Glossary of Terms

About Brain Injury

The language used in brain injury can be complex and confusing. Please find below a glossary of brain injury terms that you may find useful.

This section of the website is designed to provide more information to anyone interested in brain injury. We’ve included a glossary of terms, frequently asked questions (FAQ’s) and links to other organisations working in the field of brain injury.


Acceleration/Deceleration injury – A closed head injury often sustained in car accidents. The brain is forced forwards then backwards, rebounding against the walls of the skull. Damage is caused both to the frontal lobe and to the back of the brain.

Amnesia – Partial or total loss of the ability to remember things. May be either retrograde (inability to remember events that happened before the injury) or anterograde (problems remembering things that happened after the injury).

Aneurism – A balloon like deformity in the wall of a blood vessel. This may eventually burst, causing haemorrhage.

Anoxia – Lack of oxygen supply to brain cells (also called hypoxia).

Aphasia – May be either expressive (inability to express oneself in speech) or receptive (inability to understand what is said).

Apraxia – Inability to plan and perform purposeful movements (whilst still having the ability to move and be aware of movements).

Ataxia -Abnormal and unsteady movements due to loss of co-ordination of the muscles.


Blood Clot (see haematoma)


Cerebrospinal Fluid (CSF) – Clear, colourless fluid in the spaces inside and around the brain and spinal cord.

Closed head injury – Damage to the brain in which there is no penetration through the scalp or skull to the brain tissue. This is the most common type of brain injury and happens when the brain is thrown forwards and/ or backwards, or rotated sharply, e.g. in a car crash.

Cognition – General term used to cover all areas of intellectual functioning. Includes skills such as thinking, remembering, planning, understanding, concentrating and using language.

Coma – State of unconsciousness. Depth of coma is measured by the Glasgow Coma Scale. Contractures Stiffness and resistance to stretching in joints and muscles which are not used regularly.

Contrecoup – Bruising of brain tissue on the opposite side to where the blow was struck. Contusion A bruise caused by a blow with a blunt object.

Craniotomy – Operation to open the skull.

CT scan/ CAT scan – Computerised Axial Tomography. A series of X-rays taken at different levels of the brain. Used to identify bruising and clots on the brain.


Diffuse axonal injury – Widespread tearing of nerve fibres across the whole of the brain.

Disinhibition – Difficulty in controlling urges and impulses to speak, act, or show emotions.

Dysarthria – Difficulty speaking, due to weakness and lack of co-ordination of the muscles used for speech.

Dysgraphia – Difficulty in writing.

Dysphagia – Difficulty in swallowing

Dysphasia – May be either expressive (difficulty in expressing oneself in speech) or receptive (difficulty in understanding what is said.

Dyspraxia – Difficulty in planning and performing purposeful movements (whilst still having the ability to move and be aware of movements).

Dystonia – Abnormal muscle tone.


Epilepsy – Abnormal electric discharge in the brain. Involves seizures or fits, affecting parts or all of the body.

Executive functions – Planning, organising, problem solving, sequencing, self-monitoring and controlling behaviour.


Haematoma -The collection of blood into pools or clots. This forms a swelling, which compresses the brain around it.

Hemipareses – Weakness of one side of the body. Hemiplegia Paralysis of one side of the body.

Hydrocephalus – Build-up of fluid in the spaces inside and around the brain, which can cause injury to the brain.

Hypoxia (see anoxia) – Infarct Areas where brain cells have died as a result of loss of blood supply.


Intracranial – Inside the skull


Magnetic resonance imaging (MRI) scanner – A scanning machine that enables highly detailed pictures of the brain to be taken. Uses a strong magnet rather than X-rays.


Oedema – Excess fluid in tissue, causing swelling.

Open head injury – An injury where the skull is broken open by a blow to the head.


Perseveration – Involuntary prolonged repetition of words or actions.

Post traumatic amnesia (PTA) – The period after being unconscious when there may be confused behaviour and inability to remember continuous events.

Proprioception – Perception of the position and movement of the body, limbs and head.


Respirator (see ventilator)


Shunt – Device to remove excess fluid or divert blood.

Skull fracture – May be either a compound fracture (a crack in the skull) or a depressed fracture (in which bone fragments are pushed inwards into the skull).

Spasticity – An involuntary increase in muscle tone (tension).


Tracheostomy – An operation to open up blocked airways by cutting through the neck and inserting a plastic tube into the windpipe.


Ventilator (also called a respirator) – A machine which pumps oxygen-enriched air into the lungs when they are not working efficiently. This encourages quiet breathing and creates best conditions for healing the brain.

Ventricle – A cavity in the brain that makes and contains cerebrospinal fluid.

If you’d like us to add some terms, or explain them in more details contact us