HMN 2025: How to Investigate the safety and efficacy of a hypoglossal nerve stimulator in young children with Down syndrome

Sleep apnea, or difficulty breathing at night, is common among children with Down syndrome—affecting up to 80% compared to just 5% of the general pediatric population. Sleep apnea can negatively impact any child’s ability to function and learn, but for children with Down syndrome who have neurocognitive differences, good sleep may be even more crucial to their development.

Standard treatments like tonsil or adenoid removal are often less effective for these children due to anatomical differences including a larger tongue that can block the airway during sleep.

Christopher Hartnick, MD, MS, director of the Division of Pediatric Otolaryngology at Mass Eye and Ear and Brian Skotko, MD, MPP, the director of the Down Syndrome Program and Emma Campbell Endowed Chair on Down Syndrome at Massachusetts General Hospital, have demonstrated the safety and efficacy of a hypoglossal nerve stimulator—an implant that acts like a tongue pacemaker by moving it forward to open the airway when apnea occurs—for patients with Down syndrome between the ages of 13 and 21. That data contributed to the device being approved by the FDA for this age group.

Their paper, “Hypoglossal nerve stimulator for obstructive sleep apnea in children with down syndrome younger than 13,” was published in the International Journal of Pediatric Otorhinolaryngology,

Since the early school years are a crucial period for development, the new research aimed to determine if this treatment is also safe and effective for younger children with Down syndrome, potentially allowing them to gain key neurocognitive benefits.

The primary questions their study addressed were around the hypoglossal nerve stimulator’s safety and therapy response. Safety was assessed by the number of adverse events the children experienced, including from the surgery and the device itself.

The researchers need to collect data that shows the procedure can be done safely in a 4-year-old who has a different anatomy than an adult or teen who undergoes the surgery, or whether there are surgical challenges unique to this age group that prevent success.

Then the team needed to know whether the treatment was effective. Therapy response was defined as a reduction in their obstructive apnea-hypopnea index (OAHI) by 50% or more. OAHI is a measure of the number of apnea events, or time a child stops breathing, per hour.

The study was a retrospective review of 29 children between the ages of 4 and 13 who underwent hypoglossal nerve stimulator implant surgeries at two hospitals: Mass Eye and Ear and Phoenix Children’s Hospital. The children who received the surgeries had sleep studies performed before surgery and then at one to three months, six months, one year, and three years after surgery.

The Mass Eye and Ear patients were treated and monitored as part of a collaborative, multidisciplinary team at Mass General Brigham including clinicians at Massachusetts General Hospital who specialize in Down syndrome and pediatric sleep medicine. Children with Down syndrome have unique care needs, and a multi-disciplinary care approach is vital.

The researchers found that the hypoglossal nerve stimulator surgery was safe in all 29 children, with no serious adverse events. One child had a minor adverse event with surgical wound healing that was resolved. There were no adverse events related to the device itself.

The children in the study showed striking reductions in their sleep apnea events. At six months post-operation, more than 95% of the children had an OAHI reduction of more than 50% or more. Prior to surgery, the median OAHI was more than 18 apnea events per hour, and after surgery the median was nearly four events. That’s a tremendous difference, say the researchers.

This research has major implications, the first being that the safety results can alleviate concerns about whether this procedure is possible in young children. There had been concerns about whether the safety of the implant remains as a child grows, and by tracking children for three years, the researchers saw it remained stable.

Next, based on these safety and efficacy results, the researchers feel this study provides data that the FDA can review to approve the treatment for younger children.

The team also feels this research offers a message of hope to parents of young children with Down syndrome who have worried about their children’s sleep apnea.

These findings will allow the team to submit grants to fund trials that answer the question of whether neurocognition improves more for children with Down syndrome, the younger they receive the treatment.

Following a trial in teens and young adults, the team studied neurocognition and language outcomes in teens over 10 years of age with Down syndrome who underwent the surgery. That study is ending soon. The team want to conduct a similar study in children between 4 and 10 years old.