Biomedical subjects
J VanSwearingen
Publications and source records attributed to J VanSwearingen.
Quantitation of patterns of facial movement in patients with ocular to oral synkinesis.
As patients with facial paralysis regain facial nerve function, they must endure and adapt to complications associated with recovery, such as synkinesis. Synkinesis is the presence of unintentional movement in one area of the face when intentionally performing movement in another area of the face. We used the Maximal Static Response Assay of facial motion to better define the differences between eye closure-associated perioral motion in normal individuals, motion of the affected side in patients with synkinesis, and motion of the unaffected side in patients with synkinesis, thereby characterizing the syndrome of ocular to oral synkinesis. The study population consisted of 78 patients with clinically defined ocular to oral synkinesis of the left or right hemiface and 27 individuals without facial impairment (control subjects). We used the Maximal Static Response Assay to quantify facial motion on the affected and unaffected sides during the motions of eye closure and smile in both groups. Patients with ocular to oral synkinesis had decreased supraorbital and infraorbital motion of the orbicularis oculi during eye closure on both the affected and unaffected sides relative to control subjects. They also had increased modiolar motion during eye closure on both sides relative to control subjects. On the affected side, the modiolus tended to move laterally; on the unaffected side, the modiolus tended to move medially (i.e., toward the side affected by the synkinesis). Modiolar motion present during eye closure in patients with ocular to oral synkinesis was not statistically different from modiolar motion present during smile on the affected side (eye closure, 0.39 cm +/- 0.25; smile, 0.47 cm +/- 0.30, p > 0.05). Using the Maximal Static Response Assay, we have quantitatively defined synkinesis of the affected hemiface and have shown that movement of the unaffected hemiface is influenced by the synkinetic movements of the affected hemiface. These data may provide the basis for a rational system of facial neuromuscular rehabilitation in this patient group.
An electromyographic study of vastus medialis oblique and vastus lateralis activity while ascending and descending steps.
Imbalances in the firing pattern and contraction intensity of the vastus medialis oblique (VMO) and the vastus lateralis (VL) have been considered important factors contributing to patellofemoral joint dysfunction. Vastus medialis oblique and vastus lateralis electromyographic (EMG) activity were measured for 15 individuals without patellofemoral pain (asymptomatic group) and 13 subjects with patellofemoral pain (symptomatic group) while ascending and descending steps. The peak VMO/VL ratios of EMG activity and the difference in peak VMO and VL onset times were measured. Two-way mixed-model analyses of variance (ANOVA) were used to determine the main effects of group (asymptomatic and symptomatic), phase (concentric phase ascending and two eccentric phases descending stairs), and the interaction between group and phase. The ANOVAs indicated no difference between groups for the peak VMO/VL EMG ratio or for the onset timing between peak VMO and VL muscle activity. Combining groups, the peak VMO/VL EMG ratio was less for the eccentric weight acceptance phase of descent compared with the concentric phase of ascent. These findings suggest no differences between asymptomatic and symptomatic individuals, but differences may exist between concentric and eccentric VMO/VL ratios. Further research is needed to determine if VMO and VL muscle imbalances contribute to patellofemoral dysfunction.
Impairment and disability in patients with facial neuromuscular dysfunction.
Integration of impairment measures and disability measures may provide clinicians with an accurate and comprehensive picture of the patient's dysfunction. The purpose of this study was to indicate the usefulness of two new scales of measuring facial impairment and disability in describing characteristics of individuals with facial neuromuscular dysfunction. Fifty-one individuals with unilateral facial neuromuscular dysfunction and a House-Brackmann grade of III or higher were included in the study. The subjects' movement impairments were assessed using the Facial Grading System (FGS). The subjects reported their physical and social function on the Facial Disability Index (FDI). Nine variables were subjected to a confirmatory principal-components factor analysis to indicate important factors in describing patients with facial nerve disorders. The confirmatory principal-components factor analysis identified three factors, impairment, disability, and temporal characteristics of disease, accounting for 72% of the variance in describing individuals with facial neuromuscular dysfunction. Integration of these measures may provide clinicians with an accurate and comprehensive picture of the patient's dysfunction, thus aiding in the determination of intervention and the measurement of clinical outcomes.
Measuring fatigue related to facial muscle function.
OBJECTIVE: The purpose of this study was to explore the expression of facial muscle fatigue in individuals without impaired muscle function using surface electromyography (EMG). DESIGN: Descriptive study of the expression of facial muscle fatigue in individuals without impaired muscle function. PARTICIPANTS: Convenience sample. Twenty individuals, 5 men and 15 women, between 20 and 50 years of age who volunteered to participate. OUTCOME MEASURES: Two tests of fatigue, a 10-second sustained contraction test, and a 25 repeated 3-second contractions test, were conducted on three facial expressions: brow raise, smile, and pucker. Surface EMG quantification of the muscle activity of the voluntary maximal facial muscle contractions was recorded during the fatigue tests. RESULTS: For the sustained fatigue test, all three expressions had a significant decline in activity (brow raise 34.51%, smile 22.96%, and pucker 29.05%); confirmed by a one-way ANOVA with repeated measures (brow raise df = 2, 38; f = 53.28; p = 0.00; smile df = 2, 38; f = 39.913; p = 0.00; pucker df = 2, 38; f = 76.002; p = 0.00). For the repeated fatigue test, percent fatigue was significant for smile (11.62%; df = 1, 19; f = 13.823; p = 0.001) but not for brow raise (7.27%; df = 1, 19; f = 1.945; p = 0.179) or pucker (4.22%; df = 1, 19; f = 2.508; p = 1.30). CONCLUSIONS: The muscle activity of sustained maximal voluntary muscle contractions of facial muscles fatigues significantly with time for brow raise, smile, and pucker expressions. The same facial muscles are more resistant to fatigue of muscle activity with repeated, brief contractions. Knowing the amount of facial muscle fatigue of individuals without impairment can be beneficial in developing outcome measures and goals for rehabilitation of individuals with facial neuromuscular dysfunction. Changes in fatigue tests of an individual with facial neuromuscular dysfunction with rehabilitation is reviewed for comparison.