Toward an Adapted Neurofeedback for Post-stroke Motor Rehabilitation: State of the Art and Perspectives

Abstract

Stroke is a severe health issue, and motor recovery after stroke remains an important challenge in the rehabilitation field. Neurofeedback (NFB), as part of a brain-computer interface, is a technique for modulating brain activity using on-line feedback that has proved to be useful in motor rehabilitation for the chronic stroke population in addition to traditional therapies. Nevertheless, its use and applications in the field still leave unresolved questions. The brain pathophysiological mechanisms after stroke remain partly unknown, and the possibilities for intervention on these mechanisms to promote cerebral plasticity are limited in clinical practice. In NFB motor rehabilitation, the aim is to adapt the therapy to the patient's clinical context using brain imaging, considering the time after stroke, the localization of brain lesions, and their clinical impact, while taking into account currently used biomarkers and technical limitations. These modern techniques also allow a better understanding of the physiopathology and neuroplasticity of the brain after stroke. We conducted a narrative literature review of studies using NFB for post-stroke motor rehabilitation. The main goal was to decompose all the elements that can be modified in NFB therapies, which can lead to their adaptation according to the patient's context and according to the current technological limits. Adaptation and individualization of care could derive from this analysis to better meet the patients' needs. We focused on and highlighted the various clinical and technological components considering the most recent experiments. The second goal was to propose general recommendations and enhance the limits and perspectives to improve our general knowledge in the field and allow clinical applications. We highlighted the multidisciplinary approach of this work by combining engineering abilities and medical experience. Engineering development is essential for the available technological tools and aims to increase neuroscience knowledge in the NFB topic. This technological development was born out of the real clinical need to provide complementary therapeutic solutions to a public health problem, considering the actual clinical context of the post-stroke patient and the practical limits resulting from it.

Keywords: brain plasticity; brain–computer interface; motor rehabilitation; neurofeedback; stroke.

FIGURE 1

Description of the Neurofeedback loop. NFB, neurofeedback; EEG, electroencephalography; fMRI, functional magnetic resonance imaging; NIRS, near infrared spectroscopy; MEG, magnetoencephalography.

FIGURE 2

Physiological recovery mechanism in brain motor areas after stroke. Increasing activity of the non-affected side motor-related areas at the acute recovery phase (A). Non-affected side brain motor area activity decreased in the first months after stroke onset (B). Brain motor area activity in the affected side increases after 6 months (C). SMA, supplementary motor area; PM, premotor area; M1, primary motor area.

FIGURE 3

Evolution of NFB studies in the literature. Number of NFB studies in stroke population according to the time since the stroke. The studies included in the graph are those cited in the main meta-analyses since 2018 (Carvalho et al., 2019; Bai et al., 2020; Kruse et al., 2020; Baniqued et al., 2021). (A) Acute phase. (B) Subacute phase. (C) Chronic phase.

FIGURE 4

Clinical, electrophysiological, pathophysiological, and material parameters to be taken into account in an NFB study.