The Contribution of Surface Electromyographic Assessment for Defining the Stage of Peripheral Facial Paralysis: Flaccid or Sequelae Stage

Abstract

Introduction Surface electromyographic activity may not be symmetric, even in subjects with no facial paralysis history. Objective To evaluate the contribution of the index of electromyographic (IEMG) activity in the identification of the two extremes of the facial paralysis course. Methods Thirty-four subjects with unilateral peripheral facial paralysis were selected. A control group was composed of volunteers without a history of facial paralysis. The electromyographic assessment of the facial muscle was performed by placing surface electrodes during movements of the forehead, eyes and lips using MIOTEC equipment, such as the MIOTOOL (Miotec, Porto Alegre, Brazil) software. The electromyographic activity was also recorded in other channels during the primary activity to identify the presence of synkinesis. The statistical analysis was performed using the Statistical Package for Social Sciences for Macintosh (SPSS Inc, Chicago, IL, USA). The IEMG activity was obtained from the division of the electromyographic activity root mean square (RMS) values on both sides. Results There was a statistically significant difference among the groups in all the analyzed indexes. The ocular-oral synkinesis in all patients must be correctly identified (with 100% sensitivity and specificity) using an IEMG activity of 1.62 as a cutoff point. The oral-ocular synkinesis must be correctly identified (93.3% sensitivity and 95.9% specificity) using the IEMG activity of 1.79 as a cutoff point. Conclusion The IEMG activity is below the normal scores in patients in the flaccid stage, whereas patients in the sequelae stage can either show normal values or values above or below the normal scores. The IEMG activity was shown to have high sensitivity and specificity in the identification of synkinesis.

Keywords: electromyography; facial paralysis; surface.

Fig. 1

Error bars representing the mean and the standard deviation of the IEMG activity of the movement raising the eyebrows in the studied groups.

Fig. 2

Error bars representing the mean and the standard deviation of the IEMG activity of the movement of eye closure in the studied groups.

Fig. 3

Error bars representing the mean and the standard deviation of the IEMG activity of the movement of puckering lips in the studied groups.

Fig. 4

Error bars representing the mean and the standard deviation of the index of electromyographical activity in the movement of lip retraction in the studied groups.

Fig. 5

Receiver operator characteristics (ROC) curve for the clinical diagnosis of synkinesis in lips during the movement of eyes closure (ocular-oral) through index of electromyographical activity.

Fig. 6

Receiver operator characteristics (ROC) curve of the index of electromyographic activity using different cutoff points for clinical identification of synkinesis in the eyes during the movement of puckering lips (oral-ocular).