Jesse Jackson reveals he has Parkinson's disease

Rev. Jesse Jackson disclosed publicly Friday that he has been seeking outpatient care for two years for Parkinson's disease and plans to "dedicate" himself to physical therapy.

In a Friday letter to supporters, the 76-year-old civil rights icon said family and friends noticed a change in him about three years ago and he could no longer ignore symptoms of the chronic neurological disorder that causes movement difficulties.

"Recognition of the effects of this disease on me has been painful, and I have been slow to grasp the gravity of it," he wrote.

"For me, a Parkinson's diagnosis is not a stop sign but rather a signal that I must make lifestyle changes and dedicate myself to physical therapy in hopes of slowing the disease's progression."

Jackson also released a Northwestern Medicine letter saying he was diagnosed in 2015 and has since sought outpatient care.

Jackson vowed to use his voice to help find a cure for the disease. He declined an interview Friday.

About 60,000 people in the U.S. are diagnosed with Parkinson's annually, according to the Parkinson's Foundation. It can start with tremors and symptoms generally worsen over time. The exact cause isn't known and treatments include medications, surgery and physical therapy.

Plans to write memoir

The disease itself isn't fatal, but people can die from complications. Jackson noted that Parkinson's had "bested" his birth father, Noah Lewis Robinson Sr., who died in 1997 at age 88 after suffering a heart attack.

It was unclear how Jackson's diagnosis will affect his civil rights work through the Rainbow/PUSH Coalition, the Chicago-based civil rights group he founded more than two decades ago.

A protg of the Rev. Martin Luther King, Jackson was instrumental in guiding the modern civil rights movement, from issues involving voting rights to education.

Twice a candidate for the Democratic presidential nomination in the 1980s, he's remained a strong voice in numerous anti-discrimination efforts, including advocating for affordable housing. He's often seen at protests nationwide.

He said Friday in the letter that he is also working on a memoir.

"I will continue to try to instill hope in the hopeless, expand our democracy to the disenfranchised and free innocent prisoners around the world," he wrote. "I steadfastly affirm that I would rather wear out than rust out."