Active versus passive training of a complex bimanual task: is prescriptive proprioceptive information sufficient for inducing motor learning?

Abstract

Perceptual processes play an important role in motor learning. While it is evident that visual information greatly contributes to learning new movements, much less is known about provision of prescriptive proprioceptive information. Here, we investigated whether passive (proprioceptively-based) movement training was comparable to active training for learning a new bimanual task. Three groups practiced a bimanual coordination pattern with a 1:2 frequency ratio and a 90° phase offset between both wrists with Lissajous feedback over the course of four days: 1) passive training; 2) active training; 3) no training (control). Retention findings revealed that passive as compared to active training resulted in equally successful acquisition of the frequency ratio but active training was more effective for acquisition of the new relative phasing between the limbs in the presence of augmented visual feedback. However, when this feedback was removed, performance of the new relative phase deteriorated in both groups whereas the frequency ratio was better preserved. The superiority of active over passive training in the presence of augmented feedback is hypothesized to result from active involvement in processes of error detection/correction and planning.

Figure 1. Experimental setup.

A. Apparatus consisting of torque motors, forearm rests, moving hand pieces, and a pc providing feedback. B. Positioning of participants during task execution. C. Lissajous plot of the goal (1∶2 frequency ratio with a 90° phase offset between limbs) produced by both limb displacements.

Figure 2. Movement goal and reproduction.

A. Visual representation of the target coordination pattern according to the required 1∶2 frequency ratio with a 90° phase offset. The relative phase was calculated at the turning points, where the goal was 90°. B. Lissajous plots of active movement production in test trials where feedback was present for a representative subject in the active (top) and the passive (bottom) training groups during pretest and across training days.

Figure 3. Performance of absolute error of relative phase across days.

Absolute error (AE) of the required relative phase (90) in degrees (°) across practice for each group in the absence (left) and presence of augmented feedback in the form of a Lissajous plot (right). Error bars represent SE of mean.

Figure 4. Performance of standard deviation of relative phase across days.

Standard deviation (SD) of relative phase in degrees (°) across practice for each group in the absence (left) and presence of augmented feedback in the form of a Lissajous plot (right). Error bars represent SE of mean.

Figure 5. Performance of frequency ratio across days.

Frequency ratio error changes across practice for each group in the absence (left) and presence of augmented feedback in the form of a Lissajous plot (right). Error bars represent SE of mean.

Figure 6. Improvement from Pre-test to Retention.

Improvement (in percentage), i.e., inverse of error decrease, of Retention compared to Pre-test under feedback per group for AE (left) and SD (right). Filled dots & striped lines: improvements on relative phase (RPH); Open dots & solid lines: improvements on relative cycling frequency ratio (CFR).