Importance of the brow in facial expressiveness during human communication.

OBJECTIVE: The objective of this study was to evaluate laterality and upper/lower face dominance of expressiveness during prescribed speech using a unique validated image subtraction system capable of sensitive and reliable measurement of facial surface deformation. RATIONALE: Observations and experiments of central control of facial expressions during speech and social utterances in humans and animals suggest that the right mouth moves more than the left during nonemotional speech. However, proficient lip readers seem to attend to the whole face to interpret meaning from expressed facial cues, also implicating a horizontal (upper face-lower face) axis. STUDY DESIGN: Prospective experimental design. Experimental maneuver: recited speech. OUTCOME MEASURE: image-subtraction strength-duration curve amplitude. METHODS: Thirty normal human adults were evaluated during memorized nonemotional recitation of 2 short sentences. Facial movements were assessed using a video-image subtractions system capable of simultaneously measuring upper and lower specific areas of each hemiface. RESULTS: The results demonstrate both axes influence facial expressiveness in human communication; however, the horizontal axis (upper versus lower face) would appear dominant, especially during what would appear to be spontaneous breakthrough unplanned expressiveness. CONCLUSION: These data are congruent with the concept that the left cerebral hemisphere has control over nonemotionally stimulated speech; however, the multisynaptic brainstem extrapyramidal pathways may override hemiface laterality and preferentially take control of the upper face. Additionally, these data demonstrate the importance of the often-ignored brow in facial expressiveness. LEVEL OF EVIDENCE: Experimental study. EBM levels not applicable.

Computerized objective measurement of facial motion: normal variation and test-retest reliability.

OBJECTIVE: Objective quantitative measurements of facial motion for the assessment of outcomes in patients with facial paralysis have been elusive. This paper will reintroduce an objective computerized program for measurement of facial motion and present data on symmetry in healthy subjects and test-retest reliability in patients with facial paralysis. STUDY DESIGN: Cross-sectional analysis of archived images. SETTING: Tertiary referral center. PATIENTS: Good quality video-recordings of 38 healthy subjects and 30 facial paralysis subjects with a wide range of paralysis that had been tested twice were selected. INTERVENTION: Using image subtraction techniques of digital video recordings, computer-generated strength-duration curves of prescribed facial movements were automatically constructed. MAIN OUTCOME MEASURES: The areas under the curve for specific regions of each side of the face were compared as a proportion described as a percentage (left/right in healthy subjects, abnormal/normal side in paralysis) in which 100% would be perfect symmetry. RESULTS: Thirty-eight healthy subjects had the following left/right symmetry means (95% confidence interval): brow, 98.95 (93.94-103.95); eye, 99.18 (96.31-102.06); and mouth, 96.87 (93.10-100.63).Thirty patients with varying degrees of facial paralysis, tested twice, were evaluated to determine the degree of agreement between trials as measured by the intraclass correlation coefficient. The results showed the intraclass correlation coefficient (95% confidence interval) for brow was 0.972 (0.943-0.987), eye 0.950 (0.898-0.976), and mouth 0.951 (0.901-0.976). CONCLUSION: These results demonstrate no substantial side bias in healthy subjects and excellent test-retest reliability in patients with facial paralysis. This program may be made available for interested investigators upon request.