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In order to understand what has happened to a person who has received a brain injury, it is important to look at the normal brain. The brain is part of the central nervous system. This is the most highly developed and important system of the body. The brain sends and receives chemical and electrical signals throughout the body. Different signals control different processes, and the brain interprets each. The brain controls the body’s functions, such as:
- Movement and motor skills
- Vision
- Breathing
- Temperature
- Hunger
- Speech
- Thought
- Memory
and every process that regulates our body. It also controls and helps us to identify feelings and emotions which make up our personalities. It allows us to make sense of the world around us and enables us to make decisions. The brain also plays a key role in regulating the body’s hormones.
The brain is a complex organ, and it has two halves called hemispheres. These are divided into different sections called lobes, all with separate functions. Each half of the brain controls the movement and feeling in the opposite half of the body. In general, the left side of the brain also deals with speech, and the written and spoken word, and the right side of the brain controls the ability to:
- Judge distance
- Make sense of shapes
- Recognise objects and faces
Towards the front is the part of the brain used in making complex decisions and solving problems. The brain controls everything that we do and every aspect of who we are as a person. So, when the brain is injured it can impact a person’s life in many ways, including physically, psychologically and socially.
According to the Medical Research Council (MRC) in the UK, annually there are 900,000 accident and emergency attendances with head injuries, with 160,000 people admitted to hospital each year. There are approximately 1.3 million people living with disabilities resulting from these injuries.
Brain injuries are commonly categorised as traumatic or acquired. A traumatic brain injury (TBI) is the result of a blow to the head which might be caused by anything from a simple trip to a collision on the sports field to a major road accident or assault. A traumatic brain injury is further classified as mild, moderate or severe. An acquired brain injury (ABI) is an injury that occurred at or since birth. Whilst that does include traumatic brain injuries, it is more commonly used to refer to injuries due to, for example, an infection, a tumour, a stroke or even a medical accident.
Brain injuries can result from a variety of causes, both traumatic and non-traumatic. Non-traumatic causes are more usually associated with acquired brain injury.

Acquired brain injuries: Causes and characteristics
Acquired brain injury includes a wide range of injuries that occur after birth and that are not genetically or congenitally linked, i.e. that they have not developed prenatally. Instead, they result from various neurological conditions and injuries, making acquired brain injuries a complex and diverse category. The specific symptoms or losses of functioning depend on which brain areas are affected. Some of the causes of acquired brain injury include:
- Alcohol or drugs which can poison the brain
- Diseases such as meningitis, encephalitis, cancer, HIV Aids, Alzheimer’s disease, multiple sclerosis or Parkinson’s disease
- Lack of oxygen, which is called anoxic brain injury, for example, a brain injury caused by a near drowning or suffocation
- Stroke when a blood vessel inside the brain breaks or is blocked, destroying the local brain tissue
Alcohol-related brain injury
This is caused by a person regularly drinking or binge-drinking much more alcohol than the recommended limit. Alcohol can damage the brain in several different ways, but the most common are the following:
- Damage to nerve cells – alcohol can cause brain cells to die and a person’s brain tissue to shrink. This means there are fewer cells to carry the messages that the brain needs to do different tasks
- Damage to blood vessels – alcohol damages blood vessels in a person’s brain and can lead to high blood pressure.
The risks associated with alcohol-related brain injury include:
- Increased risk of having a stroke
- A higher risk of malnutrition through replacing food with alcohol
- Increased risk of causing symptoms of dementia
- Low levels of thiamine (vitamin B1) needed by the brain to work properly
- Increased risk of traumatic head injuries from falls
Drugs-related brain injury
Injuries may happen either as a direct result of the toxic effects of drugs or as a consequence related to drug use. Brain injury resulting from drug use can range from minor damage to brain cells to severe physical damage such as in the case of brain hypoxia due to overdose. Brain hypoxia is a lack of sufficient oxygen to the brain.
Sustained misuse of certain substances can cause potential long-term neurological effects or changes to brain function. The risks associated with drug-related brain injury include:
- A range of persistent neurological and cognitive complications, and brain changes, such as the loss of grey matter
- Short-term memory loss
- Stroke
- Mental disorientation
- Loss of body movement
- Changes in gait
- Incontinence
- Temporary leg paralysis
- Reduced motor skills
- Slowed reaction time
- Seizures
- Nerve injury
- Memory impairment

Disease-related brain injury
Severe brain infections such as meningitis, an infection of the outer layer of the brain, or encephalitis, an infection of the brain itself, if not treated, or not treated swiftly, can cause brain injury. Other diseases such as cancer may cause tumours in the brain. Brain tumours that start as a growth of cells in the brain are called primary brain tumours. Secondary brain tumours happen when cancer starts somewhere else and spreads to the brain. When cancer spreads, it is called metastatic cancer. Brain tumours are graded from 1 to 4, according to how they look under the microscope, how fast they are likely to grow, and how likely they are to spread. A tumour can cause huge, irreversible damage to the brain.
