HEROES: Human Extremity Robotic Rehabilitation and Outcome Enhancement for Stroke

HEROES project's full title is <Human Extremity Robotic Rehabilitation and Outcome Enhancement for Stroke>. It is a multidisciplinary neurophysiological \& neural rehabilitation engineering project, developed by the Lab of Medical Physics \& Digital Innovation, School of Medicine, Faculty of Health Science Aristotle University of Thessaloniki and supported by a Neurosurgical Department. The website for the project can be accessed at https://heroes.med.auth.gr .

The HEROES project involves:

• A clinical study for rehabilitation of patients with Chronic Stroke (CS), using multiple immersive man-machine interfaces (Brain-Computer Interface (BCI) controlled robotic arms device, Wearable Robotics Jacket \& Gloves, Serious Gaming Application, Augmented Reality presentation)
• A secondary off-line neurophysiological analysis of brain activation, connectivity and plasticity as well as muscle electrophysiology in patients with CS undergoing motor imagery (MI) and BCI training and assistance through electrical muscle stimulation

Milestones of the study:

• The investigators aim to develop, test and optimize an intervention based on multiple immersive man-machine interfaces
• The investigators aim to develop and validate self-paced neuro-rehabilitation protocols for patients with CS.
• The investigators aim to identify and study the neurophysiological functionality and alteration of brain activity in chronic CS.

The brain neuron networks of Chronic Stroke (CS) patients and healthy individuals share similar connectivity patterns of, but new functional interactions have been identified as unique to CS patient networks and can be attributed to both adaptive and maladaptive organization effects after the stroke. The importance of such phenomena both as possible prognostic factors and as contributors to patient rehabilitation remains unspecified yet. The exact underlying neurophysiological process and the extent that this is modulated by higher-order interactions is also not fully understood. The investigators used rich visual and tactile feedback, virtual reality environments (VRE), BCI controlled exoskeleton and robotic actuators and furthermore documented plasticity effects at the brain networks.

Retraining brain circuits and promoting plasticity to restore body functions have been recognized among key principles of spinal cord repair by the US National Institute of Neurological Disorders and Stroke (US NIH/NINDS). Nonetheless, existing literature does not yet portray with precision the pathophysiological process and effect of CS on Central Nervous System (CNS) and the sensorimotor networks. Studies needed to address this issue (such as our study) should be considered, identifying specific questions to be answered through further investigation: a) how and why reorganization of CNS networks is established, b) how this reorganization evolves in time with respect to the severity and chronicity of the stroke, c) when can it be considered an adaptive or maladaptive evolution, and d) how can it be promoted or prevented respectively. The gained insight is expected to hold clinical relevance in preventing maladaptive plasticity after CS through individualized neuro-rehabilitation, as well as in the design of assistive technologies for CS patients.

This HEROES study is a both a pre-clinical neurophysiological investigation on human CS patients that aims to advance basic knowledge on CS sequelae to CNS and also a translational implementation in clinical (rehabilitation) practice. Our analysis aims to eventually help produce a model of CNS function along different stages of stroke (Acute, Sub-acute, Chronic), during different activity (resting state, simple motor tasks, complex sensorimotor activity), and ideally being able to predict negative outcome versus possible Recovery. The HEROES project aims to investigate and promote dormant neuroplasticity after chronic stroke, a type of injury that causes hemiparesis, hemiplegia, tetraparesis or tetraplegia. Our protocol will deploy training in brain computer interfaces and robotic arms, virtual environments (brain-controlled virtual arms, avatars and augmented reality wearable robotics with sensors and actuators (gloves \& jacket) and rich audio/visual/tactile stimuli along with serious gaming applications to enhance motivation. Visual and kinesthetic sensorimotor brain networks will also be studied using high density electroencephalography in order to demonstrate and monitor CNS plasticity.

This research project was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) https://www.elidek.gr under the "2nd Call for H.F.R.I. Research Projects to support Faculty Members \& Researchers" (Project number: 4391).