"They have been absolutely superb. I can’t praise them highly enough, because I wouldn’t be where I am now if it hadn’t been for them."

– Diane, client's wife

Effects of brain injury

As far as modern science understands, the brain controls everything that we do and houses our memories and personality - though how this happens is not fully understood.

However, the brain's importance means that when injured, the after-effects range from the minimal to the extreme, and from physical defects to drastic changes in personality.

The effects of brain injury fall into three main categories, cognitive, physical and behavioural/emotional.

Cognitive brain injury

A cognitive brain injury is one that impairs a person’s mental abilities. These include problems with memory, attention span, the ability to concentrate, the ability to correctly perceive surroundings, and the speed at which information can be processed.

Memory problems

Memory problems are a common symptom of brain injury because in order for a brain to process, store and retrieve information, many different areas of the brain must be used at once. If one or more of these areas are damaged, it will affect a person’s memory.

Post-traumatic amnesia (PTA), the medical term for memory loss, is the period of time where the injured person cannot remember what happened either before or after a traumatic brain injury. During this period, the person may find it difficult, or be unable to create new memories.

The severity of the injury will determine the extent of the memory loss, meaning that it can range from the moments just before the accident, to a period of days, months or even years.

PTA is usually temporary, and given time memories can partially or fully return. However it is also possible that these memories will never be recovered, and this again depends on the exact circumstances of the injury.

In cases of permanent memory loss, brain injury rehabilitation efforts are focused on creating coping strategies because as of yet, there is no in-depth scientific understanding of how to reconstitute a person’s memory abilities.

Attention span and poor concentration

Attention span and concentration are controlled by a part of the brain known as the frontal lobe, so it's common for someone who has suffered a head injury to have attention difficulties—in particular, the inability to multi-task.

Our modern lifestyles are quite badly affected when the ability to plan or follow simple instructions is compromised, and poor attention span can be further affected by factors such as stress, fatigue and anxiety. This can lead to a vicious cycle, where a person is irritated by their inability to perform a simple task, which in turn makes them less capable of achieving it.

In order to regain the ability to concentrate, it is necessary to ‘relearn’ how to do so through rehabilitation and distraction management. It may be necessary to isolate yourself from distractions as much as possible, and slowly increase these distractions as the ability to concentrate is gradually rebuilt.

Perceptual difficulties

Perceptual difficulties are where the brain is not interpreting the information from our senses correctly. There is a very wide range of problems that can result from perceptual difficulties.

One example is when a person may try to pick up a pen but lacks the correct hand-eye coordination to do so. Despite being able to see the pen, they cannot accurately determine its position relative to their hand because of an issue with judging distances and spatial relationships. Another example would be the inability to recognise a common object when it is viewed from a non-standard angle.

Information processing

The brain may have reduced ability to process larger amounts of information in small spaces of time, usually due to changes in neural pathways. A useful analogy for this would be if the road system covering your journey to work were completely changed, then it would take you much longer to find your way to work than before.

Slower information processing will result in issues such as requiring people to speak slower, the need to be given instructions several times before they are understood, and difficulties in replying to questions in a ‘normal’ amount of time. These symptoms can be described as the person being constantly in a state of ‘information overload’.

Physical brain injury

As well as housing our thoughts, memories and personality, the brain also coordinates the subconscious physical processes that are essential to a healthy life such as breathing, hormonal balance, blood pressure regulation, the digestive system and body temperature regulation.

Without these functions, our bodies would not operate correctly and cause an exceptional amount of day-to-day living difficulties.

A severe brain injury can cause irreparable damage to the brain’s ability to control these regular functions, so rehabilitative efforts shift from fixing the problem to learning how to cope with them. In severe cases, full-time carers may be required.

Examples of physical effects

  • Movement, balance, and coordination problems

  • Fatigue

  • Chronic pain

  • Headaches

  • Spasticity

  • Incontinence

  • Epilepsy

  • Loss of sensation

  • Dysarthria (difficulty with speech)

  • Dyspraxia (difficulty with planning and executing movements)

  • Hormonal imbalances

Behavioural / emotional brain injury

A brain injury can sometimes ‘rewire’ a person’s personality, causing their behaviour and emotional reactions to change. Exactly what is changed will depend upon which parts of a person’s brain are injured. For example, the frontal lobe is the area of the brain that controls our personality and our impulsivity.

