The apt combination of chair and cushion will allow you to sit in a neutral and stable posture and to operate the chair safely. Cushions come in an assortment of depths and sizes which need to be accommodated by the size of wheelchair frame. Obviously, you need to make a decision which cushion is best for you before you can make a decision about which chair is best.
Cushion design is by no means an easy subject. There are many choices to make as you decide on the right one for you. To boot, let us be familiar with cushions. There are four basic types of cushions – foam, gel, air floatation, and urethane honeycomb. There are also designs and systems for more specialized needs.
Foam technology has come a long way. It now comes in a range of densities with varying degrees of memory, holding its shape as you sit, contributing to your stability. The new foams can adapt to any shape, and still provide even support, spreading pressure across the sitting surface. On the downside, foam wears out faster than other materials and loses its shape, but because of its lower price, this might not worry you.
Gel cushion designs endeavor to substitute the consistency of atrophied muscle tissue. Gel fluids are placed in pouches and usually attached to a foam base, so that the cushion matches to the pressures put on it. Unfortunately, gel cushions are much heavier than other types, which can cancel out some of the benefits of your lightweight wheelchair. Gel leaking can also happen.
Air floatation cushions, on the other hand, support the body entirely on air. Air cushions can be less stable for those who move around a lot in their chair, but recent designs offer either low profile or quadrant options that minimize this problem. The balloons used in air cushions can be pricked, of course, and leaks do occur, although a fairly heavy duty rubber is used. But patching them is easier than with the gel design. The biggest drawback to air cushions is that they require more maintenance.
Thermoplastic urethane honeycomb cushions are the most recent development in cushions. These cushions are able to distribute weight evenly but there is no risk of leaking gel or of an air bladder being punctured. The many open spaces in the beehive structure of the cushion allow air to travel more efficiently. Urethane honeycomb cushions are very light, absorb shock, and a low profile cushion can provide significant support.
The latest exploration regarding cushions is the use of an air pump to create alternating pressure to those with more severe disabilities who cannot perform their own weight shifts to relieve pressure. Sitting for a long period of time without relief from pressure causes the separation of muscle and fatty tissues, as a result, the delicate skin layer has closer contact with the bone causing more pressure on the skin. Lack of air circulation increases the temperature between you and the cushion. Moisture, on the other hand, is trapped against the skin. This may further cause sores.
An example of alternating pressure solution is the ErgoDynamic Seating System from ErgoAir in New Hampshire. It pumps air into and out of alternating portions of the cushion. Some of the alternating pressure products are heavier because they uses batteries and air pumps and like air floatation cushions, susceptible to puncture. Nonetheless, the technology for these innovative systems is likely to advance further in the future, as new materials and batteries are developed.
