Glossary
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A
ACCELERATION/DECELERATION
A CLOSED HEAD INJURYoften sustained in car accidents, where the brain smashes forwards and then backwards, rebounding against the walls of the skull, causing damage to both the FRONTAL LOBES and the back of the brain.
AMNESIA
Failure of memory. Hence, POST-TRAUMATIC AMNESIA (PTA) which is the lapse of time after the injury until continuous recall, and RETROGRADE AMNESIA .
ANOSMIA
Loss of sense of smell.
ANEURISM / ANEURYSM
Swelling or dilation of an artery due to a weakened wall.
ANOXIA
Complete oxygen starvation. A condition in which the oxygen supply to the tissues is cut off completely. Partial loss of oxygen supply to the tissues is known as HYPOXIA .
APATHY
A direct result of brain injury to frontal lobe structures which concern emotion, motivation and forward planning.
APHASIA/DYSPHASIA
Difficulty understanding or expressing language as a result of damage to the brain.
APRAXIA/DYSPRAXIA
Inability to plan and perform purposeful movements, while still having the ability to move and be aware of movements.
ARTERIAL LINE
A very thin tube (catheter) inserted into an artery to allow direct measurement of the blood pressure, the amount of oxygen and carbon dioxide in the blood.
ARACHNOID
The middle of the three membranes covering and protecting the brain and spinal cord. The arachnoid membrane lies below the DURA mater and directly above the SUBARACHNOID SPACE .
ATAXIA
Abnormal movements due to loss of co-ordination of the muscles.
AXON/DENDRITES
Parts of nerve cells in the brain which look like small hair-like tentacles. The cells receive information via the dendrites and communicate with each other by passing electrical signals down the axons and releasing chemical signals at their ends.
ANOMIA
The inability to name objects or items.
B
BRAIN STEM
The lower extension of the brain where it connects to the spinal cord. Neurological functions located in the brain stem include those necessary for survival (breathing, heart rate) and for arousal (being awake and alert).
BRAIN PLASTICITY
The ability of intact brain nerve cells (neurones) to make new connections and, in some cases, take over functions of damaged cells. Neuronal plasticity plays a crucial role in memory and diminishes as a person gets older.
BROCA’S AREA
An area of the brain crucial to language processing, speech production and understanding. (see also: WERNICKE’S AREA ) .
C
CATHETER
A tube which is inserted into any body part to withdraw or introduce fluids.
CEREBRAL
Concerning the brain.
CEREBRAL ANGIOGRAM
An X-ray picture of the blood vessels inside the head. A drug is injected via the groin artery to outline these cerebral vessels.
CEREBRAL CORTEX
The highly folded, thin outer layer of the brain. It controls thought processes (such as memory and learning) and voluntary motor functions (such as picking things up).
CEREBRO-SPINAL FLUID (CSF)
Liquid which fills the ventricles of the brain and surrounds the brain and spinal cord.
CEREBRUM
The largest part of the brain. Composed of the two cerebral hemispheres.
CEREBELLUM
Located at the back of the head between the cerebrum and the brain stem. The cerebellum is responsible for the coordination of movement and balance and is thought to play a role in emotion.
CLOSED HEAD INJURY
Damage to the brain where there is no penetration from the scalp or skull through to brain tissue. Often there is no injury to scalp or skull.
CONCUSSION
Unconsciousness after a blow to the head.
CONFABULATION
Verbalisations about people, places or events with no basis in reality.
COMA
The state of not being responsive or able to be aroused. The person does not open their eyes, follow commands or speak.
CONTRA COUP
Bruising of the brain tissue in the side opposite to where the blow was struck.
CONTRACTURES
Joints and muscles which are not used regularly quickly becoming stiff, and rendering them resistant to stretching.
CRANIOTOMY
Surgical removal of the skull in small pieces.
CRANIUM
The bony skull which completely engulfs the brain to protect it.
CRANIAL NERVES
A set of 12 pairs of nerves originating in the brainstem, the oldest part of the brain. Functions of the cranial nerves include control of eye movement and blinking.
