OBJECTIVES:
Muscle strength is a fundamental measure of function for
neuromuscular systems; however, mimetic
facial muscle strength has never been recorded. The objective of the present feasibility project was to measure
facial muscle strength. STUDY DESIGN: The
study design was a prospective experimental trial in 10 normal subjects.
Descriptive statistics, tests, and
analysis of variance were used to summarize and compare data. METHODS: Subjects were
selected by convenience following submission and approval of a prospectively designed protocol and consent form to the Human Studies Committee. Application of a force transducer to the central
eyebrow and
commissure during
eyebrow raising,
eyelid closing,
smiling, and puckering was performed by two methods: surface
adhesion method (n = 5) and direct probe application method (n = 5). Data were recorded in pounds. Three repetitions of each movement were made. RESULTS:
Rank order of
muscle strengths (in pounds) by the surface
adhesion technique was as follows:
brow, 0.758;
eye, 0.549; pucker, 0.387; and
smile, 0.307. By direct probe application the
rank order of
muscle strengths was as follows:
eye, 0.880;
brow, 0.773; and
smile, 0.730. CONCLUSIONS: Objective measures of
facial motion are crucial for quantitative investigations of preventative, therapeutic,
reconstructive, and rehabilitative interventions for
facial nerve and
muscle lesions. Until the present, objective measures required
cross-correlations with current standards that were subjective. This is the first time an actual
physical measure of
facial muscle function has been performed. The purpose of presenting this preliminary work is to stimulate advancement along this line of research.
