LAVALE — Sandy McWilliams doesn’t have a single blister, though she’s walked almost 500 miles so far to raise awareness about a rare disease that is killing her mother.

The ice water soaks could be helping.

“Every day I fill up a cooler and stick my feet in,” said McWilliams, 53, who set out from her home in Louisville, Ky., on June 8 to walk to Pennsville, N.J.

That’s where her mother, 76-year-old Allene Stoneman, spends most of her days sitting in a wheelchair at home, barely able to speak or move.

The disease that put her there — Progressive SupraNuclear Palsy, or PSP — is incurable and cruel, a rare brain disorder that is often misdiagnosed as Alzheimer’s or Parkinson’s disease. Around 20,000 Americans, most of them elderly, suffer from the disease.

McWilliams had never heard of it before her mother was diagnosed in 2005.

“A lot of my colleagues hadn’t heard of it,” said McWilliams, a speech pathologist. “I started asking some of my friends who are nurses and nurse’s assistants. They had never heard of it. I talked to my own physician and he hadn’t heard of it. I just thought, this really needs to get out there.”

So she began planning the 700-mile trek — 20 miles a day over seven weeks across seven states.

On Tuesday morning, she walked along the Great Allegheny Passage in Allegany County, stopping in LaVale to eat lunch (peanut butter and jelly) and soak her feet. Since beginning the journey, she’s heard from hundreds of people who have been touched by the disease, which typically begins with loss of balance and forgetfulness and progresses to loss of mobility, loss of speech, and difficulty eating and swallowing.

“It’s got to be miserable for her to be aware of everything that’s going on and not be able to respond,” said McWilliams, whose mother can no longer move her eyes, and therefore, can no longer read.

“Finding alternative means of communication, even as a speech pathologist, I can’t come up with anything.”

A member of Springdale Presbyterian Church in Louisville, McWilliams has stayed at the homes of fellow Presbyterians along the way, including Deb Hendrickson of Cumberland’s First Presbyterian Church. Hendrickson’s cousin David Lewis, of Pittsburgh, died from PSP 18 months ago. He was 64.

“I heard about the walk and I thought, well, I’ll look into it,” said Hendrickson, who planned to walk with McWilliams for about five miles Tuesday afternoon. “Just in memory of my cousin, who was a good guy, even though I hadn’t seen him in years.”

McWilliams, who has called her parents every night of the journey, expects to arrive at her mother’s doorstep July 25.

“She has told me to be careful,” said McWilliams, adding that her mother speaks infrequently and in short sentences, often automatic responses. “I told her people want to know what she thinks about the walk, and she said, ‘I think it’s great.’ She’s said that twice.”

Though she’s been accompanied on short stretches by family, friends and supporters such as Hendrickson, McWilliams has walked most of the 500 miles so far by herself.

“You know, you think about everything,” she said. “There’s a lot of spiritual thought that happens when you’re out in a place like this. Because you’re not alone.”

Contact Kristin Harty at kharty@times-news.com.