Proprioception (also known as kinaesthesia) is a term that describes the brain’s ability to track precise muscle/joint position and orientation in 3D space. That is to say that the brain not only knows and controls every muscle of every part of the body continuously, it also knows their exact location.
This ability is achieved with the help of sensory receptors in the skin, muscles and joints. These sensory receptors help the brain determine movement, a joint’s position, a muscle’s force and the effort exerted by the muscle. They also assist in the brain’s understanding of the sense of heaviness.
To demonstrate how complex the proprioceptive loop is between muscles and brain; close your eyes, extend your arms away from your body and then slowly bring both index fingers to touch the tip of your nose. This small example of proprioceptive ability is achieved by a constant feedback loop between the brain, nerves, proprioceptors and muscles. The brain orchestrates the whole process. Concurrently sensing location and tension, and activating necessary muscles in order to maintain a posture. It is also important to note that as you were focusing on not poking yourself in the eye, your proprioceptive awareness also made sure that you sat upright and that the rest of your body was also controlled.
The proprioceptive loop is determined by the brain’s model and understanding of the body it controls and the movement that that body is undertaking at every given moment in time.
We are unaware of all proprioceptive activity within our bodies because they provide no recognisable sensation. However, without looking at our body we still have a relatively precise understanding of the position of our limbs, trunk and head.
The reason for this is that when we move, the movement itself helps us anticipate the sensory input that is created. Another way to explain this, is that what we feel is the difference between what is expected and what actually happens.
Proprioception does not only relate to gross motor skills; necessary for walking, running, standing or jumping; it also refers to fine motor skills needed when holding a pencil, brush, fork or knife for example.
Proprioception and cerebral palsy.
Proprioception is fundamental in controlling proper movement and coordination. Therefore, as cerebral palsy is a condition affecting both movement and coordination, the person’s proprioceptive capabilities are inevitably affected. Severity of the cerebral damage usually determines the level of ulterior physical complications experienced by the individual.
Proprioception and cerebral palsy are therefore at odds with each other. As the brain of a cerebral palsy individual is damaged, that brain’s ability to control its body is limited.
However, by challenging your child to his highest level of ability, as early as possible in life, offers a greater chance of improved ability due to the brain’s capacity to ‘rewire’ itself early-on in development. This ‘rewiring’ that the brain can do is called neuroplasticity.
Even though neuroplasticity and proprioception are not directly related, by challenging the damaged brain’s control of the muscles to the extreme, the brain will hopefully be forced to adjust the way it approaches the physical challenge at hand. Ultimately creating new pathways to healthy areas of the brain that can, from then on, deal with the similar challenge in the future.
As mentioned earlier, proprioception is achieved by the feedback loop between your brain, nerves, proprioceptive receptors and muscles. There are two other factors however that need to be thrown into the equation to achieve more precise movement and body control.
Both vision and the vestibular system are necessary to help the brain achieve higher accuracy in its proprioceptive challenges.
The vestibular system is part of the inner ear, and deals with motion, equilibrium and spatial orientation. These functions coincide exactly with proprioception and are included in the feedback loop information to help the brain achieve the highest level of accuracy in determining posture and muscle control.
Because the vestibular system is internal, short of shaking your head, proprioception cannot easily be challenged this way. Proprioception however, depends heavily on vision, and sight can easily be removed from the loop by blindfolding. Thus providing no visual clues to the brain.
Preventing visual clues to the brain has other benefits. Covering eyes not only removes external distraction, it also allows the brain to dedicate more attention on muscle/joint control and vestibular functions.
How Julian does it
Any movement done without vision adds an increased level of challenge. So when considering appropriate exercises for Julian, what we do is simple; half of his standing/kneeling work is done blindfolded. The task at hand is done first without blindfold and then repeated the same amount of times with the blindfold. We have been doing this for many years now.
People often ask whether the technique helps. Due to the nature of cerebral palsy, and the fact that quantifying the results of habilitation is impossible, the question can’t be answered. So, I approach Julian’s physio sessions, and all of his treatment options, with the same motto:
If it doesn’t hurt…it might just help!