Abstract:
Unilateral vestibular hypofunction patients have damage to one ear which
causes them to have balance and postural control problem. The purpose of this study
was to investigate the effect of muscular vibration on postural adjustment in these
patients who were standing still and had their eyes open. Muscular vibration (90Hz)
was applied to the upper leg muscles, lower leg muscles, or both upper and lower
muscles of the lesion side. The postural control parameters-average sway velocity,
medial-lateral sway magnitude, anterior-posterior sway magnitude, percentage of
ankle strategy, and percentage of maximum stability-were recorded for 20 seconds in
before, during, and after muscular vibration.
Twenty-five patients of various ages who had more than a 25% difference in
vestibular function in ear participated in the study. Subjects were asked to stand still
on the force platform and open their eyes.
The results revealed that there was significant difference in medial-lateral
sway magnitude between before and during muscular vibration. In addition, there was
significant difference in anterior-posterior sway magnitude between during and after
muscular vibration. No difference in sway velocity, postural control strategy, and
maximum stability was observed between before, during and after muscular vibration.
Similarly, there was no difference in average sway velocity, medial-lateral, anteriorposterior
sway, postural control strategy, and maximum stability between any
muscular vibration areas. No interaction between the muscular vibration periods and
areas was shown in average sway velocity, medial-lateral, anterior-posterior sway,
postural control strategy, and maximum stability.
In conclusion, during muscular vibration the medial-lateral sway magnitude
can be reduced in unilateral vestibular hypofunction patients. It is suggested that in
unilateral vestibular hypofunction patients the simultaneous stimulation of the anterior
and posterior muscles of the lower limb of the lesion side stabilizes the medial-lateral
postural sway. Therefore, the muscular vibration is a possible method for improving
postural control and balance through vestibular substitution. It is suggested that in
addition to caloric test screening, postural balance ability should be screened and
muscular vibration on dynamic standing will be further study