Comprehensive reviewUsing EEG-based brain computer interface and neurofeedback targeting sensorimotor rhythms to improve motor skills: Theoretical background, applications and prospects
Introduction
Neurofeedback is a neurophysiological technique that aims to teach users/patients to self-regulate targeted brain activity patterns in order to specifically enhance cognitive abilities or reduce clinical symptoms. The choice of target brain activity patterns is thus a key issue, in order for neurofeedback procedures to be efficient. From the multitude of EEG targets [61], sensorimotor rhythms (SMR) appear to be a very promising and interesting neurophysiological target to try to enhance motor skills. Many Brain Computer Interface (BCI) and neurofeedback studies have investigated the impact of SMR self-regulation training procedures on motor skills enhancement in healthy subjects and patients with motor disabilities. This critical review aims first to introduce the neurophysiological framework, in line with the motor imagery literature, which led to SMR being considered as a reliable and valid EEG target to improve motor skills through BCI/neurofeedback procedures. The different definitions of SMR target in BCI/neurofeedback studies will be introduced and the relationship between neuroplasticity, motor skills and SMR BCI/neurofeedback training discussed. The second objective of this review is to introduce the main findings regarding SMR BCI/neurofeedback in healthy subjects. The impact of such procedures on sport, acting and surgical skills will be analyzed. Third, the main findings regarding SMR BCI/neurofeedback efficiency in patients with hypokinetic activities (in particular motor deficit following stroke) as well as in patients with hyperkinetic activities (in particular Attention Deficit Hyperactivity Disorder, ADHD) will be introduced. This review is not meant to be a systematic, exhaustive review. Rather, it aims to propose a critical synthesis of the existing literature from a clinical neurophysiological point of view. Indeed, the opinions within the scientific and medical community are divided regarding the efficacy of BCI/neurofeedback. Most of the randomized clinical trials show significant weaknesses and do not enable us to clearly conclude on the efficacy of BCI/neurofeedback procedures, since the level of evidence remains too low. However, when compared to other potential EEG targets, SMR present the advantage of having a relatively well-identified neurophysiological relationship with motor imagery and motor skills. On the one hand, this characteristic results in the fact that SMR are considered as very interesting targets to better understand motor skills acquisition in various contexts. On the other hand, SMR also represent promising targets for the future development of innovative neurophysiological treatments.
Section snippets
Neuroplasticity and the acquisition of motor skills
Neuroplasticity is a normal ongoing state of the human brain. It refers to the ability of the latter to evolve its structure and function. This reorganization is observed from the molecular level to the behavioral level [41], [45], [46], [75]. One impressive example of neuroplasticity is the possibility of acquiring motor skills. This learning process involves and modifies the activity of specific brain areas such as the dorsolateral prefrontal cortex (DLPFC), the primary motor cortex (M1), the
Neurofeedback targeting sensorimotor rhythms for enhancing motor skills in healthy subjects
The efficacy of neurofeedback to improve healthy subjects’ performances has mainly been studied in three domains [104]: cognitive, sports and artistic activities. In this section, we focus on neurofeedback procedures dedicated to the improvement of motor performance, for which most of the studies have been carried out in the field of sport science. For more information regarding neurofeedback procedures dedicated to the improvement of cognitive and affective aspects of performance, please refer
BCI/Neurofeedback targeting sensorimotor rhythms for enhancing motor skills in patients with brain and mental disorders
Motor abilities can be affected in case of brain or mental disorders. In this section, we focus on SMR BCI/neurofeedback procedures dedicated to the improvement of motor skills in brain and mental disorders for which most of the studies have been conducted. Concerning brain disorders, we focus on stroke. In this disorder, SMR BCI/neurofeedback training procedures aim to reduce hypokinetic activity by training to down-regulate mu rhythm or low beta SMR activity (enhance SMR event-related
Conclusion
In this critical review, we first described and discussed the relationship between neuroplasticity, motor skills and SMR BCI/neurofeedback training in line with the MI literature. More precisely, we argued that BCI/neurofeedback could be used to train healthy subjects and patients to voluntarily self-regulate their SMR in order to trigger neuroplasticity phenomena and enable the acquisition of motor skills. Based on this theoretical background, we introduce the literature in which such
Disclosure of interest
The authors declare that they have no competing interest.
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