Education

Postural control is learned and is dependant on intact sensory and motor mechanisms (which are present from birth in healthy children). Organisation of the body segments develop one after another, starting with the ability to control the trunk, which acts as a stable base about which movement can occur³.

The development of purposeful movement is a result of trial and error⁴. Efficiency of movement develops as the individual learns to move within their own ability and within what the environment will allow. The same mechanism for learning is applicable to the disabled child, however, the sensory and motor mechanisms are often impaired. Due to these neurological impairments, the ability to develop control of the trunk can be limited and so any learnt movements are from an unstable base. As a result of this threatened balance, all body segments are required to maintain equilibrium. Learned movements are less effective and more energy intensive. Imagine walking across a frozen lake in slippery shoes, the result will require all limbs to help maintain balance and movement in the correct direction will be very difficult to achieve.

The Chunc seating system has the ability to stabilise this "inadequate" base and allow a remoulding of the strategies adopted and so help to create more efficient and effective mechanisms of movement.

It is increasingly recognized that in people with ongoing disability, the focus should be on minimizing associated /secondary complications⁵. Secondary complications can be defined as a result of the motor or neurological impairment and are not a direct result of the impairment itself. They are largely the result of the inability to move effectively, the inability to stabilize posture, and the inability to change position¹.

The inability to organise the body segments in the seated position may present in the following way:

• Slumped or arched body position.
• Trunk falling forward to one side, often with the pelvis rotated.
• Rotation of the spine.
• The head falling forward or sideways or backwards.
• Other body segments buckling or bending and finding their own level of support e.g. deviation of the lower limbs.

As a result of the above, "habitual" postures are created in the above mentioned patterns. These habitual postures have been strongly linked to the effect of gravity on the individual rather than to the disability.

These "preferred" and sustained postures can result in:

• Tissue adaptation such as contractures and eventually deformity.
• Tissue breakdown (especially with shear forces). This is due to lack of circulation and mechanical damage.
• Reduced efficiency of performance.
• Respiratory distress or difficulty.
• Respiratory infections - due to decreased respiratory efficiency or aspiration when feeding.
• Urinary tract infections.
• General discomfort.
• More specifically, a correlation has also been noted between the adducted leg and dislocation of the hip joint. (This observation has been endorsed in recent works by Porter, 2004 and Young et al, 1998⁶).

Careful contouring, shaping and positioning of the cushions and supports available in the Chunc 45 help to create forces on the body that reverse the above mentioned postural deficits and help to facilitate a balanced and stable position of the Pelvis, Mid thoracic Spine, Cervical spine and feet. Damaging forces on the body tissues can be reduced and the progression of deformity arrested. General comfort can also be enhanced and sitting tolerance may increase, which could allow for increased periods of functioning.

The purpose of special seating is:

• To arrest the progression of deformity through support and control of postural segments (on occasion some correction can be achieved).
• To stabilise the trunk and thereby free the limbs for more efficient and effective movement.
• To distribute pressure over the maximum area possible to prevent damage and enhance comfort.

A management approach to postural control ensures the therapeutic aims of the seating system are met while still ensuring proper consideration of the occupant's carers and family within his/her specific environment and circumstances. The Chunc seating system has been designed through consultation and in partnership with carers, parents, disabled individuals, and therapists from across the world to ensure the creation of a system that fulfils the requirements and expectations of not only the clinician and therapist, but the disabled user and their carers and parents.