To see the difference in facial masking, compare Michael J. Fox's expressive face in this video with the Muhammad Ali's.

Source: YouTube

Doctors and other health practitioners may need to pay more attention to their own biases when seeing people with Parkinson's disease, a neurological disorder that affects muscle control.

It's not always easy for those caring for people with Parkinson's to judge how the patients are coping with the condition because of the way it can interfere with how they express emotion.

The phenomenon, called facial masking, can make patients look as if they're unfeeling, indifferent, sad or even hostile. That could lead to an inaccurate diagnosis of depression or something else. And cultural differences between doctors and patients as well as stereotypes can complicate matters even more, according to a recent study in Social Science & Medicine.

 

"Facial masking is socially isolating," said Tufts University's Dr. Linda Tickle-Degnen, one of the researchers behind the study. "Walking is social, talking is social, and your face is social. It's like a big puzzle that's starting to come together in Parkinson's disease."

For a look at what she's talking about, Tickle-Degnen suggested watching the Parkinson's video featuring Michael J. Fox and Muhammad Ali.

In her study, 284 American and Taiwanese health practitioners watched 24 American and Taiwanese men and women with Parkinson's disease in videotaped interviews. Half the videos showed patients with moderate masking, and the other half showed patients with almost no masking.

She and her colleagues found the health professionals in both countries were more likely to judge patients with greater facial masking to be depressed or less sociable than those with little masking.

Doctors appeared to be more biased by masking when they judged the sociability of Americans versus the Taiwanese, the study found, expecting American patients to be more expressive. Female stereotypes also played a role in how the doctors judged the study participants.

"We want doctors to understand the person," Tickle-Degnen told Shots. She hopes that the study will encourage doctors to be much more patient-centered. "We've got to realize that doctors â€" who are nice people â€" have stereotypes," she said. "Those values affect us even if we have objective training."