LAURIUM - Dopamine is a chemical in the brain, which is released by nerve cells to send signals to other nerve cells, and when that process doesn't work properly, according to Dr. Bonnie Hafeman of Aspirus Keweenaw Hospital in Laurium, it causes neuromuscular dysfunction, including Parkinson's Disease.
"It's a pretty specific problem where you're having problems with dopamine," she said of Parkinson's Disease.
The symptoms of Parkinson's are varied and begin slowly but become more pronounced over time, Hafeman said. Early symptoms include falling down backwards.
Photo courtesy National Institutes of Health
Here is the dopamine pathway for the motor system. Dopamine signals travel from the substantia nigra to brain regions including the corpus striatum, the globus pallidus, and the thalamus in order to control movement and balance. In Parkinson's disease, most of the dopamine signals from the substantia nigra are lost.
"A lot of times, that's how it's picked up (by a family doctor)," she said.
Other symptoms of Parkinson's include tremors and rigidity in the fingers.
"You're very stiff," she said.
A person with the disease will often have an expressionless face with no blinking of the eyelids. Speech can become slurred and vision blurred, Hafeman said.
Also in the early stages of Parkinson's, Hafeman said a person may have difficulty sleeping, be fatigued often, and possibly develop a scaly skin rash.
Eventually, Hafeman said walking becomes difficult.
"The shuffling gait happens midway through the disease," she said.
Hafeman said the time from onset of the disease until symptoms appear can be 10 to 20 years.
More serious symptoms later in the course of the disease include psychosis and dementia, Hafeman said.
Although Parkinson's can be fatal, mostly from a person's inability to swallow, Hafeman said the disease itself isn't always the direct cause of death.
"Usually, people will die of something else," she said.
Hafeman said although some people are diagnosed with Parkinson's in their 40s or 50s, it most often is diagnosed later in life.
"It's usually a disease of people in their 70s and 80s," she said.
However, the disease can happen even earlier, as happened with actor Michael J. Fox, who was diagnosed with the disease when he was 30 years old.
Dr. Christian Dinsmore, who is a neurologist with Marquette General Hospital working out of Portage Health in Hancock, said he has a large number of patients with Parkinson's Disease.
"It's one of the more common reasons I see patients," he said. "I'll have the occasional patient in their 40s, but it's much more common for my patients to be in their 60s and 70s."
Patients who have Parkinson's are sent to him initially by their family doctor because of problems with motor functions and tremors, Dinsmore said.
Dinsmore said Parkinson's will actually change the appearance of a person's body. Besides making muscular movements slower and less coordinated, it will cause changes in the structure of muscles and joints, which become stiff and lose range of motion.
Dinsmore said Parkinson's also affects the cognitive abilities of those who develop the disease.
"Some people with Parkinson's, their thinking becomes slower," he said.
The disease can have a very detrimental affect on thinking, mood and movement, Dinsmore said.
"That's when the disease becomes truly disabling," he said.
There is a great deal of variation between patients in the symptoms and progression of Parkinson's, Dinsmore said. Some people have a slow development with a prominent family history, while some develop it quickly with no family history. Some patients have low blood pressure, while others have no problems with blood pressure. Some patients have hallucinations, but most don't.
"It's a very variable process, it seems, for different patients," he said.
Dinsmore said the medications used for Parkinson's are useful for treating some symptoms of the disease.
"They help more with the motor manifestations, than they help with the ... cognitive manifestations," he said. "The motor part of the disease is much more treatable than the cognitive part of the disease."
However, Dinsmore said there are also drugs to assist with cognitive functions.
Dinsmore said drugs used to treat Parkinson's are most effective early in the course of the disease.
"Over time, their effectiveness can wane, and the side effects can increase," he said. "It becomes an increasingly difficult disease to ameliorate."
Current medications available for Parkinson's won't slow the course of the disease, Dinsmore said.
"That's the target everyone's looking for," he said.
Dinsmore said Parkinson's Disease is receiving a great deal of attention from researchers looking both for better drugs to treat symptoms and for a cure of the disease. There is even research into using stem cells for Parkinson's but the main problem there is developing a delivery system.
"Where do you put the stem cells?" he asked.
There is also research into the genes which can lead to the development of Parkinson's, Dinsmore said.
A technological method for diagnosing the disease is a called a DaTscan, Dinsmore said.
According to the website of the Parkinson's Disease Foundation, a DaTscan uses a radioactive drug, which acts as contrast agent so the amount of dopamine in the brain can be seen using a device similar to magnetic resonance imaging machine.
Dinsmore said he expects that in the not-to-distant future there will be drugs developed to attack Parkinson's itself, and not just the symptoms.
"That would be my hope, personally," he said.