Testing Parkinson's Treatment
Priddis of Orem, Utah, comes to San Francisco State
once a year to take an unusual test. In a room in the back of the gymnasium,
Priddis walks forward about 10 yards then turns around and walks back.
As he does so, infrared cameras capture his movements and a woman holding
a clipboard takes notes.
Nine hundred miles seems like a long way to come to pace a floor. But
medical researchers at three Bay Area institutions, among them San Francisco
State, are grateful that he makes the trip. Priddis is a subject in
a clinical trial that could lead to more effective treatment for people
with Parkinson's disease, a progressive disorder of the nervous system
characterized by slowness, stiffness and shaking.
"Yes, I'm their guinea pig," said Priddis, a genial father
of five and retired Air Force officer who has had Parkinson's for nearly
half of his 53 years.
In addition to taking Sinemet, a standard Parkinson's medication, Priddis
undergoes an increasingly common therapy called deep-brain stimulation.
A few years ago, surgeons at the San Francisco Veterans Affairs Medical
Center implanted in Priddis' brain devices that produce electrical impulses
that stimulate malfunctioning circuits in his brain.
Deep-brain stimulation already seems to be producing dramatic results
in Priddis' life. He can walk faster and takes longer strides. His shaking
is vastly diminished and he doesn't fall down nearly so often.
But questions remain about deep-brain stimulation and researchers at
the University of California, San Francisco and the San Francisco Veterans
Affairs Medical Center, the two medical institutions involved in the
clinical trial, hope that the study under way at San Francisco State's
Physical Therapy Department will yield answers.
One of the key questions is whether apparent improvements in patients
like Priddis can be quantitatively measured. To find out, Priddis undergoes
what is known as a gait analysis in a specially equipped laboratory
in the gym. Melinda Piper, a student in SF State's new doctoral program
in physical therapy science, attaches plum-sized balls wrapped in silver
reflective tape to 21 points on Priddis' bare arms and legs. As Priddis
walks, infrared cameras record the movement of the reflective markers.
A software program produces a three-dimensional analysis that tells
researchers how fast Priddis is walking, the length of his stride and
other things about the way he is moving.
Researchers also hope to find out whether better results are achieved
when one area of the brain is stimulated over the other.
As Americans live longer, the incidence of Parkinson's in the population
is expected to rise. Already, the disease affects about 1.2 million
people in this country. Priddis said he doesn't necessarily expect the
clinical trial will improve his own life. But if it helps Parkinson's
sufferers in the future, his long trips to San Francisco State will
have been worthwhile.