CT SCAN/CAT SCAN
Computerised tomography. A series of X-rays at different levels of the brain. (Tomography is a technique using X-rays to build up a focused image of a “slice” through the body at a given level).
D
DENDRITE
(See AXON).
DIFFUSE BRAIN INJURY
Injury to cells in many areas of the brain rather than in one specific location.
DIENCEPHALON
The midbrain. This contains discrete nerve centres including the hypothalamus, which controls appetite regulation, sexual arousal, thirst and temperature control, and some aspects of memory. The diencephalon also contains the thalamus, the body’s sensory gateway to the brain.
DIFFUSE AXONAL INJURY (DAI)
Widespread tearing of nerve fibres across the whole of the brain.
DIPLOPIA
Double vision.
DISINHIBITION
Difficulty in controlling urges and impulses to speak, act or show emotions.
DURA
Outermost of the three membranes protecting the brain and spinal cord.
DYSARTHRIA
Difficulty speaking because of weakness and lack of co-ordination of the muscles for speech.
DYSPHAGIA
Difficulty with swallowing.
DYSPRAXIA
Inability to plan and perform purposeful movements, while still having the ability to move and be aware of the movement.
E
ECHOLALIA
Imitation of sounds or words without comprehension. This is a normal stage of language development in infants but is abnormal for adults.
ELECTROENCEPHALOGRAM (EEG)
EEG is a test used to record any changes of electrical activity in the brain by placing electrodes on the scalp.
EMOTIONAL LABILITY
Rapid and drastic changes in emotional state (such as laughing, crying or anger) that are inappropriate.
EXECUTIVE FUNCTIONS
Planning, organising, problem solving, sequencing, prioritising, self-monitoring, self-correcting, controlling or altering behaviour, and judgement.
EPILEPSY
There are many varied presentations. Seizure or fit activity involving parts of or the complete body.
F
FOCAL BRAIN INJURY
Injury restricted to one region (as opposed to diffuse).
FRONTAL LOBES
Part of the brain involved with planning, organising, problem solving, selective attention, personality and a variety of “higher cognitive functions”.
G
GASTROSTOMY
The creation of an opening into the stomach for the administration of foods and fluids when swallowing is impossible.
GLASGOW COMA SCALE
A score given to head injured patients starting immediately after the head injury to measure the degree of unconsciousness. A score of 7 or less indicates that the person is in a coma. A maximum score of 15 indicates that the person can speak coherently, obey commands to move, and can spontaneously open their eyes.
GLUTAMATE
The major excitatory neurotransmitter in the brain. Excessive glutamate release (or cascade) following TBI can be a major cause of nerve cell death in the second injury.
GYRUS (pl. GYRI)
A ridge of the cerebral cortex (also see SULCUS ) .
H
HAEMATOMA
A collection of blood forming a definite swelling which compresses and damages the brain around it.
HAEMORRHAGE
Blood loss, bleeding.
HEAD INJURY – MILD/MINOR
Causes brief loss of consciousness for 15 minutes or less with a period of post-traumatic amnesia of less than 1 hour.
HEAD INJURY – MODERATE
Defined as being a condition where the patient has been in a coma for 6 hours, and a period of post-traumatic amnesia of up to 24 hours.
HEAD INJURY – SEVERE
Defined as being a condition where the patient has been in a coma for 6 hours or more, or a post-traumatic amnesia of 24 hours or more.
HYPOXIA
A term applied to that state in which the body tissues have an inadequate supply of oxygen. This may be because the blood in the lungs does not receive enough oxygen, or because there is not enough blood to receive oxygen, or because the blood stagnates in the body.
I
IMPULSIVITY
A tendency to rush into something without reflecting or thinking first.
INTRACRANIAL PRESSURE (ICP) MONITOR
A monitoring device to determine the pressure within the brain. It consists of a small tube (catheter) in contact with the pulsing brain or the fluid cavity within it. ICP is measured by means of a metal screw or a plastic catheter connected to an electronic measuring device.
L
LIMBIC SYSTEM
A group of deep cortical structures connected to the hypothalamus, governing memory, emotions and basic drives, including sex drive.
