Spine Injury Treatment May Help Walking

Daily acute intermittent hypoxia and dAIH combined with overground walking improved walking speed and distance in persons with chronic incomplete spinal cord injury.

A new treatment may help persons with spinal cord injuries walk better. Daily acute intermittent hypoxia (dAIH) and dAIH combined with overground walking improved walking speed and distance in persons with chronic incomplete spinal cord injury (iSCI).

Hayes and associates at Emory University in Atlanta and other centers conducted a randomized, double-blind, placebo-controlled, crossover study of 19 patients. They had spine injuries between levels C2 and T12; no joint shortening; some controlled ankle, knee, and hip movements; and the ability to walk at least 1 step without human assistance.

The patients 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. Ten-Meter and 6-Minute Walk Tests were used to quantify walking speed and endurance.

Walking speed increased on a test of walking 10 meters in patients who received just the hypoxia treatment; they walked an average of 3.8 seconds faster than when they did not receive the treatment.

On a test of how far patients could walk in 6 minutes, those who had the treatment plus walking showed an increase in endurance of an average of 100 meters-more than a 250% increase compared with those who had the sham treatment plus walking.

The ability to walk improved in all patients. Walking speed increased by at least a tenth of a meter per second in more than 30% of patients, and endurance increased by at least 50 meters in more than 70% of patients.

“One question this research brings to light is how a treatment that requires people to take in low levels of oxygen can help movement, let alone in those with compromised lung function and motor abilities,” said Michael G. Fehlings, MD, PhD, with the University of Toronto in Canada, who wrote a corresponding editorial. “A possible answer is that spinal serotonin, a neurotransmitter, sets off a cascade of changes in proteins that help restore connections in the spine.”

The findings demonstrate that combinatorial therapies may promote greater functional benefits in persons with iSCI, the authors suggested. They cautioned that chronic or sustained hypoxia in untrained hands may cause serious injury and should not be attempted outside the scope of a supervised medical treatment.

The study is published in the November 27, 2013, online issue of Neurology.