Motor impairment is the partial or total loss of function of a body part, usually a limb or limbs.  This may result in muscle weakness, poor stamina, lack of muscle control, or total paralysis. Motor impairment is often evident in neurological conditions such a cerebral palsy, Parkinson’s disease, stroke and multiple sclerosis. An extreme form of motor impairment is locked-in syndrome, in which voluntary control of almost all muscles is lost, sometimes including the eyes, in an individual who retains cognitive function. The syndrome is caused by damage to portions of the lower brain and brainstem, from a stroke or other insult.

Tetraplegia, or paraplegia, is loss of the use of the arms, legs and torso, usually caused by spinal cord injury, especially in the area of the fifth to the seventh vertebrae. This level of paralysis is also associated with loss of sensation from the neck down. Neural interfaces have been explored to restore functionality for severely motor-impaired individuals. Implanted devices in the area of the brain’s motor cortex sense brain states, and the interpreted signals are transmitted to a computer. With training, users develop some command over objects in the environment, which could be applied to such basic efforts as communicating or moving a motorized wheelchair.

Cerebral palsy is a brain injury causing decreased muscle control. The condition usually occurs during fetal development or shortly after birth. Characteristics include muscle tightness or spasms, involuntary movement, impaired speech, and occasionally paralysis. In computer use, the condition primarily interferes with dexterity in using a mouse. Using a keyboard—or an adaptive keyboard—is still possible, albeit with some difficulty.

Multiple sclerosis (MS) erodes the myelin (a layer of fatty tissue which surrounds nerve fibers), blocking nerve fibers from delivering signals from the central nervous system to the muscles of the body. Effects include tremors, weakness, numbness, unstable walking, spasticity, slurred speech, muscle stiffness, impaired memory, and occasionally paralysis. Not all individuals experience all symptoms, and an individual may experience different symptoms over time. The types of assistive technologies and devices are the same as for other motor disabilities.

Regards
Meria Den
Managing Editor
Stroke Research & Therapy