Cognitive effects
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.
Our range of publications give much more detailed information on the effects of brain injury. They are available to buy from our online shop. Use the links on the right to go to the online shop homepage, or straight to relevant publications.
The cognitive system can be divided up into six separate areas:
Memory is not one thing or one skill on its own. It is easily damaged by brain injury because there are several structures within the brain that are involved in processing information, storing it and retrieving it. Damage to those parts of the brain on which these abilities depend can lead to poor memory.
Amnesia literally means 'a lack or an absence of memory'. In practice, few people forget everything, so amnesia usually refers to a failure of some part of the memory system.
Post-Traumatic Amnesia (PTA) occurs in the temporary period immediately after the accident such that the person seems relatively alright, but everyday memory for events or conversations is not working. Our factsheet 'Post Traumatic Amnesia' gives more information - you can download it now from our Factsheets page.
Retrograde amnesia describes a period during which a person cannot remember events and information for a time immediately before and after the accident. This form of memory loss stretches backwards from the accident for minutes, hours, days, months or sometimes years. Given time, memories from this period can return in part or whole but sometimes large chunks of memory are permanently lost.
It is sometimes said that people with memory problems do not remember in order to protect themselves from some kind of emotional trauma. While it is true to say that there can be psychological causes for amnesia it is found that these are rare, despite its frequent occurrence in films, plays and novels.
Short-term memory loss is the most common and troublesome type of memory problem. This can manifest itself in a variety of ways. Examples of this are forgetting what has been just said, having difficulty in learning a new skill, repeating the same question over and over, forgetting people's names, getting details mixed up, forgetting a change in routine and forgetting where things have been placed. There is no magic answer to improve this type of memory problem, and rehabilitation will try to help a person cope using tried and tested strategies. Memory is not like a muscle that can be developed just by stretching it.
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A reduced concentration span is very common after head injury, as is a reduced ability to pay attention to more than one task at the same time. These problems are usually caused by damage to the frontal lobe.
Attentional problems tend to get worse when the person is tired, stressed or worried. When there are problems with concentration, other skill areas can be affected. It is difficult to follow instructions, plan ahead, be organised and so on, when there is a problem concentrating.
Working in a place with as few distractions as possible can help and, as concentration improves, distractions can be increased. In this way, someone can slowly learn to concentrate better in a world which is crowded with distracting sights and sounds.
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Slowing down the speed at which the brain performs the task of information processing is often due to diffuse axonal damage caused by a shake up of all of the pathways the brain uses to transmit messages. This results in problems such as not understanding fast speech, being unable to absorb instructions first time around, and not being able to quickly formulate a reply to a question.
To improve the speed of information processing, it is advisable to keep mentally stimulated at the right level to avoid overload.
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Damage to the frontal lobe can affect these skills, resulting in a subtle set of deficits which have been called 'Dysexecutive Syndrome'. This covers problems in making long-term plans, goal setting and initiating steps to achieve objectives. The ability to stand back and take an objective view of a situation may be lacking, as may the ability to see anything from another person's point of view.
If the person is aware that this is a problem, then encouragement and direct feedback can be given to help the person modify their behaviour. It is useful to try to create structure in otherwise unstructured situations, by breaking down any task into specific tasks, perhaps using checklists.
Flexible thinking is made up of both divergent thinking (thinking outwards or generating ideas from a single point) and convergent thinking (thinking inwards, taking ideas and summarising them).
Exercises which practice these skills not only improve ability but help to identify difficulties and improve awareness.
Our factsheet 'Making decisions after acquired brain injury' may be helpful for people who have problems in this area. You can download it now from our factsheets page, or contact our helpline for more details.
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Organs such as ears and eyes may be working perfectly well, but the part of the brain which makes sense of incoming information from these sources may not be working properly. This gives rise to several different types of difficulty.
Problems in judging distances, spatial relationships and orientation can mean, for example, that a person may bump into furniture that they have seen, but have misjudged where it is in relation to themselves.
Sometimes a person will have a problem where one side of whatever they are looking at is not seen (visual neglect). A person may only eat half the food on their plate, or read only halfway the across the page. The ability to recognise something viewed from a different or unusual angle can be lost. This can also apply to sounds as well as vision.
Building objects or drawing them from component parts such as coloured block may be very hard.
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Problems with language loss can be either receptive such that no sense can be made of what is heard or read, or expressive which means it is not easy to find the right words to say or write. Difficulties with these areas are known as aphasia. When both problems are present the condition is known as 'global aphasia'.
There is a special area on the left side of the brain concerned with producing speech (Broca's area which is located between the frontal and temporal lobes) and another area for understanding the speech of others (Wernickes's area which is located further back between the temporal and parietal lobes). These two are connected by numerous pathways but are quite distinct.
It is useful to remember that the brain skills which produce and understand speech are different to the ability to make the sounds of language. The latter can be due to problems with the muscles in the throat and mouth, and more detailed information is given in the section on physical effects after head injury.
Other organisations can help, such as Speakability. See the link below.
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