Proprioception


Sometimes regarded as the ‘sixth sense’, proprioception refers to the perception of your body’s movement and position. Proprioception means that we know where our limbs are in relation to each other, which means that we can perform daily activities such as holding objects and standing upright. Unlike the five senses which rely on receiving information from the outside world (i.e. stimuli), other 'senses' such as proprioception and balance receive information from the body.

Proprioception is brought about by nerve pathways that link the brain to muscles to allow for two-way feedback. One set of nerves is responsible for sending messages to muscles to bring about movement. The other set sends messages to the brain to let the brain know what movement has taken place so that you are aware of where your limbs are at any given moment in time.

It is difficult to understand the significance of proprioception unless you happen to have impaired proprioception- which, in short, means that you start to lose the ability to be aware of your own body and how it is moving. The short-term cause of impaired proprioception is alcohol poisoning. A high alcohol concentration in the blood can lead to brain damage and a loss of proprioception. A permanent loss of proprioception is attributed to a neurological condition such as multiple schlerosis. MS causes demyelination of neurones which means that neuronal communication becomes less efficient. This means that messages which are sent to the brain are not transmitted quickly enough to allow for effective proprioception. 

There are wide-ranging consequences of having impaired proprioception. For a start, you may not be able to speak as well. This is because proprioception is involved in the monitoring of the position of the jaw and tongue as well as monitoring the shape of the throat as it changes during speech. Proprioception is also needed to be able to move without heavily relying on vision. For example, with decreased proprioception, you are not able to walk without looking down at your feet, type without looking down at the keys and play musical instruments without looking down at the hands all the time. As such, treatment is essential if patients are to lead healthier lives.

Treatment can be provided in the form of management strategies, environmental modifications and exercises. To help patients undertake day-to-day activities, they may instructed to call on other senses to compensate for their loss of proprioception. For example, to help patients speak, they may be told to press their fingers against their throat while speaking to allow their sense of touch to compensate for their loss in proprioception. In order to stand upright, patients will have to make use of their vision to look down at their feet to prevent falling over. Afterwards, occupational therapists may get involved in order to modify the environment in which patients live. For example, there may be more lights installed in the house because a loss of proprioception means that you cannot move about in the dark without falling over.  Finally, exercises may be offered to patients (e.g. juggling) which improve the use of vision and spatial awareness to maintain balance.

By Kumaran Rajaratnam

Sources:

https://www.painscience.com/articles/sixth-sense.php
http://synapse.org.au/information-services/proprioception-fact-sheet.aspx 
The Man Who Mistook His Wife For A Hat by Oliver Sacks (the source of inspiration for this article)

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