Paradoxical Frontalis Activation: An Underrecognized Consequence of Facial Palsy

Abstract

This study highlights the phenomenon of paradoxical frontalis activation during eye closure. This is often underrecognized and may contribute to lagophthalmos. The authors found it to be present in 27 percent of patients with moderate or severe synkinesis. Further dynamic studies are required to understand the relationship among frontalis activity, eye closure, and the effects of its inhibition.

Influence of Mirror Therapy (Specular Face Software) on Electromyographic Behavior of the Facial Muscles for Facial Palsy

“…In this same gesture, the electromyography shows substantial changes in the buccinator and frontal muscles, when the activity of these muscles is reduced 50% and 80%, respectively, when the gesture is executed with the Specular Face program. The patient presented synkinesis when performing the gesture without biofeedback, which could be due to the fact that the facial muscles decrease muscle spindles–a highly important fact, given that prolonged interruption of facial nerve function can lead to abnormal muscle function and reduced cortical reorganization [ 29 ]. Revisiting Figure 1 , the use of facial mirror therapy using the Specular Face program could be the cause to explain the reduced synkinesis in the buccinator and frontal muscles during the kiss gesture.…”

“…This change shows synkinesis inhibition of the orbicularis muscle in this gesture. As with case 1, prolonged interruption of facial nerve function can lead to abnormal function and impaired cortical reorganization [ 29 ]. Mirror therapy appears to facilitate cortical reorganization, help rebalance the intrahemispherical neuronal network and improve motor function [ 17 ].…”

Facial Nerve Palsy and the Eye: Etiology, Diagnosis, and Management

“…Unfortunately, the story of facial palsy does not usually end there as nearly one-third of patients do not recover fully. Estimates vary 30 but approximately half of those patients with incomplete recovery develop a nonflaccid form of facial paralysis with varying degrees of static or kinetic hyperactivity or hypoactivity which causes facial asymmetry at rest or during movement, along with synkinetic movements which occur during voluntary expressions caused by aberrant regeneration of the facial nerve 20,31–33 . This outcome is usually a psychologically devastating problem in FNP, 20 and is more typically encountered in patients sustaining a severe (>95%) nerve injury 28 .…”

“…It should be noted that synkinetic movements may occur in the direction of the agonist muscle either due to over-innervation of the paralyzed muscle, or aberrant regeneration of an agonist muscle. Alternatively, they may occur in the opposite direction if an antagonist muscle is aberrantly reinnervated 1,20,31–33 . The former is more commonly encountered, 31 but in the rarer situation where an antagonist muscle is involved, the actions of both muscles may cancel each other out resulting in a complete stoppage of the originally intended movement, or the so-called autoparalytic syndrome 31,34 .…”

“…31,34 Any combination of facial muscles can be involved in synkinetic action, 33 and the periocular region is a common area where those aberrant movements occur. 31 The most frequently encountered movement is the oculo-oral synkinesis (movement of the oral commissure with voluntary eye closure). Conversely, Marin Amat syndrome manifests with narrowing of the palpebral fissure during opening of the mouth or mastication.…”