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Clinical trial Recruiting at 2 sites Interventional Ages 18 to 80

Low-oxygen sessions and noninvasive spinal stimulation to improve walking after spinal cord injury.

Official title: Breathing Low Oxygen to Enhance Spinal Stimulation Training and Functional Recovery for Aging Adults With Chronic SCI: The BO2ST-II Trial

Run by Spaulding Rehabilitation Hospital · NCT06521723 · Data updated 2026-11-12

This study tries short, repeated bouts of mild low oxygen together with noninvasive spinal cord stimulation and walking practice to help adults with chronic spinal cord injury walk better and build leg strength.

Quick facts

Study typeInterventional
Ages18 Years to 80 Years
SexAll
Enrollment60 (estimated)
SponsorSpaulding Rehabilitation Hospital
Academic / other
Locations2 sites (Jacksonville, Florida and 1 other locations)
StatusRecruiting
StartedJune 6, 2025
Main results expectedSeptember 30, 2027
Study endsSeptember 30, 2028
Registry record updatedMarch 20, 2026
Trial IDNCT06521723 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults 18–80 years old with chronic (>12 months), non‑progressive spinal cord injury between C1 and L2 who are ambulatory without another person's support, have some preserved motor or sensory function below the injury, and are medically cleared to participate.

Probably not a fit

People who are non‑ambulatory, have progressive neurological disease, severe medical comorbidities (e.g., uncontrolled cardiac or pulmonary disease), severe autonomic dysreflexia, significant cognitive impairment, or other exclusionary conditions are unlikely to benefit or be eligible.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

The trial combines acute intermittent hypoxia (brief, mild low-oxygen breathing), transcutaneous spinal cord stimulation (tSTIM), and supervised walking training to determine dosing that best enhances walking recovery. Participants receive AIH as a pretreatment to tSTIM during walking sessions, with outcomes such as walking speed (10-meter walk) and lower-limb strength measured over the course of the protocol. The design stratifies by age groups to identify whether older versus younger adults need different numbers of AIH sessions to maximize plasticity and functional gains. Safety screening excludes individuals with serious cardiovascular, pulmonary, or other medical issues that could increase risk during low-oxygen exposure or stimulation.

Why it matters

Potential benefit: If successful, the combined approach could improve walking speed, leg strength, and everyday mobility, increasing independence and quality of life for people with chronic SCI.

How similar studies have gone: Preliminary studies indicate that combining AIH and tSTIM with walking training yields greater walking improvements than either intervention alone, but age- and sex-specific dosing has not been established.

Who can join: the full rules

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* 18 to 80 years of age
* medically stable with medical clearance from study physician to participate
* SCI at or below C1 and at or above L2 with at least some sensory or motor function preserved below the neurologic level
* non-progressive etiology of spinal injury
* American Spinal Injury Association (ASIA) scores of C-D at initial screen
* ambulatory (able to complete the 10-meter walk test without support from another person)
* chronic injury (define as \> 12 months post-injury) to avoid potential for spontaneous neurological plasticity and recovery

Exclusion Criteria:

* severe concurrent illness or pain, including unhealed decubiti, severe neuropathic or chronic pain syndrome, severe infection (e.g., urinary tract), hypertension, cardiovascular disease, pulmonary disease, severe osteoporosis, active heterotopic ossification in the lower extremities, severe systemic inflammation
* \< 24 on Mini-Mental Exam
* severe recurrent autonomic dysreflexia
* history of severe cardiovascular/pulmonary complications including hypertension (systolic blood pressure \> 150 mmHg)
* pregnancy because of unknown effects of AIH or tSTIM on a fetus (individuals of childbearing potential will not otherwise be excluded)
* botulinum toxin injections in lower extremity muscles within the prior three months
* history of tendon or nerve transfer surgery in the lower extremity
* untreated severe sleep-disordered breathing characterized by uncontrolled hypoxia and sleep fractionation that may impact the outcome of this study.
* active implanted devices (e.g., intrathecal baclofen pump)
* receiving concurrent electrical stimulation
* motor threshold evoked by transcutaneous spinal stimulation \>200 mA

Where it's running

  • Brooks Rehabilitation Hospital
    Jacksonville, Florida, United States     Recruiting
  • Spaulding Rehabilitation Hospital
    Cambridge, Massachusetts, United States     Recruiting

Study contacts

  • Principal investigator: Randy Trumbower, PT, PhD — Harvard Medical School (HMS and HSDM)
  • Study coordinator: Noah Piazza
  • Email: npiazza2@mgb.org
  • Phone: (617) 952-6953

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
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Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.