New Parkinson's Treatment
Parkinson's disease (PD) is a progressive neurological disorder affecting nerve cells in the brain called neurons. When they are healthy, some of these cells produce dopamine, a key brain chemical that enables smooth, coordinated body movements. In PD, neurons die, causing dopamine levels to drop. This results in the characteristic difficulties with movements and walking seen in patients with PD.
The cause of PD is unknown, but genetic factors likely play a role. Having a close relative with PD increases the chance of developing the disease, although the risk is still small. Ongoing exposure to toxins such as herbicides and pesticides may increase the risk as well. PD usually starts in mid-life, and the risk increases with age. Men are more likely to develop PD than women.
There is no laboratory test for PD. The diagnosis is made based on medical history and a neurological examination. The symptoms of PD begin and progress gradually and can include:
- Tremor or shaking in a hand, leg or other body part
- Slowness of movement (bradykinesia)
- Muscle stiffness and rigidity
- Problems with balance and coordination
Other symptoms include depression, anxiety, decreased facial expression, difficulty chewing and swallowing, cramped handwriting, urinary problems and constipation, problems sleeping and dry or oily skin.
Additionally, patients with PD develop varying degrees of cognitive dysfunction that may worsen as the disease progresses.
PD medications are designed primarily to reduce tremor and improve movement. They include:
- Levodopa, which replaces dopamine. This drug helps the majority of patients and is most effective in treating bradykinesia and rigidity.
- Dopamine agonists, which stimulate dopamine receptors in the brain.
- MAO inhibitors, which prevent the early breakdown of dopamine in the brain.
- COMT inhibitors, which are taken with levodopa to extend its effect.
“Choice of medication class, when to start a medication, whether a patient may be prone to side effects from a particular medication — these are all important and nuanced considerations that factor into the pharmacologic treatment of PD,” says Ryan Walsh, MD, PhD, Director of the Parkinson's Disease and Movement Disorders Program.