Effect of Sensory Loss on Improvements of Upper-Limb Paralysis Through Robot-Assisted Training: A Preliminary Case Series Study

Sensory disorder is a factor preventing recovery from motor paralysis after stroke. Although several robot-assisted exercises for the hemiplegic upper limb of stroke patients have been proposed, few studies have examined improvement in function in stroke patients with sensory disorder using robot-assisted training. In this study, the efficacies of robot training for the hemiplegic upper limb of three stroke patients with complete sensory loss were compared with those of 19 patients without complete sensory loss. Robot training to assist reach motion was performed in 10 sessions over a 2-week period for 5 days per week at 1 h per day. Before and after the training, the total Fugl–Meyer Assessment score excluding coordination and tendon reflex (FMA-total) and the FMA shoulder and elbow score excluding tendon reflex (FMA-S/E) were evaluated. Reach and path errors (RE and PE) during the reach motion were also evaluated by the arm-training robot. In most cases, both the FMA-total and the FMA-S/E scores improved. Cases with complete sensory loss showed worse RE and PE scores. Our results suggest that motor paralysis is improved by robot training. However, improvement may be varied according to the presence or absence of somatic sensory feedback.