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Computational and Mathematical Methods in Medicine
Volume 2014 (2014), Article ID 427826, 12 pages
Research Article

Objectifying Facial Expressivity Assessment of Parkinson’s Patients: Preliminary Study

1Department of Electronics and Informatics, Vrije Universiteit Brussel, 1050 Brussels, Belgium
2Shaanxi Provincial Key Lab on Speech and Image Information Processing, Northwestern Polytechnical University, Xi’an, China
3Department of Physical Therapy, Vrije Universiteit Brussel, 1050 Brussels, Belgium
4Department of Experimental and Applied Psychology, Vrije Universiteit Brussel, 1050 Brussels, Belgium

Received 9 June 2014; Accepted 22 September 2014; Published 13 November 2014

Academic Editor: Justin Dauwels

Copyright © 2014 Peng Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Patients with Parkinson’s disease (PD) can exhibit a reduction of spontaneous facial expression, designated as “facial masking,” a symptom in which facial muscles become rigid. To improve clinical assessment of facial expressivity of PD, this work attempts to quantify the dynamic facial expressivity (facial activity) of PD by automatically recognizing facial action units (AUs) and estimating their intensity. Spontaneous facial expressivity was assessed by comparing 7 PD patients with 8 control participants. To voluntarily produce spontaneous facial expressions that resemble those typically triggered by emotions, six emotions (amusement, sadness, anger, disgust, surprise, and fear) were elicited using movie clips. During the movie clips, physiological signals (facial electromyography (EMG) and electrocardiogram (ECG)) and frontal face video of the participants were recorded. The participants were asked to report on their emotional states throughout the experiment. We first examined the effectiveness of the emotion manipulation by evaluating the participant’s self-reports. Disgust-induced emotions were significantly higher than the other emotions. Thus we focused on the analysis of the recorded data during watching disgust movie clips. The proposed facial expressivity assessment approach captured differences in facial expressivity between PD patients and controls. Also differences between PD patients with different progression of Parkinson’s disease have been observed.