Hello, late again, this has become a habit – but I’m a busy bee…
I just wanted to share some interesting things about the senses really, specifically sight and proprioception.
Everyone knows we have five senses right? Sight, smell, sound, taste and touch. But we also have two other senses that are equally important. These are our sense of proprioception and our vestibular sense.
Vestibular sense is related to body rotation and gravitation. Our vestibular sense responds to a change in your head position or having your feet lifted off the ground. It also aids balance.
Proprioception is our sense of where our body is within space. This morning, before you opened your eyes, you would have had a sense of how you were laying on the bed and where each of your limbs were. That is your sense of proprioception, of understanding where your body is in space. As you can imagine, if you have no sense of, or lose your sense of proprioception, this can cause major problems.
For those of you who are clumsy, you may not process your proprioceptive input effectively. The reference to the ‘bull in the china shop’ might apply.
In Oliver Sacks’ ‘The man who mistook his wife for a hat’, he describes the case of Christina. Christina was admitted to hospital for gallstone surgery. In the days, preceding surgery Christina developed total proprioceptive deficit. Tests revealed that she was suffering from Guillian- Barre syndrome, affecting the spinal and cranial nerves. However, when her spinal fluid returned to normal, she did not recover her sense of proprioception. This left her feeling a complete sense of disembodiment.
At first Christina, could do nothing without using her eyes. She would collapse in a heap the moment she closed them. She had to look at each body part as she moved it. Making a conscious connection between her brain and the body part she wanted to move.
Imagine not knowing that you have hands unless you are looking at them. That every time you looked away from them, they would cease to exist. That’s what losing your sense of proprioception would feel like.
Now imagine something completely different. Imagine being diagnosed blind. Except that you have no physical impairment, merely your brain cannot interpret what your eyes see. This is called cortical vision impairment. This is usually caused by damage to the visual centres of the brain, which interferes with the communication between the brain and the eyes.
Often individuals with CVI prefer certain colours, need movement to ‘see’ an object, may have a delayed response to visual stimuli or may show a preference for looking at lights or objects at certain angles/close range.
While the deficit in the visual centres of the brain can be large, it is thoughts that individuals with CVI can develop these centres, improve the connections between the brain and the cornea, and eventually develop more sight. Individuals with extensive and severe neurological damage are less likely to improve, than those with isolate neurological damage. Studies have suggested that most children with CVI improved their visual acuity over time, but that the majority did not develop normal vision.
I don’t really know what my big ending to this blog post is. I usually like to leave the reader with a take home message, so you all feel fulfilled and like flowers are flowing through your hair and there are bunnies everywhere (joke!). I think it’s sometimes important just to appreciate that our bodies see, touch, taste, hear, smell without conscious thought. Plus, they don’t fall down when we shut our eyes, unless perhaps we are rather drunk.
Our bodies do amazing things every day. There are 100 billion neurons in the average human brain. Estimated 37.2 trillion cells in the body, not including bacteria. I just want you guys to know that the human body does a lot of us, and we are not even conscious of most what it is up to at any one time.
While the universe is mystical, beautiful and impossibly large. I’d take the human body over it any day…
Love Em (The Little Blogger) x
Ps. I guess you can apply these deficits to life. If you work hard, no matter how damaged you are, you can improve your quality of life.
Oliver Sacks – ‘The man who mistook his wife for a hat’