Face EMG Topographic analysis of mimetic movements in patients with Bell's palsy.

A face EMG topography system was newly designed and manufactured by the authors. During mimetic actions, such as wrinkling the forehead, closing the eyes, blinking, grinning and blowing out the cheeks, EMG from 16 disk electrodes were concurrently recorded from the frontalis, orbicularis oculi, and orbicularis oris muscles on both sides. The EMG spike potentials fed to on-line computer processing were integrated and calculated with an interpolation formula in the computer, and the colour topographic figures derived from these calculations were displayed on CRT and printed out. These topograms were related to the amount of muscular activity. This technique was applied to 33 patients with Bell's palsy to document the degree and the time course of their mimetic dysfunction. The results obtained were reliable and reproducible. This technique will be useful as one of the proposed methods on grading of facial movement loss in clinical practice.