Back to 2017 Annual Meeting Program
Imaging A Smile: A Novel Approach To Measuring Brain Activity Accompanying Facial Expressions And Its Application In Facial Nerve Palsy
Siba Haykal, MD, PhD; FRCSC; Cecilia Jobst, MSc; Ronald Zuker, MD FRCSC; Gregory Borschel, MD FACS; Douglas Cheyne, PhD;
University of Toronto, Toronto, ON, Canada
Purpose: Facial nerve palsy can have a profound impact on physical and social aspects impacting social communication and normal psychological development. Surgical treatment to restore facial motor control for these children improves their self-esteem and sociability Successful motor rehabilitation following surgery is critical for positive outcomes. Understanding neuroplasticity and functional reorganization of the sensorimotor cortex will allow for tailored surgical approaches and post-operative therapies. Changes with facial and oromotor movements remain unstudied. Functional MRI produces artifacts with orofacial movements, requires specific scan sequences and has low temporal resolution of the signal. Measurements obtained do not separate pre-movement activity, primary motor cortex, post-central cortex and are difficult to carry in young children. The aims of this study are the following: Aim#1 To use a novel imaging technique (MASK-MEG) for measurements of neuroplastic changes in children Aim #2 To outline functional and structural mapping in a control group of healthy children Aim #3 To measure changes in sensory and motor cortex in patients undergoing reanimation surgery
Methodology: Aim#1: 4 healthy participants were tested in the MASK-MEG system. Aim #2: Six healthy participants; 3 adults; 3 children (8, 10, 16 yo) underwent tasks in a 151-Channel MEG system with two electromyography (EMG) electrodes on left/right masseter muscles. These tasks included 50-100 cued facial movements, Left and right unilateral smiles, natural bilateral smiles and speech. Aim#3: Control and clinical patients underwent neuroplasticity mapping of their smile centre in a MASK-MEG system.
Results: The MASK-MEG system is able to determine location of smile in the precentral gyrus in both adults and children. EMG is too noisy in children and non-specific to smile. In children with facial nerve palsy, responses locations and trajectories are comparable to child control, but with less strong (and noisier) results. Motion differences can be seen between control and clinical participants.
Conclusions: We have demonstrated successful use of a novel MEG-compatible motion tracking device to measure brain activity of subtle facial expressions in children. EMG is highly non-specific for facial muscles due to the number of muscles within a small surface area and lacks ability to determine movement direction or amplitudes. The MASK system coils provide greater movement specificity and are small and light-weight enough not to impede on natural movements. MASK-MEG is a useful tool to assess location of smile in controls and patients with facial nerve palsy.
Back to 2017 Annual Meeting Program