Can Controlled Hypoxia Be Beneficial After Spinal Cord Injury?

Summary and Comment |
December 3, 2013

Can Controlled Hypoxia Be Beneficial After Spinal Cord Injury?

  1. Robert T. Naismith, MD

A small pilot study demonstrates discordant and nonsustained results, neither supporting nor excluding a possible treatment effect.

  1. Robert T. Naismith, MD

Animal studies have suggested that intermittent, repeated episodes of hypoxia after spinal cord injury may upregulate release of intrinsic neurotropic factors, which can be functionally beneficial. In this multicenter pilot study, investigators sought to translate these findings to those with remote, incomplete spinal cord injury with ambulatory difficulties. The investigators used daily acute intermittent hypoxia (dAIH), which included 15 90-second hypoxic exposures at fraction of inspired oxygen (FIO2) of 9%, followed by 60-second normoxic intervals at FIO2=21%, on 5 consecutive days.

Nineteen patients (mean age, 43; mean years since injury, 9; 18 American Spinal Injury Association [ASIA] grade D and 1 grade C) underwent a double-blind, randomized, crossover study of daily intermittent hypoxia to improve walking speed and endurance. Sham hypoxia was used with a 2-week washout interval between crossovers. Nine participants underwent dAIH (or sham) alone, and 10 underwent dAIH (or sham) in addition to 30 minutes of walking exercise. Walking outcomes (6-minute timed walk and 10-meter walk test) were measured 60 minutes after the study procedures at baseline and days 1, 5, 8, and 15.

For walking speed on the 10-meter test, patients showed a trend toward 15-day improvement with dAIH alone, but not with hypoxia plus 30 minutes of walking. On the 6-minute walking test, the dAIH intervention alone (but not combined with walking) improved distance significantly over baseline (but not over sham) at day 15. The combined dAIH/walking intervention did show improvements on the 6-minute test over sham at days 5 and 8.


Patients with spinal cord injury will likely inquire about this treatment protocol. This study was performed in those with motor preservation and antigravity strength below the level of injury (ASIA D). Some participants engaged in 30 minutes of walking intervention each day to determine whether this could be synergistic with daily acute intermittent hypoxia. While the abstract and editorial highlight some of the positive results, limitations include the small number of subjects, inconsistency of response between treatment paradigms (dAIH with 30 minutes of walking vs. dAIH alone), and inconsistency of response over time. This study demonstrates that the technique is feasible and appears safe within this cohort. Efficacy will require confirmation through additional clinical studies before being recommended to patients.

Editor Disclosures at Time of Publication

  • Disclosures for Robert T. Naismith, MD at time of publication Consultant / Advisory board Acorda Therapeutics; Biogen Idec; EMD Serono; Genzyme; Questcor Speaker's bureau Acorda Therapeutics; Bayer Healthcare; Biogen Idec; Genzyme Grant / research support NIH; Acorda Therapeutics; National Multiple Sclerosis Society Leadership positions in professional societies Consortium of MS Centers (Speaker); National Multiple Sclerosis Society (Local Chair of Clinical Advisory Committee; Program Services Committee, Research Advocate, and Research Champion)


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