Brain Injury: How Serious is it?

Traumatic Brain Injury (TBI) is an injury to the brain caused by a trauma to the the head. There are many possible causes, including road traffic accidents, assaults, falls, and accidents at home or at work.

The effects of a traumatic brain injury can be wide ranging, and depend on a number of factors such as the type, location, and severity of injury. You can read more about the symptoms in the 'Effects' section, below.


Brain injury is caused at least initially by an outside force, but includes the complications which can follow, such as damage caused by lack of oxygen, and rising pressure and swelling in the brain.

A traumatic brain injury can be seen as a chain of events:


The first injury occurs in the seconds after the accident


The second injury happens in the minutes and hours after this, depending on when skilled medical intervention occurs


A third injury can occur at any time after the first and second injuries, and can cause further complications

1 First Injury: There are 3 types of first injuries

TYPE 1: Closed Head injury

Graphic illustration representing a closed head injury.

These are the most common injury type with no break of the skin or open wound visible.

These often happen as a result of rapid acceleration or deceleration, for example: a car hits a wall or is hit from behind at traffic lights, the head is rocked back and forth or rotated, and the brain must follow the movement of the skull. It can twist, and the billions of nerve fibers which make up the brain can be twisted, stretched and even torn in the process.

Even mild injuries can produce widespread damage throughout the brain. This is defined as diffuse brain injury. The front of the skull has sharp bony ridges with which the brain can also collide, causing more damage. Arteries and veins running through the brain can be damaged, allowing blood to leak.

TYPE 2: Open or Penetrating Wound injury

Graphic illustration representing an open head injury.

These are not so common. In this type of injury, the skull is opened and the brain exposed and damaged.

This could be due to a bullet wound or collision with a sharp object, such as a motorcycle brake lever, or being hit by a pickaxe. 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.

TYPE 3: Crushing injury

Graphic illustration representing a crushing head injury.

This is the least common type of injury, and often damages the base of the skull and nerves of the brain stem rather than the brain itself.

In this type of injury, the head might be caught between two hard objects, such as the wheel of a car and the road. There may be no loss of consciousness.

2 Second Injury

This happens when the brain is starved of oxygen, which makes damage from the first injury worse.

It can happen for several reasons. Examples are choking on vomit after an accident, blood blocking a person's airway, or by the position which someone is lying in obstructing their airway. If other injuries are present, as they often are, serious blood loss can affect blood flow to the brain.

As a result, the amount of oxygen reaching the brain can be reduced. Understanding the relationship between the first injury and the effects of lack of oxygen has led to improvements in the kind of emergency treatment administered at the site of an accident by paramedics. They will make sure breathing is maintained and blood pressure is brought back to normal levels by emergency transfusions.

3 Third Injury

This can take place at any time after the first and second injury, in the days and sometimes weeks which follow, and could be as a result of bleeding, bruising or swelling in the brain or because blood clots have developed.

Blood leaking from torn blood vessels and other body fluids leaking into the area cause the brain to swell. This is a serious problem because the skull is a fixed space and there is no room for expansion. It causes complications in two ways:

  1. The walls of the skull are hard and unyielding, and damage the soft brain when it squeezes against them.
  2. When the brain swells it can squeeze the blood vessels, limiting the brain's blood circulation. This can be fatal, so intracranial pressure is monitored very carefully once the patient is in hospital.

Measures to reduce the risk of raised pressure include putting the patient on a ventilator to ensure a good supply of oxygen, and controlling the amount of water and salts in the body to cut down on the flow of fluid into the brain.

Blood clots occur when blood has leaked from damaged veins/arteries and then pools into a clot. They can press on the surrounding brain tissue which can damage it, and they also raise pressure in the brain.

Clots can occur in the brain itself (an intercerebrayl clot) or in the space between the brain and the skull (a subdural or extradural clot).

Blood clots (a.k.a. hematomas), can occur after quite minor injuries; this is why patients are often kept under observation in a hospital until the risk of a clot forming is likely to be over.

