Orbicularis oculi muscle activation during swallowing in humans

Abstract

Intraoral trigeminal afferents elicit EMG activity from the lower facial muscle, orbicularis oris (OR) during swallowing. The upper facial muscles and especially orbicularis oculi (OC) were not previously known to be associated with deglutitional events. Nevertheless, given the large area of intraoral mucosa and teeth innervated by the trigeminal nerve afferents, a connection between OC motoneurons and deglutition may theoretically be expected, which we sought to evaluate in this study. Healthy controls were investigated for the possible synchronization of orbicularis OC and OR muscles during deglutition by the following methods: EMG activities were recorded during voluntary dry, 3-, 10-, 20-ml discrete wet swallowing, and sequential swallowing from a cup, concurrent with respiratory recording. A polygraphic recording was obtained from these muscles to determine whether they were synchronously activated during spontaneous swallowing. The polygraphic recording during spontaneous swallowing demonstrated that the OC and OR muscles were synchronously activated in all subjects. This synchronous activation was less prominent in voluntary discrete swallowing. It is proposed that this might be based on trigemino-solitarii-facial pathways with weaker connection to OC muscles. The synchronization of OC muscle activity with deglutition may be an evolutionary process that should be rudimentary in higher mammals including humans. The swallowing-induced cranial muscle activities could potentially explain some movement disorders, such as craniofacial dystonias.

Effect of neuromuscular electrical stimulation on facial muscle strength and oral function in stroke patients with facial palsy

“…The oral phase parameters of the VDS include lip closure, bolus formation, and mastication, for which performance of the facial muscles is important. Facial muscles are involved in mastication of food and in formation of intraoral pressure during the oral phase and play a role in preventing the leaking of food via lip closure9 ) . Therefore, the present study demonstrated that improvement in the strength of facial muscles contributed to improvement in the oral phase of swallowing.…”

Effects on facial dysfunction and swallowing capacity of intraoral stimulation early and late after stroke

“…There are precedents for such regulation, as functional linkage has been demonstrated between the orbicularis oculi and the orbicularis oris by several authors (e.g. Ertekin, Eryasar, Gürgör, Arici, Secil, & Kurt, 2013). Additionally, Morecraft, Stilwell-Morecraft, and Rossing (2004) reported clinical observations that indicate a higher oral regulation of facial expression -both voluntary and emotionalthat does not occupy a specific site in the brain or manifest through a single neural projection system.…”

“…Ertekin, Eryasar, Gürgör, Arici, Secil, and Kurt (2013) reported that the orbicularis oris and the orbicularis oculi were intermittently synchronized with swallowing. They proposed that some reflexes, like those related to swallowing, originate partly from the intraoral trigeminal afferents.…”

Neurogenic Dysphagia in Brainstem Disorders and EMG Evaluation

“…There is no strong evidence of a cortical influence on SS in humans. SS is composed of periodic swallowing movements spread out over 24 hours (27,(31)(32)(33)(34). The pacemaker for SS seems to be related to the CPG of the brainstem network (17,18).…”