WOW! Using healthy volunteers to test recovery possibilities for stroke survivors. Whose heads are going to roll for this crapola?
Distinct and additive effects of visual and vibratory feedback for motor rehabilitation: an EEG study in healthy subjects
Journal of NeuroEngineering and Rehabilitation volume 21, Article number: 158 (2024)
Abstract
Introduction
The use of visual and proprioceptive feedback is a key property of motor rehabilitation techniques. This feedback can be used alone, for example, for vision in mirror or video therapy, for proprioception in focal tendon vibration therapy, or in combination, for example, in robot-assisted training. This Electroencephalographic (EEG) study in healthy subjects explored the distinct neurophysiological impact of adding visual (video therapy), proprioceptive (focal tendinous vibration), or combined feedback (video therapy and focal tendinous vibration) to a motor imagery task.
Methods
Sixteen healthy volunteers performed 20 mental imagery (MI) tasks involving right wrist extension and flexion under four conditions: MI alone (IA), MI + video feedback observation (IO), MI + vibratory feedback (IV), and MI + observation + vibratory feedback (IOV). Brain activity was monitored with EEG, and time-frequency neurophysiological markers of movement were computed. The emotions of the patients were also measured during the task.
Results
In the alpha band, we observed bilateral ERD in the visual feedback conditions (IO, IOV). In the beta band, the ERD was bilateral in the IA, IV and IOV but more lateralized in the IV and IOV. After movement, we observed strong ERS in the IO and IOV but not in the IA or IV. Embodiment was stronger in conditions with vibratory feedback (IOV > IV > IA and IO)
Conclusion
Conditions with visual feedback (IO, IOV) recruit the mirror neurons system (alpha ERD) and provide more accurate feedback of the task than IA and IV, which triggers motor validation pathways (beta rebound analysis). Vibratory feedback enhances the recruitment of the left sensorimotor areas, with a synergistic effect in the IOV (beta ERD analysis), thus maximizing embodiment. Visual and vibratory feedback recruits the sensorimotor cortex during motor imagery in different ways and can be combined to maximize the benefits of both techniques
Trial registration
Introduction
Mental imagery (MI) is defined as the voluntary activation of a mental representation of a movement without the movement actually being performed [1]. It can be kinesthetic (the subject feels that he or she is performing a movement) or visual (the subject visualizes himself/herself in the first or third person performing a movement) [2]. For healthy subjects, MI allows the subjects to stimulate and maintain the cortical networks involved in motor function, particularly the motor, premotor, prefrontal and parietal regions [3]. MI has also been shown effective in addition to conventional rehabilitation in poststroke rehabilitation, with improvements in motor function of the upper limb, walking speed and functional independence [4, 5]. From a neurophysiological perspective, MI increases functional connectivity between motor and premotor regions [6], corticospinal excitability [7] and induces structural connectivity reorganization [8].
Current rehabilitation techniques propose enriching MI with various feedback, notably visual (visual feedback therapies: mirror therapy, virtual reality therapy) and kinesthetic feedback (i.e., tendinous vibration therapies), to facilitate motor imagery and to provide proprioceptive and/or visual feedback on a correctly performed action.
Visual feedback therapies (VfT) are diverse. Historically, mirror therapy (MT) was the first rehabilitation technique to offer patients subjective visual feedback of correct movement performed by a paretic limb [9, 10]. However, during the last decade, video observational therapy (VOT) has emerged as an alternative to mirror therapy. In this therapy, the subject observes on a screen a projection of the paretic limb performing the action. This projection is made using a prerecorded video of the healthy limb performing the action flipped on the horizontal axis (mirror image) and displayed on a screen (Fig. 1). The VOT provides the subject with the subjective visual illusion of a correctly performed movement without requiring the use of a healthy limb. The benefits of VfT have been widely demonstrated not only in motor rehabilitation for central nervous system impairments, such as stroke [11, 12], but also in peripheral nervous system rehabilitation, such as brachial plexus palsy [13].
Video observational feedback therapy (IVS-3TM - Dessintey)
Vibratory feedback therapy consists of exciting muscle spindles by means of vibratory stimulation. These vibrations can be applied to the whole body or in a focal manner (focal vibration, FV). Vibratory stimulation devices are generally applied to tendons or related muscles (e.g., biceps brachialis and extensor radialis longus carpi). In stroke rehabilitation but also in other neurological disease rehabilitation (i.e., multiple sclerosis, cerebral palsy), FV has shown benefits for balance, motor function and spasticity [14, 15].
Visual and proprioceptive feedback, whether provided by video therapy devices, focal vibration, or other devices, is at the heart of modern rehabilitation techniques (i.e., robotic therapy seeks to provide somato-sensori feedback to the subject, along with a visual feedback of the moving arm). We know that visual feedback induces a rebalance of interhemispheric inhibition in healthy subjects [16] and stroke patients [17]. Similarly, we know that FV facilitates the recruitment of the sensory-motor regions of the subject [18, 19], with an improvement in the efficiency of the sensorimotor network [20]. However, the way each of these feedbacks might act precisely on the sensorimotor cortex remains imperfectly understood. Additionally, the synergy between visual and proprioceptive feedback remains to be explored. The addition of a vibration device to mirror therapy or virtual reality promotes the illusion of subjectivity of movements [21] as well as the perceived motor illusion of the subjects [22]. In electroencephalography (EEG), Le Franc et al. reported increased recruitment in sensory-motor regions under combined FV and VOT conditions compared to imaging conditions alone [23]. Interestingly, proprioceptive afferences alone [24] but also coupled to visual feedback [25] also enhance classification performances in motor imagery tasks in Brain Computer Interfaces training.
However, despite those results, a major challenge remains in to create a standardized and easily reproducible neurophysiological experiment in healthy subjects, that can be later extended to stroke patients, to specifically explore the integration of each type of feedback with the aim to personalize the rehabilitation therapy [26]. The aim of the study is to get a better understanding of the integration of visual, somato-sensory, and coupled feedback, along with a point of comparison for subsequent data for stroke patients.
To build this model, we recorded the EEG activity of healthy subjects performing motor imagery tasks of the right wrist under experimental conditions with visual, proprioceptive, or double feedback. For visual feedback, we chose the VOT since it enabled us to study the specific effect of visual feedback without being disturbed by the cortical activities inherent to the production of the movement of the other limb in the MT. For proprioceptive feedback, the FV allowed us to study the specific effects of proprioceptive feedback. Four experimental conditions were tested: [1] imagery alone—IA; [2] imagery with visual feedback observation—IO; [3] imagery with vibratory feedback—IV; and [4] imagery with visual and vibratory feedback—IOV; with the study of EEG alpha and beta desynchronization during the task and beta rebound after the task.
More at link.
No comments:
Post a Comment