Every part of your brain controls a specific function in your body. Hurt the brain, and you hurt the body.
The brain is an extremely complex organ; particular regions of the brain are necessary for certain abilities, such as using the muscles in the limbs, speaking or seeing. When the brain is injured, specific functions will be lost depending on which part has been affected.
In broad terms, the following common symptoms following brain injury give us clues as to where the injury occurred:
- Weakness on one side often means that the ‘motor strip’ of the opposite frontal lobe has been damaged. This narrow strip of ‘grey matter’ on the surface of the brain runs from near the top of the head right down to the ear. The left hemisphere controls the right side of the body, and the right, the left side.
- If there are personality changes, inappropiate behaviour, mood swings, lack of motivation, lack of abstract thinking, poor judgement, difficulty in planning, organising and performing tasks in the correct order, then it is likely that the frontal lobes, which lie under the forehead, are affected. This may lead to poor judgement and difficulty functioning at home and at work.
- If there are visual problems such as blindness, difficulty interpreting visual images, words look meaningless, or visual illusions, then the occipital lobes at the back of the head are damaged. Note that several parts of the brain are involved in vision and processing of visual information.
- If there are visual perception problems such as poor hand-eye co-ordination, difficulty with drawing pictures, or a lack of awareness of certain body parts in a spatial orientation, then the parietal lobe, which is near the back and top of the head, is affected. These lobes process visual and other information to make it meaningful. You will see a cat with your occipital lobe, but the parietal lobe will process the information in order for you to recognise and call it a cat, with input from your frontal and temporal lobes as well.
- Difficulty expressing thoughts as speech or writing often implies injury to ‘Broca’s area’ in the front part of the left hemisphere. The person understands what he wants to say, but finds it difficult to do so. Writing will also be impaired, but reading comprehension may be fair to good. Language and speech are complex functions, involving the frontal, parietal and temporal lobes.
- If the person has difficulty understanding speech or reading, then Wernicke’s language area in the left temporal lobe may be affected.
- Memory is often very poor in injuries of the temporal lobes, situated deeply towards the underside of the brain.