Injury Severity: After a Traumatic Brain Injury

Whether or not the person was actually unconscious, a state occurs where the person seems to be aware of things around them but is confused and disoriented. They are not able to remember everyday things or conversations, and often do or say bizarre things. This is called Post-Traumatic Amnesia (PTA), and is a stage through which the person will pass.

The term 'Coma' is often used to describe longer periods of unconsciousness.

More time = More severe

The length of PTA and/or loss of consciousness are important as they give an indication of the severity of the injury.

The table below gives a rough guide to how these measures affect the severity of the injury, although it is worth noting that everyone is different and categorizing injuries in this way doesn't always give an accurate measure of the long-term effects.

Graphic illustration representing brain injury.

Brain Injury

  • Minor
  • Moderate
  • Severe
  • Very Severe
Graphic illustration representing loss of consciousness.

Loss of Consciousness

  • < 15 minutes
  • 15 minutes – 6 hours
  • 6 – 48 hours
  • > 48 hours
Graphic illustration representing post traumatic amnesia.

Post Traumatic Amnesia

  • < 1 hour
  • 1–24 hours
  • 24 hours – 7 days
  • > 7 days


All brain injuries are different and people may be affected to a varying degree by any number of these problems depending on the severity of their injury and the area of the brain which is affected. Main effects of brain injury:

Graphic representation of cognitive brain function.


The cognitive effects of a brain injury affect the way a person thinks, learns and remembers. Different mental abilities are located in different parts of the brain, so a brain injury can damage some, but not necessarily all, skills, such as speed of thought, memory, understanding, concentration, solving problems and using language.

Icon representing memory problems.

Memory Problems

Some people may be unable to remember faces or names, what they have read or what they have heard. New learning may be affected, whilst previously learned skills may still be intact.

Icon representing reduced initiation and problems with motivation.

Reduced Initiation and Problems with Motivation

Problems with getting started on tasks are common, and can often be mistaken for laziness. These problems may also be a symptom of depression.

Icon representing reduced concentration span.

Reduced Concentration Span

Completing tasks can be a problem and the task may be abandoned before reaching the end. The person may initially appear eager to start a task, but then lose interest very quickly.

Icon representing reduced speed of information processing.

Reduced Speed of Information Processing

People can take longer to think things through or work out what has been said to them. "Information overload" can be quickly reached, and can cause frustration and anger.

Icon representing reduced problem solving abilities.

Reduced Problem Solving Abilities

It may be difficult for the person to work out what to do if they encounter an unexpected problem.

Icon representing repetition or preservation.

Repetition or Preservation

The person may be unable to move on to another topic in the same conversation, and they may return to the same topic over and over again. They may also repeat the same action, appearing unable to break the cycle.

Icon representing impaired judgement/reasoning.

Impaired Judgement/Reasoning

May affect a person's ability to think logically, understand rules, or follow discussions. The person may easily become argumentative due to lack of understanding. Can cause difficulty in accurately perceiving and interpreting one's own and other people's behavior and feelings.

Icon representing aphasia (language loss).

Aphasia (Language Loss)

May be "receptive" difficulty (making sense of what is said or read) or "expressive" (difficulty finding the right words to say or write), or both. Can be frustrating for the person and others, and patience is needed. Just because a person can't express themselves, doesn't mean they don't need or want to be heard.

Icon representing impairment in visual-perceptual skills.

Impairment in Visual-Perceptual Skills

Individual finds it difficult to make sense of ordinary pictures/shapes, finding their way around a building, or drawing/constructing objects. Can be particularly frustrating for a person who is quite competent in their language and social skills. May fail to respond to stimuli coming from one side of their visual field, or ignore a side of their body.

Graphic representation of physical function.


Most people make an excellent physical recovery after a brain injury, which can mean there are few, or no, outward signs that an injury has occurred. There are often physical problems present that are not always so apparent, but can have a real impact on daily life.

