Hypomimia: Reduced Facial Expression in Parkinson's

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Masked facies (also called hypomimia) is a reduction in facial expressions sometimes seen with certain medical disorders, such as Parkinson's disease. It is so named because the lack of facial expressiveness is said to be mask-like — hence the term "masked facies."

In Parkinson's disease, facial masking can result if the facial muscles no longer work properly. Facial masking can make life difficult for someone with Parkinson’s disease because acquaintances often misinterpret the fixed facial expression as indicating boredom, disinterest or anger.

Facial masking may also occur in certain psychological disorders, but in these cases, the cause may be an actual lack of emotional changes. In those cases, treatment for the underlying psychological condition may help.

Masked Facies in Parkinson's Disease

It's easy to see why having an expressionless face would be a problem. Humans communicate not only through words, but through subtle, fast-moving changes of facial expression: a quick smile to indicate pleasure, a grimace to show disgust or anger, or wide-opened eyes to convey surprise.

A person who wasn't able to convey these emotions over the course of a conversation would be at a disadvantage since others may discount words when the facial expressions don't match up.

What doctors call "masked facies," or "impaired emotional facial expressiveness," or "hypomimia" is a key feature of Parkinson's disease. Parkinson's causes your muscles to stop working correctly — they become rigid and uncooperative.

This occurs not only in your limbs and in your back but in your face, which contains some 43 muscles that also can be affected by Parkinson's.

The condition may affect different types of facial expressions. For example, researchers in one study looked at whether those with Parkinson's were slower to complete voluntary facial expressions (such as smiling when greeting a friend), and whether they had less movement of facial muscles on involuntary expressions (such as a startled expression from a loud noise).

In both cases, they did.

Therapy for Masked Facies

Facial expression matters. Some early research indicates that quality of life is better in people with Parkinson's disease who have undergone rehabilitation aimed specifically at improving their ability to convey emotion through facial expression.

One study compared two different approaches for rehabilitation: a DVD showing exercises they could do themselves, or therapist-guided rehabilitation. The study found (perhaps unsurprisingly) that the more intensive therapist-guided rehab program was more successful in improving facial expression in people with Parkinson's disease.

Another study looked at the Lee Silverman Voice Treatment (LSVT), which is used to help Parkinson's patients speak louder and clearer, to see if it helps with facial expression, as well. That study compared LSVT with a therapy called articulation treatment and found that LSVT does seem to help with facial expression.

Research into this area is ongoing. If you have concerns about your facial expressiveness, or if you want to improve it, talk to your doctor or to your physical therapist, if you have one, about the problem.


Dumer AI et al. Effects of the Lee Silverman Voice Treatment (LSVT® LOUD) on hypomimia in Parkinson's disease. Journal of the International Neuropsychological Society. 2014 Mar;20(3):302-12.

Ricciardi L et al. Rehabilitation of hypomimia in Parkinson's disease: a feasibility study of two different approaches. Neurological Sciences. 2015 Nov 21. [Epub ahead of print]

Ricciardi L et al. Reduced facial expressiveness in Parkinson's disease: A pure motor disorder? Journal of the Neurological Sciences. 2015 Nov 15;358(1-2):125-30.

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