Effects of the Alternate Combination of “Error-Enhancing” and “Active Assistive” Robot-Mediated Treatments on Stroke Patients

Abstract

This paper aimed at investigating the effects of a novel robotic-aided rehabilitation treatment for the recovery of the upper limb related capabilities in chronic post stroke patients. Eighteen post-stroke patients were enrolled in a six-week therapy program and divided into two groups. They were all required to perform horizontal pointing movements both in the presence of a robot-generated divergent force field (DF) that pushed their hands proportional to the trajectory error and perpendicular to the direction of motion, and according to the typical active assistive (AA) approach used in robotic therapy. We used a crossover experimental paradigm where the two groups switched from one therapy treatment to the other. The hypothesis underlying this paper was that the use of the destabilizing scenario forced the patient to keep the end-point position as close as possible to the ideal path, hence requiring a more active control of the arm with respect to the AA approach. Our findings confirmed this hypothesis. In addition, when the DF treatment was provided in the first therapy cycle, patients also showed straighter and smoother paths during the subsequent AA therapy cycle, while this was not true in the opposite case. In conclusion, the results herein reported provide evidence that the use of an unstable DF field can lead to better recovery outcomes, and therefore it potentially more effective than solely active assistance therapy alone.

Optimizing learning of a locomotor task: Amplifying errors as needed

“…Research on motor learning has emphasized that errors are fundamental signals that drive motor adaptation [6], [7], [8], [9]. Thereby, there has been a progression in the development of training strategies that amplify movement errors rather than decrease them [1].…”

“…Thereby, there has been a progression in the development of training strategies that amplify movement errors rather than decrease them [1]. In patients with chronic stroke, amplifying errors with a robotic force field during reaching resulted in straighter movements when the force field was removed [7], [9]. Increasing limb phasing error in post-stroke participants' gait through a split-belt treadmill induced a long term increase in walking symmetry [8].…”

The effects of error-augmentation versus error-reduction paradigms in robotic therapy to enhance upper extremity performance and recovery post-stroke: a systematic review

“…Table 1 (EA only), Table 2 (ER only) and Table 3 (EA and ER) described all 13 studies as well as their results. Among the 13 selected studies, there are six randomized controlled trials (RCT) [ 52 – 57 ], five crossover studies [ 52 , 54 , 58 – 60 ], one quasi-experimental study [ 24 ], two randomized comparative study [ 61 , 62 ] and one pilot study [ 63 ]. Among all thirteen studies, only four could be found in clinical trials registry [ 52 , 56 , 57 , 63 ].…”

“…The different between EA and ER groups was significant [F(1,13) = 4.29, p < 0.001]. Stroke subjects showed less adaptation capacity than healthy subjects (26% less) Initial direction error: 1.53 (very large effect) 1/10, poor quality Tropea et al [ 54 ] Crossover randomized controlled trial. Trial not registered 18 in total EA = 9 ER = 9 (before cross-over) Ages: 21–71 (EA: mean = 49.7± 18.7; ER: mean = 44.9 ± 15.9), 9 males and 9 females, all participants suffered from a chronic stroke (mean/SD unknown), CM: First EA group: mean = 4.9 ± 0.9 First ER group: mean = 4.2 ± 1.0 InMotion2 robotic system Experimental tasks: reaching targets in a plane.…”

“…The mean age of all 13 studies is 55.04 ± 11.3 years. In terms of baseline clinical assessments, nine studies used Fugl-Meyer (FM) assessment scores [ 24 , 52 , 53 , 56 , 57 , 60 – 63 ], three studies used Chedoke-McMaster Stroke Assessment (CM) scores [ 54 , 55 , 58 ], and one did not include any baseline clinical information [ 59 ]. Among the studies that used FM scores, five studies included stroke survivors with the average FM scores ranging between 30 and 40 (the lowest being 15 and the highest being 50) [ 24 , 52 , 53 , 60 ].…”