People who have high level spinal cord injuries do not have adequate strength to manipulate a wheelchair compared to those with low level spinal cord injuries or paraplegics. Power wheelchairs are wheelchairs that have a power source to move the chair without the requirement of good upper body strength and hand dexterity needed in manual wheelchairs. Electric wheelchairs can be used to reduce the strain on a person's shoulders and arms so that transfers can still be performed safely. These wheelchairs give the user more freedom to drive them rather than just on another person to push the wheelchair.
Electric wheelchairs are composed of a base, front-wheel drive, rear-wheel drive, mid-wheel drive, seating and controls. All these components make the power wheel much heavier than the manual wheelchair. Recline and tilt-in-space systems can be added for more ease in helping the occupant with toileting and transfers. These technologies are also responsible for providing the user better posture, pressure relief and additional comfort.
The type of power chair depends very much on where it will be used, the surfaces it will be driven over and the spaces it will be maneuvered between. Travel power wheelchairs are portable for the home and use in public areas. Heavy duty power chairs are designed to assist larger people. It supports up to 650 pounds. Folding power wheelchairs are the most convenient type for transport. Center-wheel drive chairs are easily maneuvered in small areas but are less portable.
Power wheelchairs are controlled by a device known as an access control or drive control. There are different kinds of drive controls which are prescribed depending on the user's level of function. Switches and joysticks can be used by a person who still has the necessary minimal hand function.
There are many alternatives to hand controls when a person can not move their hands. The person driving the chair can use sip-and-puff access control by sipping (inhaling) or puffing (exhaling). The speed and direction of the wheelchair is altered by sharp sips and puffs while low sips and puffs can steer the chair. Head control is available for individuals that have head mobility. Moving the head in different positions can move and change the direction of the wheelchair. Vocal commands like “forward”, “back”, “right” or “left” are used in power wheelchairs with speech control. There is even a tongue controller which was introduced to the market in the 1990's for those tetraplegics who can not speak. A mouthpiece is placed on the roof of the mouth. Touching the keypad with the tongue changes the speed of the wheelchair.
Various accessories are available for more convenience to the user. A wheelchair bag can protect the chair from dirt and dust when not in use. Removable armrests give extra comfort. Cup holders and mobile phone holders are other convenient additions. Cushions in different sizes and materials are also optional. Wheelchair lifts are necessary accessories to allow the chair to be elevated so that the occupant can be transported to a truck or van.