Dataset Information

Daily intermittent hypoxia enhances walking after chronic spinal cord injury: a randomized trial.

ABSTRACT:

Objectives

To test the hypothesis that daily acute intermittent hypoxia (dAIH) and dAIH combined with overground walking improve walking speed and endurance in persons with chronic incomplete spinal cord injury (iSCI).

Methods

Nineteen subjects completed the randomized, double-blind, placebo-controlled, crossover study. Participants received 15, 90-second hypoxic exposures (dAIH, fraction of inspired oxygen [Fio2] = 0.09) or daily normoxia (dSHAM, Fio2 = 0.21) at 60-second normoxic intervals on 5 consecutive days; dAIH was given alone or combined with 30 minutes of overground walking 1 hour later. Walking speed and endurance were quantified using 10-Meter and 6-Minute Walk Tests. The trial is registered at ClinicalTrials.gov (NCT01272349).

Results

dAIH improved walking speed and endurance. Ten-Meter Walk time improved with dAIH vs dSHAM after 1 day (mean difference [MD] 3.8 seconds, 95% confidence interval [CI] 1.1-6.5 seconds, p = 0.006) and 2 weeks (MD 3.8 seconds, 95% CI 0.9-6.7 seconds, p = 0.010). Six-Minute Walk distance increased with combined dAIH + walking vs dSHAM + walking after 5 days (MD 94.4 m, 95% CI 17.5-171.3 m, p = 0.017) and 1-week follow-up (MD 97.0 m, 95% CI 20.1-173.9 m, p = 0.014). dAIH + walking increased walking distance more than dAIH after 1 day (MD 67.7 m, 95% CI 1.3-134.1 m, p = 0.046), 5 days (MD 107.0 m, 95% CI 40.6-173.4 m, p = 0.002), and 1-week follow-up (MD 136.0 m, 95% CI 65.3-206.6 m, p < 0.001).

Conclusions

dAIH ± walking improved walking speed and distance in persons with chronic iSCI. The impact of dAIH is enhanced by combination with walking, demonstrating that combinatorial therapies may promote greater functional benefits in persons with iSCI.

Classification of evidence

This study provides Class I evidence that transient hypoxia (through measured breathing treatments), along with overground walking training, improves walking speed and endurance after iSCI.

SUBMITTER: Hayes HB

PROVIDER: S-EPMC3897437 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Restoring community walking remains a highly valued goal for persons recovering from traumatic incomplete spinal cord injury (SCI). Recently, studies report that brief episodes of low-oxygen breathing (acute intermittent hypoxia, AIH) may serve as an effective plasticity-inducing primer that enhances the effects of walking therapy in persons with chronic (>?1?year) SCI. More persistent walking recovery may occur following repetitive (weeks) AIH treatment involving persons with more acute SCI, but this possibility remains unknown. Here we present our clinical trial protocol, designed to examine the distinct influences of repetitive AIH, with and without walking practice, on walking recovery in persons with sub-acute SCI (<?12?months) SCI. Our overarching hypothesis is that daily exposure (10 sessions, 2?weeks) to AIH will enhance walking recovery in ambulatory and non-ambulatory persons with subacute (<?12?months) SCI, presumably by harnessing endogenous mechanisms of plasticity that occur soon after injury. METHODS:To test our hypothesis, we are conducting a randomized, placebo-controlled clinical trial on 85 study participants who we stratify into two groups according to walking ability; those unable to walk (non-ambulatory group) and those able to walk (ambulatory group). The non-ambulatory group receives either daily AIH (15, 90s episodes at 10.0% O2 with 60s intervals at 20.9% O2) or daily SHAM (15, 90s episodes at 20.9% O2 with 60s intervals at 20.9% O2) intervention. The ambulatory group receives either 60-min walking practice (WALK), daily AIH?+?WALK, or daily SHAM+WALK intervention. Our primary outcome measures assess overground walking speed (10-Meter Walk Test), endurance (6-Minute Walk Test), and balance (Timed Up & Go Test). For safety, we also measure levels of pain, spasticity, systemic hypertension, and autonomic dysreflexia. We record outcome measures at baseline, days 5 and 10, and follow-ups at 1?week, 1?month, 6?months, and 12?months post-treatment. DISCUSSION:The goal of this clinical trial is to reveal the extent to which daily AIH, alone or in combination with task-specific walking practice, safely promotes persistent recovery of walking in persons with traumatic, subacute SCI. Outcomes from this study may provide new insight into ways to enhance walking recovery in persons with SCI. TRIAL REGISTRATION:ClinicalTrials.gov, NCT02632422 . Registered 16 December 2015.

Project description:ObjectiveTo investigate the effects of an 8-week walking training program on glycemic control, lipid profile, and inflammatory markers in individuals with chronic spinal cord injury (SCI).DesignA pilot, single-group, pretest-posttest study.SettingA neuromuscular research laboratory.ParticipantsEleven participants with chronic SCI.InterventionAn 8-week walking training program using a treadmill, a body weight-supported system, and an assistive gait training device.Outcome measuresLevels of glycated hemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), C-reactive protein (CRP), and interleukin-6 were assessed before and after the walking training.ResultsFollowing the walking training, there was a statistically significant decrease in HbA1c level (P<0.01) of uncertain clinical significance. The lipid profile improved after training, as shown by a statistically and clinically significant increase in HDL-C level (P<0.01) and a statistically significant decrease in LDL-C level (P<0.1) of no clinical significance. The ratio of LDL-C to HDL-C was significantly reduced (P<0.01). In regard to inflammatory markers, concentrations of IL-6 showed a significant reduction after training (P=0.05) of unknown clinical significance, while those of CRP trended to decrease (P=0.13).ConclusionThe findings of this pilot study suggest that an 8-week walking training program may produce favorable changes in risk markers of cardiovascular disease in individuals with chronic SCI as shown by clinically meaningful improvements in HDL-C, and small changes in the right direction, but uncertain clinical significance, in HbA1c, LDL-C and IL-6. A randomized controlled trial is needed to compare the effects of walking training on these outcome measures with those of other exercise modalities suitable for this population, and to see if more prolonged exercise exposure leads to favorable parameters of significant size to justify the exercise modality.