What are the main groups that require specialised seating/body support
The elderly Cerebral palsy RA (non-elderly) Muscular dystrophy MS Motor neurone disease
What are the problems associated with insufficient support
Poor/asymmetrical postures
Prevents function
May encourage development of deformities
What are the problems associated with excessive support
Impedes function by obstructing movement
Encourages dependence on support (esp. in cerebral palsy children)
What pattern of hypertonia is commonly seen in cerebral palsy children
Extensor spasm pattern: all four limbs forced into extension
What stimuli can trigger extensor/flexor spasm pattern
Noise, movement, position, head orientation, heat, discomfort
How can the extensor pattern in cerebral palsy children be diminished
Flex the hips beyond 90degrees
Alternative: extend hips and support the body via the knees and chest
How should paresis be compensated for
Ensuring the centre of gravity is positioned as close to the mid-line as possible
What are the 3 main stability pathologies
Hypertonia
Paresis
Dyskinesia
What conditions is athetosis commonly seen in
Cerebral palsy and Friedrich’s ataxia
Why do disabled people tend to have different proportional body size segments
Due to lack of/excessive loading/movement imposed by their condition which can stimulate or inhibit growth
Why is obesity more common in disabled populations
Normal food intake is maintained despite reduced energy requirements
Hormonal and psychological problems
What is the ‘windswept’ configuration
Combination of pelvic obliquity, rib deformities, hip contractures and dislocations
Creates a z-shaped body due to muscle imbalance
Which conditions are characterised by pain during sitting
RA
MS
Back pain
Why might sitting lead to back pain
Compression on spinal nerve roots
Often the cause is unknown
Which condition is often associated with abdominal problems such as impaired swallowing ability and gastric reflux
Cerebral palsy
Why does prolonged sitting lead to oedema
Venous pooling because muscle pump is not active
Lack of lymphatic flow
What is the most common reason for seat rejection
Lack of comfort
What factors can lead to discomfort
Over-restriction of movement: sustained loading
Inadequate support: requires more muscle action
How are interface pressures kept to a minimum
Ensure a large surface area and contour to follow body shape
What are the 2 main categories of seating support
Sagittal support
Lateral support
Why is the ischial support so important
Area where the highest supporting pressures are encountered: may require extra consideration to avoid pressure sores
What materials are used to minimise peak pressures at the ischial supports
Foam
Gel
Air filled material
Why is the femoral support important
Governs hip angle and orientation of the femurs
What is the ideal positioning of the horizontal femur
The femoral support should be angled higher distally than proximally
Usually around 15degrees to the horizontal
What is the function of the posterior pelvic support
Maintain the upright pelvis in the sagittal plane
What are the 2 applications of use of pelvic straps
Prevent person from falling out of chair
To hold the pelvis in the desired position
What position should be pelvis straps be used at
At an angle that bisects the angle between the ischial and posterior pelvic supports
What is the most effective way of holding the pelvis in position
The ASIS bar: padded metal bar locked in position across the ASIS, curves over the abdomen
What can knee blocks be used for
Preventing forwards motion of the pelvis
Controlling windswept deformities (when combined with adduction blocks)
Potential problem with knee blocks
May exacerbate hip dislocation/subluxation
What position do foot supports normally create
Plantigrade foot position
When does the degree of thoracic support become important
When backrest recline increases
Should head support be maximised or minimised
Minimised
What is the most effective chest/shoulder harness design
A waistcoat: prevents forwards trunk flexion
How should lateral supports be applied
In combinations of 2 or 3 elements on opposite sides of the body
What is the most effective method of providing lateral trunk support
Lateral pelvic supports
What is the maximum height that lateral spinal support should reach
2cm below the axilla: nerves here are vulnerable to compression
What is the difference in lateral spinal support for symmetrical and asymmetrical trunks
Symmetrical: use in pairs
Asymmetrical: use a 3-point loading system
Why is lateral instability of the head a frequent problem
Lateral head supports can be overcome by the person moving their head forwards
(extending the supports forwards then limits visual fields)
What is another name for adduction blocks
Pommels
What benefits does using adduction blocks have
Reduces extensor tone/pattern
What postural position is commonly seen in hypotonic patients. How can this be overcome
Wide hip abduction and external hip rotation
Overcome by using abduction blocks
When are abduction and addiction knee blocks used together
To correct windswept deformities
What is the benefit and disadvantage of tilting back a seat
More comfortable but less functional ability
What is the difference between tilt and recline
Tilt: moving the seat and backrest angle back simultaneously
Recline: moving only the backrest angle
When should lateral tilt be used
Only in some cases of asymmetrical postures in the frontal plane
What is a benefit of a higher seat height
Facilitates for easier standing
What are some basic features of ‘easy chairs; or ‘orthopaedic chairs’ produced for the elderly
Minimal contouring = provide very upright posture High seat height = facilitates rising Small wheels = ease of movement \+/- trays = for eating/leisure \+/- restraints for confused patients
What are benefits and disadvantages of using sling-seats
Benefit: folding ability
Disadvantage: sags, encourages flexed posture and pelvic obliquity
Describe modular seating
Assembling a seat from a standard kit of components to give the desired size and configuration
Segments can be adapted to accommodate for changing needs
Benefits of modular seating
Versatile and adjustable
Avoids expensive fabrication costs of customised sating
Disadvantages of customised seating
Expensive
Limited lifespan
Tends to lock the person into one posture
Disadvantages of foam and wood customisable seating designs
Time consuming
Requires high skill level to achieve acceptable quality of finish
Errors in configuration are difficult to adapt
Describe Shapeable surface systems of seating
Relies on a series of small interlocking components which can be released to produce a flexible surface
Benefits of Shapeable surface system
Allows a wide variety of shapes to be formed
Adjustable = can adapt to changing needs
Good ventilation to the seating surface
Can re-use the supporting framework
Disadvantages of Shapeable surface system
Heavy
May be difficult to manipulate to the required shape
Require patient cooperating when setting up
Describe the process of creating a moulded foam seat
Polyurethane foam obtained by mixing liquid components to release gas and foam. The foam sets into a honeycomb structure. When contained in an enclosed space, the foam will set into the shape of the container
Benefits of moulded foam seat
Very comfortable
Useful for patients who dislike being confined to one position (e.g. muscular dystrophy patients)
Disadvantages of moulded foam seat
Difficulty maintaining desired posture during foaming process
Cannot be adjusted other than by cutting away areas of foam
Describe the bead bag vacuum consolidation technique
Uses plastic bags filled with small polystyrene beads that conform to shape of individual. Vacuum applied to the bag = consolidates into a rigid structure
Disadvantage of bead bag system and method of overcoming this
Needs frequent reshaping
Use adhesive in with the beads
