How we measure hypoglossal nerve stimulator outcome matters: titration vs single amplitude efficacy sleep studies

Hypoglossal nerve stimulator (HGNS) is a common treatment for obstructive sleep apnea. Objective assessment of HGNS efficacy measures apnea-hypopnea index (AHI) by multiamplitude titration polysomnography (tPSG) and/or a single amplitude, full-night type 3 home sleep study (eHST). Both tests have been used to determine efficacy despite significantly different protocols. This project's aim was to determine differences in objective outcomes in HGNS patients who underwent both tPSG and eHST postoperatively.

Data from 379 consecutive HGNS patients were retrospectively reviewed. Inclusion requirements were a preoperative sleep study, a postoperative tPSG, and then an eHST, which at our institution is a type 3 home study. AHI mean and differences were calculated. Wilcoxon rank sum tests were used to analyze differences between tPSG and eHST. Sher₁₅ criteria (postoperative AHI ≤ 15 events/h and ≥ 50% reduction from baseline) were calculated and compared by χ² tests.

Ultimately 61 patients met inclusion criteria with an average preoperative AHI = 33.2 events/h. When comparing the patient's tPSG vs eHST, tPSG AHI was significantly lower (AHI = 8.8 events/h vs AHI = 17.6 events/h; respectively, P < .001). There was also a difference in the percentage of patients that met Sher₁₅ criteria when using tPSG (80.3%) vs eHST AHI (45.9%).

HGNS patient's postoperative tPSG AHI was significantly lower than their eHST outcome. This work highlights the importance of reporting the type of postoperative study used in evaluating HGNS efficacy and the need for single amplitude, full-night studies to assess HGNS efficacy more accurately.

Kaffenberger TM, Sina EM, Hambach B, et al. How we measure hypoglossal nerve stimulator outcome matters: titration vs single amplitude efficacy sleep studies. J Clin Sleep Med. 2025;21(1):47-53.