Williams, Camille K., and Heather Carnahan. "Motor learning perspectives on haptic training for the upper extremities." IEEE Transactions on Haptics 7.2 (2014): 240-250.

May 27, 2023

• A review on motor learning with haptic training for the UE.
• Motor skill is understood as the degree of effectiveness with which a movement is carried out, i.e. one’s ability to plan and execute movements.
• Motor skill acquisition is an important aspect of neurorehab. In conditions like stroke, control and execution of motor skills are impaired, but the ability to learn is assumed to be spared.
• Learning vs Performance.
  • Learning is a set of processes associated with practice or experience that lead to relatively permanent changes in the ability to perform a skill.
  • Most studies only look at short-term retention or learning with a delay on 24 hours. There are few studies that go beyond 24 hours!
• Feedback
  • Feedback or movement-induced feedback is sensory information received as a result of performing an action.
  • Can be inherent or augmented; the paper only deals with augmented feedback.
  • In the context of this paper, feedback refers to haptic feedback which includes both tactile and proprioceptive sensor information.
  • Augmented feedback can be a good or a bad thing. There is evidence to show that learning without augmented feedback leads to better retention.
  • Can we relate KR to reinforcement learning and KP to error-based learning?
• Haptic guidance improves performance
  • Guidance will reduce errors and improve performance. But retention might not always improve with guidance.
  • Guidance might be suitable for some tasks, but it is not clear which types of tasks.
  • The largest learning effects are observed when feedback is less frequent and/or delayed.
  • Frequent feedback might inhibit information processing of inherent proprioceptive feedback, which limits the error detection capabilities required for retention and transfer of performance.
  • It's not clear what the authors mean by a complex task
  • How much role does proprioception play in motor learning?
  • There are examples of studies where retention is not that bad even when fixed guidance is used (study by Laura and David on steering tasks). So, how valid is the guidance hypothesis?
• Haptic feedback that degrades the performance
  • Talks about literature on error amplification studies.
• Observation learning
  • This section was quite interesting. It talks about subjects learning from observing the demonstration of a task.
  • Learning different types of tasks has been shown to benefit from observational learning.
  • Most common form is visual demonstration.
  • Providing a model of the task might allow subjects to learn complex tasks by facilitating action planning.
  • Observing an expert helps to learn.
  • Observing an expert and a novice is better for retention than just observing two experts or two novices.
  • Observing followed by or interspersed by physical practice is better than observation alone.
  • There might be differences between demonstration through vision or haptics: vision promotes external focus of attention, while haptics promotes internal focus. External might be better for experts, internal for novices. Could this be consistent with the observation from previous studies that say haptic guidance benefits novices?
  • But in the next section the authors say that observation learning that does not involve physical practice might not challenge subjects and thus not allow them to learn! But this contradicts what they have reported in this section.