Immersive augmented reality system for the training of pattern classification control with a myoelectric prosthesis.

BACKGROUND: Hand amputation can have a truly debilitating impact on the life of the affected person. A multifunctional myoelectric prosthesis controlled using pattern classification can be used to restore some of the lost motor abilities. However, learning to control an advanced prosthesis can be a challenging task, but virtual and augmented reality (AR) provide means to create an engaging and motivating training. METHODS: In this study, we present a novel training framework that integrates virtual elements within a real scene (AR) while allowing the view from the first-person perspective. The framework was evaluated in 13 able-bodied subjects and a limb-deficient person divided into intervention (IG) and control (CG) groups. The IG received training by performing simulated clothespin task and both groups conducted a pre- and posttest with a real prosthesis. When training with the AR, the subjects received visual feedback on the generated grasping force. The main outcome measure was the number of pins that were successfully transferred within 20 min (task duration), while the number of dropped and broken pins were also registered. The participants were asked to score the difficulty of the real task (posttest), fun-factor and motivation, as well as the utility of the feedback. RESULTS: The performance (median/interquartile range) consistently increased during the training sessions (4/3 to 22/4). While the results were similar for the two groups in the pretest, the performance improved in the posttest only in IG. In addition, the subjects in IG transferred significantly more pins (28/10.5 versus 14.5/11), and dropped (1/2.5 versus 3.5/2) and broke (5/3.8 versus 14.5/9) significantly fewer pins in the posttest compared to CG. The participants in IG assigned (mean ± std) significantly lower scores to the difficulty compared to CG (5.2 ± 1.9 versus 7.1 ± 0.9), and they highly rated the fun factor (8.7 ± 1.3) and usefulness of feedback (8.5 ± 1.7). CONCLUSION: The results demonstrated that the proposed AR system allows for the transfer of skills from the simulated to the real task while providing a positive user experience. The present study demonstrates the effectiveness and flexibility of the proposed AR framework. Importantly, the developed system is open source and available for download and further development.

Virtual reality interventions for balance prevention and rehabilitation after musculoskeletal lower limb impairments in young up to middle-aged adults: A comprehensive review on used technology, balance outcome measures and observed effects.

BACKGROUND: Balance training is an important aspect in prevention and rehabilitation of musculoskeletal lower limb injuries. Virtual reality (VR) is a promising addition or alternative to traditional training. This review aims to provide a comprehensive overview of VR technology and games employed for balance prevention and rehabilitation, balance outcome measures, and effects for both balance prevention and balance rehabilitation following musculoskeletal lower limb impairments. METHODS: A systematic literature search was conducted in electronic databases to identify all related articles with a longitudinal study design on VR, balance, and prevention or musculoskeletal rehabilitation of the lower limbs in adult subjects between 19 and 65 years. RESULTS: Eleven articles concerning balance prevention and five articles regarding balance rehabilitation were included. All studies used screen-based VR and off-the-shelf gaming consoles with accompanying games. The Star Excursion Balance Test (SEBT) was the most frequently used outcome measure. Two studies found positive effects of VR balance training in healthy adults, while none reported negative effects. None of the included studies showed a significant difference in balance performance after a VR balance rehabilitation intervention compared to traditional balance training. CONCLUSION: Few studies have been published concerning musculoskeletal balance rehabilitation and balance prevention in healthy adult subjects. However, the studies published have shown that VR exercises are equally effective compared to traditional balance training for both domains of application. As there is large variability between studies, recommendations for future research are given to prospectively investigate the use of VR technology for balance training.

Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury.

Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or reduced risk of subsequent injuries. In fact, recent evidence has shown that only around half of post-ACLR patients can expect to return to competitive level of sports. A rising concern is the high rate of second ACL injuries, particularly in young athletes, with up to 20% of those returning to sport in the first year from surgery experiencing a second ACL rupture. Aside from the increased risk of second injury, patients after ACLR have an increased risk of developing early onset of osteoarthritis. Given the recent findings, it is imperative that rehabilitation after ACLR is scrutinized so the second injury preventative strategies can be optimized. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re-)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high re-injury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of second ACL injury. The following key concepts to enhance rehabilitation and prepare the patient for re-integration to sports after an ACL injury that is as safe as possible are presented: (1) external focus of attention, (2) implicit learning, (3) differential learning, (4) self-controlled learning and contextual interference. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce second ACL injury risk and early development of osteoarthritis by targeting changes in neural networks.

Correction to: Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury.

"As ACL injury may alter intracortical facilitation [34] and depressed intracortical inhibition is correlated with decreased quadriceps voluntary activation capability [35], external focus training may provide a means to restore quadriceps muscle activity via increasing intracortical inhibition.