VALSE: Integration of Neuromodulation and Exoskeleton Systems for Mobility in Individuals With Chronic Spinal Cord Injury

Overview

The purpose of this clinical study is to evaluate the preliminary safety and feasibility of using the VALSE system, which combines spinal cord stimulation with the TWIICE robotic exoskeleton, to support motor recovery and reduce reliance on laboratory-based equipment during rehabilitation in participants with traumatic spinal cord injury. The TWIICE exoskeleton is integrated through the NR system, a platform developed by EPFL. The goal is to assess the clinical safety and practical application of this combined neuroprosthetic approach in a small number of participants, in order to guide future refinements of the device and protocol, support the development of scalable interventions integrating spinal stimulation with robotic assistance, and inform strategies for delivering rehabilitation in more accessible, real-world environments.

Detailed description

Spinal cord injury (SCI) disrupts communication between the brain and spinal cord below the lesion, often resulting in severe and permanent motor impairments. Despite advances in rehabilitation, recovery of walking remains limited and restoring mobility is consistently identified as a top priority by individuals living with SCI.

Epidural electrical stimulation (EES) of the spinal cord has emerged as a promising approach to restore movement after paralysis. By activating spinal motor circuits below the lesion, EES can enable standing, stepping, and walking in individuals with chronic SCI. ONWARD Medical has developed the ARC-IM spinal stimulation platform, which is currently being evaluated in several clinical studies, including BoxSwitch (NCT05942339), Think2Go (NCT06243952), and STIMO-BSI (NCT04632290).

In the BoxSwitch trial, optimized spatiotemporal EES protocols enabled participants with chronic SCI to perform standing, stepping, and walking movements. Building on these findings, the Think2Go and STIMO-BSI studies integrated the WIMAGINE implantable electrocorticography (ECoG) system developed by Clinatec (CEA, Grenoble, France) with spinal stimulation, creating a brain-spine interface capable of decoding motor intentions and translating them into spinal stimulation. These studies demonstrated that implantable brain-spine interfaces can restore voluntary control of lower-limb movements and support functional walking after severe paralysis.

Although these technologies have shown encouraging results, their use remains largely restricted to specialized rehabilitation settings. In parallel, robotic exoskeletons have been developed to support overground walking in individuals with SCI. The TWIICE exoskeleton is a lightweight and modular system specifically designed for use beyond rehabilitation centers and may complement spinal stimulation by providing functional support during walking.

In this study, the investigators will evaluate the preliminary safety and feasibility of the VALSE system, which combines the ARC-IM spinal cord stimulation platform with the TWIICE robotic exoskeleton in individuals with chronic traumatic SCI. Participants will be recruited from ongoing clinical studies at Lausanne University Hospital (CHUV), including BoxSwitch (NCT05942339), Think2Go (NCT06243952), and STIMO-BSI (NCT04632290), after completion of the relevant study phases.

As an early feasibility investigation, the study aims to generate preliminary safety and usability data on the combined use of spinal neuromodulation and robotic assistance during mobility tasks. The results will support the development of future neuroprosthetic solutions designed to improve walking ability, independence, and quality of life for people living with SCI.

Interventions

• Combination product TWIICE Rise 1.0 robotic exoskeleton combined with epidural electrical stimulation (EES)
  Participants will use the VALSE system, which combines the TWIICE Rise 1.0 robotic exoskeleton with epidural electrical stimulation (EES) delivered through previously implanted neuromodulation systems. The system is intended to support upright mobility and overground walking in individuals with chronic spinal cord injury (SCI) who are currently enrolled in, or have completed key phases of, neuromodulation clinical trials at CHUV, including Think2Go (NCT06243952), STIMO-BSI (NCT04632290), and Box

Primary outcome measures

• Preliminary safety [Time frame: From enrollment until the end of study timepoint, up to 1 year after enrollment.]

Secondary outcome measures (12)

• Assessment of the experimental session conditions [Time frame: At each in-clinic training session during the three study periods, up to 1 year after enrollment.]
• Number of steps [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Step frequency [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Mid-stride pauses [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Distance walked [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Walking time [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Standing time [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Kinematic gait parameters [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Electromyographic (EMG) activity [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Brain-computer interface (BCI) performance [Time frame: At each experimental (EX) session during the three study periods, up to 1 year after enrollment.]
• Donning and Doffing Time [Time frame: At the last experimental (EX) session of each of the three study periods, up to 1 year after enrollment.]
• Level of Assistance (LOA) [Time frame: At the last experimental (EX) session of each of the three study periods, up to 1 year after enrollment.]

