Sensory System

The term ‘Sensory Processing’ refers to our ability to take in information through our senses, and to organise and interpret that information, and make a meaningful response.  The seven senses are fundamental to a child’s ability to learn & function in any environment. For those with Sensory Processing Disorder (SPD), there are a range of sensory sensitivities, from hyper (over responsive) to hypo (under responsive) reactions to the particular sensory input. These reactions can have a major impact on behaviour in response to sensory stimulation.

The Vestibular System is important for development of balance, coordination, eye control, attention, being secure with movement and some aspects of language development. It is composed of receptors in the inner ear, and connections between them and other areas in the central nervous system. Other senses also contribute to the vestibular system:

Sight – visual neurons respond to vestibular stimulation (e.g. when spinning, head shaking, or rocking).   Damage to the vestibular organs of the inner ear can be compensated by using visual information to maintain their balance. Hearing – the vestibular and auditory nerves join in the auditory canal and anything that disrupts auditory information can also affect vestibular functioning Touch – hands and fingers, for example, send information to the brain about the relationship between the body and stationary surfaces in the environment.  If the brain loses information from the vestibular organs of the inner ear, balance can be maintained by simply touching a vertical or horizontal surface with the fingertips.

Proprioception is the process by which the body utilises receptors in the muscles to track the position of joints in the body (JettProof sensory compression provides continual proprioceptive feedback to the wearer throughout the day).  The proprioceptive sense is composed of information from sensory neurons located in the inner ear (motion and orientation) and in the stretch receptors located in the muscles and the joint-supporting ligaments.

A neuro typical person is able to move a part of their body, such as a hand or foot, and without looking can know what that part is doing and where it is in space.  Proprioception makes this easy to do. Without proprioception, the brain cannot feel what the body part is doing, and the process must be carried out in more conscious and calculated steps, using vision to compensate for the lost feedback. A recent example was a woman with Autism who needed to look at her feet to navigate stairs, not just to see the stairs, but because she did not have the proprioceptive feedback to know the position of her feet.

These mechanisms along with the vestibular system, a fluid filled network within the inner ear that can feel the pull of gravity and helps the body keep oriented and balanced, are used by the brain to provide a constant input of sensory information. The brain can then make unconscious adjustments to the muscles and joints in order to achieve movement and balance.