If this area of the brain becomes damaged after a brain injury, it is possible that the person will have reduced self-control or restraint and may not be able to moderate their emotions, resulting in irrational behaviour.

Another example would be constantly saying inappropriate things, without any understanding of how or why they may be inappropriate. The person may also go to the other extreme, and have what seems to be an emotionless personality.

This is known as “flat affect”. These types of symptoms are perhaps less obviously noticeable than physical problems, but also have a large impact on the injured person and their loved ones' lives.

It is often the case that the injured person does not realise that they act differently compared to how they were before the brain injury, and examples of behavioural and emotional changes may include:

  • Mood swings

  • Lack of judgement, awareness and disinhibition

  • Agitation

  • Apathy

  • Depression

  • Self-centredness

  • Obsession

  • Anxiety

  • Inflexibility / stubbornness

  • Sexual problems

Mood Swings

A brain injury can sometimes change a way that a person feels or expresses their emotions. Damage to the frontal lobes may mean that they lose the ability to regulate their emotions, and experience random mood swings that are unrelated to how they are actually feeling.

Unpredictable outbreaks of laughter or crying are common and they may feel like they are on an ‘emotional roller-coaster’. They may have a reduced tolerance for stress and frustration, so even something as minor as having the television volume too loud or losing a set of keys can lead to an extreme verbal or physical outburst.

Examples: seemingly random changes from one emotion to another

Lack of judgement, awareness and disinhibition

The ability to evaluate and adjust our personal behaviour to the circumstances around us is a complex skill, largely controlled by the brain's frontal lobes.

Damage to this area can affect self-awareness, insight into the consequences of one's actions, and ability to show empathy or sensitivity. Those injured may also be unable to distinguish when they are being impolite or breaching social etiquette.

Examples: touching someone inappropriately, speaking your mind regardless of the circumstances, recklessness.


It's common for a recently injured person to be uncooperative due to disorientation, confusion and anxiety. They may do things like pull out their IV tubes or experience restlessness because the behaviour acts as a coping mechanism to relieve the stress of the situation.

An unusual level of agitation is most often a temporary symptom, going away with time as the person becomes less confused by their situation.

Examples: restlessness, fidgeting, pacing.


Damage to the frontal lobe can also cause a lack of motivation or spontaneity. This is because the person has reduced levels of emotion and forward planning, which makes activities appear extremely overwhelming.

Examples: staying in bed all day, a lack of interest in previous hobbies.


Once the rehabilitation process starts, it is very common for the person to experience depression. This is especially the case towards the later stages of rehabilitation, as they realise the full extent of the problems caused by their injury and any permanent damage that they will have to cope with.

It is worthwhile to note that depression is an important stage of mental recovery, because it means they are aware of the reality of their situation. Only then can the person begin to accept the situation and move forward.

Examples: wishing they had not survived the accident, believing life will never be good again.


It is normal for an injured person to suffer from anxiety, due to the loss of confidence they experience with situations and tasks that used to be commonplace but are now difficult. For example if the person has writing difficulties, they may be worried about signing a cheque at a restaurant.

It is important that these difficult situations be faced head on, with an attitude of independence in mind, because if these fears are left to fester then the more likely they are to become a long-term problem.

Examples: panic attacks, paranoia, poor quality sleep.

Inflexibility and obsessionality

The frontal lobe is where our ability to reason and make sense of things originates. If the frontal lobe is damaged, the person may be unable to do things differently, and stubbornly stick to a routine or habit.

This is because they have lost the ability to consider alternatives on their relative merit, and make a decision based on that analysis. Anxiety will make this worse, because the injured person may think that sticking to a routine will make them feel better.

Examples: strange patterns of behaviour, unreasonable stubbornness, over-attachment to belongings.

Sexual problems

After a head injury, a person’s sex drive can either increase or decrease. There are a great many physiological and psychological reasons for this, most of which are due to the hypothalamus (an important structure in the brain which controls hormone levels) being over or under-active.

Examples: increase or decrease in sex drive, misinterpretation of sexual advances

As the after-effects of a brain injury may be so varied and severe, rehabilitation is vital in helping those injured achieve a level of recovery.

To find out more, please visit our brain injury rehabilitation section.