Evidence Trace, complete trial record
In plain terms
In plain terms: Hypoglossal nerve stimulation for obstructive sleep apnea has some human trial evidence supporting it, but the evidence is not yet strong enough for EBL to call it established. It is worth knowing about and worth discussing with your clinician.
Hypoglossal nerve stimulation for obstructive sleep apnea
B
Supported: a good trial, backed by more
The endpoint this grade is based on: Surrogate biomarker endpoint
The evidence as the record states it
Heiser et al. (J Clin Med, 2021; PMID 34209581): EFFECT, sham-controlled randomized crossover, 89 patients. Malhotra et al. (Ann Intern Med, 2026; PMID 42008810): OSPREY, 104 patients randomized 2:1 to early or delayed activation, unblinded, funded by the device maker. Woodson et al. (Otolaryngol Head Neck Surg, 2014; PMID 25205641): randomized therapy withdrawal in 46 responders. Strollo et al. (N Engl J Med, 2014; PMID 24401051): STAR, a single-group cohort of 126 implanted patients, shown as context and not counted toward the letter. Dedhia et al. (JAMA Otolaryngol Head Neck Surg, 2024; PMID 38032624): sham-controlled crossover on blood pressure, null.
PMID 34209581 PMID 42008810 PMID 25205641 PMID 24401051 PMID 38032624
Evidence by specific use
Apnea-hypopnea index and Epworth sleepiness in implanted adults with moderate to severe sleep apnea who cannot use CPAP
Grade B
In a sham-controlled crossover of 89 implanted adults, stimulation lowered the apnea-hypopnea index by 15.5 events an hour and Epworth scores by 3.3 points (Heiser et al., J Clin Med, 2021; PMID 34209581). A second device, tested by delayed activation in 104 adults, met its response definition in 58 percent against 14 percent (Malhotra et al., Ann Intern Med, 2026; PMID 42008810), and switching therapy off returned breathing to baseline (Woodson et al., Otolaryngol Head Neck Surg, 2014; PMID 25205641). The trials were run with or funded by the device makers. Surrogate and self-reported outcomes cap the letter at B.
PMID 34209581 PMID 42008810 PMID 25205641
Blood pressure in implanted adults with obstructive sleep apnea
Grade C
A double-blind sham-controlled crossover in 60 implanted adults found no difference in 24-hour systolic pressure (0.18 mmHg) or in vascular function (Dedhia et al., JAMA Otolaryngol Head Neck Surg, 2024; PMID 38032624). One trial, null and unrepeated: C.
PMID 38032624
Why Grade B and not Grade A
Grade B reflects moderate human evidence -- typically a single strong trial, multiple smaller trials, or surrogate endpoint data without hard clinical outcome replication. To reach Grade A, Hypoglossal nerve stimulation for obstructive sleep apnea would require at least one additional independent randomized trial demonstrating a hard clinical endpoint or objectively measured functional outcome in a comparable population.
What this grade covers and what it does not
Grade B on apnea severity and Epworth sleepiness in implanted adults who cannot use CPAP, from a sham-controlled crossover (Heiser et al., 2021; PMID 34209581), a delayed-activation trial of a second device (Malhotra et al., 2026; PMID 42008810) and a withdrawal trial (Woodson et al., 2014; PMID 25205641), each run with or funded by the device maker. Grade C on blood pressure: one sham-controlled crossover was null (Dedhia et al., 2024; PMID 38032624). WHY NOT A: surrogate and self-reported outcomes. WHAT THIS GRADE DOES NOT COVER: people with a body mass index above the trials' range of about 28 to 31, people with central sleep apnea, people who can use CPAP, and cardiovascular events, which no cited trial measured.
What would move this grade
An independent randomized trial demonstrating a hard clinical endpoint -- mortality, major adverse event, or objectively confirmed functional improvement -- in an adequately powered sample, with results independently replicated, would support Grade A.
How to track whether this is working
Apnea-hypopnea index on a titration or home study with the device on, nightly hours of use, and the Epworth Sleepiness Scale.