Does replacing dopamine help with facial masking in PD?

By Anna Shavers

Dr. Dawn Bowers (left), Rachel Schade (right)
Dr. Dawn Bowers (left), Rachel Schade (right)

Muscle stiffness and slowness commonly impact people living with Parkinson’s disease (PD). This stiffness not only affects large muscles found in the legs, leading to reduced physical movement, but can also impact smaller muscles found in the face, causing a reduction in facial expressions called hypomimia or facial masking.

In a previous study, researchers in the Cognitive Neuroscience Lab at the University of Florida College of Public Health and Health Professions found muscle stiffness reduced facial movement and slowed down facial response for people living with Parkinson’s.

Commonly prescribed for managing PD symptoms, dopamine replacement medications like levodopa can relieve muscle stiffness and slowness for patients. However, care providers have raised questions about the usefulness and effectiveness of dopamine replacement medications for managing facial expressivity and response.

Rachel Schade, NINDS T32 Pre-Doctoral Fellow in Movement Disorders and Neurorestoration and graduate research assistant in the Cognitive Neuroscience Lab, and Dawn Bowers, Ph.D., ABPP/CN, director of the Cognitive Neuroscience Lab and professor in the Department of Clinical and Health Psychology and the Department of Neurology, recently published a paper in Movement Disorders Clinical Practice exploring the effectiveness of dopamine replacement medication on facial expressivity in people living with Parkinson’s.

With the use of imaging technology and computer algorithms, researchers recorded 34 people living with Parkinson’s making different, voluntary facial expressions. Researchers asked participants to make four facial expressions: happy, fear, anger and disgust.

Video recordings were taken when participants were “on” their levodopa and again when participants were “off” their levodopa. Researchers compared the two results to determine if any change occurred when levodopa was present versus absent.

“We found that dopamine medications in fact did improve facial movement and expressions in patients living with Parkinson disease. This is important for two reasons. First, a masked expressionless face is one of the features of PD. It can lead to the impression that individuals with PD are depressed or disinterested in those around them, when this is not the case,” said Schade. “Second, there is some disagreement about the usefulness of dopamine medications for facial expressivity. This research shows that levodopa can be useful for people living with PD and struggling with facial masking.”

Read the full article in Movement Disorders Clinical Practice.