There's a whole world of cushion inners on the market - in fact deciding on the right one can be boggling. They very from foam, honeycomb foam for air circulation, foam with memory, gel for even pressure, donuts for the coccyx, and cushions made of air pockets. A cushion should suit the disability you have and the wheelchair you are using, so an assessment of how well you sit in your wheelchair and the problems you are likely to have sitting for several hours is the first step in selecting a cushion that is right for you. The right cushion should give you a comfortable ride and increase your wheelchair use.

What's the purpose of wheelchair cushions?

Although you may not be able to feel the lower part of your body a good cushion should protect you from pressure sores, improve posture so you are upright and stable, and help maintain your balance during wheelchair rolling. It replaces the natural "padding" for thin people and prevents the slide to the front of the wheelchair so you don't fall out and shouldn't place extra stress on the skin you are sitting on. Some cushions keep you cool and prevent sweating, and others keep you warm. They should also have antibacterial qualities to protect you from infection. Remember cushions come in different thicknesses, or heights and can be custom made for the user.

How to tell you need a replacement cushion?

Just like a pillow on your bed turns from light and fluffy to a leaden brick that spoils your sleep a wheelchair cushion has a lifespan for providing good support and comfort (even if you can't feel that comfort). Foam cushions may last up to two years but you may need a new one after six months depending on your weight, activity and the type of wheelchair you have. The most common reason for replacing a cushion is that it is "flat" and no longer provides the cushioning effect you need. If the material cover is broken and you have a leaking bladder then the cushion soaks up the urine and keeps all the bacteria from so you end up with a smelly cushion and one that is bad for your health. If you find you can't keep sitting straight and slide to the front, or slump to the side then you need a new cushion or one with a different shape.

The cushions:

Government- supplied wheelchair cushions: Although the tender document for suppliers have specifications for "thin" (5 to 7.5cm ) and "thick" (11.5cm ) foam, contoured foam, gel and air cushions; due to budget constraints the lowest cost foam cushions are usually ordered. If the hospital budget for assistive devices is R20000 pa then there is no contest between 10 expensive cushions and 10 wheelchairs! Even when the therapist motivates for a specialist cushions only the Chief Finance Officer can sanction it.

Foam types: Standard, layered, nodule/honeycomb and memory. Foam cushions are usually cheaper and easily changes shape and give you good protection from bumps. They have good spring back and can regain their original shape within a few minutes after use. The softer ones can be washed in a machine. A firm foam cushion may gain elasticity the longer you sit on it resulting in bottoming out. Simple foam cushions are best for people who are not high risk for pressure sores. Layered foam cushions have hard foam for cushion side rigidity, medium foam for general seating area and soft foam for pressure points. The more layers, the more expensive. Layered cushions may be contoured* into shapes to suit your sitting pattern with less foam or softer foam in the areas of most pressure. One user said that using a contoured cushion gave her the first comfortable ride in 17 years ! Manufacturers include: Pentaflex, Chairman, Synergy, Netti and Invacare.

* Note "contoured" can refer to the extra foam needed on a "sling seat" wheelchair to bring the cushion to a level position, or foam cut to specific body part shapes.

Honeycomb/Egg-box foam allows air to circulate, so it keeps you cooler, and spreads your weight so you are less likely to get sores. They were used by the USA Women's Wheelchair Basketball team in the 2012 Olympics!

Memory foam or viscoelastic foam cushions that react to body temperature and mould to your shape give extra comfort, decreased pressure points and more support. They can retain this shape but slowly return to their original shape. It also responds to humidity and some users have found cushions too hot in hot temperatures and high humidity, so it may not suit those living on the KZN coast. This type of foam has been used to seat airline pilots and astronauts. Manufacturers include: Tempur, and Posturite.

Gel: These fluid filled cushions replace any "muscle" you have lost rather than providing insulation from bumps. Shonaquip describes their gel cushion like "vaseline jelly". The gel may be the full width of the chair or only where you need extra cushioning (these are usually in combination with a contoured foam cushion). They are good for correcting posture and providing a feeling of stability, but you need to ensure they have a minimum 3 or 4 gel pockets so that you don't push the gel to the sides. The Owl cushions from Solutions Medical have four variations in where the gel is placed and the shape of the cushion.

Gel cushions tend to be heavier so you need to think about whether you can pick them up. They can either deform or develop hard areas over time, although products with many individual pockets of gel and those containing Technogel have overcome this problem. Manufacturers include Amovida, Jay, Columbia, Invacare, Performer, FloTech, Owl, and Bioform.

Air filled: Either individual small air sacks the number of which can be increased or decreased, or sacks that can be pumped to have low. or high amounts of air in each, to create a seat specifically for you. These are very good for people at high risk of pressure sores, and if you have a sore you can lower the pressure in the bubbles below the sore to avoid skin contact in that area. The air pockets can be used as sacral inserts in foam cushions, or as top layers. Users report that they are comfortable over a longer time, no skin breakdown, better balance, improved transfers using transfer board, and good protection from bumps. On the negative side some people find they are unstable when sitting on them. Manufacturers include: Roho, Posturite, Columbia, Starlock and Vicair.

What sort of cushion do you need?

A cushion that is right for someone with paraplegia may not be right for someone with quadriplegia, or an amputation as they all sit differently. People sitting upright have different pressure points to those who have a slight recline (low pressure on points) Equally, a thinner person will need a different cushion to someone with more "internal padding." Gel cushions are good for hot climates as they absorb the heat away from the body and helps to reducing sweat. Foam cushions are better in cold climates or for "cold" people as they retain the heat at point of contact

Some people with lower back pain prefer cushions with sacral cut-outs. A high cushion can prevent using your feet or reaching to the floor whilst in the chair. Apart from the cushion you sit on there are a number of "add ons" to improve your posture and length of sitting time. These include: wedges and abduction blocks, back and sides' supports, donuts, thigh contours, anti slip pommels.

The more expensive cushions have these as standard. If you are looking for "cool looking cushions" then try the combination foam and gel "owl" cushions from Solutions Medical, or the Amovida cushion. New and second hand cushions are available on the web, but your individuality is the reason it is recommended you have a seating assessment.

Picture of Roho cushion Showing thigh moulds, pommel and air pocket insert courtesy of CE Mobility

Services offered by supply shops

The majority of the suppliers have professional rehabilitation staff who have specialised in seating. Some of their services include giving guidelines to users when selecting cushions such as these from Shonaquip that include: type of disability, hours in wheelchair, pressure sore and postural deformity risk factors, trying out cushions to see how they fit the wheelchair and how close the client's posture is to ideal as well as any negative effects on wheelchair mobility once cushion is in place. The SITKIT from Mobility One is based on calliper measurement of client and chair, and a laser light for checking height of person and wheelchair parts. Pressure mapping your sitting can be anything from a large piece of carbon paper placed between you and your cushion to sophisticated electronic mapping and is done by several wheelchair suppliers. CE Mobility offers pressure mapping services and occupational therapists at all their branches and Chairman Industries also have an Occupational Therapist to assist with seating as does Sitwell.

SIT lab (seating information technology laboratory) by a team of physical therapy experts who also have community programmes and support Disabled People's organisations. Their service points are based in Auckland Park (Johannesburg), Benoni, and Vereeniging.

Make sure that you discuss your seating choice with your rehab team as well as the seating expert at the supplier where you are making your purchase.