Measuring emotion recognition by people with Parkinson’s disease using eye-tracking with dynamic facial expressions

Background
Motion is an important cue to emotion recognition, and it has been suggested that we recognize emotions via internal simulation of others’ expressions. There is a reduction of facial expression in Parkinson’s disease (PD), which may influence the ability to use motion to recognise emotions in others. However, the majority of previous work in PD has used only static expressions. Moreover, few studies have used eye-tracking to explore emotion processing in PD.

New method
We measured accuracy and eye movements in people with PD and healthy controls when identifying emotions from both static and dynamic facial expressions.

Results
The groups did not differ overall in emotion recognition accuracy, but motion significantly increased recognition only in the control group.Participants made fewer and longer fixations when viewing dynamic expressions, and interest area analysis revealed increased gaze to the mouth region and decreased gaze to the eyes for dynamic stimuli, although the latter was specific to the control group.

Comparison with existing methods
: Ours is the first study to directly compare recognition of static and dynamic emotional expressions in PD using eye-tracking, revealing subtle differences between groups that may otherwise be undetected.

Conclusions
It is feasible and informative to use eye tracking with dynamic expressions to investigate emotion recognition in PD. Our findings suggest that people with PD may differ from healthy older adults in how they utilise motion during facial emotion recognition. Nonetheless, gaze patterns indicate some effects on emotional processing, highlighting the need for further investigation in this area.