Navigation test
Abstract
The balance system allows to our body to have a right relation with environment, this is probably due by different structures that collaborate to maintain the correct voluntary posture during erect position and the clear vision of the ambience; with regard to its synergetic purpose the balance system can therefore be schematised on the base of two main subfunctions: coordination and orientation, also divided into other sublevels or subfunctions:
Coordination:
> motor ocular coordination (coordination of eye movement in order to maintain the foveal vision);
> static coordination (between gravity force and antigravitary muscles) in order to maintain the posture
> dynamic coordination (between gravity force, muscular system, ambience) to harmonically move in the ambience.
Orientation;
> perception of the mutual orientation of body segments (perception of body shape)
> perception of body orientation in the ambience, especially with reference to the direction practised by gravity force .
The elements that guarantee it at a receptorial level are:
1. otoliths
2. proprioceptors, (limbs, column, joints),
3. visual, tactile, auditory inputs.
They are not generally excited isolately, but they provoke a perceptive complex of concordant information, whose integration is perceived as body orientation.
The individual knowledge that one has of his body acts at a preconscious level and is involved in every action; this means that many situations are normally resolved in an unconscious way; the function of orientation can be refined by several cognitive factors and by training, while external factors (dark, etc.) and internal (illusions, vestibular pathology) can alter it, provoking the loss of the visual-sense-moving dependent scheme, forcing the subject to use only the vestibular system………