Postural Control on the Compliant Surface in the Absence of Somatosensation

軟墊是臨床上經常用來作平衡測試及訓練的工具，藉由軟墊的特性，可以改變腳踝本體覺以及足底表皮感覺的體感覺輸入，來觀察視覺及前庭覺代償能力的表現。然而，站在軟墊上的平衡表現，除了受到體感覺改變的影響，是否還有其他因素共同影響，是值得深思的。因此，本實驗的目的，藉由實驗操作的方式，去除來自於足部的體感覺輸入，來證明站在軟墊上是否只改變了體感覺訊息。方法：利用血壓帶加壓缺血阻斷的方式，將腳踝以下的體感覺暫時去除，觀察十四位年輕受試者在四種情況下觀察其閉眼站立時姿勢搖晃的情況：缺血前站在地面、缺血前站在軟墊、缺血後站在地面、缺血後站在軟墊。利用動作分析系統觀察姿勢搖晃的情況，並比較以下的位移參數：軌跡、前後及左右向最大位移範圍、前後及左右向平均瞬間速度。結果：實驗結果顯示體感覺的狀態與支撐表面兩者之間沒有顯著的交互作用，且兩者都具有顯著的主要作用效果。即使在足部體感覺喪失的情況下，站在軟墊與站在平地上有較大的姿勢搖晃的軌跡、範圍，以及速度。結論：移除來自足部的體感覺訊息後，站在軟墊與站在地面上的平衡表現仍舊有顯著的差異，代表站在軟墊上不只是改變了足部及腳踝的體感覺輸入，還有其他與平衡表現相關的因素也被改變。因此，在臨床的檢查中，站在軟墊上的表現不能完全推論為視覺及前庭覺的代償能力，必須作更進一步的檢查才能確定。

關鍵字

軟墊；體感覺；姿勢搖晃

並列摘要

Background and Purposes: Rubber foams have been used extensively clinically to alter somatosensory inputs from the ankle joints and the foot soles so that the compensatory ability of the visual and vestibular systems can be examined. However, it is not clear if other balance-related factors are also altered in such maneuvers. The purpose of this study was, by experimentally inducing somatosensory loss of the foot and ankle, to verify if the somatosensation of the ankle and foot was the only factor changed during standing on the foam. Methods: Somatosensory loss was induced in 14 healthy subjects by inflating pneumatic cuffs above bilateral ankle joints to produce vascularischemia. Postural sway was assessed under four conditions: pre-ischemia ground standing, pre-ischemia foam standing, post-ischemia ground standing, and post-ischemia foam standing. The motion of a reflective marker placed on the center of the sacrum was used to reflect postural sway, and the variables of interest included trajectory, maximum range of anterior-posterior (AP) and medial-lateral (ML) trajectory, and mean instantaneous velocity in the AP and ML directions of the sacrum marker. Results: Multivariate ANOVA showed a lack of significant interaction between somatosensory status and support surface, and significant main effects of both on postural sway. Foam standing led to greater postural sway than ground standing even after a total loss of somatosensation of the feet. Conclusions: Somatosensory inputs might not be the only factor changed when standing on a compliant surface because greater postural sway occurred even after a total loss of somatosensation. Clinically, a declined balance performance in foam standing should not be completely attributed to impaired visual or vestibular compensation.

並列關鍵字

Rubber foam ； Somatosensation ； Postural sway

國際替代計量

Postural Control on the Compliant Surface in the Absence of Somatosensation

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