Scientists have developed a novel way to address a deadly disorder that afflicts at least 30 million Americans.
Researchers from the University of California San Diego developed a new implant that helps people with sleep apnea breathe better at night without the bulkiness of a breathing machine. It targets specific nerves in the tongue to keep the airway open while sleeping.
Obstructive sleep apnea (OSA) is a serious sleep disorder in which the soft palate and throat muscles relax during sleep, repeatedly blocking the airway. This causes a person to snore and jerk awake as they choke for air.
Unlike older versions of the implant, this device is easier to insert and does not require an overnight procedure to map the tongue beforehand.
In a recent trial, nearly 60 percent of patients who received the implant had far fewer breathing interruptions during sleep and felt less tired during the day. No serious complications were reported.
For people who cannot tolerate a CPAP machine — a face mask with an elephant trunk-like tube that connects to a breathing machine — this may be a promising alternative.
Over time, the frequent breathing interruptions caused by OSA stress the heart, flood the body with fight-or-flight hormones and cause blood pressure to rise and stay high.
That chronic stress on the cardiovascular system damages blood vessels, drives up blood sugar and increases the risk of heart attack, stroke and diabetes. The resulting exhaustion is a separate but equally dangerous consequence.
Obstructive sleep apnea is a serious condition where the soft palate and throat muscles relax during sleep, blocking the airway over and over. This leads to loud snoring and gasping awake as the person struggles to breathe (stock)
The new implant for OSA showed promising results in a clinical trial, published in the Annals of Internal Medicine.
The device, called proximal hypoglossal nerve stimulation (pHGNS), targets specific nerves in the tongue to keep the airway open during sleep.
It is a small, rechargeable battery-powered device, about the size of a pacemaker. It is surgically implanted under the skin in the upper chest, just below the collarbone.
A thin, flexible wire connects the chest generator to the nerve in the neck. This wire runs under the skin and is not visible from the outside.
At the end of the wire is a small, multicontact electrode cuff. This cuff wraps directly around the hypoglossal nerve, which controls tongue movement.
When the patient turns the device on before sleeping, the cuff delivers mild electrical pulses to the hypoglossal nerve.
These pulses stimulate the tongue and other airway muscles to contract and stiffen. This keeps the airway open during sleep, preventing the throat from collapsing and blocking breathing.
Researchers randomly assigned 104 adults 22 and older with moderate OSA to receive the implant. All had a body mass index of 35 or lower and could not tolerate standard CPAP therapy.
Researchers used the Aura6000 hypoglossal nerve stimulator, which consists of a small generator implanted in the chest and a cuff-shaped electrode wrapped around the hypoglossal (tongue) nerve, which activates airway muscles to prevent collapse during sleep
After seven months, 58.2 percent of patients in the treatment group (square) achieved a significant reduction in breathing interruptions, compared to just 13.5 percent in the control group (circle)
All patients received the implanted device at the start of the study. They were then randomly assigned to one of two groups. The treatment group, comprising 67 patients, had their devices turned on 1 month after implantation.
The control group, comprising 37 patients, had their devices turned off for the first 7 months. This design allowed researchers to compare outcomes between patients receiving active therapy and those not receiving active therapy.
The main goal was to see how many patients achieved a significant reduction in breathing interruptions.
Researchers also measured oxygen desaturation levels, daytime sleepiness and the study participants’ own perspectives on their improvement.
The study met its main goal. At seven months, over 58 percent of patients in the treatment group achieved a significant drop in their breathing interruptions.
In contrast, only 13 percent of patients in the control group achieved the same result, though they showed no clinically meaningful improvement during the first seven months while their devices were off.
Patients in the treatment group also saw improvements in other key measures. Their oxygen desaturation index, which measures how often blood oxygen levels drop during sleep, improved by at least 25 percent in 69 percent of treated patients compared to just 38 percent of control patients.
Daytime sleepiness also improved significantly. The clinical sleepiness score in the treatment group dropped from 10 to six, moving from excessive daytime sleepiness into the normal range. The control group, meanwhile, saw no improvement.
This graph shows changes in daytime sleepiness scores, measured by the Epworth Sleepiness Scale (ESS). At baseline, the treatment group had a median score of 10, while the control group scored nine. After seven months, the treatment group’s score dropped to six, moving into the normal range, while the control group remained at nine
After the initial seven months, the control group had their nerve stimulation devices turned on. By month 13, both groups showed continued improvement.
Patients whose devices had been turned off caught up substantially, though those who had been treated from the start kept their lead.
The number of breathing interruptions in the treatment group fell from 34.3 events per night on average at the start to 11.6 at month seven, moving from severe to mild.
No serious complications related to the device or the implantation procedure were reported over the 13-month study.
The most common side effects included headache, implant site pain and temporary tongue discomfort, which affected less than three percent of patients.
The researchers concluded that proximal hypoglossal nerve stimulation is a safe and effective option for sleep apnea patients who cannot tolerate CPAP.
However, they noted that longer and larger studies are still needed to determine whether the device reduces hard clinical outcomes like heart attack and stroke.