Stroke
A stroke occurs when the blood supply to part of the brain is cut off. This starves the brain of oxygen, with devastating consequences. Stroke is the fourth biggest killer in the UK, and a leading cause of disability. There are two types of stroke:
- Ischaemic strokes – these are caused by a blockage, usually a blood clot, cutting off the blood supply to the brain. About 85% of strokes are ischaemic.
- Haemorrhagic strokes – these are caused by a blood vessel bursting in the brain.
The range of disabilities following a stroke is greater than for any other condition and includes limb weakness, visual problems, and language and communication problems. Extreme fatigue is also a common side effect, and depression and anxiety are common. However, the brain has the ability to re-wire itself following a stroke, allowing the person to improve skills such as walking, talking and using their affected arm. This process is known as neuroplasticity; it begins after a stroke, and can continue for years.
Anoxic brain injury
This is caused by a complete lack of oxygen to the brain, which results in the death of brain cells after approximately four minutes of oxygen deprivation. Anoxic brain injuries often cause an initial loss of consciousness, which can be short-term or long-term, depending on the severity and length of oxygen deprivation. Initial loss of consciousness may result in a comatose state. Other anoxic brain injury symptoms may include slurring and difficulties with speech, confusion, disorientation, or facial drooping. Someone with mild anoxic brain injury is capable of making a full or partial recovery; a full recovery from severe anoxic brain injury is rare. The effects of an anoxic brain injury may include:
- Acting inappropriately
- Changes in sensory perception
- Changes in sexual function
- Changes in sleep pattern
- Depression
- Difficulty coordinating balance
- Difficulty communicating, speaking and/or forming sentences, and swallowing
- Difficulty with reason, focus and logic
- Disorientation and/or confusion
- Forgetfulness
- Headache
- Lack of bowel and bladder control
- Limited attention span
- Memory impairments
- Mood swings
- Motor impairment
- Personality changes
- Poor concentration
- Seizures
- Vision problems
The long-term effects of an acquired brain injury are difficult to predict. They will vary according to the cause, will be different for each person and can range from mild to profound.

Traumatic brain injuries: Causes and characteristics
A traumatic brain injury means that there has been some form of trauma or shock to the head and is typically caused by some kind of forceful bump or jolt to the head. There are two main types of traumatic brain injury: closed traumatic brain injury and open traumatic brain injury.
Closed traumatic brain injuries
These are the most common type, and are so called because the skull remains intact. These often happen as a result of rapid acceleration (i.e. speeding up) or deceleration (i.e. slowing down or stopping suddenly, for example when a vehicle hits a brick wall, or is hit from behind such as at traffic lights). The head is rocked back and forth or rotated, and the brain follows the movement of the skull. This causes the billions of nerve fibres which make up the brain to be twisted, stretched and even torn in the process. Arteries and veins running through the brain can be damaged, allowing blood to leak.
Open or penetrating traumatic brain injuries
These types of injuries are not so common. In this type of injury, the skull is opened and the brain is exposed and damaged. This could be due to a bullet wound, or collision with a sharp object. If the damage is limited to one specific area, outcomes can be quite good, even though the accident may have seemed horrific. In many cases, however, this type of injury may be combined with an acceleration type injury as well.
Traumatic brain injuries can range from mild through to moderate and severe. Mild traumatic brain injuries may affect the brain cells temporarily. More serious traumatic brain injuries can result in bruising, torn tissues, bleeding and other physical damage to the brain. These injuries can result in long-term complications or death.
Traumatic brain injury is not the same as a head injury, since a person can sustain damage to the face, scalp and skull without necessarily injuring their brain.
Traumatic brain injuries can result from a variety of causes; the most common causes for a traumatic brain injury include:
- Trips or falls
- Vehicle accidents
- Violence
- Sports injuries
- Military attacks or bomb blast
The problems caused by a traumatic brain injury depend on:
- The part of the brain that has been affected
- Any complications such as brain swelling or blood clots
- The nature of the injury (closed or open)
Often there are several areas of damage throughout the brain. This means that the brain as a whole may be less efficient and the person can experience an assortment of difficulties. The problems which a traumatic brain injured person is likely to encounter can include any one or more of the following:
- Cognitive (thinking) problems, for example with memory, attention and concentration, difficulty in making decisions, unusual behaviour, confusion
- Communication difficulties, for example difficulties understanding and speaking, aphasia, problems with reading and writing, poor eye contact, shifting from topic to topic, rambling or repetitive speech
- Physical changes such as loss of movement, balance and coordination difficulties, dyspraxia, loss of sensation(s), dysphagia (this is a problem affecting the ability to chew and swallow), fatigue, post-traumatic epilepsy
- Emotional changes, for example depression, stress/anxiety, agitation and anger, loss of inhibitions such as being outspoken, over friendly, sexually suggestive, childish or self-centred
- Change in social circumstances, such as inability to work or attend school or college, relationship problems, inability to drive, loss of interest in favourite activities

Key differences between acquired and traumatic brain injuries
As we have seen above, some of the key differences between acquired and traumatic brain injuries lie in the causes of the injury. Acquired brain injury is caused by a medical condition or illness, whilst traumatic brain injury is caused by a traumatic event. There are cases, however, when a person may experience both types of brain injury, for example following a stroke the person may suffer a fall which further injures the brain.
