ABLE Exoskeleton with integrated electrical stimulation for gait assistance

Clinical Investigation to Validate the Safety and Performance of Integrating Functional Electrical Stimulation Into the ABLE Exoskeleton

This project will try the ABLE Exoskeleton with added electrical stimulation to help people with spinal cord injury, acquired brain injury, or multiple sclerosis improve walking.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 15 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: ABLE Human Motion S.L. (industry)
• Locations: 1 site (Vienna, State of Vienna)
• Trial ID: NCT07550699 on ClinicalTrials.gov

What this trial studies

This single-centre, pre-post quasi-experimental project in Vienna will enroll at least 15 adults across spinal cord injury, acquired brain injury, and multiple sclerosis groups to complete baseline testing and eight supervised gait-training sessions over 4–5 weeks. Each approximately 60-minute session uses the ABLE Exoskeleton combined with tailored functional electrical stimulation (FES), with electrode placement and stimulation parameters adapted per participant. Primary outcomes focus on device safety (adverse events, withdrawals) and clinical performance measures such as donning/doffing time, walking distance, steps, standing time, therapist assistance, and gait parameters. Secondary measures include spasticity, pain, perceived exertion, user satisfaction, and tolerance to FES.

Who should consider this trial

Good fit: Adults 18–80 with spinal cord injury (neurological level C5–L2, AIS B–D), acquired brain injury, or multiple sclerosis who are already receiving physiotherapy at the investigating centre and can give informed consent are the intended candidates.

Not a fit: People with significant osteoporosis, unresolved lower‑limb or pelvic fractures, spinal instability, very severe spasticity (Modified Ashworth Scale 4), uncontrolled orthostatic hypotension, or recent rapid neurological deterioration are unlikely to benefit or may be excluded for safety reasons.

Why it matters

Potential benefit: If successful, the integrated exoskeleton+FES approach could make walking training safer and more effective, improving walking distance, independence, and comfort for some people with neurological gait impairments.

How similar studies have performed: Smaller trials combining wearable exoskeletons and FES have reported promising improvements in gait metrics and user tolerance, but evidence is still preliminary and limited in scale.

Eligibility criteria

Inclusion Criteria:

* 18 to 80 years old
* Diagnosis of acquired brain injury, spinal cord injury (neurological level between C5 and L2, AIS B to AIS D), or multiple sclerosis
* Currently undergoing physiotherapy treatment, either as an inpatient or outpatient at the investigating center
* Ability to provide informed consent

Exclusion Criteria:

* Significant osteoporosis that may increase the risk of fracture
* Unresolved fractures in the pelvis or limbs, or a history of fragility fractures in the lower limbs within the past 2 years
* Spinal instability (or use of spinal orthoses, unless medically approved)
* Deterioration \>3 points of the total in the motor score of the International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI) in the last 4 weeks. Loss of sensation and/or motor activity above the level of injury detected that has not been evaluated by a doctor.
* Severe spasticity: Level 4 on the Modified Ashworth Scale
* Orthostatic hypotension: Inability to tolerate at least 10 minutes in an upright position
* Uncontrolled autonomic dysreflexia
* Medical instability
* Unstable cardiovascular condition, hemodynamic instability, untreated hypertension (SBP \> 140 mmHg, DBP \> 90 mmHg), deep vein thrombosis (DVT), or uncontrolled autonomic dysreflexia
* Severe comorbidities, including any condition deemed inappropriate by the investigator for using the ABLE Exoskeleton or for completing the study
* Pressure ulcers Grade I or higher (as defined by the European Pressure Ulcer Advisory Panel - EPUAP) in areas that will be in contact with the device
* Anthropometric measurements incompatible with the ABLE Exoskeleton, specifically height outside the 1.5-1.9 m range or weight exceeding 100 kg
* Anatomical constraints (such as leg length differences, users unable to position themselves inside the device) that are incompatible with the device
* Range of motion restrictions preventing normal gait or sit-to-stand transitions, including: Ankle: ability to achieve at least neutral (0°) position; Knee: ability to extend to at least -10°; Hip: bilateral hip flexion of at least 100° and extension of at least 0°
* Heterotopic ossification
* Pregnant or breastfeeding women
* Cognitive impairment that results in the inability to follow simple instructions, particularly psychological or cognitive problems that do not allow a participant to follow study procedures
* Requires assisted ventilation.
* Scoliosis \>40-50º Cobb angle.
* Presence of pacemakers, defibrillators, or other non-compatible electronic implants.
* Open wounds, infections, or active irritation at the electrode placement sites.
* Severe dermatological conditions in the stimulation area.
* Uncontrolled active epilepsy.
* Malignant tumors in the area of application.
* Severe loss of sensation in the areas where electrodes are to be placed.
* Medical conditions where electrical stimulation is contraindicated by physician recommendation.
* Inability to communicate pain, discomfort, or adverse reactions during stimulation.
* Venous thrombosis, thrombophlebitis, or severe arterial obstruction.
* Chronic venous insufficiency with significant varicosities.
* Hemophilia.
* Ongoing infectious process or fever.
* Presence of metallic implants in the flow area between the electrodes

Where this trial is running

Vienna, State of Vienna

• therapy2people GmbH — Vienna, State of Vienna, Austria (RECRUITING)

Study contacts

• Study coordinator: Peter Lackner, Dr.

Conditions: Acquired Brain Injury, Spinal Cord Injury, Multiple Sclerosis, Gait training, Wearable exoskeleton, Lower-limb exoskeleton, Functional Electrical Stimulation, Robotic exoskeleton