Long-Term Training with a Brain-Machine Interface-Based Gait Protocol Induces Partial Neurological Recovery in Paraplegic Patients

Abstract

Brain-machine interfaces (BMIs) provide a new assistive strategy aimed at restoring mobility in severely paralyzed patients. Yet, no study in animals or in human subjects has indicated that long-term BMI training could induce any type of clinical recovery. Eight chronic (3–13 years) spinal cord injury (SCI) paraplegics were subjected to long-term training (12 months) with a multi-stage BMI-based gait neurorehabilitation paradigm aimed at restoring locomotion. This paradigm combined intense immersive virtual reality training, enriched visual-tactile feedback, and walking with two EEG-controlled robotic actuators, including a custom-designed lower limb exoskeleton capable of delivering tactile feedback to subjects. Following 12 months of training with this paradigm, all eight patients experienced neurological improvements in somatic sensation (pain localization, fine/crude touch, and proprioceptive sensing) in multiple dermatomes. Patients also regained voluntary motor control in key muscles below the SCI level, as measured by EMGs, resulting in marked improvement in their walking index. As a result, 50% of these patients were upgraded to an incomplete paraplegia classification. Neurological recovery was paralleled by the reemergence of lower limb motor imagery at cortical level. We hypothesize that this unprecedented neurological recovery results from both cortical and spinal cord plasticity triggered by long-term BMI usage.

Augmenting intracortical brain-machine interface with neurally driven error detectors

“…Chronic intracortical electrode signals degrade with time, which decreases BMI performance and success rates [92–95]. To date, efforts to rescue performance have focused on designing new kinematic decoders [56–59,63,65,96,97].…”

Enhancing Nervous System Recovery through Neurobiologics, Neural Interface Training, and Neurorehabilitation

“…Researchers have been dedicated to improving the quality of life for these patients in several ways, e.g., (1) biological manipulation of the cellular milieu to encourage neuronal repair and regeneration (Magavi et al, 2000; Chen et al, 2002; Lee et al, 2004; Freund et al, 2006; Benowitz and Yin, 2007; Park et al, 2008; Maier et al, 2009; de Lima et al, 2012b; Dachir et al, 2014; Li et al, 2015; Omura et al, 2015), (2) creation of neural- or brain-machine interfaces designed to circumvent lesions and restore functionality (Wolpaw and McFarland, 1994; Kennedy and Bakay, 1998; Leuthardt et al, 2004; Monfils et al, 2004; Hochberg et al, 2006, 2012; Moritz et al, 2008; O'Doherty et al, 2009; Ethier et al, 2012; Collinger et al, 2013; Guggenmos et al, 2013; Ifft et al, 2013; Memberg et al, 2014; Zimmermann and Jackson, 2014; Grahn et al, 2015; Jarosiewicz et al, 2015; Soekadar et al, 2015; Bouton et al, 2016; Capogrosso et al, 2016; Donati et al, 2016; Hotson et al, 2016; Rajangam et al, 2016; Vansteensel et al, 2016), and (3) new rehabilitation techniques that include electrical stimulation and pharmacological enhancement of spinal circuitry to stimulate recovery (Carhart et al, 2004; Levy et al, 2008, 2016; Dy et al, 2010; Harkema et al, 2011, 2012; Dominici et al, 2012; van den Brand et al, 2012; Gad et al, 2013b, 2015; Angeli et al, 2014; Gharabaghi et al, 2014a,c; Wahl et al, 2014; Gerasimenko et al, 2015b). Unfortunately, the path to clinical relevance for these individual approaches remains long, and each field tends to operate largely in its own sphere of influence.…”

An EEG-based brain-computer interface for gait training

“…In these paradigms, either healthy subjects or patients were required to imagine movement of the arms to modulate EEG activity to generate motor commands to control the lower-limb movement. For instance, MI of hand movement was used to control the Lokomat (Hocoma AG, Volketswil, Switzerland), a commercially available robotic walker [9]. Another work by Lee et al used MI of both hands to build a cascaded ERD classifier, to control the Rex (Rex Bionics LTD, Auckland, New Zealand), a hand-free, self-supporting robotic mobility device [10].…”