Results published in the New England Journal of Medicine report that mild electronic stimulation therapy to the upper airway during sleep is effective in reducing obstructive sleep apnea (OSA).
In the Stimulation Therapy for Apnea Reduction study – known as the STAR Trial – researchers across the United States and Europe tested an implantable electronic stimulation device called Inspire™ Upper Airway Stimulation Therapy, which is designed to significantly reduce the burden of obstructive sleep apnea by delivering stimulation to the hypoglossal nerve timed to each breathing cycle. The mild stimulation is intended to restore tone to the muscles that control the base of the tongue, preventing it from collapsing and obstructing the airway during sleep.
“This device is a first-of-its-kind therapy and has the potential to help the many people suffering from moderate to severe sleep apnea who are unable to use or cannot tolerate CPAP,” said Kingman Strohl, MD, senior author of the study and pulmonologist at University Hospitals Case Medical Center and Professor of Medicine at Case Western Reserve University School of Medicine.
“At a year following surgical implantation, patients experienced substantial decreases in the number of interruptions of sleep by apnea, and improvements in symptoms of waketime sleepiness, snoring, and quality of life.”
The Phase III safety and efficacy study was conducted at multiple American and European clinical sites. There were 126 participants, 83 percent of whom were men. To enroll, the research participants had to have moderate to severe sleep apnea and be unable to accept or adhere to CPAP therapy. In addition, the patients had to have a BMI of less than 32 and evidence that the sleep-related obstruction might be at the level of the tongue.
“These selection criteria require careful team assessments of each patient by the surgeon and the sleep specialist,”Strohl said. “And to optimize the stimulation, there was a new skill needed in the sleep laboratory to adjust the electrical stimulation over a couple of nights.”
According to study results, objective outcomes were measured on two scales: The apnea-hypopnea index (AHI; the number of apnea or hypopnea events per hour) and the oxygen desaturation index (ODI; the number of times per hour of sleep that the blood oxygen level drops by more than four percent). At 12 months, the median AHI score decreased 68 percent and the ODI score decreased 70 percent. Most participants reported a reduction of sleep apnea effects and improved quality of life.
After the 12-month assessment, a sub-study compared 23 participants who continued with the therapy to 23 participants who had the therapy withdrawn for a week. The withdrawal group experienced a sharp rise in their median AHI score, along with snoring and fatigue, indicating that the stimulation by the device was the agent for effectiveness.
“While many patients have found help with CPAP, some patients struggle with CPAP or cannot tolerate the mask, and thus remain untreated,” Strohl notes. “The severity of OSA in this group might not be easily managed by oral appliance or surgery. Upper-airway stimulation could provide an effective alternative.”