Symptoms – Mask-like Expression

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Some people with Parkinson’s disease (PD) experience a mask-like expression as one of the motor symptoms from the disease. Not all people with PD experience the same symptoms, or to the same severity. When people with PD have a mask-like expression, their face has less facial movements and appears less animated. The scientific term for this is hypomimia, which means a reduction in the expressiveness of the face that is marked by diminished animation and movement of the facial muscles.1,2

Challenges of the mask-like expression in Parkinson’s disease

Interaction with others is a mixture of verbal and nonverbal communication, and facial expressions play a large role in the nonverbal communication, displaying our emotions and interest. When PD affects the facial muscles, causing a mask-like expression, many of the nonverbal cues are not present, which may lead to challenges communicating with others and negatively impact relationships. The relationships most often affected are those with family and friends, as well as relationships with healthcare providers. The emotion behind the words may be further compromised by a monotone voice, another symptom that makes it difficult for a person with PD to vary the tone of their voice.3,4

Research into the facial masking that occurs with PD has found that people with PD have less facial masking when responding to positive questions (such as, what do you enjoy doing?) and more facial masking is seen when patients respond to negative questions. Unfortunately, most healthcare appointments focus on problems, which may lead to more missed cues in relationships between people with PD and their healthcare providers.4

Why does Parkinson’s disease cause a mask-like expression?

PD is a chronic, progressive disease that affects the nerves, especially the nerves that control muscle movement. There are at least 43 muscles in the face, which move in concert to create expressions ranging from happiness to anger and despair. Dopamine is the neurotransmitter (chemical messenger) that transmits the signal from the brain to the muscles to produce movement. When PD damages the nerve cells that produce dopamine, the motor symptoms and ability to control muscles are affected.4,5

Treating the mask-like expression in Parkinson’s disease

Most people with PD are started on medication to help manage their symptoms. Initial therapy is usually levodopa (administered with carbidopa), dopamine agonists, and/or monoamine oxidase-B (MAO-B) inhibitors. The combination of levodopa and carbidopa is the most effective treatment available for the management of motor symptoms of PD, including rigidity. However, it can cause a side effect known as dyskinesia, which are abnormal involuntary movements. Dopamine agonists are less effective on the motor symptoms of PD but have a lower rate of causing dyskinesia, although they have other side effects. MAO-B inhibitors are less effective than levodopa or dopamine agonists, however they have fewer side effects. Choice of therapy should be customized to the individual patient with an understanding of the risks and benefits of each class of medication.6

In addition to medication, rehabilitation has shown benefit for patients who experience mask-like expression due to PD. Rehabilitation includes facial exercises, which seem to help patients retain their facial expressivity to some extent. People with PD who receive rehabilitation also show higher levels of quality of life.4

Other symptoms of Parkinson’s disease

The primary motor symptoms of PD are tremor, rigidity, postural instability (impaired balance), and bradykinesia (slowing down and loss of spontaneous movement). PD also causes many secondary motor symptoms, including micrographia (small or cramped handwriting), changes in speech, stooped posture, dystonia (muscle contractions that cause twisting), cramping, difficulty swallowing, sexual dysfunction, impaired fine motor dexterity, and akathisia (restless movement). In addition to these motor symptoms, PD can cause non-motor symptoms such as depression, difficulty swallowing or chewing, urinary problems, constipation, skin problems, sleep problems, pain, and cognitive problems, such as memory problems or slow thinking.1,7