Purpose, Subjects and Methods] Prediction distances, as subjective estimates of upper limb reach without trunk movement, were measured for 21 spatial directions in 9 hemiplegic patients, 10 healthy elderly person and 9 healthy adults, in order to investigate motor image disorder in hemiplegic patients with cerebrovascular accident. Error rates (ERs) were then calculated for 21 directions for each subject using the formula, ER (%) = 100 × |X-Y |/ X, where X represents the actual length of the

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... er limb (from the acromial process to the middle fingertip) and Y the prediction distance. [Results and Conclusion] The results clearly demonstrated 1) that ERs with the paralyzed limb were not different from ERs with the healthy limb in hemiplegic patients, and 2) that ERs in hemiplegic patients were reliably higher than those of healthy elderly persons and healthy adults, suggesting that hemiplegic patients hold motor image disorders not only in the paralytic but also healthy limb sides. These findings are discussed in relation to some supposed neural mechanisms of the motor image.