The brain cells, called neurons, can only tolerate a lack of blood and oxygen for a short period of time before they die. Stroke results in loss of blood supply and devastating loss of function of those body parts controlled by the affected area of the brain. Since the brain has a limited ability to replace its neurons, functional recovery from stroke was also believed to be limited. This leaves post-stroke patients with long-term impaired function. However, the field of neuroscience is changing how we rehabilitate patients suffering from a stroke.
It is true the adult brain has limited capacity to generate new neurons. However, the brain has a property known as neural plasticity; the capacity for healthy neurons to pick up the lost function of damaged neurons. The discovery of neural plasticity, and its application to rehabilitation following a stroke, is truly a game-changer. For example, a common finding in patients post-stroke is that their hand can be fixed in a clenched-fist posture. This is called an abnormal motor synergy and is due to the scrambled signals from the brain to the hand muscles. Recent research suggests that stimulating the spinal cord can help to break down this abnormal synergy and promote more normal movement of the hand. A technique known as mirror-box therapy has also been shown to promote the restoration of normal hand function.
These and other techniques that incorporate the concept of neural plasticity have helped patients recover lost function even years after their stroke.