A robot-aided visuomotor wrist training induces gains in proprioceptive and movement accuracy in the contralateral wrist

Abstract

Proprioceptive training is a neurorehabilitation approach known to improve proprioceptive acuity and motor performance of a joint/limb system. Here, we examined if such learning transfers to the contralateral joints. Using a robotic exoskeleton, 15 healthy, right-handed adults (18–35 years) trained a visuomotor task that required making increasingly small wrist movements challenging proprioceptive function. Wrist position sense just-noticeable-difference thresholds (JND) and spatial movement accuracy error (MAE) in a wrist-pointing task that was not trained were assessed before and immediately as well as 24 h after training. The main results are: first, training reduced JND thresholds (− 27%) and MAE (− 33%) in the trained right wrist. Sensory and motor gains were observable 24 h after training. Second, in the untrained left wrist, mean JND significantly decreased (− 32%) at posttest. However, at retention the effect was no longer significant. Third, motor error at the untrained wrist declined slowly. Gains were not significant at posttest, but MAE was significantly reduced (− 27%) at retention. This study provides first evidence that proprioceptive-focused visuomotor training can induce proprioceptive and motor gains not only in the trained joint but also in the contralateral, homologous joint. We discuss the possible neurophysiological mechanism behind such sensorimotor transfer and its implications for neurorehabilitation.

Robot-Aided Assessment of Human Ankle Joint Position Sense and Motion Sense

“…This shows the importance of measuring both position and motion sense for complete insight into ankle proprioception and its de cits in clinical populations. While we lack comparable data on ankle motion sense acuity, our JND position sense threshold results at the ankle are in a reasonable and comparable range of proprioceptive acuity reported in other joints [23,47,49].…”

“…In healthy adults, Elangovan et al (2014) reported elbow joint position sense thresholds of 1.05° for a 10° reference position (relative bias ~10.5%) [23]. The same psychophysical approach applied to measure wrist joint position sense thresholds using a wrist robotic device yielded a mean wrist exion threshold of 1.37° in healthy adults, which was about 9% relative to the reference displacement of 15° [49]. The data of the current study document that the position sense acuity of the ankle joint is in the approximate range of the wrist and elbow joints (i.e., 0.80° for a reference position of 15°).…”

Three-Dimensional Assessment of Upper Limb Proprioception via a Wearable Exoskeleton

“…The implementation of further MJ movements would help understand the proprioceptive mechanisms involved in a 3D-workspace to be included in a proprioceptive assessment protocol. Our findings provide the first proof of concept that can be considered to develop "evaluation protocols" and "ad-hoc rehabilitative interventions" for somatosensory retraining as published in recent works [52,53], also providing real-time feedback of the proprioceptive errors.…”

Tactile Sensation Improves Following Motor Rehabilitation for Chronic Stroke: The VIGoROUS Randomized Controlled Trial

“…12 The feedback loop present under typical conditions between somatosensation and movement supports the bidirectional process of sensorimotor learning 13 that is associated with motor and somatosensory system network changes. 14…”

“…12 The feedback loop present under typical conditions between somatosensation and movement supports the bidirectional process of sensorimotor learning 13 that is associated with motor and somatosensory system network changes. 14 Despite physiological evidence in support of bidirectional sensory and motor learning and their documented cooccurrence under typical conditions, 10,15,16 stroke rehabilitation research has largely siloed the two. Post-stroke motor recovery has been studied following motor rehabilitation paradigms, [17][18][19] while somatosensory recovery has been examined following somatosensory training paradigms, such as somatosensory discrimination training.…”