What Is Acquired Brain Injury? A Guide for Care Teams

An acquired brain injury (ABI) is any injury to the brain that happens after birth. It includes traumatic brain injuries from falls, assaults and road collisions, and non-traumatic causes such as stroke, brain tumours, infections and a lack of oxygen. Many of its effects, like fatigue, memory problems and changes in behaviour, can't be seen, so it is often called a hidden disability.

ABI vs TBI: what's the difference?

Headway, the brain injury charity, defines an acquired brain injury as an injury caused to the brain since birth. It doesn't cover conditions a person is born with. A traumatic brain injury (TBI) is one type of ABI, caused by trauma to the head.

• Every TBI is an ABI. A fall, an assault or a road collision can cause one.
• Not every ABI is a TBI. A stroke, a brain tumour or an infection such as meningitis can cause a brain injury with no blow to the head at all.

On shift, the label matters less than the effects. Support follows what the injury does to the person, not what caused it.

Common causes of acquired brain injury

Headway lists these as the main causes:

• Head injury: road accidents, falls, assaults, and accidents at home or at work.
• Stroke: a disruption of the blood supply to part of the brain.
• Brain haemorrhage: bleeding in or around the brain, for example from a ruptured aneurysm.
• Brain tumour: an abnormal growth of tissue inside the skull.
• Infection: encephalitis (inflammation of the brain, most often from infection) and meningitis.
• Hypoxia or anoxia: the brain's oxygen supply is reduced or cut off, for example by carbon monoxide poisoning.

It is common. Headway's statistics record 335,409 UK hospital admissions for acquired brain injury in 2023 to 2024, about one every 90 seconds. Stroke accounted for 143,446 of those admissions and head injury for 123,969.

If many of the people you support are stroke survivors, our stroke awareness training is a useful companion to brain injury training.

The hidden effects of brain injury

Headway notes that most people recover well physically. The harder effects to support are often the ones you can't see. Headway's guide to the effects of brain injury groups them broadly like this.

Fatigue

Not ordinary tiredness. Headway describes overwhelming tiredness that rest or sleep doesn't fix, often worse at certain times of day or after busy, noisy activities.

Memory, attention and thinking speed

Slower thinking, poor concentration and memory problems are among the most common effects. The person may forget what was agreed this morning or need longer to answer.

Executive function

These are the skills we use to plan, start, organise and adapt. Headway describes several difficulties that often follow an injury to the frontal lobes:

• Starting things: losing their "get up and go", which is easy to mistake for laziness.
• Planning and organising: mixing up appointments or getting stuck halfway through a task.
• Rigid thinking: finding it hard to switch tasks or cope when plans change.
• Impulsivity: acting too quickly, such as overspending.
• Lack of insight: not recognising the effects of their own injury, which can mean turning down help they need.

Communication

Communication problems are very common. The NHS describes aphasia as difficulty speaking, understanding, reading or writing, caused by damage to the parts of the brain that handle language. Stroke is its most common cause, and severe head injury, tumours and infections can cause it too.

Emotions and behaviour

Changes in mood, anger, frustration and social behaviour can follow a brain injury. Headway notes the emotional changes can be among the hardest for the person and their family to deal with. A partner may say, "He's not the same man."

What it looks like on shift

Hidden effects are easy to misread. A few familiar scenes:

• A man agrees to have a shower after breakfast, then doesn't. He isn't being awkward. He may not be able to start the task without a prompt.
• A woman is chatty and capable at 10am and tearful and snappy by 4pm. That pattern often points to fatigue, not mood alone.
• Someone tells a visiting professional they're managing fine, and staff know they aren't. That may be lack of insight, not dishonesty.

When staff understand the cause, they stop taking it personally and adjust the support instead.

Brain injury rehabilitation

Rehabilitation helps people regain skills, find new ways of doing things and take part in what matters to them. Specialist teams lead it, but care staff carry it into daily life because they see the person every day.

NICE's guideline on rehabilitation for chronic neurological disorders including acquired brain injury (NG252, published October 2025) sets out what good rehabilitation looks like. Points that matter for care teams:

• Goals belong to the person. Long-term goals are agreed with them and broken into short-term steps, focused on what matters most in their life.
• Family and carers have a role. Ask who is important to the person and how they want those people involved.
• Fatigue is managed, not ignored. Explain why fatigue happens and use pacing and energy-saving strategies.
• Cognitive difficulties shouldn't exclude anyone. Make reasonable adjustments so the person can take part in assessments and decisions.

Supporting someone with ABI day to day

• Keep routines steady. Familiar order and timing take pressure off memory and planning.
• Write it down. Visual planners, checklists and notes by the door help more than repeating yourself.
• One step at a time. Give one instruction, wait, then give the next. Allow time to answer.
• Prompt, don't take over. A cue to start keeps skills going.
• Plan rest. Spread demanding activities through the day and watch for early signs of fatigue, such as yawning, losing concentration or irritability.
• Look for triggers. Record what happened before an outburst: noise, fatigue and changed plans are common. Our behaviour that challenges and de-escalation training helps staff respond calmly.
• Follow the care plan and your local policy, using the strategies agreed with the person and their specialist team.

Brain injury and mental capacity

A brain injury doesn't mean someone lacks capacity. In England and Wales, the Mental Capacity Act 2005 starts from a presumption of capacity, requires all practicable help before deciding a person can't make a decision, and says an unwise decision isn't proof of incapacity. Capacity is decision-specific. In Scotland, the Adults with Incapacity (Scotland) Act 2000 applies. For the principles in more detail, see our guide to Mental Capacity Act principles and DoLS.

How Kasorb can help

Our acquired brain injury training helps care staff understand the types and causes of brain injury, the signs of a head injury, assessment and diagnosis, the common problems after an injury, working with people with an ABI, and the types and goals of rehabilitation. Your trainer has used these skills for real, and teaches brain injury in terms of the people you support, using case studies and discussion, so staff understand the hidden effects and know how to respond day to day.

It runs as a half day or a full day, on-site anywhere in the UK or live online, at one flat rate for the group. Certificates are emailed the next day.

FAQs

What is the difference between an acquired brain injury and a traumatic brain injury?

An acquired brain injury is any injury to the brain that happens after birth, whatever the cause. A traumatic brain injury is one type of ABI, caused by trauma to the head, such as a fall, assault or road collision. Stroke, infection and lack of oxygen cause ABIs that aren't traumatic.

What are the most common causes of acquired brain injury?

Stroke and head injury are the most common causes. Headway's figures for 2023 to 2024 show 143,446 UK hospital admissions for stroke and 123,969 for head injury. Other causes include brain tumours, brain haemorrhage, infections such as encephalitis and meningitis, and lack of oxygen to the brain.

What are the hidden effects of brain injury?

They are the effects you can't see: fatigue that rest doesn't fix, memory and concentration problems, slower thinking, difficulty planning or starting tasks, impulsivity, lack of insight, communication problems, and changes in mood and behaviour. Because they are invisible, others often misread them as laziness, rudeness or lack of effort.

Can people recover from an acquired brain injury?

Many people improve, especially with rehabilitation, but recovery varies widely and some effects are long term. Rehabilitation focuses on goals that matter to the person. Care staff help by practising agreed strategies every day and recording progress for the specialist team.

Does a brain injury mean someone lacks mental capacity?

No. In England and Wales, the Mental Capacity Act 2005 presumes capacity unless it is shown otherwise, and capacity is assessed one decision at a time. A person with a brain injury may be able to make some decisions and not others. Making an unwise decision doesn't on its own show a lack of capacity.