A preliminary study for quantitative assessment of upper limb proprioception.

Proprioception, or sense of position and movement of the body, strongly correlates with motor recovery of the hemiplegic arm. The evaluation of the awareness of the location of joints in space involves measuring the accuracy of joint-angle replication. Robotic devices allow an accurate manipulation of joint movements necessary to assess proprioceptive status. This study evaluated the proprioceptive performance of healthy subjects by mean of the H-Man, a planar robot designed for upper-limb rehabilitation to gather preliminary normative data for neurorehabilitation applications. Twelve participants were equally divided into Aged and Young groups and were asked to indicate when their dominant hand position matched a predefined target in the contralateral, sagittal and ipsilateral direction. Results indicated a better performance for movements towards the contralateral target in terms of both absolute and signed error while there was not a significant effect of age group. Error variability was not affected by the target location and participants' age. The present study established preliminary proprioceptive metrics that could assist in providing information about the normal range of proprioceptive acuity of healthy subjects of different age.