Limits...
Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke.

Secoli R, Milot MH, Rosati G, Reinkensmeyer DJ - J Neuroeng Rehabil (2011)

Bottom Line: With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully.These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke.This effect was greater for the hemiparetic arm, suggesting that the increased demands associated with controlling an affected arm make the motor system more prone to slack when distracted.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biomechatronic Lab,, Department of Mechanical Engineering, University of California, 4200 Engineering Gateway, Irvine, CA 92697-3875, USA. rsecoli@uci.edu

ABSTRACT

Background: Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task.

Methods: Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error.

Results: Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke.

Conclusions: Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm, suggesting that the increased demands associated with controlling an affected arm make the motor system more prone to slack when distracted. Providing an alternate sensory channel for feedback, i.e., auditory feedback of tracking error, enabled the participants to simultaneously perform the tracking task and distracter task effectively. Thus, incorporating real-time auditory feedback of performance errors might improve clinical outcomes of robotic therapy systems.

Show MeSH

Related in: MedlinePlus

Robot force in Z dimension between the experimental group and the control group (non-impaired arm of stroke and healthy participants). Change of robotic assistance force in the z (vertical) direction for stroke participants using their paretic arm ("Stroke-P"), stroke participants using their non-paretic arm ("Stroke-N"), and control participants without stroke ("Control"). Task A: Baseline tracking without distractor or sound feedback. Task B: with visual distractor. Task C: with visual distractor and sound feedback. Task D: with sound feedback and no distractor. (* = significant difference in the change of robotic assistance compare to zero assistance: in particular Task B -Task A has p = 0.0004, the Task C -Task B has p = 0.0085 and the Task A - Task D has p = 0.0023).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3104373&req=5

Figure 6: Robot force in Z dimension between the experimental group and the control group (non-impaired arm of stroke and healthy participants). Change of robotic assistance force in the z (vertical) direction for stroke participants using their paretic arm ("Stroke-P"), stroke participants using their non-paretic arm ("Stroke-N"), and control participants without stroke ("Control"). Task A: Baseline tracking without distractor or sound feedback. Task B: with visual distractor. Task C: with visual distractor and sound feedback. Task D: with sound feedback and no distractor. (* = significant difference in the change of robotic assistance compare to zero assistance: in particular Task B -Task A has p = 0.0004, the Task C -Task B has p = 0.0085 and the Task A - Task D has p = 0.0023).

Mentions: We analyzed whether the decrease in effort caused by the distracter task was related to the use of the hemiparetic arm for tracking, or whether a similar decrease was seen when a control group of 13 young, non-impaired participants and 5 participants with stroke, using their non-paretic arm, performed the tracking task. The robot adapted to provide near zero assistance when these participants used their non-paretic/non-impaired arms for the default tracking task (Figure 5). Figure 6 shows that introduction of the visual distracter caused a significant increase (*p = 0.004) in robot assistance force for hemiparetic arm, but not for the non-paretic/non-impaired arms. The size of this increase was larger for the hemiparetic arm as compared to the non-impaired arm of the young participants (p = 0.004), but not as compared to the non-paretic arm of the stroke participants (p = 0.11). The introduction of sound feedback had a greater differential impact on the force produced by the hemiparetic arm compared to the non-paretic/non-impaired arm, with or without the visual distracter (respectively: *p = 0.0085 and *p = 0.0023).


Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke.

Secoli R, Milot MH, Rosati G, Reinkensmeyer DJ - J Neuroeng Rehabil (2011)

Robot force in Z dimension between the experimental group and the control group (non-impaired arm of stroke and healthy participants). Change of robotic assistance force in the z (vertical) direction for stroke participants using their paretic arm ("Stroke-P"), stroke participants using their non-paretic arm ("Stroke-N"), and control participants without stroke ("Control"). Task A: Baseline tracking without distractor or sound feedback. Task B: with visual distractor. Task C: with visual distractor and sound feedback. Task D: with sound feedback and no distractor. (* = significant difference in the change of robotic assistance compare to zero assistance: in particular Task B -Task A has p = 0.0004, the Task C -Task B has p = 0.0085 and the Task A - Task D has p = 0.0023).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104373&req=5

Figure 6: Robot force in Z dimension between the experimental group and the control group (non-impaired arm of stroke and healthy participants). Change of robotic assistance force in the z (vertical) direction for stroke participants using their paretic arm ("Stroke-P"), stroke participants using their non-paretic arm ("Stroke-N"), and control participants without stroke ("Control"). Task A: Baseline tracking without distractor or sound feedback. Task B: with visual distractor. Task C: with visual distractor and sound feedback. Task D: with sound feedback and no distractor. (* = significant difference in the change of robotic assistance compare to zero assistance: in particular Task B -Task A has p = 0.0004, the Task C -Task B has p = 0.0085 and the Task A - Task D has p = 0.0023).
Mentions: We analyzed whether the decrease in effort caused by the distracter task was related to the use of the hemiparetic arm for tracking, or whether a similar decrease was seen when a control group of 13 young, non-impaired participants and 5 participants with stroke, using their non-paretic arm, performed the tracking task. The robot adapted to provide near zero assistance when these participants used their non-paretic/non-impaired arms for the default tracking task (Figure 5). Figure 6 shows that introduction of the visual distracter caused a significant increase (*p = 0.004) in robot assistance force for hemiparetic arm, but not for the non-paretic/non-impaired arms. The size of this increase was larger for the hemiparetic arm as compared to the non-impaired arm of the young participants (p = 0.004), but not as compared to the non-paretic arm of the stroke participants (p = 0.11). The introduction of sound feedback had a greater differential impact on the force produced by the hemiparetic arm compared to the non-paretic/non-impaired arm, with or without the visual distracter (respectively: *p = 0.0085 and *p = 0.0023).

Bottom Line: With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully.These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke.This effect was greater for the hemiparetic arm, suggesting that the increased demands associated with controlling an affected arm make the motor system more prone to slack when distracted.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biomechatronic Lab,, Department of Mechanical Engineering, University of California, 4200 Engineering Gateway, Irvine, CA 92697-3875, USA. rsecoli@uci.edu

ABSTRACT

Background: Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task.

Methods: Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error.

Results: Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke.

Conclusions: Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm, suggesting that the increased demands associated with controlling an affected arm make the motor system more prone to slack when distracted. Providing an alternate sensory channel for feedback, i.e., auditory feedback of tracking error, enabled the participants to simultaneously perform the tracking task and distracter task effectively. Thus, incorporating real-time auditory feedback of performance errors might improve clinical outcomes of robotic therapy systems.

Show MeSH
Related in: MedlinePlus