Atrophy and Learned Non-use
Due to loss of activity, muscle, bone, and skin atrophy occur after spinal cord injury. In addition, parts of the neural circuitry in the brain and spinal cord may turn off.
- Atrophy. When parts of the body are not used, they undergo atrophy. For example, muscles shrink, bones lose calcium and strength, and skin gets thinner. Activity of muscles, stress on bones, and contact with skin prevent atrophy. Even passive movement will help prevent muscle atrophy and fibrosis. Spasticity and spasms prevent atrophy and maintain muscle bulk. It is not a good idea to take so much anti-spasticity medication that the legs become flaccid (i.e. show no movement). Electrical stimulation (functional electrical stimulation) can be used to activate muscles to drive legs to pedal bicycles and prevent muscle atrophy. Weight bearing may prevent bone loss or osteoporosis while ambulation training on treadmills may reverse osteoporosis. Many drugs are available for increasing calcium in bones. Without exercise or stress on the bones, such drugs may increase the brittleness of bone without increasing ability of the bones to support weight.
- Learned non-use. Neural circuits in the spinal cord may also turn off when they are not used. Spinal cord injury causes a prolonged period of inactivity in people. For example, a person may not walk for many months after a spinal cord injury and this may turn off neuronal circuits needed for walking. In the early 1990’s, several groups reported that intensive ambulation training can restore independent locomotion to 50% or more of people who have some residual sensory or motor function but have never walked after spinal cord injury. Suspending a person over a treadmill and manually moving the legs until they start stepping on their own is one approach to ambulation training. Many rehabilitation centers around the world are studying these effects of weight-supported treadmill walking.
For Friends and Family of the Newly Injured Topic List
Here is what I say to families
Some frequently asked questions
How is acute spinal cord injury treated?
What is spasticity and neuropathic pain?
Atrophy and Learned Non-use
What happens to the bladder, bowel, and sexual function?
How does spinal cord injury affect the skin?
What is autonomic dysreflexia?
Preventing atrophy and reversing “learned non-use” are important goals of rehabilitation. Learned non-use may prevent recovery of function despite regenerative and remyelinative therapies. Some rehabilitation programs offer intensive motor training programs that can prevent or reverse learned non-use. Unfortunately, intensive and prolonged ambulation programs are very labor-intensive and consequently costly. Various clinical trials are being conducted to determine the optimal parameters for weight-supported ambulation, biofeedback, and other forms of motor training. Many rehabilitation centers in the United States have biofeedback, weight-supported ambulation, and functional electrical stimulation (FES) programs.