DOI: https://doi.org/10.21203/rs.3.rs-26382/v1
Background Moving the Goal Posts (MGP) typically refers to a progressive change of goal or objective - a classic mechanism to promote motor function improvement in neuro-rehabilitative therapy. However, this MGP idea is still missing in the literature of robotic-assisted strategies to improve quality of movement, which is of high-importance in motor neuro-rehabilitation. This study aims to investigate if an MGP approach in a robotic-assisted upper limb movement pattern modification leads to a larger swivel angle change on healthy subjects during a reaching task training.
Methodology Randomised control single blind study. Healthy naive subjects were allocated into two groups: Control (N=10) and MGP (N=10) and performed the same reaching tasks under different interventions provided by a manipulandum robotic device. During the intervention, the robotic device applied an Indirect Shaping Control (ISC): a resistive viscous force applied at the subject's hand as a function of the subject's swivel angle to encourage a modification of the later towards a 10° increase. In the MGP group, the goal was altered progressively towards the overall 10° increase in swivel angle, while in the Control group, the goal was set constant to the 10° from the beginning.
Results A significant increase of the swivel angle, of 4.0° and 6.2° respectively, was observed in both groups (p<0.05). A significantly larger change was observed in the MGP group (p<0.001). All but one subject adapted into a new movement pattern, but no significant retention was observed in any of the two groups after intervention.
Conclusion The superior effect of the intervention with the MGP approach compared to the constant goal demonstrates that the progressivity of learning plays an important role in this context and can ultimately lead to larger changes. Nevertheless, in both cases the effect of the intervention was small and longer interventions and/or steeper progressivity should be investigated to obtain larger changes. Retention was not observed in any group, but this may be different in a motor neuro-rehabilitation context where the newly taught movement pattern may result in additional movement capabilities or other benefits for neurologically impaired individuals.
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