"The biggest frustration is lack of knowledge from doctors, public, family, friends," she adds. "Nobody understands it, so they don't understand what you're going through."
PLS is a distant cousin of ALS, commonly known as Lou Gehrig's disease. Lou Gehrig's disease affects two to three people per 100,000 Americans, according to information about PLS at emedicine.com.
PLS is believed to affect about two of every 1 million Americans, but the condition is so rare that doctors are not sure of such estimations.
For people diagnosed with rare diseases, finding answers, camaraderie and support in the medical world can be a huge challenge, say those who have been affected by disorders similar to PLS.
That's why people with PLS and patients with a related disorder, hereditary spastic paraplegia (HSP), recently joined forces and created the Spastic Paraplegia Foundation.
The group is proving there's comfort in numbers.
In the four years the foundation has been in operation, it has raised more than $1.1 million. All of that money has been directed toward research grants to study both disorders.
Although there were efforts to raise awareness and funding for both conditions prior to formation of the foundation, a single national foundation is drawing more attention to rare neurological disorders, says Annette Lockwood, president of the foundation and an HSP patient.
The group also is helping by educating patients and doctors about both conditions and providing a social network through which patients can communicate.
Because relatively few people have HSP and PLS, there is little knowledge or research about these conditions, Lockwood adds. The foundation estimates there are 1,000 to 2,000 people with PLS in the U.S. and about 20,000 people in the U.S. with hereditary spastic paraplegia.
That adds up to fewer directly affected people and their families to raise awareness and funds about the conditions compared to other conditions, but more money is needed for research.
"Research really needs millions of dollars for the work that (researchers) do," Lockwood says. "We need to continue to push the envelope."
Grove's family physician, Dr. Andrew Berens, says PLS might be "one of the rarest neurological conditions" he's ever seen. In the 15 years he's been practicing, in his years at medical school and in his residency, Grove's is the first case of PLS he has come across.
Hereditary spastic paraplegia and primary lateral sclerosis are both conditions that affect the nerve endings that control muscles and glands.
"Basically, nerve impulses do not travel the way they are supposed to," Berens explains. "The symptoms range from weakness to paralysis and difficulty in coordination. The brain sends the information, but it doesn't get to where it's supposed to be."
Neither disorder is fatal, but they are progressive, and symptoms generally continue to get worse over time.
In Grove's case, PLS is causing her to lose control of the left side of her body. She cannot move her left arm or hand much, and her left leg and foot do not respond to the brain's commands for movement.
As its name suggests, hereditary spastic paraplegia is an inherited disorder that affects the lower half of the body. Like people with PLS, people with hereditary spastic paraplegia have trouble with balance and walking, because the body's nerve endings do not relay commands from the brain.
Janet Hawbaker, 59, of Chambersburg, Pa., was diagnosed with hereditary spastic paraplegia a year ago. Although the disorder is hereditary, no one in Hawbaker's family had been diagnosed with the condition. The diagnosis, however, helped explain the lifelong problems Hawbaker's mother has had with walking.
Hawbaker vividly remembers being told she has a rare, incurable disorder and probably will not walk normally again.
"I kept on asking the doctor questions, but I thought, 'He's mistaken. This can't be something that can't be cured,'" she says. "At first you are shocked and in denial.
"My brain thinks I can run. But because those neurons are broken down in my spinal cord, my legs are not getting the message."
Hawbaker, a former tennis player and competitive bowler, still walks using a walker, and she is encouraged by the work the Spastic Paraplegia Foundation is doing to bring awareness and more funding to disorders like hers.
"Eventually, with enough funding, someone is going to figure out how to repair those neurons or regenerate them," she says. "Maybe not in my lifetime, but hopefully for someone else."