Insomnia Features in Hypoglossal Nerve Stimulation for Obstructive Sleep Apnoea

Purpose of Review Hypoglossal nerve stimulation (HNS) is an established treatment for selected patients with obstructive sleep apnoea (OSA) who cannot tolerate or benefit adequately from positive airway pressure. Insomnia symptoms are common in this population. This review examines how insomnia should be assessed and managed before and after implantation. Recent Findings Observational evidence is heterogeneous. A large international registry found similar respiratory response and adherence across baseline insomnia-severity groups, although questionnaire-defined insomnia was far more prevalent than insomnia recorded by clinical history. Smaller cohorts have reported reduced nightly use, lower stimulation levels, less favourable respiratory response or poorer patient-reported outcomes with insomnia. Associations appear more consistent for device use and patient-reported benefit than for respiratory efficacy. No insomnia intervention has been evaluated in a controlled study of HNS recipients. Summary Clinicians should distinguish chronic insomnia disorder from respiratory-event-related awakenings and identify circadian, restless legs and medication contributors. Cognitive behavioural therapy for insomnia remains first-line for established chronic insomnia. When insomnia persists after activation, stimulation timing and intensity should be reviewed alongside objective confirmation of respiratory control. A questionnaire score should not be treated as an automatic contraindication. Opinion Statement Insomnia should inform, rather than determine, candidacy for hypoglossal nerve stimulation (HNS). We favour clinical assessment before implantation to distinguish chronic insomnia from respiratory-event-related awakenings and identify relevant comorbidities. The Insomnia Severity Index can quantify symptom severity and monitor treatment response, supplemented by a sleep diary where appropriate. Cognitive behavioural therapy for insomnia (CBT-I) remains first-line treatment for chronic insomnia. We propose considering it before implantation or activation, particularly in patients with persistent sleep-onset insomnia or conditioned arousal, without routinely delaying otherwise appropriate HNS treatment. Whether this approach improves HNS outcomes remains untested. If insomnia develops or worsens after activation, respiratory control, device use and stimulation tolerability should be assessed together. Individualised adjustments to start delay or stimulation parameters may improve tolerability, provided effective airway treatment is maintained. Persistent sleep disturbance despite adequate respiratory control warrants assessment of non-respiratory causes. Pharmacotherapy may be considered selectively, recognising the limited HNS-specific evidence and the importance of respiratory safety.