Impact of Bell's palsy in facial emotion recognition: a prospective observational study of 60 patients.

Purpose: Patients with Bell's palsy suffer from functional deficits and cannot convey their emotions through the face as well as they used to. According to embodied cognition, automatic mimicry and facial feedback modulate emotion perception. The aim of our study was to determine the impact of Bell's palsy on facial emotion perception. Facial motor skills, the use of botulinum toxin injections, and anxiety were studied.

Methods: 60 patients completed Emotest-VA, an assessment tool of facial emotion perception, facial motor assessment and affective questionnaires. Facial perception scores of patients were compared to the normative data provided by Emotest-VA. Relationships between facial motor skills, anxiety and perceptual abilities were carried out with Pearson's correlations.

Results: Perception accuracy scores were abnormal in 12% of patients. Patients were more ambiguous than normative population to perceive emotion (t(23) = 4.14, p < .001). Happiness arousal was negatively correlated to smile asymmetry (n = 60, r=-.294 p = .022). Patients who received botulinum toxin were more accurate to perceive disgust (Z = 3.60, p < .001). State anxiety decreased when patients could improve their horizontal smile (r = - 440, p < .001).

Conclusion: Bell's palsy impaired sensorimotor simulation, thereby reducing emotional contagion. Smile measures could indicate patients' recovery and patients' anxiety. It could also predict patient's perceptual abilities. These results provide new directions in the management of Bell's palsy. Additionally to physical therapy, it is relevant to improve emotional contagion both in its productive and perceptive aspects through facial feedback.