Insomnia is a highly prevalent sleep disorder characterized by persistent difficulty initiating or maintaining sleep, often accompanied by impaired daytime functioning. Chronic insomnia affects approximately 10-15% of the adult population and is associated with significant physical, psychological, and socioeconomic burden. Traditional management strategies, including cognitive behavioral therapy for insomnia (CBT-I) and pharmacotherapy, have shown varying levels of effectiveness, with some patients remaining refractory to standard interventions or experiencing unwanted side effects.

Recent advances in sleep neuroscience have revealed that disturbances in endogenous brain rhythms, particularly reductions in slow-wave activity (SWA) and altered sleep spindle patterns, play a key role in the pathophysiology of insomnia. These findings have sparked interest in non-pharmacological neuromodulation approaches to restore healthy sleep architecture.

One such approach is personalized nocturnal sound frequency therapy, in which low-frequency auditory stimuli (e.g., pink noise or slow oscillation-matched tones) are delivered during sleep to entrain and enhance specific sleep-related brain oscillations. Studies in healthy individuals and patients with insomnia have demonstrated that such stimulation can augment slow-wave sleep (N3), reduce nocturnal arousals, and improve perceived sleep quality. Personalized algorithms that adapt sound delivery based on real-time EEG signals further enhance these devices' efficacy and user experience.

Despite growing evidence supporting the utility of sound-based sleep modulation, there is limited data on its application in diverse insomnia subtypes and its effect as measured by gold-standard sleep studies such as polysomnography (PSG). This study uses a pre-post PSG design to evaluate the impact of personalized sound frequency therapy on objective sleep architecture and subjective sleep outcomes in patients with insomnia. The findings may provide new insights into the therapeutic potential of acoustic brainwave modulation and support its integration into personalized insomnia care.

Primary Objective:

To evaluate the effect of daily personalized sound frequency therapy on sleep architecture (N1/N2/N3 %, REM %, total sleep time, sleep latency, sleep efficiency) measured by polysomnography after 12 weeks of intervention.

Secondary Objectives:

• To evaluate the effect of daily personalized sound frequency therapy after 12 weeks of intervention
• Sleep quality; using Pittsburgh Sleep Quality Index(PSQI) questionnaire ,
• Insomnia; using Insomnia severity index(ISI) questionaire,
• apnea-hypopnea index (AHI) assessed by polysomnography
• daytime sleepiness; using the Epworth Sleepiness Score (ESS) intervention.
• To assess user adherence, tolerability, and acceptability of the sound therapy.

Hypothesis There is an improvement in terms of sleep architecture, sleep quality (PSQI), insomnia severity (ISI), apnea-hypopnea index (AHI), and daytime sleepiness (ESS) with sound frequency therapy after 12 weeks of intervention.

Study Design:

A prospective, single-arm, longitudinal pre-post interventional study. Intervention duration: 12 weeks.

Baseline and follow-up PSG (full-night polysomnography).

Study Population:

Insomnia patients/hospital staff in Hospital Canselor Tuanku Muhriz UKM

Inclusion Criteria:

• Adults aged 18-60 years
• With sleep disturbances based on the PSQI score of >5 and/or ISI score > 15

Exclusion Criteria:

• Central sleep apnea
• Epilepsy
• Current use of sedative-hypnotics or neurostimulation devices
• Shift workers (people with different working hours patterns, for example morning, afternoon, night shifts)
• Pregnancy
• Moderate to severe OSA (AHI >15)
• Presbycusis or other significant hearing loss
• Patients with psychiatric disorder