本研究の目的は, 座位到達動作課題を使用して, 到達させる対象物の性質や被験者との位置関係の変化が姿勢調節にどのような影響を及ぼすかを明らかにすることである。対象は健常若年者(以下, 健常者)12名と脳卒中片麻痺患者(以下, 片麻痺患者)8名であった。方法は, 対象者とコップの配置を自由に設定できるテーブルを自作し, 対象者には座位で前方に置かれたコップを口に運ぶという到達動作を行わせた。与えた到達動作の課題は, 二つの対象物と三つの配置条件を組み合わせた6種類であり, 各課題を実施した時の到達時間, 垂直床反力, そして筋電活動量を測定した。健常者と片麻痺患者における各測定項目を群間検定したところ, 到達時間は健常者に比べて片麻痺患者が延長し, 下肢筋は健常者に比べて片麻痺患者が大きな筋電活動量を示していた。また, 健常者と片麻痺患者各々の対象物と配置条件の二要因に関する分散分析の結果, 両群とも対象物の違いに有意な主効果を認めた測定項目はなかったが, 健側三角筋の筋電活動量以外の測定項目において配置条件の違いによる5%水準以下の有意な主効果を認めた。

The purpose of this study was to investigate the effects of 1) the change of position of an object in relation to the subject, and 2) the change of the nature of the object, on the postural adjustment during seated reaching movements in healthy subjects and in hemiplegic patients. The subjects were 12 healthy volunteers who were neurologically intact (healthy group) and 8 hemiplegic patients (patient group). Subjects reached with the right hand to pick up and drink water from two types of glasses under three different reach conditions : streight forward, 45° toward the right side, and 45° across the body toward the left side. The subjects in the patient group reached out with the unaffected hand. The hand reach time was measured using a foot. Five channels of electromyographic (EMG) signals were recorded from the anterior fibres of the deltoid, and five muscles of the lower limbs. The signals from the hand and object switches were used to synchronise the EMG signals with the vertical ground reaction force data from force plates. The hand reach time, the vertical ground reaction force, and EMG activity were analyzed for each of the six conditions. A two-way analysis of variance was conducted. In both groups, the effects of the change of the object on postural adjustment was significant, and the effects of the change of the position of the object on postural adjustment was not significant. However, it is suggested that the change of the position and a change in the nature of the object strongly influence postural adjustment in hemiplegic patients. Therefore, frequent practice of a variety of tasks with a variety of different visual information may be required to improve the ability for postural adjustment in the hemiplegic patient.

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