Another key difference lies in the prognosis for acquired brain injury and traumatic brain injury which can vary significantly.
In general, the prognosis for acquired brain injury depends on the underlying medical cause of the injury and the severity of the damage. For example, with a stroke, with good treatment and care people can make the best recovery possible for them. But even with good care, a severe stroke may leave someone with serious disabilities or unable to live independently. Whereas, with an infection of the brain, which may cause inflammation and the brain to swell, it can be treated with antibiotics, generally resulting in no permanent damage or further ill effects.
With traumatic brain injury, the prognosis depends on the severity of the injury and the extent of brain damage. For example, a mild traumatic brain injury may affect brain cells temporarily resulting in no more than a headache with no further ill effects. Whereas a severe traumatic brain injury, such as a penetration injury, can cause significant damage to the brain and can be fatal.
In both categories of brain injury, the prognosis can range from a full recovery to permanent impairment or death; however, the cause of the injury is less significant in traumatic brain injuries than it is in acquired brain injuries. This is because the cause of the injury as well as the brain injury itself can also be treated in acquired brain injuries.
There are some differences in the symptoms of acquired brain injury and traumatic brain injury, although many of the symptoms can be very similar. For example, traumatic brain injury often results in loss of consciousness, while acquired brain injury may not. Also, symptoms of traumatic brain injury tend to be more immediate and severe, whilst the symptoms of acquired brain injury may develop more slowly over time.
Treatment for acquired brain injury and traumatic brain injury may also differ. Both types of injuries may require medical treatment; however, the treatment approach for acquired brain injury may focus more on managing the underlying condition or illness, whilst the treatment approach for traumatic brain injury may focus more on addressing the specific brain injury and its effects.
Diagnosis and treatment approaches
The diagnosis of acquired brain injury involves a comprehensive assessment to evaluate the extent of brain damage and determine the most appropriate course of treatment. Clinical evaluation plays a vital role in the diagnostic process for acquired brain injuries.
When a traumatic brain injury is suspected, timely medical attention is essential. Physicians or emergency medical professionals typically employ the Glasgow Coma Scale, a 15-point test, to assess the potential severity of the injury by examining motor responses, eye movements and verbal responses. A lower score on this scale indicates a more severe injury, while a higher score suggests a less severe one.
Computerised tomography (CT) scans are often the initial choice in A & E when traumatic brain injury is suspected. These scans utilise X-rays to create detailed cross-sectional images of the brain, offering crucial insights into injuries such as fractures, bleeding, blood clots and contusions, which is bruised brain tissue.
For both categories of brain injury, Magnetic Resonance Imaging (MRI) scans, which employ powerful radio waves and magnets, provide a more detailed view of the brain’s structures. These scans are typically used once the individual’s condition has stabilised or if symptoms persist. In cases where tissue swelling is a concern, an intracranial pressure monitor can be inserted to measure pressure within the skull. Additionally, electroencephalography (EEG) can be used to assess blood vessel damage and measure electrical activity in the brain, contributing to a comprehensive evaluation of the brain injury. Early and accurate diagnosis is vital for determining appropriate treatment strategies and optimising recovery for individuals with brain injury. These diagnostic tools collectively improve the understanding and management of brain injury.
New research led by Queen Mary University of London and Barts Health NHS Trust has studied a new approach to traumatic brain injuries that could revolutionise diagnosis and treatment. Their research suggests that biochemical analysis of brain tissue could be used for diagnosis and prognosis of severe traumatic brain injury to improve patient outcomes. Brain biopsy is used very commonly in brain cancer diagnosis, and this study shows that it is also safe for patients who have suffered severe traumatic brain injury to undergo brain biopsy.
Acquired brain injuries are complex medical conditions that often require a combination of treatments to address a wide range of symptoms. Treatment can include medication, physical therapy, occupational therapy, psychological counselling or other forms of support, and a rigorous rehabilitation plan. Medical professionals may also provide antidepressants to help treat depression and other emotional effects.