Icon representing fatigue.


Excessive tiredness is common to all severities of brain injury. Simply getting dressed or walking around can require much more effort. Allow for rest periods at regular intervals during the day, and don't feel that everything has to be done at once.

Icon representing mobility.


Movement can become slow and balance affected. Brain injury can feel like "living life in the slow lane". Some may need a wheelchair or other mobility aids. The fact that they use a wheelchair does not necessarily mean that the person cannot stand or walk for short distances.

Icon representing sensory impairment.

Sensory Impairment

Sensation of touch on the skin may be reduced, lost or exaggerated. May be difficult for the person to know where their limbs are positioned. Eyesight may be affected. Odd postures or walking patterns may occur. Taste or sense of smell may be impaired or lost, either in the short or long term.

Icon representing speech difficulties.

Speech Difficulties

Slow, indistinct, or rapid speech is common. May be hard to understand. People may repeat what they have said many times over: known as perseveration. Some may lose their ability to speak altogether. Their inability to express themselves does not mean that they have lost their intelligence.

Icon representing epilepsy.


Brain injury can make a person prone to epileptic seizures or "fits". Many who have had a seizure after brain injury are given a drug to reduce the chance of it recurring. The drug may have an overall "dampening" effect on the person's level of arousal, and therefore on the performance of everyday tasks.

Icon representing weakness/paralysis.


Often affects one side of the body more than the other. This could mean that help is needed during personal care and when getting dressed or undressed. Muscle weakness may affect continence, and continence aids may be needed.

Icon representing ataxia.


Irregular, uncontrolled movement or tremor affecting the coordination of movements. The person's hands may be shaky or clumsy, and handwriting may be difficult or impossible.

Icon representing hormonal imbalances.

Hormonal Imbalances

Brain injury may cause damage to the hypothalamus/pituitary gland, which responsible for regulating the body's hormones. Damage to these areas can lead to insufficient or increased release of hormones, causing disruption of the body's ability to maintain a stable internal environment (homeostasis).

Graphic representation of behavior function.

Emotional Behavior

Everyone who has had a brain injury can be left with some changes in emotional reaction and behavior. These are more difficult to see than the more obvious problems such as those which affect movement and speech, for example, but can be the most difficult for the individual concerned and their family to deal with.

Icon representing loss of confidence.

Loss of Confidence

This is very common after brain injury and a person can need a lot of encouragement and reassurance.

Icon representing mood swings.

Mood Swings

The person may have a tendency to laugh or cry very easily, and to move from one emotional state to another quite suddenly.

Icon representing anxiety.


Life has been changed forever in a matter of seconds, and the future can look frightening. Anxiety can quickly lead to frustration and anger and needs to be identified and alleviated as early as possible.

Icon representing depression or sense of loss.

Depression or Sense of Loss

Caused by injury to the areas of the brain that control emotion, but also associated with gaining insight into other effects of the injury. After brain injury, many things that are precious to the individual may be lost forever and there may be great sadness, anger, guilt, and confusion, surrounding this.

Icon representing disinhibition.


There may be a loss of control over social behavior, so that the person may behave in an over-familiar manner or make sexual advances with the wrong people at the wrong time. They may also be unable to inhibit their thoughts and may make inappropriate and offensive outbursts.

Icon representing abusive/obscene language.

Abusive/Obscene Language

This may be spontaneous and uncontrollable, and may be an outlet for the person's anger and frustration. This behavior can obviously be embarrassing and upsetting for those nearby.

Icon representing impulsiveness.


A person with a brain injury may tend to speak or act without thinking things through properly first.

Icon representing obsessive behavior.

Obsessive Behavior

For example, a person may be afraid that their possessions will be stolen, and may check their belongings repeatedly.

Icon representing frustration/anger.


Frustration can build up quickly, especially when things that were once so easy are now difficult or impossible. The resulting anger may be very difficult for the person to control.