DO WHEELCHAIRS INHIBIT RECOVERY?

NewScientist Aug 2008 - INJURED rats strapped to tiny "wheelchairs" that restrict their movements recovered less limb function and coordination than those left to fend for themselves. This might mean that people with a spinal cord injury would recover better if they were encouraged to use their limbs sooner after injury and relied less on wheelchairs.

"Our data suggests that wheelchair restriction definitely impairs functional recovery in rats, and logically it would seem to apply also to humans," says David Magnuson of the Kentucky Spinal Cord Injury Research Center, University of Louisville.

There seems to be an optimal time period following spinal cord injury during which the brain is better able to relearn some of the functions lost. Missing this "window of opportunity" is thought to reduce the amount of movement an injured person can recover, says Magnuson. ‘Some studies suggest putting body weight onto the legs is best, while others stress moving the feet, for example’.

Lab animals tend to recover from spinal cord damage much more quickly and completely than humans. Magnuson believes this is partly because their movements are less restricted during recovery - they tend to drag themselves around using their undamaged limbs and, being four-legged, have fewer balance problems.

His team created rat-sized wheelchairs attaching four wheels to small plastic platforms. Then they took half of a group of rats with loss of movement in their hind legs and strapped them to the wheelchairs five nights a week for eight weeks. The wheelchairs restricted their hind legs but the rats wheeled themselves around on their forelegs. The other rats were left to move about freely.

After another eight weeks, in which all the animals were allowed free movement, their walking and swimming abilities were assessed using standard tests that measure joint movements, weight support, limb coordination, foot placement and gait stability.  The team also filmed the rats while they had reflective tape stuck to their joints, so they could analyze their movements in detail.

They found that rats given wheelchairs recovered significantly less function than those left to move about as best they could. The team presented their results at the National Neurotrauma Society Symposium in Orlando, Florida, earlier this week.

"Most people when they see the rat wheelchair, their first response is to chuckle, because it does look comical, but then they realize we are trying to address some pretty important questions," says Magnuson.

While the study points to the importance of movement during spinal cord recovery, and suggests less reliance on wheelchairs might help, it provides no indication of what kind of movements would improve recovery for humans, nor when exactly during rehabilitation these movements should take place. "This study indicates the importance of providing the appropriate feedback to the damaged cord to get the best functional outcome," says Mark Bacon, head of research at Spinal Research, a UK charity. "It remains to be seen what rehabilitation regime will be the most appropriate for humans."