Error augmentation as a possible technique for improving upper extremity motor performance after a stroke - A systematic review

Background: Improvement of motor performance is crucial in rehabilitation after a stroke. A new concept in motor learning and rehabilitation is error augmentation (EA): using erroneous sensory feedback to enhance adaptation to a new environment. However, the clinical efficacy of this method to enhance motor learning after a stroke needs to be evaluated. Objectives: To determine whether there is enough evidence-based knowledge to justify using the EA concept for upper extremity rehabilitation after a stroke over traditional rehabilitation methods. Methods: Two reviewers systematically searched the English-language literature in six databases: PubMed, Web of science, PEDro, CINAHL, Cochrane, and Scopus, using the key words: "error augmentation" or "error enhancement" or "negative viscosity" and "stroke" and "upper extremity." The studies were evaluated based on their main characteristics and methodology. Results:There is limited evidence about the effectiveness of this new method, as only eight studies, with limited methodological quality were found. The participants were usually in the chronic stage after the stroke. Two studies were randomized controlled trials, four used a crossover design, and two were pilot studies. Fugl-Meyer was the most common clinical outcome measure used to assess the effect of treatment. Three studies reported a significant improvement in the effects of EA training compared to control training, and two studies reported a significant treatment effect over time. Conclusions: Most of the studies reviewed have significant methodological drawbacks that resulted in equivocal results. Therefore, we recommend that additional randomized controlled trials, with larger sample sizes and acceptable protocols be conducted to determine the long-term efficacy of EA training.