Hung You-Jou, Miller Jacob
You-jou Hung, Jacob Miller, Department of Physical Therapy, Angelo State University, San Angelo, TX 76909, United States.
World J Orthop. 2016 Dec 18;7(12):801-807. doi: 10.5312/wjo.v7.i12.801.
To investigate the impact of extrinsic visual feedback and additional cognitive/physical demands on single-limb balance in individuals with ankle instability.
Sixteen subjects with ankle instability participated in the study. Ankle instability was identified using the Cumberland Ankle Instability Tool (CAIT). The subject's unstable ankle was examined using the Athletic Single Leg Stability Test of the Biodex Balance System with 4 different protocols: (1) default setting with extrinsic visual feedback from the monitor; (2) no extrinsic visual feedback; (3) no extrinsic visual feedback with cognitive demands; and (4) no extrinsic visual feedback with physical demands. For the protocol with added cognitive demands, subjects were asked to continue subtracting 7 from a given number while performing the same test without extrinsic visual feedback. For the protocol with added physical demands, subjects were asked to pass and catch a basketball to and from the examiner while performing the same modified test.
The subject's single-limb postural control varied significantly among different testing protocols (F = 103; = 0.000). Subjects' postural control was the worst with added physical demands and the best with the default condition with extrinsic visual feedback. Pairwise comparison shows subjects performed significantly worse in all modified protocols ( < 0.01 in all comparisons) compared to the default protocol. Results from all 4 protocols are significantly different from each other ( < 0.01) except for the comparison between the "no extrinsic visual feedback" and "no extrinsic visual feedback with cognitive demands" protocols. Comparing conditions without extrinsic visual feedback, adding a cognitive demand did not significantly compromise single-limb balance control but adding a physical demand did. Scores from the default protocol are significantly correlated with the results from all 3 modified protocols: No extrinsic visual feedback (r = 0.782; = 0.000); no extrinsic visual feedback with cognitive demands (r = 0.569; = 0.022); no extrinsic visual feedback with physical demands (r = 0.683; = 0.004). However, the CAIT score is not significantly correlated with the single-limb balance control from any of the 4 protocols: Default with extrinsic visual feedback (r = -0.210; = 0.434); no extrinsic visual feedback (r = -0.450; = 0.081); no extrinsic visual feedback with cognitive demands (r = -0.406; = 0.118); no extrinsic visual feedback with physical demands (r = -0.351; = 0.182).
Single-limb balance control is worse without extrinsic visual feedback and/or with cognitive/physical demands. The balance test may not be a valid tool to examine ankle instability.
探讨外在视觉反馈以及额外的认知/身体需求对踝关节不稳定个体单腿平衡的影响。
16名踝关节不稳定的受试者参与了本研究。使用坎伯兰踝关节不稳定工具（CAIT）来确定踝关节不稳定情况。使用Biodex平衡系统的单腿运动稳定性测试，采用4种不同方案对受试者不稳定的踝关节进行检查：（1）默认设置，有来自监视器的外在视觉反馈；（2）无外在视觉反馈；（3）无外在视觉反馈且有认知需求；（4）无外在视觉反馈且有身体需求。对于增加了认知需求的方案，要求受试者在不进行外在视觉反馈的情况下进行相同测试时，从给定数字开始持续减7。对于增加了身体需求的方案，要求受试者在进行相同修改测试时，与考官来回传球和接球。
在不同测试方案中，受试者的单腿姿势控制差异显著（F = 103；P = 0.000）。受试者在有身体需求时姿势控制最差，在有外在视觉反馈的默认条件下最好。两两比较显示，与默认方案相比，所有修改后的方案中受试者表现均显著更差（所有比较中P < 0.01）。除了“无外在视觉反馈”和“无外在视觉反馈且有认知需求”方案之间的比较外，所有4种方案的结果彼此均有显著差异（P < 0.01）。比较无外在视觉反馈的情况，增加认知需求并未显著损害单腿平衡控制，但增加身体需求则会。默认方案的得分与所有3种修改后方案的结果显著相关：无外在视觉反馈（r = 0.782；P = 0.000）；无外在视觉反馈且有认知需求（r = 0.569；P = 0.022）；无外在视觉反馈且有身体需求（r = 0.683；P = 0.004）。然而，CAIT得分与4种方案中任何一种的单腿平衡控制均无显著相关性：有外在视觉反馈的默认方案（r = -0.210；P = 0.434）；无外在视觉反馈（r = -0.450；P = 0.081）；无外在视觉反馈且有认知需求（r = -0.406；P = 0.118）；无外在视觉反馈且有身体需求（r = -0.351；P = 0.182）。
没有外在视觉反馈和/或有认知/身体需求时，单腿平衡控制较差。平衡测试可能不是检查踝关节不稳定的有效工具。
