What is Parkinson's Disease?
Parkinson’s Disease is a disorder that slowly robs a person of their ability to get around, perform tasks, and interact with the outside world. Although the disease can result in depression, other psychological disturbances, and dementia (loss of thinking and memory abilities), it is best known for its effects on a person’s “motor” abilities – that is, the ability to move smoothly and efficiently.
There are areas on the surface of your brain that give final commands to move extremities on the opposite side of the body. Movement of a limb occurs through contraction of the appropriate muscles – for example the biceps muscle when one wants to flex his or her arm. These movement areas of the brain are part of what is called the “motor cortex” or “motor strip”. If you were to stimulate one of these areas with a small electrical current, you would cause the contraction of muscles on the opposite side of the body, and thus some form of movement (depending on the muscles contracted).
But control of your movement is far more complex than this. There are several other areas deep within your brain (called the basal ganglia) and in the back of your brain (called the cerebellum) that constantly process plans for movement, and analyzes information coming in about how the movement is going. Through complex circuitry these regions of the brain are constantly comparing how your actual movement is going compared with what your brain had planned, and modifying the movement to make it smoother and more coordinated. Most of this processing and refinement of your movement is done without you thinking about it – it is automatic and sub-conscious. It is how you can walk smoothly and without thinking across a room, or swing a tennis racquet accurately and efficiently at a moving ball, or climb a set of stairs without tripping and falling.
Parkinson’s disease affects these deep movement areas of the brain, actually causing loss of whole groups of nerve cells and their connections with other movement nerve cells elsewhere in the brain. It messes up the circuitry of these deep movement “computers.” We don’t exactly know how or why this happens.
Over time, the smooth and coordinated execution of movement deteriorates. People with Parkinson’s begin to notice that it is harder and harder to move – particularly to start movements (called “akinesia”). Arms and legs feel stiff and lead-like (called “rigidity”). Tremors of the extremities start, balance is lost. Eventually, normal movement can become impossible. Devastating falls are common. The ability to care for oneself may become impossible. The disorder is progressive, meaning it gets worse and worse over time, although the time course differs a fair amount from person to person.
There is currently no cure for Parkinson’s Disease. But there are medicines that often help a fair amount with many of the movement difficulties of the disorder. With medicines, many people can function quite well for many years. It is also becoming apparent that rigorous therapy focusing on activities requiring lots of movement and coordination (e.g. boxing, aerobics, etc.) also seem to decrease the movement effects of the disorder, and help with mood. There are also surgeries that can help a fair amount, particularly surgeries that involve placing pacemaker electrodes deep into the brain.