Eligibility criteria

Inclusion criteria

• Currently enrolled participants who have completed the relevant phase of their parent study at CHUV: BoxSwitch (NCT05942339, after the optimisation phase), Think2Go (NCT06243952, after the rehabilitation phase, or STIMO-BSI (NCT04632290, after the calibration and training phase of the optional extension with system upgrade),
• Must have a functional neuromodulation system,
• Must be at least 18 years old,
• Must be suffering from non-progressive traumatic spinal cord injury, sustained at least 12 months before signing the consent form,
• Must weigh less than 100 kg,
• Must have a standing height between 160 and 190 cm,
• Must be able to grasp and lift bilateral crutches in a seated position,
• Must have stable medical, physical and psychological condition as considered by the investigator,
• Must be able to understand and interact with the study team in French or English,
• Must agree to comply in good faith with all conditions of the study and to attend all scheduled appointments,
• Must provide Informed Consent as documented by signature prior to any study-related procedures.

Exclusion criteria

• Must not be diagnosed with severe osteoporosis/penia:

Dual Energy X-ray Absorptiometry (DEXA) results indicating a t-score below -3.5 at either the femoral neck or the total proximal femur.

Dual Energy X-ray Absorptiometry (DEXA) results indicating a bone mineral density (BMD) < 0.60 gm/cm2 at any knee region (distal femur, proximal tibia)

• Must not have deep vein thrombosis in lower extremities within the past 6 months.
• Must not have experienced lower extremity fractures within the last two years.
• Must not have current pressure ulcer of the arms, trunk, pelvic area, or lower extremities
• Must not present with a flexion contracture >15° at the hip or knee
• Must not have severe concurrent medical conditions that contraindicate moderate to intense exercise (e.g., uncontrolled hypertension, coronary artery disease, congestive heart failure).
• Must not have heterotopic ossification that impairs joint mobility
• Must not be implanted with a life-supporting medical device (devices implanted in the parent study are not considered life-supporting),
• Must not be pregnant,
• Must not be the investigator himself, his/her family members, employees, or other dependent persons.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Treatment

Study locations

Switzerland · 1 center

• Centre Hospitalier Universitaire Vaudois (CHUV) — Lausanne

Publications

• Gorgey AS, Gill S, Holman ME, Davis JC, Atri R, Bai O, Goetz L, Lester DL, Trainer R, Lavis TD. The feasibility of using exoskeletal-assisted walking with epidural stimulation: a case report study. Ann Clin Transl Neurol. 2020 Feb;7(2):259-265. doi: 10.1002/acn3.50983. Epub 2020 Feb 5. PMID 32023011
• Hong E, Gorman PH, Forrest GF, Asselin PK, Knezevic S, Scott W, Wojciehowski SB, Kornfeld S, Spungen AM. Mobility Skills With Exoskeletal-Assisted Walking in Persons With SCI: Results From a Three Center Randomized Clinical Trial. Front Robot AI. 2020 Aug 4;7:93. doi: 10.3389/frobt.2020.00093. eCollection 2020. PMID 33501260
• Vouga T, Fasola J, Baud R, Manzoori AR, Pache J, Bouri M. TWIICE One powered exoskeleton: effect of design improvements on usability in daily life as measured by the performance in the CYBATHLON race. J Neuroeng Rehabil. 2022 Jun 27;19(1):63. doi: 10.1186/s12984-022-01028-0. PMID 35761399
• Zhang T, Jia Y, Wang N, Chai X, He Q, Cao T, Mu Q, Lan Q, Zhao J, Yang Y. Recent advances in potential mechanisms of epidural spinal cord stimulation for movement disorders. Exp Neurol. 2025 Oct;392:115330. doi: 10.1016/j.expneurol.2025.115330. Epub 2025 Jun 4. PMID 40480308
• Rowald A, Komi S, Demesmaeker R, Baaklini E, Hernandez-Charpak SD, Paoles E, Montanaro H, Cassara A, Becce F, Lloyd B, Newton T, Ravier J, Kinany N, D'Ercole M, Paley A, Hankov N, Varescon C, McCracken L, Vat M, Caban M, Watrin A, Jacquet C, Bole-Feysot L, Harte C, Lorach H, Galvez A, Tschopp M, Herrmann N, Wacker M, Geernaert L, Fodor I, Radevich V, Van Den Keybus K, Eberle G, Pralong E, Roulet M PMID 35132264

Identifiers

NCT: NCT07745686 · VALSE

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