• Ischaemic versus haemorrhagic stroke

    Dr Jack Lewis believes that it is important to realise that the brain needs a constant supply of blood to remain healthy and is capable of recovering from even serious brain injuries given sheer determination and absolute dedication to training undamaged regions to take over:

    The brain is a very delicate piece of equipment, yet head impacts resulting from trips and slips, or sports like rugby or boxing, only rarely result in brain damage. This is all thanks to the clever design of the skull’s inner surface and the three-layered sack that envelopes and protects the brain – the meninges. The meninges act as a shock absorber, cushioning the brain against blows and holding the brain tissue firmly together (similar to the way a weightlifter’s belt prevents hernias by holding the gut in place during the lifting of heavy weights which exerts large and potentially harmful forces across the abdomen). Special grooves inside the skull spread the brain’s impact evenly against its inner surface – in order to help minimise the damage that would occur if all the force was focused upon one small area. Although these design features help to protect the brain from the potential damage of most blows to the head, if blood flow to any area of the brain is interrupted for more than just a few seconds, then brain damage quickly follows.

    The brain is extremely energy demanding, using 20% of the blood that leaves the heart at rest, and a whopping 50% during intense mental exertion. The requirement of a constant supply of freshly oxygenated blood to keep the highly energy demanding cells of the brain alive and firing on all cylinders means that blockages within the brain’s blood vessels (ischaemic stroke) or rips in the blood vessel that leak into the surrounding tissue (haemorrhagic stroke) can quickly lead to catastrophe.

    Different brain areas are responsible for different mental functions – a division of labour across different regions – and so the disabilities suffered by stroke and haemorrhage victims vary widely according to which brain areas are cut off from that vital supply of fresh blood. For instance, damage the left motor cortex – a strip of brain containing different parts that each control head, arm, body and leg muscles, respectively – and the right side of the body becomes paralysed. You are unable to talk properly, slurring your words and drooling out of the side of your mouth, due to loss of control over the muscles in one side of your face and mouth. The muscles of your right leg are locked in a state of permanent contraction, so you cannot walk and must be pushed around in a wheelchair. Similarly the muscles in your right arm have also gone into spasm so it curls up uselessly and often painfully against your chest. Mentally you are the same old you, but the slurred speech, inability to move around under your own volition etc creates a different impression. When friends and family visit they speak to your partner or carer not to you – judging a book by its cover.

    An incredibly inspirational man, whom I met whilst on a summer holiday on the south coast of England, suffered exactly this injury when the jack holding up a car he was working beneath collapsed, crushing the left side of his skull like an egg. Yet he refused to believe the numerous medical physicians who, in his words – “threw him on the rubbish heap” – by saying that he would never walk again and that there was no realistic hope of recovery. Undaunted by this hopeless prognosis, he researched extensively on the internet and found reams of rehabilitation exercises that enabled him, painstakingly, muscle-by-muscle, through hours and hours of dedicated practice, to retrain intact parts of his brain to take over the functions of the damaged areas. He even learned to play the 12-string sitar in the process and I distinctly remembering marvelling at the fact that, had he not told me his story, I would never have guessed as his recovery was so advanced, that he seemed completely normal to the outside world. He achieved this miraculous recovery, regaining the ability to function normally and completely independently, through sheer grit and determination. When he discovered that I was neuroscientist, he told me his story saying that, one day, he hoped I would be in a position to pass his story on to a wider audience so that others could benefit from his experience.

    His example demonstrates that dedication to brain training can fix damaged brains – just think what you can do with a healthy one…

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