Insomnia in Patients Undergoing Hypoglossal Nerve Stimulation Therapy for Obstructive Sleep Apnea

SIMPLE SUMMARY: Obstructive sleep apnea (OSA) is a very prevalent disease. OSA is quite often accompanied by insomnia and the reported prevalence rate of comorbid insomnia and sleep apnea (COMISA) is 30–50%. Positive airway pressure (PAP) therapy delivered via nasal or oronasal interfaces has been established as the gold standard of therapy. Insomnia may complicate treatment of OSA and patients suffering from COMISA have reduced adherence to PAP-therapy. Respiration-coupled hypoglossal nerve stimulation (HGNS) has been established as a reliable therapeutic method in patients not tolerating PAP therapy. HGNS is associated with a significant improvement of sleep-related respiratory metrics, such as apnea-hypopnea index (AHI) and improvement of patient-reported sleep-related outcome measures. In this report, we provide evidence that HGNS therapy is also associated with a significant reduction of insomnia-related symptoms in OSA patients. Nonetheless, the preoperative severity of patient-reported insomnia symptoms is inversely correlated with the respiratory PSG-outcomes in OSA patients after HGNS therapy. In addition, we show a strong correlation between daytime sleepiness- and insomnia-related patient-reported outcomes. We suggest that insomnia should be carefully considered in future studies of excessive daytime sleepiness in OSA patients, especially those treated with HGNS. ABSTRACT: Hypoglossal nerve stimulation (HGNS) is a treatment for obstructive sleep apnea (OSA) patients with intolerance of positive airway pressure therapy. Comorbid insomnia is quite prevalent in OSA patients. We investigated the impact of insomnia and excessive daytime sleepiness (EDS) on polysomnography metrics after HGNS treatment. Data of 27 consecutive patients (9 female; mean age 55.52 ± 8.6 years) were retrospectively evaluated. Insomnia was assessed using the ISI (insomnia severity index) and EDS using the Epworth sleepiness scale (ESS). The median ISI was reduced significantly 3 months after HGNS activation (preoperative: 19; postoperative: 14; p < 0.01). Significant correlations emerged between preoperative ISI and postoperative AHI (apnea/hypopnea index; Spearman’s rho = 0.4, p < 0.05), ∆ AHI (r = −0.51, p < 0.01) and ∆ ODI (oxygen desaturation index; r = −0.48, p < 0.05). ISI correlated strongly with EES both preoperatively (r = 0.46; p < 0.02) and postoperatively (r = 0.79; p < 0.001). Therefore, HGNS therapy is associated with a significant reduction of insomnia-related symptoms, in addition to the improvement in respiratory metrics in OSA. Nonetheless, the preoperative severity of patient-reported insomnia symptoms was inversely correlated with the respiratory PSG-outcomes after HGNS. Insomnia should be considered in studies of EDS in OSA patients, especially those treated with HGNS.