Effect of Brain Training Through Visual Mirror Feedback, Action Observation and Motor Imagery on Orofacial Sensorimotor Variables: A Single-blind Randomized Controlled Trial

Objectives: The main objective was to evaluate the effects of action observation (AO), visual mirror feedback (VMF) and motor imagery (MI), combined with an oro-facial exercise programme, on sensorimotor variables in asymptomatic participants.

Methods: We designed a randomised, single-blind, controlled trial that included 52 asymptomatic participants who were randomly assigned to 4 groups, 13 to each of the VMF, MI and AO groups and 13 to the control group (CG), which only performed the exercise programme. The primary outcomes were pain pressure sensitivity and tongue muscle strength. The secondary outcomes were maximum mouth opening, tongue length and the ability to generate mental motor images. Each group underwent a 3-session intervention using their respective exercise. Measurements were performed before starting the intervention and after each of the 3 sessions (pre, mid1, mid2 and post).

Results: ANOVA revealed significant changes in PPTs in the masseter muscle region in the MI and AO groups in the pre-post and mid1-post changes. ANOVA revealed significant differences in tongue muscle strength in the anterior direction only in the AO group in the pre-mid2 and pre-post changes.

Conclusions: AO and MI, in conjunction with exercise, could induce changes in PPTs for the masseter muscle. In addition, only AO produced changes in tongue muscle strength. More research is needed to determine the role of brain representation techniques in the oro-facial region and transferring this exercise to the rehabilitation setting.