Behavioral Mechanisms of a Digital Health Intervention for Self-Management in Type 2 Diabetes Mellitus: Prospective Longitudinal Cohort Study.

Insomnia is one of the most prevalent sleep disorders worldwide. Global estimates suggest that approximately 16.2% of adults meet criteria for insomnia disorder [], while a substantially larger proportion report insomnia symptoms that do not reach the full diagnostic threshold (subthreshold insomnia) []. Difficulties initiating sleep are among the most commonly reported complaints and are frequently linked to heightened presleep cognitive arousal, including worry and racing thoughts []. According to international guidelines [], the first-line treatment for insomnia is cognitive behavioral therapy for insomnia (CBT-I). CBT-I typically consists of psychoeducation, sleep hygiene recommendations, stimulus control, sleep restriction, relaxation techniques, and cognitive restructuring targeting maladaptive sleep-related beliefs []. Despite its strong empirical support, access to face-to-face delivery is often associated with long waiting lists, limited availability of trained providers, and cost barriers. Pharmacological treatments, including hypnotic and sedative medications, are also commonly used, particularly in the short term; however, concerns regarding side effects, tolerance, dependency, and long-term efficacy limit their suitability as a primary treatment strategy []. Together, these limitations highlight the need to better understand the self-initiated strategies that individuals use to facilitate sleep onset or overcome sleep initiation difficulties. Given that sleep initiation problems are closely tied to presleep cognitive arousal [], patients frequently use cognitive and attentional strategies to manage racing thoughts at bedtime. These include listening to music, relaxation recordings, white noise, guided imagery, and other forms of auditory stimulation [-]. Auditory input may function as a structured attentional anchor, reducing internally generated rumination by redirecting cognitive resources outward. In experimental paradigms that manipulated attentional orientation [], externally delivered auditory stimulation shifted attentional balance from internal to external sources and was associated with reduced internal distraction, supporting the idea that sound can modulate internally generated cognition.