The wake-to-sleep transition is a physiologically vulnerable period during which benign and pathologic motor phenomena may emerge. Current sleep nosology recognizes isolated hypnic jerks, propriospinal myoclonus at sleep onset, sleep-related rhythmic movement disorder, and other minor sleep-related motor activities, but these entities may not fully explain patients with persistent, repetitive motor activation recurring across successive attempts to fall asleep. We describe eight representative cases characterized by recurrent motor events centered on sleep onset or early sleep-state transitions, associated sensory and autonomic symptoms, clinically meaningful sleep fragmentation, and absence of a more satisfactory alternative diagnosis. On the basis of these observations, we introduce sleep-state transition instability with recurrent multisystem activation (SSTI-RMA) as a provisional, hypothesis-generating phenotypic construct rather than an established diagnostic entity. The recurring clinical pattern comprises recurrent motor activation during wake-to-sleep or early sleep transitions together with variable sensory, autonomic, cardiovascular, respiratory, or other non-motor manifestations, repetition or clustering of events, difficulty initiating or stabilizing sleep, clinically significant distress or impairment, and absence of a more satisfactory alternative explanation. We conceptualize the SSTI-RMA phenotype as a possible disorder of sleep-state instability rather than as an isolated motor phenomenon, potentially involving impaired coordination among neural, autonomic, and vascular processes during sleep entry. No validated polysomnographic signature, frequency threshold, biomarker, or prevalence estimate is currently available, and the relationship of this phenotype to severe or recurrent sleep starts remains unresolved. SSTI-RMA should therefore be regarded as a descriptive research framework intended to facilitate standardized phenotyping and prospective studies capable of determining whether it represents a distinct entity, part of a continuum of established sleep-onset phenomena, or a heterogeneous phenotype with multiple causes.

Sleep is increasingly recognized as a multifaceted construct; however, most studies rely on self-reported sleep duration and overlook other key characteristics. We analyzed cross-sectional data from the REACT project, which included 738 Portuguese children (398 girls) aged 6 to 10 years, using 7-day wrist actigraphy. Latent profile analysis based on total sleep time, sleep onset, wake-up, sleep efficiency, and sleep regularity identified four profiles: "Relatively Favorable Sleepers" (45.4%), "Late Starters & Short Sleepers" (34.3%), "Long Sleepers & Late Risers" (15.6%), and "Early Risers & Poor Quality" (4.7%). Children in the "Early Risers & Poor Quality" profile had higher odds of having overweight or obesity (OR: 2.09, 95% CI: 1.03-4.22) compared to those in the "Relatively Favorable Sleepers" profile. Children in the "Long Sleepers & Late Risers" profile were more likely to meet moderate-to-vigorous physical activity (MVPA) recommendations (OR: 1.78, 95% CI: 1.05-3.03) and accumulated less sedentary time (β = -0.26, 95% CI: -0.50 to - 0.03). Conversely, the "Late Starters & Short Sleepers" profile was associated with higher sedentary time (β = 0.55, 95% CI: 0.38-0.73) and higher unhealthy diet scores (β = 0.41, 95% CI: 0.24-0.57), although no differences were observed in healthy diet scores. These findings highlight the value of multidimensional sleep assessment using objective measures for identifying pediatric subgroups at risk of adverse health outcomes.

Sudden unexpected infant death remains a significant public health concern, with South Africa reporting among the highest incidence globally. However, little is known about infant sleep practices, motivations for sleep arrangements, or adherence to safe sleep recommendations within this context. This study explored caregiver and child characteristics associated with potential sleep-related risk, and caregiver motivations underlying infant sleep arrangements, among South African caregivers. A cross-sectional online survey was completed by 201 caregivers of infants. Prevalence of adherence to American Academy of Pediatrics guidelines was determined. A safe sleep composite score, derived from items of the Brief Infant Sleep Questionnaire-Revised, classified caregivers into low-, moderate-, and high-adherence groups. Bivariate associations between demographic characteristics and low-adherence group membership were examined using chi-square tests, with hierarchical multiple regression to identify predictors of adherence to guidelines. Prevalence of motivations for sleep arrangements were determined and compared across demographic characteristics. Bed-sharing and non-supine sleeping was common. Unemployed caregivers were more than twice as likely to fall into the low-adherence group (45.9% vs. 20.5%), and caregiver characteristics explained significant variance beyond child characteristics (ΔR[2] = 0.20, p = .022), with unemployment the only significant independent predictor. No child characteristics were associated with adherence. Feeding, bonding, and safety were the primary motivations for bed and room-sharing, while separate-room sleeping motivations centered on caregiver sleep quality. Adherence to guidelines is complex. Caregiver characteristics were associated with potential sleep-related risk. Findings support safe sleep interventions tailored to caregivers' practical and socioeconomic circumstances, particularly for unemployed and single caregivers.

Consumer health trackers (CHTs) capable of estimating sleep have become widely adopted and are increasingly used by individuals, researchers, and healthcare professionals to characterize habitual sleep patterns and their relationship to health. Although many manufacturers report similarly named sleep measures, these are often defined, computed, and represented differently across the industry, hindering interpretation. Population reference values, risk thresholds, and outcome associations can only be established reliably when measurements are standardized to represent the same underlying constructs. To address this standardization gap, a multidisciplinary working group comprising academic and industry experts developed a minimum viable standard, specifying a common semantic framework for Fundamental Sleep Measures generated by CHTs. The proposed specification balances scientific rigor, clinical utility, and practical implementation while accommodating proprietary algorithms and user interfaces. By standardizing backend data semantics rather than frontend product implementation, the framework enables interoperability across manufacturers without constraining innovation and product differentiation. The standard specifies metadata, provenance, quality indicators, and circumstances in which wearable-derived sleep measures should be interpreted with greater caution. It provides the technical foundation for consistent integration of CHT sleep data into electronic health records, digital health platforms, and population health systems.

Alzheimer's Disease (AD) is estimated to account for up to 75% of all dementia cases, of which there is a global prevalence of 50 million. There are no curative treatments available for AD dementia, therefore, early identification of risk factors is paramount. Up to 40% of all dementia cases may be attributable to modifiable risk factors. One such risk factor is poor sleep. Obstructive sleep apnoea (OSA) is a common sleep disorder characterised by repeated upper airway collapse, contributing to intermittent hypoxaemia and sleep fragmentation. Hypertension is frequently comorbid with OSA and is an established risk factor for dementia, with recent literature exploring potential mechanistic contributions to AD pathogenesis. Despite current literature exploring associations between OSA and hypertension on AD individually, little research has investigated the potential combined impact of these two pervasive disorders. To this end, this review will synthesise existing literature investigating potential pathogenic mechanisms between OSA and AD, including oxidative stress and altered sleep architecture. Further, shared pathophysiological consequences of OSA and hypertension will be reviewed in the context of AD to highlight the potential for effective management in mid-life to preserve neurological and cognitive health in late life.