Rev. Jesse Jackson, civil-rights activist and two-time presidential candidate, revealed last Friday that he was diagnosed with Parkinson's disease. This disease is characterized by brain cells gradually dying, resulting in the patient having difficulty moving, among other effects on motor skills and coordination. It has no known cure.

Jackson, 76, said in a letter that his friends and family noticed changes in him roughly three years ago. As of now, he can no longer ignore the symptoms of the neurodegenerative disease.

The civil-rights activist decided to exclusively dedicate himself to physical therapy, hoping that the progression of the disease will be slowed down. Meanwhile, he also promised to use his voice and influence to help find a cure for the disease.

In a letter to his supporters, Jackson revealed that it was "painful" for him to recognize that the disease is affecting him. He admitted that he had been "slow to grasp the gravity of it," because his father was "bested" by Parkinson's disease as well.

However, the activist did not lose hope. He affirmed by stating, "For me, a Parkinson's diagnosis is not a stop sign but rather a signal that I must make lifestyle changes."

While Jackson decided to focus on therapy, not much is known about how this decision will affect the Rainbow/PUSH Coalition. Two years ago, this civil-rights group was founded by Jackson and its headquarters is in Chicago.

Parkinson's disease usually starts with less noticeable symptoms, like hand tremors. Over time, the effects become more severe and can even result in muscle stiffness in the major parts of the body.

While it is easier to see the effects Parkinson's has on a person's motor skills, it can also affect the patient's psychological state. The disease has been known to cause depression, anxiety, and sleeping problems. While the disease itself is not fatal, there have been cases where patients die because of complications.