円描画動作における速度—精度トレードオフ関係—若年者と高齢者の比較

The speed-accuracy trade-off for a circle drawing task

要旨：円描画動作における速度と精度のトレードオフ関係を明らかにすることを目的に，若年者と高齢者を対象として，所定の円を速くかつ正確になぞる動作(円描画)を行った．その際運動時間と絶対誤差を測定し，若年者では両者間に高い精度でトレードオフ曲線が得られた．この曲線に比べ，高齢者では運動時間が延長し誤差が増大する方向にシフトした．若年者のトレードオフ曲線からの運動時間と誤差の偏差を成績として定量化し，高齢者の成績低下の指標とした．偏差は高齢者で有意であり，非利き手では利き手に比べ偏差が大きかった．以上より，速度と精度を同時に測定することによって，加齢に伴う円描画動作の成績低下を定量化する可能性が示唆された．

　The purpose of this study is to quantitatively analyze the performance of a drawing task by considering both speed and accuracy. Healthy young and older adults traced a target circle as quickly and accurately as possible. Movement time (MT) and absolute error (E) in the circle drawing task showed a trade-off relationship for young subjects, and MT was well approximated by a power curve of E. The relationship between MT and E for the elderly shifted towards longer MT and larger E as compared to the young subjects. The deviation of MT and E from the trade-off curve of young subjects was calculated as a measure of performance deterioration in the elderly. The deviation was significantly different from zero for the elderly, and larger in the non-preferred than the preferred hand. The results suggest that the measurement of speed and accuracy at the same time is essential for coordinated manual tasks.