But sleep apnea worsened in about 20 patients using the device, though it is unclear why.
In the second phase of the study, 46 patients doing well with the stimulators after one year were randomly assigned to either continue with the therapy or have it withdrawn for a week. The therapy-continuation group had little change in the number of breathing pauses per hour or drops in blood oxygen levels. But in the patients from whom the stimulation therapy was withdrawn, the number of such breathing pauses increased sharply, to 25.8 per hour on average from 7.6 per hour. The episodes of blood oxygen level drops rose to 23 per hour on average, from 6 per hour.
“That rebound was compelling evidence that this device did something for their sleep apnea,” said Dr Christine H. Won, the medical director of the Yale Sleep Center.
An alternative therapy for patients who can’t or won’t use standard continuous positive airway pressure (CPAP) masks diligently would be “very valuable,” Dr Won said.
The neurostimulator is not yet approved by the Food and Drug Administration and may only benefit a subset of sleep apnea patients, including those with a body mass index of less than 32 and people whose obstructions stem from airway collapse behind their tongues. Only patients who could not or would not use mask therapy participated.
Less than 2 per cent of study participants experienced serious adverse events. Still, more than half reported discomfort from stimulation, tongue abrasion, incision discomfort and other issues.
After her chin incision became inflamed after implantation of the neurostimulator in 2011, Jackie Kopplin, 45, who runs a housecleaning business in Coon Rapids, Minnesota, was “blown up like a basketball” and in pain for six weeks. “I was regretting it at first,” she said.
But she now sleeps eight to nine hours at night, is not bothered by the tongue thrusting, and no longer dozes off while driving.
As long as she remembers to turn on the stimulator nightly, Kopplin said, “I wake up and I have energy to make it through the whole day.”
- By Catherine Saint Louis