Neuromodulation of Facial Expressions and Emotions

Goals/Purpose: The wearing of masks due to the COVID-19 pandemic has limited facial expressions and the communication of emotions to just the upper face. Thus, physicians must be cognizant of the potential limitations of previously-routine anti-aging treatments, particularly those targeting upper face wrinkles that are associated with expressive communication. Neuromodulators are widely used in aesthetic medicine to remove facial lines and wrinkles, but can also be applied to specific facial areas to modulate facial expressions. The facial mimetic muscles are interlinked with the superficial musculo-aponeurotic system (SMAS) layer which incorporates flat muscular tensioning parts and exert a directional pull on it. This linkage facilitates the movement of different areas of the SMAS and produces different facial expressions and emotions. Physicians using neuromodulators must therefore understand the facial musculature as a single layer that does not work in isolation. We previously published a review of facial anatomy and recommendations on neuromodulator usage to rebalance the musculo-aponeurotic layer for natural outcomes. Using this anatomical understanding, we present an algorithm for assessing patients’ facial communication of emotions. We then demonstrate a neuromodulator treatment strategy to improve the facial appearance at rest while preserving the capacity for dynamic expression.

Methods/Technique: To prioritize the locations of neuromodulation treatments, patients’ resting and dynamic facial expressions were assessed and photographed. Dosages and placements were judged according to changes in muscle resting tone as well as in the muscular activities associated with facial expressions and communication of emotions. Neuromodulator was injected into points that target selected areas of SMAS tensioning and directional muscular pull. The patient’s resting and dynamic facial expressions were then assessed and photographed after the treatment.

Results/Complications: Because it was challenging to determine the exact dose of neuromodulators needed, some patients still required additional product until their individual dosing map was achieved. In all presented patients, resting muscle tone was improved without compromising the expressive muscle movements that are essential for the communication of emotions.

Conclusion: A careful botulinum toxin placement strategy that considers how facial mimetic muscles are modulated can be used to achieve an expressive and well-balanced face free from unnatural facial expressions.