Clinical Investigation on the Impact on Safety, Feasibility and Usability of the Design Changes Performed on ABLE Exoskeleton Device With Spinal Cord Injured Patients in a Hospital Setting

Investigación Clínica Sobre el Impacto en la Seguridad, Viabilidad y Usabilidad de Los Cambios de diseño Realizados en el Dispositivo ABLE Exoskeleton en Pacientes Con lesión Medular en un Entorno Hospitalario

The loss of the ability to walk and the associated restriction of mobility presents a major challenge to people with spinal cord injury in an everyday environment designed for pedestrians. Exoskeletal technology has the potential to help people with impaired leg function to regain ambulation and thus improve their independence. This technology is not completely new, but due to their high access price (~120k€/unit), high size and weight (~25 kg), and need for trained physiotherapist supervision, commercially available exoskeletons are only found in large hospitals and only in very few cases get into patients' homes.

The company ABLE Human Motion S.L. (Barcelona, Spain) has developed a novel exoskeleton to overcome these disadvantages, which is more compact, lighter and easier to use.

The primary objective of the study is to investigate the impact of recent design changes performed on the device on the safety, feasibility and usability of the ABLE exoskeleton device in people with spinal cord injury during a five to six weeks gait training programme in a clinical setting. Furthermore, potential effects of the training on walking, general health status, user satisfaction, and quality of life will be assessed.

The primary objective of this study is to determine the impact of the performed design changes on safety, feasibility, and usability of the ABLE Exoskeleton for patients with SCI in a hospital setting during a 5-6 week training programme.

The secondary objectives are as follows:

• Assess the impact of ABLE Exoskeleton training on gait and function.
• Assess the effect on the perceived rate of exertion for patients using the ABLE Exoskeleton.
• Assess the level of user satisfaction from participants and therapists of the ABLE Exoskeleton.

Patients who match inclusion and exclusion criteria and pass pre-study screening will be enrolled in the study. Following the screening, baseline assessments will be conducted without the device. Participants will undergo a training programme with the ABLE Exoskeleton two times a week for five weeks for a total of 10 sessions. Standardized clinical assessments with the device will be performed during the last training sessions. During the training period, several safety and usability measurements will be taken. Two weeks after the final training session a follow-up assessment will be conducted with participants. At the end of the study, the participating therapists will be asked to fill out a satisfaction questionnaire.

The primary hypothesis of this study is that the ABLE Exoskeleton remains safe, feasible, and usable for the intended patient population with SCI in a hospital setting after the implementation of the design changes improving its performance. The secondary hypothesis is that the device will have a positive impact on the perceived rate of exertion, mobility, and level of satisfaction of the study participants with SCI.

Inclusion Criteria:

• 18 to 70 years of age.
• Traumatic and non-traumatic SCI.
• SCI with Neurological Level of Injury (NLI) C5-L5 (from AIS A to AIS D).
• Currently treated as inpatient or outpatient in the investigation center.
• Ability to give informed consent.

Exclusion Criteria:

• WISCI II without exoskeleton of >13
• 5 or more risk factors for fragility as stated by Craven et al (Craven et al., 2009).
• History of lower limb fragility fractures in the last 2 years.
• Deterioration > 3 points of the total International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor score within the last 4 weeks.
• Spinal instability.
• Modified Ashworth scale (MAS) of 4 in lower limbs.
• Unable to tolerate 30 min standing without clinical symptoms of orthostatic hypotension
• Psychological or cognitive issues that do not allow a participant to follow the study procedures.
• Known pregnancy or breastfeeding.
• Any neurological condition other than SCI.
• Medically unstable: Unstable CVS, hemodynamic instability, untreated hypertension (SBP>140, DBP>90 mmHg), unresolved DVT, uncontrolled AD.
• Severe comorbidities: any condition that a physician considers to not be appropriate to complete participation in the study.
• Ongoing skin issues: Grade I or higher on EPUAP on areas that will be in contact with exoskeleton (European Pressure Ulcer Advisory Panel, 2019).
• Range of motion (ROM) restrictions in lower extremities, that are incompatible with the device.
• Height, width, weight or other anatomical constraints (such as leg length differences) incompatible with the device.