The effects of wobble board training on the eyes open and closed static balance ability of adolescents with down syndrome

The Static Standing Postural Stability Measured by Average Entropy

Static standing postural stability has been measured by multiscale entropy (MSE), which is used to measure complexity. In this study, we used the average entropy (AE) to measure the static standing postural stability, as AE is a good measure of disorder. The center of pressure (COP) trajectories were collected from 11 subjects under four kinds of balance conditions, from stable to unstable: bipedal with open eyes, bipedal with closed eyes, unipedal with open eyes, and unipedal with closed eyes. The AE, entropy of entropy (EoE), and MSE methods were used to analyze these COP data, and EoE was found to be a good measure of complexity. The AE of the 11 subjects sequentially increased by 100% as the balance conditions progressed from stable to unstable, but the results of EoE and MSE did not follow this trend. Therefore, AE, rather than EoE or MSE, is a good measure of static standing postural stability. Furthermore, the comparison of EoE and AE plots exhibited an inverted U curve, which is another example of a complexity versus disorder inverted U curve.

Test-retest reliability of the Wii Balance Board for assessing standing balance in young people with intellectual disability

Objectives: The main objective was to identify the test-retest reliability of the Wii Balance Board (WBB) for assessing standing balance when administered to a population of people with intellectual disability (ID). A secondary objective was to provide information regarding the reliability of the WBB, taking into account the severity of cognitive impairment. Methods: The WBB was administered two times to a group of 50 people (mean age: 20.44 ± 5.73 years) with mild (n=32), moderate (n=6), or severe ID (n=12) within a 15-day period. The relative reliability of the WBB for the 'standing balance with open eyes' test was analyzed by means of intraclass correlation coefficients (ICCs). The standard error measurement and the minimum detectable change were used to identify absolute reliability. Results: For the whole sample, the WBB showed a fair (ICC=0.71), poor (ICC=0.66), and excellent (ICC=0.99) relative reliability for assessing weight-bearing asymmetry, center of pressure, path length, and sway area, respectively. In people with moderate/severe ID, statistically significant differences between the WBB test and retest scores were found. The absolute reliability of the WBB was considered poor. Conclusion: The WBB showed accurate adequate test-retest reliability for assessing standing balance in young people with ID. When using this device with people with moderate/severe ID, it is advisable to perform several testing trials, in order to avoid a possible learning effect. Standard error of measurement and minimal detectable change were high, indicating that this device might not be sensitive enough to properly identify static balance changes in this population.

A study on balance assessment according to the levels of difficulty in postural control

[Purpose] This study aimed to determine appropriate measures for assessing balance ability according to difficulty level during standing tasks. [Subjects and Methods] The subjects were 56 old (>65 years) and 30 young (20–30 years) adults. By using the Berg balance scale, the subjects were divided into three groups: 29 healthy older (Berg score≥52), 27 impaired older (Berg score≥40), and 30 healthy young (Berg score≥55). One inertial measurement unit sensor was attached at the waist, and the subjects performed standing tasks (1 min/task) with six difficulty levels: eyes open and eyes closed on firm ground, one foam, and two foams. Thirty-nine (24 time-domain, 15 frequency-domain) measures were calculated by using acceleration data. The slope of each derived measure was calculated through the least-squares method. [Results] Five (95% ellipse sway area, root mean squares [anterior-posterior and resultant directions], and mean distance [anterior-posterior and resultant directions] in time domain) of the 39 measures showed significant differences among the groups under specific standing conditions. The slopes of derived measures showed significant differences among the groups and significant correlations with the Berg scores. [Conclusion] The slope according to the difficulty level can be used to assess and discriminate standing balance ability.