Abstract
Objectives The aim of this study was to verify during facial expressions (“happy,” “sad,” “fearful,” “angry,” “surprised,” and “disgusted”) if: (1) there would be difference in the electromyography (EMG) of the occipitofrontalis, temporal, masseter, and sternocleidomastoid muscles on the normal side (NS) compared with the affected side (AS) (without the use of an ocular prosthesis) in individuals with unilateral absence of the eyeball, and (2) the rehabilitation with a new ocular prosthesis would affect the EMG of the muscles studied on the AS in these individuals. Materials and Methods Thirteen individuals, without temporomandibular disorder, with good health, with unilateral absence of the eyeball (the eye must have been removed by evisceration or enucleation), and users or nonusers of an ocular prosthesis were included. EMG of the occipitofrontalis, temporal, masseter, and sternocleidomastoid muscles was performed during rest and facial expressions (“happy,” “sad,” “fearful,” “angry,” “surprised,” and “disgusted”) before (T0) and 90 days after (T1) rehabilitation with a new ocular prosthesis. The analyses were performed in T0 on NS and AS (without the use of an ocular prosthesis), and in T1 on AS with the new ocular prosthesis. Statistical Analysis All data were submitted to the Student's t -test with p < 0.05. Results There was no statistically significant difference comparing the AS with the NS in T0 for all muscles studied, during all facial expressions evaluated ( p > 0.05). There was no statistically significant difference comparing the AS in T0 with itself in T1 for all muscles studied, during all facial expressions evaluated ( p > 0.05). Conclusion Eye loss did not affect the EMG of studied muscles when comparing NS with AS (without the use of an ocular prosthesis). The rehabilitation with ocular prosthesis was not capable of changing the EMG on AS.
Highlights
Movements and contractions of the orofacial muscles are managed by a complex cortical control that is subject to reflexive reactions, besides the emotional and volitional controls.[1]
The aim of this study was to verify during facial expressions (“happy,” “sad,” “fearful,” “angry,” “surprised,” and “disgusted”) if: (1) there would be difference in the electromyography (EMG) of the occipitofrontalis, temporal, masseter, and sternocleidomastoid muscles on the normal side (NS) compared with the affected side (AS) in individuals with unilateral absence of the eyeball, and (2) the rehabilitation with a new ocular prosthesis would affect the EMG of the muscles studied on the AS in these individuals
These processes depend on rest and the movement which comes from the peripheral mechanoreceptors, which are centrally processed according to the corporal map.[2,3]
Summary
Movements and contractions of the orofacial muscles are managed by a complex cortical control that is subject to reflexive reactions, besides the emotional and volitional controls.[1] These controls depend on proprioception, which is a complex sensation that involves central and peripheral processes of information. These processes depend on rest and the movement which comes from the peripheral mechanoreceptors, which are centrally processed according to the corporal map.[2,3] Despite this motor complexity, the facial muscles contribute significantly to human behavior in many activities such as alimentation, production of speech, and visual communication for emotional states.[1]. The polyneural innervation of facial muscles in adult humans occurs in other muscles of the cranium, such as the larynx[8] and extraocular,[9] though the clinical significance is not known
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