Acoustic Stimulation to Study and Modulate Sleepwalking and Related Arousal Disorders

Disorders of Arousal (DoA)-including sleepwalking, sleep terrors, and confusional arousals-are NREM parasomnias whose underlying neurophysiological triggers remain poorly understood. A growing body of evidence suggests that DoA episodes do not emerge randomly from sleep but arise from identifiable pre-episode EEG states characterized by increased slow-wave activity and reduced cortical activation, consistent with a transient state of arousal instability. Closed-loop acoustic stimulation (CLAS) is an established, non-invasive method for probing and modulating NREM sleep physiology, but has not previously been applied in the specific context of NREM parasomnias.

This study investigates whether controlled acoustic stimulation, initially delivered with randomized timing and subsequently in a real-time, EEG-triggered closed-loop fashion, can reliably elicit or modulate DoA episodes under supervised laboratory conditions. A small group of healthy volunteers undergoes a single stimulation night to estimate the specificity of stimulation-elicited motor responses, helping distinguish genuine DoA vulnerability from a non-specific arousal response to sound.

The within-subject, randomized-order design in DoA participants allows each to serve as their own control, isolating the effect of acoustic stimulation from other sources of night-to-night variability. The exploratory closed-loop sub-study tests the technical feasibility of triggering stimulation based on real-time EEG markers of vulnerability, representing a first step toward future predictive or modulation-based approaches for this condition.

This study is part of a broader research programme on the neurobiological characterization of Disorders of Arousal; related observational components (including neuroimaging, neuropsychological assessment, and home monitoring) are registered separately.

Inclusion criteria

For participants with Disorders of Arousal (DoA):

• Diagnosis of a Disorder of Arousal (sleepwalking, sleep terror, or confusional arousal) per ICSD-3 criteria, confirmed by video-polysomnography or by clinical diagnosis plus a positive Arousal Disorders Questionnaire (ADQ) and compatible history
• Age 6-17 years (paediatric) or 18-60 years (adult) at enrollment
• At least one documented episode in the 4 weeks (paediatric) or 6 months (adult) prior to enrollment
• Ability to understand and complete study materials in Italian
• Written informed consent (and age-appropriate assent for minors, per Swiss Human Research Act Art. 22-23)

For healthy volunteers:

• No documented sleep disorder, confirmed by clinical interview, questionnaires, or prior instrumental examination
• Age- and sex-matched to the paediatric DoA group
• No clinically significant psychiatric or neurological history
• Written informed consent and age-appropriate assent

Exclusion criteria

(all participants):

• Epilepsy or other major neurological disorder
• Comorbid REM sleep behavior disorder or other REM parasomnia
• Current psychopharmacological or psychotropic medication (except melatonin ≤2 mg)
• Neurodevelopmental disorder precluding protocol collaboration (paediatric participants)
• Clinically relevant sleep-disordered breathing (Apnea-Hypopnea Index >5 events/hour)
• Clinically significant hearing deficit
• Significant sleep deprivation in the 48 hours prior to laboratory recording
• Pregnancy (adult participants)
• Inadequate EEG recording quality (>40% artifact channels or epochs) - applied at the session level