Acronym: STAND-ALONE
Functional recovery of paralyzed limbs has a high priority in the rehabilitation of spinal cord injuries (SCIs). In recent years, there has been an increased focus on robotic technologies for recovery and rehabilitative treating. Several complex lower limb exoskeletons (EXO) are commercially available, and others are in the prototype stage. The connection between the EXO and the body residual potential in SCI may play a substantial role in promoting human machine interactions and in potentiating plasticity mechanisms to sustain recovery. Walking with a powered EXO also requires specialist training and practice. These operations call for intensive sensorimotor learning in SCI patients, and STAND-ALONE provides an important scientific platform to study neural plasticity.
According to a growing evidence on the cortical (plastic) changes during sleep associated to sensorimotor learning, the project addresses some crucial aspects of the consolidation of learning and memory during sleep in shaping/reshaping new learning, contributing to basic research on sleep functions and potentially maximizing the success of neurorehabilitation via EXO prototypes.
Due to the expected cortical changes during sleep as a consequence of sensorimotor training, the projects crucially needs of an EEG with higher spatial resolution (SR). The acquisition of a 64 ch polygraph (by expanding a pre-existing 32ch polygraph) will guarantee higher SR.
Based on various approaches ranging from hd-EEG and multisensory methods, the project will be aimed to
Aims 1: Study topographical EEG changes during sleep that are strictly linked to modifications related to the use of EXO, and examine how these measures predict the extent of rehabilitation.
Aims 2: Develop new methods for enriching bodily perceptions in patients with an SCI, thus inducing strong senses of identification and agency that are crucial for making the inclusion of a robotic EXO much more flexible and effective.
The specific outcomes described in STAND-ALONE facilitate the remapping of sensory signals and the augmentation of experiences, enriching bodily perceptions and improving (neuro) rehabilitation where a lost function has to be re-learned in an altered or transformed sense of body. We hypothesize that intuitive, symbiotic and natural communication between users and an assistive EXO can be developed, integrating self-confidence (agency/embodiment) and social needs within specific medical constraints (pain/sensorimotor loss). On the other hand, these operations call for intensive sensorimotor learning in SCI patients, and STAND-ALONE provides an important scientific platform to study neural plasticity. The project addresses some crucial aspects of the consolidation of learning and memory during sleep in shaping/reshaping new learning, contributing to basic research on sleep functions and potentially maximizing the success of neuro-rehabilitation via EXO prototypes.
Expected outcomes
The objective of the ramp-up phase will be to (a) clarify if a specific prosthetic learning directly affect regional sleep EEG activity in humans ; (b) evaluate the predictive power of sleep changes in the range of slow-frequency activity on the magnitude of rehabilitation; (c) develop new methods for enriching bodily perceptions in patients with SCI, thus inducing a strong sense of identification and agency that are crucial to obtaining and optimizing the control over wearable exoskeletons; (d) identify the requirements for tool embodiment, including in situations of brain-body disconnections; (e) add an important evaluation, based on the analysis of pain-related signals, to the standard procedures, making the inclusion of new tools much more flexible and effective than before; (f) understand how body maps in the brains of people with disabilities change to include assistive tools, for example, by compensating for bodily changes, such as the loss of a limb, by adjusting the internal body map; (g) disseminate the key findings to relevant stakeholders, resulting in enhanced safety and functionality of wearable exoskeletons in neuro-rehabilitation centers.
Risk analysis
In general, the proposed research integrates several different, complementary approaches, which ensure achievement of scientific objectives (encompassing both theoretical as well as experimental research) in multiple ways with limited risk. This is because the project is based on solid theoretical and practical data from our previous investigations of the mechanisms of embodiment in patients with SCI (Lenggenhager et al., 2012; 2013; Fuentes et al., 2013) and on functionally relevant tools such as a wheelchair and exoskeletons that are used following SCI (Pazzaglia et al., 2013, Pazzaglia et al., 2014; Sylos-Labini et al., 2014). The dimension of pain is central in embodiment processes; therefore, we added an important evaluation, based on the analysis of pain-related signals, to the standard procedures to avoid the risk of adverse side effects in the SCI subjects. The work plan is broken down into a number of experimental designs, each of which consists of clearly described tasks, timing, participants, and deliverables. This division will allow for effective quality research control, timely assessment of results obtained, and frequent progress monitoring. Despite limitations in the use of exoskeletons (e.g., dependence on the severity of the lesion, exclusion of individuals with minimal forearm strength), the important collaboration with two SCI centers (including 500 patients with SCI) will allow us to include many cases of SCI in our study; thus, the risk of failure due to a limited number of patients is minimal. Regular meetings will permit the identification of relevant scientific and technological problems, and alternative solutions can be envisaged for solving any problems that may arise.
References
Fuentes CT, et al. Body image distortions following spinal cord injury. J Neurol Neurosurg Psychiatry. 2013;84:201-7. doi: 10.1136/jnnp-2012-304001.
Lenggenhager B, et al. The sense of the body in individuals with spinal cord injury. PLoS One. 2012;7:e50757. doi: 10.1371/journal.pone.0050757.
Lenggenhager B, et al. Restoring tactile awareness through the rubber hand illusion in cervical spinal cord injury. Neurorehabil Neural Repair. 2013;27:704-8. doi: 10.1177/1545968313491009.
Pazzaglia M, et al. A functionally relevant tool for the body following spinal cord injury. PLoS One. 2013;8:e58312. doi: 10.1371/journal.pone.0058312.
Pazzaglia M, Molinari M. The embodiment of assistive devices-from wheelchair to exoskeleton. Phys Life Rev. 2016;16:163-75. doi: 10.1016/j.plrev.2015.11.006.
Sylos-Labini, et al. EMG patterns during assisted walking in the exoskeleton. Front Hum Neurosci 2014; 8, 423.Gancet, J., Hauffe, R., Zanov, F., Lacquaniti, F., and Ivanenko, Y.P. EMG patterns during assisted walking in the exoskeleton. Front Hum Neurosci 2014; 8, 423.