Combination Therapy to Improve SCI Recovery. (BO2ST)

March 18, 2026 updated by: Randy Trumbower, PT, PhD, Spaulding Rehabilitation Hospital

Breathing Low Oxygen to Enhance Spinal Stimulation Training and Functional Recovery in Persons With Chronic SCI: The BO2ST Trial

The purpose of this study is to determine how combining bouts of low oxygen, transcutaneous spinal cord stimulation, and walking training may improve walking function for people with chronic spinal cord injury.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The goal of the study is to determine whether repeatedly breathing mild bouts of low oxygen for brief periods (termed acute intermittent hypoxia (AIH)) combined with transcutaneous spinal cord stimulation (tSTIM) improves recovery of walking and strength after spinal cord injury. This idea stems from animal studies on respiration, in which investigators showed that mild AIH improves breathing in rats with spinal injuries as well as studies involving spinal cord stimulation. These studies showed that AIH induces plasticity, strengthening neural connections by increasing the production of key proteins and improving the sensitivity of spinal cord circuitry. Additional studies have shown that tSTIM may enhance function and strength for people with spinal cord injuries. The ultimate goal of this research is to assess if combining AIH and tSTIM with walking training can enhance individuals walking training greater than just AIH or tSTIM. By using low oxygen as a pre-treatment to tSTIM during walking training, functional independence and quality of life for servicemen and civilians may improve.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Shirley Ryan AbilityLab
        • Contact:
        • Contact:
        • Principal Investigator:
          • Arun Jayaraman, PT, PhD
    • Massachusetts
      • Cambridge, Massachusetts, United States, 02138
        • Recruiting
        • Spaulding Rehabilitation Hospital
        • Principal Investigator:
          • Randy Trumbower, PT, PhD
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 18 to 70 years of age
  • medically stable with medical clearance from study physician to participate
  • SCI at or below C2 (phrenic sparing) 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: AIH + Walking Training with transcutaneous spinal stimulation (WALKtSTIM)
Acute Intermittent Hypoxia will be used as a pretreatment before walking training paired with transcutaneous spinal cord stimulation.
Other: Daily acute intermittent hypoxia
Each participant will be exposed to 8 sessions of daily acute intermittent hypoxia via air generators over the span of two weeks. The generator will fill reservoir bags attached to a non-rebreathing facemask. Each session will consist of 15 episodes which include intervals of 1.5 minute hypoxia (FIO2=0.10±0.02, i.e. 10% O2) and 1 minute normoxia (FIO2=0.21±0.02).
Other: Walking + tSTIM
Individuals will participate in 45 minutes of gait training while having transcutaneous spinal cord stimulation. Stimulation intensity will be 80% involuntary motor threshold.
Sham Comparator: Sham + WALKtSTIM
Sham acute intermittent hypoxia will be used as a pretreatment before walking training paired with transcutaneous spinal cord stimulation.
Other: Walking + tSTIM
Individuals will participate in 45 minutes of gait training while having transcutaneous spinal cord stimulation. Stimulation intensity will be 80% involuntary motor threshold.
Other: Room air (SHAM)
Each participant will be exposed to 8 sessions of daily room air via air generators over the span of two weeks. The generator will fill reservoir bags attached to a non-rebreathing facemask. Each session will consist of 15 episodes of 1.5 minute normoxia (FIO2=0.21±0.02).
Sham Comparator: AIH + Walking Training with sham transcutaneous spinal stimulation (WALKtSHAM)
Acute Intermittent Hypoxia will be used as a pretreatment before walking training paired with sham transcutaneous spinal cord stimulation.
Other: Daily acute intermittent hypoxia
Each participant will be exposed to 8 sessions of daily acute intermittent hypoxia via air generators over the span of two weeks. The generator will fill reservoir bags attached to a non-rebreathing facemask. Each session will consist of 15 episodes which include intervals of 1.5 minute hypoxia (FIO2=0.10±0.02, i.e. 10% O2) and 1 minute normoxia (FIO2=0.21±0.02).
Other: Walking + Sham transcutaneous spinal stimulation (tSHAM)
Individuals will participate in 45 minutes of gait training while having SHAM transcutaneous spinal cord stimulation. The stimulation will briefly increase to 80% involuntary motor threshold and then brought down to 0 within 30 seconds.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in walking recovery, assessed by 10 meter walk test (10MWT)
Time Frame: Through study completion, an average of 12 weeks
Participants walk ten meters without assistance at their fastest, but safest speed with a minimum of 1-minute of rest between two trials. Average speed across the up to three 10MWT trials will be used for analysis. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Rate of change in walking recovery, assessed by 10 meter walk test (10MWT)
Time Frame: Through study completion, an average of 12 weeks
Participants walk ten meters without assistance at their fastest, but safest speed with a minimum of 1-minute of rest between two trials. Average speed across the up to three 10MWT trials will be used for analysis. Rate of change is the number of treatment sessions required to achieve an increase in 10MWT speed of at least the minimal clinically important difference (0.06 m/s) as compared to pre-treatment baseline.
Through study completion, an average of 12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in walking recovery, assessed by 6 minute walk test (6MWT)
Time Frame: Through study completion, an average of 12 weeks
Participants perform the 6MWT at their fastest, most comfortable walking speed sustainable for 6 minutes. Distances will be recorded at 2 and 6 minutes. The test will be based upon the participant's ability to finish each assessment without human assistance. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in walking recovery, assessed by timed up-and-go (TUG) test
Time Frame: Through study completion, an average of 12 weeks
The TUG test is used to assess the dynamic balance of an individual. It measures the amount of time (recorded in seconds) it takes for the individual to rise from a standard arm chair, walk a distance of 3 meters and return to the initial position resting against the back of the chair. Participants will perform up to three trials of the TUG test. Average speed across TUG trials will be used for analysis. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in pain severity, assessed by the Numeric Pain Rating Scale (NPRS)
Time Frame: Through study completion, an average of 12 weeks
Participants will report their pain level using the Numeric Pain Rating Scale. The scale is from 0 to 10; 0 being no pain and 10 being extreme pain. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in cognitive function, assessed by the California Verbal Learning Test (CVLT)
Time Frame: Through treatment completion, an average of 4 weeks
The CVLT is a brief, individually administered battery to measure cognitive decline or improvement and assesses verbal learning and memory for older adolescents and adults. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through treatment completion, an average of 4 weeks
Systemic hypertension incidence rate
Time Frame: Through treatment completion, an average of 4 weeks
Participants will have their systolic and diastolic blood pressure measured. A systemic hypertensive event is quantified as a systolic pressure exceeding 140 mmHg and/or diastolic pressure exceeding 90 mmHg. A hypertension incident rate is the number of hypertensive events divided by the total person-time. Person-time is in units of person-measures (the sum of the total number of BP measurements) taken for each person. Person-measures accounts for the total number of chances for detecting a hypertensive event and accounts for measurements not made due to drop-out or a disqualifying adverse event.
Through treatment completion, an average of 4 weeks
Autonomic dysreflexia incidence rate
Time Frame: Through treatment completion, an average of 4 weeks
The occurrence of autonomic dysreflexia will be assessed. An autonomic dysreflexia event will constitute a participant having a SBP increase from baseline of 20 mmHg not associated with exercise or systolic blood pressure (SBP) greater than 150 mmHg with complaints of headache, diaphoresis, and/or blurred vision and will be diagnosed by our study team clinicians. We will compute autonomic dysreflexia incident rate as the number of autonomic dysreflexia events divided by the total person-time. We define person-time in units of person-days (the number of days a person remains in the study). Person-days account for the total number of chances for detecting autonomic dysreflexia and accounts for days on which measurements were not made due to drop-out or a disqualifying adverse event.
Through treatment completion, an average of 4 weeks