For traumatic brain injury, the treatment approach focuses more on addressing the specific brain injury and its effects. This might include therapy to help with any vision or hearing problems, physical therapy to improve mobility and coordination, cognitive therapy to address any issues with memory or problem-solving, occupational therapy for activities of daily living, or psychological counselling for managing emotions. Treatment may also involve medications to manage symptoms such as pain, seizures or depression.
Examples of therapies that may be used can include:
Neuroplasticity – this allows undamaged portions of the brain to take over functions from damaged areas. The best way to activate neuroplasticity is through repetitive exercises and/or activities. When a certain skill is practised, the brain strengthens its existing neural connections and creates new neural pathways in response.
Physical therapy – this works to rebuild mobility, strength, endurance, coordination, balance and flexibility after a brain injury. It encourages neuroplasticity and helps individuals improve function through restorative techniques. Physical therapy interventions can also help increase cerebral blood flow, which provides the brain with the oxygen-rich blood and nutrients it needs to function and heal properly.
Occupational therapy – helps a person relearn how to perform activities of daily living such as eating, getting dressed and bathing. An occupational therapist can address the physical and cognitive effects of a brain injury by providing individuals with the tools they need to enhance independence. Typically, occupational therapy involves a combination of compensatory tactics, including adaptive equipment training, and restorative techniques.
Speech therapy – focuses on improving cognitive communication disorders, which is difficulty communicating because of an injury to the part of the brain that controls the ability to think. Speech therapy exercises can help with speech, language and cognitive communication. Therapy may also include retraining of the swallowing function if a brain injury has caused swallowing difficulties. Therapists can also provide exercises that address memory, attention and concentration, making speech therapy an integral aspect of acquired brain injury treatment.
Cognitive-behavioural therapy (CBT) – this offers an effective way to help people cope with the emotional and psychological tolls of brain injury. Most brain injuries, no matter the level of severity, will cause the person to experience emotional and behavioural changes. The goal of cognitive-behavioural therapy after brain injury is to retrain the brain to replace negative thoughts with positive ones. Cognitive restructuring teaches people to identify ‘automatic or distorted thoughts’ and question them. Many of the emotional problems that people experience following brain injury stem from not having the appropriate skills to handle the situations that they encounter. CBT can help remedy this problem through skills training such as social communication, problem-solving and assertiveness.
Many people who suffer a brain injury will require the services of a wide range of health and social care professionals over a long period and their needs will change over time once they emerge from hospital whether their stay has been short or long term.
How and when support is delivered will depend on the nature of the injury and the services available through local NHS Clinical Commissioning Groups and social services teams, as well as charities and voluntary organisations. Both the NHS and local authorities are obliged to assess the needs of a brain injured person and their carers, and often have a statutory duty to provide a range of support services and care.
Living with either acquired brain injury or traumatic brain injury can be challenging; however, the right recovery strategies and treatments can help improve quality of life.
Rehabilitation plays a critical role in the recovery process for individuals with acquired brain injury and traumatic brain injury, helping them to achieve a fulfilling life after the injury. Rehabilitation focuses on equipping individuals with the skills and strategies necessary to adapt to changes resulting from brain injuries. The ultimate goal of rehabilitation is to enable individuals to regain their independence and safely perform daily activities.
Rehabilitation programmes are offered in various settings, from inpatient rehabilitation hospitals to outpatient facilities, home-based care, and independent living centres. Many individuals and their families prefer to receive care and support within the comfort and familiarity of their own homes. Home-based rehabilitation and care offer a unique opportunity for individuals to maintain their independence.
Recovery following a brain injury is unique for each individual; while healing may become more evident after a year, psychological recovery can take considerably longer. A personalised rehabilitation programme and brain injury support ensure individuals receive the care and support necessary to maximise their independence and wellbeing. Rehabilitation programmes include the continuation of therapies often first used in treatment.

The importance of proper identification
Diagnosing acquired brain injury can be a challenging process, particularly with acquired brain injury where there are other medical factors to take into consideration. However, early intervention and proper treatment are crucial as they can significantly improve outcomes and reduce the long-term impact of the injury. Accurate and timely diagnosis is critical in creating an effective treatment plan that best suits the person’s individual needs.
The treatment of brain injury is a complex process requiring multiple healthcare professionals’ coordinated efforts as treatment aims to address the person’s symptoms, prevent further damage, and promote recovery.
Final thoughts
Brain injury can have a profound effect both on the person themselves and on their family and friends. There are a number of support groups available to provide advice, information and support. These include but are not limited to:
British Brain and Spine Foundation Tel: 020 7404 6106
The Brain and Spinal Cord Injury Charity (BASIC) Tel: 0870 750 0000
Carers National Association Tel: 0808 808 7777
Stroke Association Helpline: 0303 3033 100
The Brain Charity Tel: 0151 298 2999
The Brain Injury Group Tel: 0800 612 9660 or 03303 112541
The Child Brain Injury Trust Tel: 0303 303 2248