Fumio Yagi

Effects of perceptual learning exercises on standing balance using a hardness discrimination task in hemiplegic patients following stroke: a randomized controlled pilot trial

Objective: To investigate the effect of perceptual learning exercises for hardness discrimination by the soles on standing balance in stroke patients with hemiplegia. Subjects: Twenty-eight subjects were randomly assigned to an experimental or a control group and participated in a rehabilitation programme. Intervention: The experimental group received perceptual learning exercises on hardness discrimination using three different levels of hardness of a rubber sponge for 10 days. Main measures: Length, enveloped area and rectangular area of the parameter of postural sway were measured by a stabilometer on entry into the study and after 10 days. Results: Twenty-six subjects completed the study. Data indicate that more parameters indicating postural sway were significantly decreased in the experimental group than in the control group. Also, there was a significant difference between the groups in change scores (pre-exercise minus postexercise) of length and enveloped area. Conclusion: The plantar perception exercise used as a method in this study is considered to be effective as a supplemental exercise for standing balance. The possibility of clinical application using the hardness discrimination task with rubber as a balance exercise is therefore suggested.

Influence of perceptual learning on standing posture balance: repeated training for hardness discrimination of foot sole

The current study investigated the influence of perceptual learning training for hardness discrimination of sponge rubber by the soles on postural sway. Subjects consisted of 30 healthy male volunteers. They were divided into two groups of 15 each at random: perceptual learning training group and a control group. For hardness discrimination training, rubber sponges 5, 10, and 20 mm thick were combined to change the thickness of rubber to 5, 10, 15, 20, and 25 mm. The hardness discrimination training was administered with eyes closed in the standing position for each day for 10 days. The center of pressure measured using a stabilometer was used as the indicator for postural sway. Postural sway was measured for 30 s with eyes open and closed before and after hardness discrimination training. Statistical analysis was performed for length, enveloped area, and rectangular area. Postural sway after training showed a significant decrease compared to sway before training in the perceptual learning training group. However, there was no change on postural sway in the control group. In conclusion, data indicate that the ability of the healthy subjects to regulate their standing posture improved with improvement of the perceptive ability of the soles.

A new simple performance test focused on agility in elderly people: The Ten Step Test.

Background: Not only the reduction of muscle strength or balance, but also the reduction of the agility are regarded as important factors of falls in elderly people. If an agility test for elderly people is established, the precision of the fall prediction rises and can be used for individual training. Objectives: To develop a new performance test focused on agility for elderly people and to evaluate the usefulness of this test. Design: Cross-sectional study. Setting: The Welfare Center of Kagami Town, Kagami Town Office, etc., Kochi, Japan. Participants: 828 community-dwelling, independent adults aged 20–99 years with no obvious cognitive or functional disability, were randomly recruited from Kagami town and the surrounding areas. Measurements: The Ten Step Test (TST, a new performance test), motor reaction time (MRT), knee extensor isometric strength, single leg standing time (SLST), and some other tests were used to evaluate the criterion-related validity and the content validity. TST was developed as a modified version of other step tests which require the subjects to place the whole foot on a block, then return it to the floor. In addition, female participants over 70 were asked whether or not they had fallen in the past year. Results: Excellent reliability for TST was found for interrelation (intra-class correlation coefficients, ICC = 0.96), and re-test reliability was sufficient (ICC = 0.86). Evidence for criterion-related validity was found through high single correlation with the timed supine-to-stand (r = 0.68) and high single correlation with MRT (r = 0.59). In addition, content validity was found through low correlation with knee extensor strength (–0.35) and SLST (–0.36) in 112 women over 70 years of age. The error rate by TST to predict falls (35.2%) was lower than the error rate by muscle strength (44.4%) and the balance (38.7%). TST confirmed decline after 50 years of age, and it conformed to a cubic curve. Conclusion: The findings indicate that TST is a reliable measure of agility, and it can help to predict the risk of falls. The decline of agility accelerates after 50 years of age. It shows that the decline of agility differs from the decline of leg muscle strength and balance.

Effects of plantar hardness discrimination training on standing postural balance in the elderly: a randomized controlled trial

Objective: To investigate the effects of sensory perception exercises for discrimination of surface hardness by the soles of the feet on standing postural balance in the elderly. Design: A randomized two-group parallel controlled trial. Subjects: Twenty-four healthy people aged from 61 to 71 years were enrolled and randomly assigned to a perception exercise group (n = 12) or a control group (n = 12). Intervention: The perception exercise group were given a task designed to train ability to discriminate different degrees of hardness of foam rubber. The training period was 10 days. Control group subjects were instructed to maintain a standing posture on foam rubber for 10 seconds for a total of 10 days. Measurements: Before and after training we measured centre-of-gravity sway with the subject standing, obtaining sway path length and area of ellipse. The Functional Reach Test was used to measure the forward displacement distance of the centre of gravity. Results: Our data revealed a significant reduction in centre-of-gravity sway post training in the perception exercise group as well as a significant increase in forward displacement of the centre of gravity. These parameters were unchanged in the control group. As to change values (difference between pre- and post-training values), the perception exercise group had significantly better values than the control group, indicating the efficacy of sensory perception exercises. Conclusions: We demonstrated that standing postural balance was improved by sensory perception exercises involving the soles of the feet. Used in addition to balance training, such training for hardness discrimination could be effective in the clinical setting to improve balance in the elderly.

Interaction interference between arm and leg: Division of attention through muscle force regulation

The first purpose of this study was to examine whether decreases in muscle force similar to the bilateral deficit occur during simultaneous use of arm and leg. The second purpose was to examine the effect on the muscle force of one leg by a division of attention through the regulation of the muscle force in the arm. Six participants completed each of the following three tasks in a random order: (1) maximal unilateral flexion of the right or left elbow, (2) maximal unilateral extension of the left knee, and (3) multilimb effort (a maximal contraction of the muscles in the leg while maintaining a constant submaximal isometric elbow flexion force at 25%, 50%, 75%, or 100% MVC). The results showed that muscle force was lower during simultaneous exertion of arm and leg than during exertion of one limb alone. The maximal knee extension force was significantly (p<.05) lower, by as much as 40% or so, during regulation at 25% MVC. The division of attention is also thought to be involved in task execution and may thus explain the test results. A decrease in the muscle force of the leg due to the level of regulation of the muscle force of the arm indicates that the regulation of the muscle force affects the division of attention, and the finer level of muscle force regulation is a task that requires greater attention. When the muscle force is precisely controlled, a more accurate and more appropriate adjustment is required to focus attention.