Understanding Parkinson’s Disease: Insights on World Movement Disorders Day

Every year, World Movement Disorders Day draws attention to neurological conditions that affect movement, with Parkinson’s disease being one of the most prevalent and widely recognized. This day serves as an important opportunity to reflect on the ongoing challenges faced by individuals with Parkinson’s, and to highlight insights into diagnosis, progression, and treatment.

Parkinson’s is a progressive neurodegenerative disorder, that is known to affect the brain's ability to control movement. The hallmark symptoms include tremor at rest, muscle rigidity, and bradykinesia (slowness of movements), but the disease also has a significant impact on cognition, emotional health, daily functioning, and quality of life.

Samer D. Tabbal, M.D., a neurologist and director of the Movement Disorders Program at Baptist Health Miami Neuroscience Institute.

Two leading experts in the field: Samer D. Tabbal, M.D., a neurologist and director of the Movement Disorders Program at Baptist Health Miami Neuroscience Institute, and Sameea Husain Wilson, D.O., director of Movement Disorder Neurology for Marcus Neuroscience Institute at Boca Raton Regional Hospital, part of Baptist Health

The Progression of Parkinson’s: What Happens in the Brain?

The progression of Parkinson’s disease varies greatly from person to person, but it always involves the degeneration of dopamine-producing neurons in the brain. Dopamine is a crucial neurotransmitter responsible for smooth, controlled movements, and its loss leads to the motor symptoms characteristic of the disease.

Dr. Tabbal describes the tremors associated with Parkinson’s disease  as "tremor at rest," which typically occurs when the muscles are relaxed. "The tremor is usually in the jaw, hands, or legs, occurs specifically when the muscles are relaxed, and goes away on movement. Thus, the term 'tremor at rest,'" Dr. Tabbal explains. However, tremor can become bothersome if it re-emerges rapidly when holding a hand in certain postures, such as when holding a cup against the lips.

What many people may not realize is that about 40 percent of people with Parkinson’s disease never develop tremor. In these cases, the disease manifests primarily through other symptoms like muscle rigidity or slowness of movement. Regardless of whether tremors are present, the motor symptoms tend to become more noticeable and challenging over time.

Dopamine is not the only neurotransmitter that is lacking in the brain of Parkinson’s disease patients. Other neurotransmitters, such as serotonin, noradrenaline and acetylcholine, are also deficient in these brains resulting in the medley of non-motor symptoms that Parkinson’s patients have, such as anxiety, depression, fatigue, pain, cognitive symptoms, constipation, bladder symptoms, blood pressure fluctuations, and abnormal sweating.

Sameea Husain Wilson, D.O., director of Movement Disorder Neurology for Marcus Neuroscience Institute at Boca Raton Regional Hospital.

Under Dr. Husain’s direction, Marcus Neuroscience Institute recently became one of just a handful of highly specialized centers of excellence in the region to offer a Syn-One Test, which identifies abnormal alpha-synuclein proteins in the cutaneous nerve fibers of the skin. These proteins are linked to Parkinson’s disease and a variety of other movement disorders.

“The procedure involves applying a numbing agent to three different areas on the body which include near the neck, the outer thigh and the outer calf, explains Dr. Husain. “The skin is totally numb. So, the patient feels nothing and the procedure is over in about 15 minutes. These skin samples are sent off to be analyzed and when they come back to me, they're going to confirm my clinical suspicion that the patient indeed has Parkinson’s disease.”

What Determines the Rate of Progression?

"The rate of progression of Parkinson’s disease varies tremendously among patients," says Dr. Tabbal. "We don’t know enough about why that is so. Some genes are associated with a faster rate of progression."

For example, over-expression of the SNCA gene (that codes for the alpha-synuclein protein) and the "severe variant" of the GBA gene (that codes for the enzyme glucocerebrosidase) have been linked to more severe manifestations of Parkinson’s disease. However, as Dr. Tabbal points out, genetic testing is not yet useful for treatment planning, since specific therapies targeting these genes have yet to be developed.

Research suggests that lifestyle factors, particularly exercise, may influence how quickly Parkinson’s disease advances.

"It is thought, but not scientifically proven in humans, that physical exercise may slow down the progression of the illness. Studies to confirm this are difficult to control for,” Dr. Tabbal explains. “However, it is very well-established that physical exercise increases chemicals in the brain (called neurotropic factors) that promote the health of brain cells." These neurotropic factors not only reduce the risk of dementia but may also help slow Parkinson’s disease progression.

Current and Future Treatments: What’s on the Horizon?

While no treatments currently exist to slow or stop the progression of Parkinson’s disease, there are medications and surgical interventions, such as deep brain stimulation (DBS), that can help alleviate symptoms and improve quality of life.

"The medications that we currently have for Parkinson’s disease only treat symptoms," Dr. Tabbal notes. "It is a severity of the symptoms that dictates the need to start medications. If the patient’s symptoms are mild, we do not start him/her on medications." While medications like levodopa are effective at controlling tremor, rigidity and slowness of movements, no treatment has yet been found to modify the disease itself.

However, research is ongoing, particularly in the area of disease-modifying therapies. "Over the last 30 years, multiple medications have been tried to specifically slow down or block the disease. Unfortunately, to date, no such 'neuroprotective medication' has been found to be effective," Dr. Tabbal says. This shortcoming may be in part due to the lack of knowledge about the disease process.

Currently, with the advancement of our knowledge, several studies are investigating drugs designed to clear the alpha-synuclein protein that accumulates in the brains of people with Parkinson’s disease.

The Emotional Toll of Parkinson’s: More Than Just Physical Symptoms

While the physical symptoms of Parkinson’s disease are often the most visible, the emotional and psychological impact can be just as profound. Anxiety, depression, and social isolation are common among those living with Parkinson’s disease, particularly as the disease advances.

In addition, maintaining strong social connections can have a significant impact on both emotional and physical well-being. "Several studies have shown that people who socialize with family and friends, not only do better psychologically in the long run, but they also do better physically. They have less strokes, less heart attacks, and less cancer," Dr. Tabbal adds.

While an early diagnosis of Parkinson’s disease is essential for managing symptoms, Dr. Tabbal explains that, at present, early diagnosis does not yet influence the rate of progression. "The medications that we currently have for Parkinson’s disease only treat symptoms. It is the severity of the symptoms that dictates the need to start medications. If the patient's symptoms are mild, we do not start him/her on medications."

However, this could change once disease-modifying treatments are developed. "Once we have a neuroprotective medication that slows down or blocks the disease, it would then be essential to start such medication as soon as possible, preferably even before motor symptoms appear," Dr. Tabbal said.

Looking Ahead: Hope for the Future

Despite the challenges, the future holds promise. Ongoing research into the genetic, molecular, and environmental factors of Parkinson’s disease continues to unlock new insights that could lead to more effective treatments.

For those living with Parkinson’s disease, the road ahead may seem daunting, but as Dr. Tabbal advises: "With a lot of exercise, a good social support system of family and friends, and the right attitude, patients can continue to live fulfilling lives. Count your blessings and never give up. "