Masked Faces in Parkinson Disease: Mechanism and Treatment

Masked Faces in Parkinson Disease: A Randomized Double-blind Sham-treatment Controlled Clinical Trial of High Intensity Respiratory Muscle Strength Training (MST) for Treatment of Reduced Facial Expression in Parkinson Disease

The purpose of this study is to examine the effectiveness of high intensity respiratory muscle strength training in treating blunted facial expression in people with Parkinson disease.

Facial expressions are complex signals that last only a few minutes and are important for communicating intention, motivation, and emotional states. In humans, a variety of neurological and psychiatric conditions alter the tendency to use facial signals. One of the main symptoms of Parkinson disease (PD) is diminished facial expressivity or "masked facies," which refers to the expressionless appearance of individuals with the disorder. Unfortunately, little progress has been made over the years regarding the basis of "masked faces" or strategies that might improve facial expressivity among individuals with PD. This is unfortunate because the particular symptom can have significant medical and social consequences ranging from misdiagnosis of depression to the misattribution of negative emotional states and motivation by family members and healthcare providers. The goal of this trial is to study the effectiveness of a novel, behavioral treatment approach-high intensity respiratory muscle strength training (MST)-for blunting of facial expressions in people with PD. The MST device, a mouthpiece that the participant uses to inspire against resistance, may improve the strength and mobility of muscles around the mouth that are involved in forming facial expressions. Study participation includes screening, baseline evaluations, 4 weeks of behavioral intervention, immediate post-treatment followup, and a 3-month follow-up. Participants will be randomly assigned to take part in high intensity respiratory MST, or a Sham MST. Participation in the study will last for approximately 5 months.

Parkinson's disease, PD, masked faces, diminished facial expressivity, diminished facial expression, high intensity respiratory muscle strength training, MST

This arm involved high intensity muscle strength training at 75% maximum inspiratory pressure (MIP). Training took place for 4 weeks, 5 days a week. Each daily session involved 5 sets of breathing exercises that required participants to take deep breaths (i.e., inspire) using use a breathing device. Settings on the breathing device were determined by obtaining the individual's maximal inspiratory pressure (MIP)using a specialized breathing gauge. The MIP was determined at the beginning of each week and the training device was adjusted and set at 75% MIP. Exercises took place in home setting, with weekly visit by staff. Participants kept daily exercise log.

This arm (low intensity MST) was identical to the real intervention in all ways except that the training device was set at 5% maximum inspiratory pressure (MIP). Thus less muscle and breathing effort was required during this sham treatment.

The Muscle Stength Training (MST)device is a mouthpiece that the participant uses to inspire against controlled resistance; Intervention involves use of this device for breathing exercises over 4 week period, 5 days a week, approximately 20 minutes/day.

Primary outcome is change in entropy score from baseline to immediate completion of 4 week intervention. Entropy is a computer derived index of facial movement that is computed by quantifying changes in pixel intensity as the face moves over a series of video frames. Entropy values range from 0 up to 100. Higher scores reflect greater movement and expressivity (desired). In this condition ("off dopamine), entropy scores were obtained when participants were tested "off" their normal dopamine medications. Off-dopamine testing occurred after a 12-hour overnight washout period.

Outcome is entropy change from baseline to immediate completion of 4 week intervention when participants remained on their normal dosage of dopamine medication. Entropy is quantitative index of facial movement that is computed from changes in pixel intensity as the face moves. Entropy values range from 0 up to 100. Higher scores reflect greater movement and expressivity. Greater expressivity is desired outcome.

The PDQ-39 is a widely used quality of life measure that is specific to Parkinson disease. Total raw score on the PDQ-39 ranges from 0 to 156. Higher scores reflect worse quality of life rating. Total score on PDQ-39 was used to compute pre-post treatment changes.

The dependent variable is the change in maximal inspiratory pressure (MIP) from baseline to immediate completion of 4-week intervention. MIP refers to how much air pressure force an individual creates by inhaling through the mouth as hard as possible. This was measured over 5-7 trials by placement of lips around a mouthpiece attached to a calibrated fluke digital pressure gauge. From these trials, an average maximum inspiratory pressure (MIP) was computed. This was done at baseline and post-treatment. Greater MIP changes correspond to greater treatment-related effects of exercise.

Inclusion Criteria: A clinical diagnosis of idiopathic Parkinson disease Hoeh-Yahr Stage 1-3 when off medication Stable and optimal medical regimen for at least 3 months No previous surgical interventions for Parkinson's disease (i.e., deep brain stimulation, pallidotomy, stem cell implantation) Participants will include men and women between the ages of 45 and 80 years Exclusion Criteria: Evidence of dementia based on neurocognitive testing Current or past history of major psychiatric disturbance (e.g., schizophrenia, bipolar disorder, substance abuse). Participants who are taking anti-depressants will not be excluded as long as they are not currently depressed (Beck Depression, SCID) Other neurologic disturbance (e.g., tumor, stroke, traumatic brain injury, epilepsy) or severe chronic medical illness (e.g., HIV, metastatic cancer) Presence of oro-facial dyskinesias Previous surgeries to the larynx that result in poor vocal fold closure and/or positive history of head and neck cancer History of smoking in the past 5 years Untreated hypertension Failing a baseline test of pulmonary function during baseline respiratory evaluation Known respiratory complications such as chronic obstructive pulmonary disease (POCD), asthma Previous surgical interventions for Parkinson's disease (i.e., deep brain stimulation, pallidotomy, stem cell implantation)

Assistant Professor, Co-Director Movement Disorders Program, Medical Director, National Parkinson Foundation, Department of Neurology

Associate Professor and Director of Clinical Trials, Movement Disorder Program, Department of Neurology, University of Florida