Differential Effects Of Explicit Verbal And Visual Feedback On Proprioceptive Learning: Examining Position Sense Acuity Of The Forearm During Active And Passive Displacement

Abstract

Both intrinsic feedback derived from proprioceptive and tactile mechanoreceptors, and extrinsic visual or auditory feedback play an important role in sensorimotor learning. However, the interaction between intrinsic and extrinsic forms of feedback and the effect of extrinsic feedback on proprioceptive function during sensorimotor learning are only incompletely understood. The purpose of this study was to compare the differential effects of intrinsic and extrinsic verbal and visual feedback on proprioceptive learning. Specifically, this study investigated how the acuity of the forearm position sense changes during sensorimotor learning under different conditions of feedback. Methods: Thirty healthy young adult participants underwent a sensorimotor training program delivered in two training sessions in a single day. Using a forearm manipulandum, participants performed forearm flexion movements and learnt to actively match a previously experienced forearm position. After the matching movement, participants received either proprioceptive only or a combination of intrinsic and extrinsic feedback (proprioceptive + visual or proprioceptive + verbal feedback) about the final forearm position error. Vision was blocked for the proprioceptive only and proprioceptive + verbal feedback conditions. All participants received 150 training trials. Retention was tested 24 hours after training. Proprioceptive acuity was evaluated: Just-noticeable difference (JND) position sense thresholds served as a measure of passive elbow proprioceptive acuity. Absolute joint position matching error (JPME) represented a measure of active proprioceptive acuity. Results: First, none of feedback conditions led to a significant decrease in JND after training (p > 0.05). Second, all three feedback conditions induced a statistically significant reduction in JPME after training (p < 0.05) with both the proprioceptive only (Cohen’s d = 1.62) and proprioceptive + verbal (Cohen’s d = 1.57) feedback conditions showing the very large effect sizes. However, change in JPME with training was not significantly different between the three feedback conditions (p > 0.05). Third, the observed reduction in JPME at post-test had vanished 24 hours after training. Discussion: I found no evidence that providing additional extrinsic feedback in a proprioceptive learning task can boost joint position sense accuracy. Proprioceptive training relying solely on proprioceptive signals is sufficient to induce measurable improvements of active position sense. However, such learning was not retained after 24 hours.