while rehabilitating. Download pdf(external link)(external link)


Falls and concussion(external link) Live Stronger, NZ

Clinical guidelines

Traumatic brain injury – diagnosis, acute management and rehabilitation guidelines(external link)(external link) ACC and Ministry of Health, NZ, 2006
Head injury clinical guidelines(external link)(external link) Starship Hospital NZ
Serious illness conversation guide(external link)(external link) Aotearoa Health Quality & Safety Commission, NZ, 2019

Post-traumatic headache

Key information about post-traumatic headache provided by Dr Pyari Bose, neurologist, Auckland

ost-traumatic headache (PTH) is the most frequent symptom after mild traumatic brain injury (mTBI). It is estimated that annually 69 million suffer from TBI worldwide, mostly attributable to mTBI. In New Zealand it is estimated that up to 36,000 people suffer TBIs each year, of which 95% are mild. 

The leading causes of TBI in New Zealand are falls, mechanical forces, driving-related accidents and assaults. Just over 20% of all TBIs in New Zealand are sustained through sport-related activity.(7) 

The underlying cause of PTH is not fully known. It is thought that mechanisms related to both migraine and traumatic brain injury (TBI) are implicated. These include impaired descending pain control networks in the brain, neurochemical changes, neuroinflammation, cortical spreading depression, and release of the pain protein- calcitonin gene-related peptide (CGRP).

The treatment would be determined by evaluation of the underlying headache phenotype. Common patterns of PTH include migraine type and tension type headache patterns. Part of the management also includes addressing if patients are overusing pain medications. 

Headaches may resolve within 3 months of the traumatic brain injury but in some patients this may last longer.  

Other clinical resources

Stagg K, Douglas J, Iacono T. A scoping review of the working alliance in acquired brain injury rehabilitation(external link) Journal of Disability and Rehabilitation. 2019;41(4):489-497.
Forrest RHJ, Henry JD, McGarry PJ, Marshall RN, Mild traumatic brain injury in New Zealand: factors influencing post-concussion symptom recovery time in a specialised concussion service(external link) Journal of Primary Health Care 10:159-166.

Continuing professional development

Trauma Assessment & Care of the Trauma Patient Webinar - Toni Johnston

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(Mobile Health, NZ, 2020) 

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Stephen Kara, MBChB, FRNZCGP, Dip Sports Med, Dip Obs, MPhil (Hons)

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