Progressive neurological condition includes symptoms both classic and subtle

seniors walking
As with so many health conditions, one of the most powerful ways to slow down the progression of Parkinson’s disease is through exercise. People with PD who exercise daily have better control over their motor symptoms than those who do not. 

By Norika Malhado-Chang, M.D.

“Think of it like a glacier.”

This is how I describe Parkinson’s to patients asking what the disease is all about. PD is a progressive neurological condition that is always moving slowly and never stops.

About the author
Dr. Malhado-Chang is a UC Davis neurologist who specializes in diagnosing and treating movement disorders such as Parkinson's disease.





On the surface, we have the classic Parkinson's motor symptoms, including muscle stiffness and slowness, typically worse on one side. Some people develop a resting tremor, but not everyone.

However, below the water’s surface lies the body of the iceberg. This is the far bigger piece of the disease that hasn’t been well-recognized until recently: all the non-motor symptoms of Parkinson’s. 

The non-motor symptoms of Parkinson's

  • Depression. Beyond the natural response to receiving a diagnosis of a chronic neurodegenerative disease, people with Parkinson's have altered neurochemistry that often results in apathy as well as depressed mood.
  • Cognitive slowing. There is delayed processing speed, which often results in challenges with multitasking in day-to-day life.
  • Postural lightheadedness. Delay in the orthostatic reflexes, or our ability to maintain blood pressure against gravity, results in dizziness upon standing.
  • Dry eyes. A decrease in eyelid blink rate results in diminished eye lubrication and dry eyes vulnerable to blepharitis.
  • Soft voice and drooling. The automatic functions of the pharynx and larynx are slowed, resulting in soft voice and decreased swallow rate. When saliva isn’t swallowed as often, while posture is bent forward, drooling may occur.
  • Constipation. Slowed gastro-intestinal transit is one of the most common non-motor symptoms of Parkinson’s, and microscopic evidence of the disease can be found in the intestinal wall years before the motor symptoms even begin.
  • Bladder dysfunction. Urinary troubles can take the form of overactive bladder or urinary retention. These must be differentiated as treatments are distinct.
  • Learn more
    on public television

    Dr. Malhado-Chang appears in Living with Parkinson’s, an upcoming ViewFinder documentary produced by the Sacramento region's public television station KVIE.

    For more information, visit the KVIE website or its ViewFinder page.

  • Erectile dysfunction.
  • Sleep disturbances. Some examples include sleep fragmentation (waking up frequently throughout the night without reason), obstructive sleep apnea, restless leg syndrome, and REM behavior disorder (talking or moving during sleep, as if “acting out dreams.”)

These are some of the multitude of symptoms that plague people living with PD.  Recognition and treatment of these seemingly disparate non-motor symptoms is critical for improving quality of life. Moreover, we now know that many of these symptoms, particularly depression, constipation, and sleep disturbance, often precede the first motor symptoms of Parkinson’s by up to ten years!

While PD cannot be diagnosed on these “pre-motor” symptoms alone, we are slowly developing tools to identify patients at risk for Parkinson’s earlier. This is important because once disease-modifying treatments become available, we would want to start therapy as soon as possible. 

The role of exercise

For more information about neurology services at UC Davis, please visit the Department of Neurology website.

At the present time, one of the most powerful ways to slow down the progression of Parkinson’s disease is through exercise.  The term used in research is “exercise-induced neuroplasticity.” People with PD who exercise daily have better control over their motor symptoms than those who do not. 

If you are living with Parkinson’s, one of the best lifestyle changes you can make is carving out 30 minutes of each day for stretching and conditioning exercise. This can mean walking outside, or riding a stationary bicycle. The key is that the exercise becomes part of one’s day-to-day life.