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in lower extremity strength, assessed by American Spinal Injury Association Impairment Scale (AIS) lower extremity motor scores (LEMS)
Time Frame: Through study completion, an average of 12 weeks
The LEMS uses ASIA key muscles in both the lower extremities, with a total possible score of 50 (maximum score of 5 for each muscle group). Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in spasticity, assessed by the Spinal Cord Assessment Tool for Spastic Reflexes (SCATS)
Time Frame: Through study completion, an average of 12 weeks
The study team will quantify the total lower extremity spasticity score using the cumulative sum of 3 SCATS subscales: clonus (0=no spasticity; 3=severe), flexor (0=no spasticity; 3=severe), and extensor (0=no spasticity; 3=severe). Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in bladder dysfunction, assessed by the Neurogenic Bladder Symptom Score (NBSS)
Time Frame: Through study completion, an average of 12 weeks
This questionnaire is a symptom-based score for neurogenic bladder dysfunction. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in walking ability and assistive device use, assessed by Spinal Cord Injury Functional Ambulation Inventory (SCI-FAI).
Time Frame: Through study completion, an average of 12 weeks
The SCI-FAI assesses functional walking ability in ambulatory individuals with SCI. Component scores range from 0 to 20 in the gait parameter component, 0 to 14 in the assistive device component, and 0 to 5 in the walking mobility component. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in physical assistance needed, assessed by Walking Index for Spinal Cord Injury (WISCI) II
Time Frame: Through study completion, an average of 12 weeks
The WISCI is used to assess the amount of physical assistance is needed as well as devices required for walking following paralysis. This assessment is from 0-20 with value corresponding to a physical assistance description. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks
Change in bowel dysfunction, assessed by the Neurogenic Bowel Dysfunction Score (NBDS) v2.1
Time Frame: Through study completion, an average of 12 weeks
This questionnaire is a symptom-based score for neurogenic bowel dysfunction. Change is the difference between the post-treatment assessment 2 and pre-treatment baseline.
Through study completion, an average of 12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Spaulding Rehabilitation Hospital

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
United States Department of Defense
Shirley Ryan AbilityLab

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Randy Trumbower, PT, PhD, Harvard Medical School (HMS and HSDM)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 17, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 26, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 28, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 3, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 20, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 18, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2022P002036
  • W81XWH-22-1-0998 (Other Grant/Funding Number: US Dept. of Defense)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Deidentified IPD will be available to other researchers upon request.

IPD Sharing Time Frame

The study protocol and statistical analysis plan will be disseminated by December 2022. Participant data will be available at the end of the trial.

IPD Sharing Access Criteria

Principal investigators will be able to receive deidentified data.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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