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Purpose: An important medical and social problem for the elderly is falls. Some studies have focused on the effect of static vibratory stimulation for human postural control. There is limited research on brief moving vibratory stimuli for maintaining postural stability. The purpose of this study was to investigate the effect of brief moving vibratory stimulation on the toes and the soles of the feet for standing balance in adults of different ages. Method: The subjects were divided into two groups, the young group (mean age 23.7 years, 12 males and 7 females), and the elderly group (mean age 81.1 years, 6 males and 14 females). The system can produce mechanical vibrations up to 100 Hz. The 8 vibrators were placed in the foot mat (30 mm x 30 mm). In the study, six directions (right side, left side, forward, backward, clockwise, counterclockwise) were used in the brief moving vibratory stimuli. The instrument for measuring standing balance was a force platform. The subjects were instructed to stand relaxed, with bare feet, and their eyes closed for a period of 10 seconds on the mat placed over the force platform. After quiet standing, the subjects tried to remain standing while the vibrators stimulated the soles of the feet for one second. Subjects kept standing after completion of stimuli for more than one second. The six different vibration patterns were randomly used. Result: According to the data of body sway parameters, there were no significant differences between stimulation and non-stimulation in both groups. The data on body sway in the elderly group was greater than that in the young group. The data on body sway with stimulation was greater than that of body sway without stimulation. Moreover, the anteroposterior body sways during the vibratory stimulation pattern in the condition of back or forth direction were greater than the lateral sway in the same vibratory stimulation pattern. Conclusion: The results suggest that the brief moving vibratory stimulation system may be positively affected by postural balance within the base of support. It might be hypothesized that the system may be able to help in the control of body sway. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the limitation of the head and lumbar movements in relation to the center of gravity which is needed to maintain standing balance with aging. The subjects of the study were 22 healthy volunteers. The subjects were divided into two age categories, the younger group (mean 21.7 +/- 2.9 years, 7 males and 6 females); and the elderly group (mean 71.3 +/- 2.6 years, 3 males and 4 females). The instruments for measuring lumbar and head movements and the center of pressure (COP) were a three-dimensional motion analysis system and a force plate. In addition, the peak foot pressure was measured during standing using the F-Scan system. The subjects were first asked to stand for 10 s. They then shifted from starting position to the four directions (sways); anterior, posterior, right and left. They tried to maintain standing balance at the maximal possible distance position for each sway for 10 seconds. Analyzing parameters were performed by measuring the average maximal linear displacement (cm) of the head and lumbar markers, the COP (cm), and the peak foot pressure (percentage of body weight per squared centimeters; BW%/cm2) in each subject. The data of the young group for lumbar maximal displacement were greater of those for the elderly group in the anterior, posterior and lateral sways. A significant difference was found between the young and elderly in the posterior sway. According to the data of the head's maximal displacement, the elderly group was greater than the young group in all sways except for the anterior side. For the data of peak foot pressure in the posterior sway, the elderly group's data was greater than the young group's data. The forefoot area data of the young group was significantly greater than that of the elderly group and the heel area data of the elderly was significantly greater than that of the young group in the right sway. The results suggest that evaluating maximal displacement of head and lumbar positions ad toe's activity in the forefront are all important factors associated with the center of gravity in healthy adults. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this study was to examine the relationships between the toe's pressure and tactile sense and measures of postural stability. SUBJECTS: The subjects of the study were 21 healthy volunteers who were divided into two age groups: young group (mean 21.0 +/- 1.6 years): 7 males and 6 females, elderly group (mean 71.4 +/- 2.8 years): 4 males and 4 females. METHODS AND MATERIALS: First experiment (balance test): The instrument for measuring standing balance was a stabilometer. A computer program built into the device provides information on the subject's stance balance through calculation of two variables: (1) Body sway index (SI: mm), and (2) Foot pressure (%BW/cm2). The subjects were asked to stand as motionless as possible for 20 seconds. The same test was repeated with the subject's eyes closed. Second experiment (tactile sense test): utilized a new system which was developed to measure tactile-proprioceptive sensation. The tactile threshold value was measured with the subject seated in a chair, the back supported, and hip and knee flexed at 90 degrees. The contactor moved longitudinally along the toe axis at a constant velocity, 1000 micro m/s. CONCLUSIONS: There were significant differences between young and elderly groups for the tactile sense of the great toe (p < 0.001). No significant difference between age and postural sway while the subject stood with eyes open was found. However, when the subjects stood with their eyes closed, there were significant differences between young and elderly groups for the body sway parameters (p < 0.05). The results suggest that the deprivation of visual information, age effect, reduced tactile sensation, and insufficiency of muscle control in the toes are all important factors associated with postural instability. [ABSTRACT FROM AUTHOR]