LOCKED IN SYNDROME
A condition in which the patient is awake and retains the ability to sense and perceive, but is unable to communicate except by limited eye movements. This is due to the motor nervous system being paralysed. It can sometimes be confused with persistent vegetative state.
M
MAGNETIC RESONANCE IMAGING (MRI)
Enables detailed pictures of the brain to be acquired using a scanning machine. It uses a strong magnet rather than X-rays.
MANNITOL
A solution which removes water from the brain by accelerating urinary excretion and thus reduces raised intracranial pressure.
MINIMUM CONSCIOUS STATE
See PERSISTENT VEGETATIVE STATE .
MOTOR CORTEX
The part of the brain involved in planning and executing voluntary movements. The primary motor cortex lies directly in front of the primary SENSORY CORTEX on the upper surface of the brain.
N
NASOGASTRIC TUBE
This is the very thin tube that is threaded through the nose and throat into the stomach for giving liquid food and pureed meals. Used if there are swallowing difficulties.
NEURON
This is a nerve cell.
NEURO-TRANSMITTERS
Chemicals made in the nervous system that serve as messengers, aiding or interfering with the functions of the nerve cells.
O
OEDEMA
Increased water content in the brain, causing brain swelling.
OCCIPITAL LOBES
A region in the back of the brain which processes visual information.
OPEN HEAD INJURY
An injury where there is penetration of the scalp and skull through to brain tissue.
P
PARIETAL LOBES
The part of each cerebral hemisphere primarily concerned with the perception and interpretation of sensation and movement.
PERSEVERATION
The inappropriate persistence of a response in a current task which may have been appropriate for a former task. Perseveration may be verbal or motoric.
PERSISTENT VEGETATIVE STATE (PVS)
A long-standing condition in which the patients utters no words and does not follow commands or make any response that is meaningful. Also called MINIMUM CONSCIOUS STATE .
PIA
One of the three membranes surrounding and protecting the brain and spinal cord. The pia lies below the SUBARACHNOID SPACE in direct contact with the surface of the nerve tissue.
POST-CONCUSSION SYNDROME
A group of symptoms occurring after minor head injury that may persist for days, weeks or months.
POST-TRAUMATIC AMNESIA (PTA)
The period after being unconscious when there may be confused behaviour and no continuous memory of day to day events.
PROPRIOCEPTION
The sensory awareness of the position of body parts with or without movement.
R
RIGIDITY
This simply means stiffness, resistance to movement.
RETROGRADE AMNESIA
The loss of memory of events for a period prior to the injury.
S
SENSORY CORTEX
The primary sensory cortex is situated on the upper surface of the cerebrum, directly behind the MOTOR CORTEX . Different areas of the sensory cortex specifically deal with the sensations experienced in different parts of the body.
SHUNT
A devise to draw off excess fluid in the brain. A surgically placed tube runs from the ventricles and deposits fluid into either the abdominal cavity, heart or large veins in the neck.
SPASTICITY
An involuntary increase in muscle tone (tension).
SUBARACHNOID SPACE
The space between the ARACHNOID membrane and PIA mater. The subarachnoid space is filled with fluid (see: CSF).
SULCUS (pl SULCI)
A groove of the cerebral cortex (also see GYRUS ).
T
TEMPORAL LOBES
Located on each side of the brain, the temporal lobes are concerned with speech generation, sound and language interpretation, and are important in memory function and some aspects of visual processing.
TRACHEOSTOMY
An operation to insert a plastic tube in the neck just below the Adam’s apple. Through this tube, an adequate air passage can be maintained. It may be necessary to leave the tube in the windpipe for a prolonged period.
TREMOR
Regular repetitive movements which may be worse either at rest or on attempted movement.
V
VENTILATOR
A machine that does the breathing work for the unresponsive patient. It delivers moistened (humidified) air with the appropriate percentage of oxygen and at the appropriate rate and pressure.
VENTRICLES
Cavities (spaces) inside the brain which contain cerebro-spinal fluid.
VESTIBULAR
System in the middle of the ear which senses movement. Injury can lead to dizziness.
W
WERNICKE’S AREA
Located in the temporal lobes, this is an area of the brain concerned with producing speech (See also
