Short apneas and periodic breathing in preterm infants in the neonatal intensive care unit-Effects of sleep position, sleep state, and age.

This observational study investigated the effects of sleep position and sleep state on short apneas and periodic breathing in hospitalized preterm infants longitudinally, in relation to postmenstrual age. Preterm infants (25-31 weeks gestation, n = 29) were studied fortnightly after birth until discharge, in prone and supine positions, and in quiet sleep and active sleep. The percentage of time spent in each sleep state (percentage of time in quiet sleep and percentage of time in active sleep), percentage of total sleep time spent in short apneas and periodic breathing, respectively, the percentage of falls from baseline in heart rate, arterial oxygen saturation and cerebral tissue oxygenation index during short apneas and periodic breathing, and the associated percentage of total sleep time with systemic (arterial oxygen saturation < 90%) and cerebral hypoxia (cerebral tissue oxygenation index < 55%) were analysed using a linear mixed model. Results showed that the prone position decreased (improved) the percentage of falls from baseline in arterial oxygen saturation during both short apneas and periodic breathing, decreased the proportion of infants with periodic breathing and the periodic breathing-associated percentage of total sleep time with cerebral hypoxia. The percentage of time in quiet sleep was higher in the prone position. Quiet sleep decreased the percentage of total sleep time spent in short apneas, the short apneas-associated percentage of falls from baseline in heart rate, arterial oxygen saturation, and proportion of infants with systemic hypoxia. Quiet sleep also decreased the proportion of infants with periodic breathing and percentage of total sleep time with cerebral hypoxia. The effects of sleep position and sleep state were not related to postmenstrual age. In summary, when sleep state is controlled for, the prone sleeping position has some benefits during both short apneas and periodic breathing. Quiet sleep improves cardiorespiratory stability and is increased in the prone position at the expense of active sleep, which is critical for brain maturation. This evidence should be considered in positioning preterm infants.

Oral appliance therapy vs. positional therapy for managing positional obstructive sleep apnea; a systematic review and meta-analysis of randomized control trials.

AIM: To assess the efficacy of positional therapy and oral appliance therapy for the management of positional obstructive sleep apnea. METHODS: We searched PubMed, Web of Science, Cochrane, and SCOPUS for relevant clinical trials. Quality assessment of the included trials was evaluated according to Cochrane's risk of bias tool. We included the following outcomes: The apnea-hypopnea index (AHI), AHI non-supine, AHI supine, sleep efficiency, percentage of supine sleep, Adherence (≥ 4 h/night, ≥ 5 days/week), Oxygen desaturation Index, Arousal Index, Epworth Sleepiness Scale score (ESS), Mean SpO2, and Functional Outcomes of Sleep Questionnaire. RESULTS: The AHI non-supine and the ESS scores were significantly lower in the OAT cohort than in the PT cohort. The PT cohort was associated with a significantly decreased percentage of supine sleep than the OAT cohort (MD= -26.07 [-33.15, -19.00], P = 0.0001). There was no significant variation between PT cohort and OAT cohort regarding total AHI, AHI supine, ODI, sleep efficiency, arousal index, FOSQ, adherence, and mean SpO2. CONCLUSION: Both Positional Therapy and Oral Appliance Therapy effectively addressed Obstructive Sleep Apnea. However, Oral Appliance Therapy exhibited higher efficiency, leading to increased supine sleep percentage and more significant reductions in the Apnea Hypopnea Index during non-supine positions, as well as lower scores on the Epworth Sleepiness Scale.

The effect of sleep position on sleep bruxism in adults with obstructive sleep apnea.

BACKGROUND: Most of the respiratory events in adults with obstructive sleep apnea (OSA) occurs in supine position. It has been reported that the contraction of masseter muscles is dependent on the occurrence of arousals rather than on the occurrence of respiratory events. OBJECTIVES: This study had two aims: (1) to compare the rhythmic masticatory muscle activity (RMMA) index in supine position (RMMA_sup) and in non-supine positions (RMMA_nsup) in adults with OSA; and (2) to determine the associations between RMMA index in both supine position and non-supine positions on the one hand, and several demographic and polysomnographic variables on the other hand. METHODS: One hundred OSA participants (36 females and 64 males; mean age = 50.3 years (SD = 10.5)) were selected randomly from among patients with a full-night polysomnographic recording. RMMA_sup index and RMMA_nsup index were compared using Mann-Whitney U-test. Multivariate linear regression analyses were used to predict RMMA index both in supine and non-supine positions based on several demographic and polysomnographic variables. RESULTS: In patients with OSA, the RMMA_sup index was significantly higher than the RMMA_nsup index (p < .001). RMMA_sup index was significantly associated with the arousal index (p = .002) and arousal index in supine position (p < .001). RMMA_nsup index was only significantly associated with the arousal index in non-supine positions (p = .004). CONCLUSION: Within the limitations of this study, RMMAs occur more frequently in supine position than in non-supine positions in patients with OSA. In both sleep positions, RMMAs are associated with arousals.

Higher awakening threshold of preterm infants in prone position may be a risk factor for SIDS.

AIM: The supine sleeping position in the prevention of sudden infant death syndrome in preterm infants is poorly understood. We aimed to investigate the effect of sleep posture on cardiorespiratory parameters and movement patterns in preterm infants close to discharge. METHODS: This observational study included neonates born in 2022 at the University Hospital Schleswig-Holstein, Lübeck, Germany. Motion sensor data, heart rate, respiratory rate and oxygen saturation were recorded for infants with postconceptional age 35-37 weeks during sleep in the prone and supine positions. RESULTS: We recorded data from 50 infants, born at 31 (24-35) weeks of gestation (mean(range)), aged 5.2 ± 3.7 weeks (mean ± SD), of whom 48% were female. Five typical movement patterns were identified. In the prone position, the percentage of calm, regular breathing was higher and active movement was less frequent when compared to the supine position. The percentage of calm irregular breathing, number of apnoeas, bradycardias, desaturations and vital sign changes were not influenced by position. CONCLUSION: The prone position seems to be associated with a higher arousal threshold. The supine position appears advantageous for escape from life-threatening situations such as sudden infant death syndrome.

Risk factors for unexpected infant death among very premature infants in France.

BACKGROUND: Prematurity is one of the risk factors for sudden unexpected infant death (SUID), a phenomenon that remains poorly explained. MATERIALS AND METHODS: The analysis of specific factors associated with SUID among very premature infants (VPI) was performed through a retrospective review of data collected in the French SUID registry from May 2015 to December 2018. The factors associated with SUID among VPI were compared with those observed among full-term infants (FTI). Results are expressed as means (standard deviation [SD]) or medians (interquartile range [IQR)]. RESULTS: During the study period, 719 cases of SUID were included in the registry, 36 (incidence: 0.60 ‰) of which involved VPI (gestational age: 29.2 [2] weeks, 1157 [364]) g] and 313 (0.18 ‰) involved FTI (gestational age: 40 [0.8] weeks, 3298 [452] g). The infants' postnatal age at the time of death was similar in the two groups: 15.5 (12.2-21.8) vs. 14.5 (7.1-23.4) weeks. We observed low breastfeeding rates and a high proportion of fathers with no occupation or unemployment status among the VPI compared to the FTI group (31% vs. 55 %, p = 0.01 and 32% vs. 13 %, p = 0.05, respectively). Among the VPI, only 52 % were in supine position, and 29 % were lying prone at the time of the SUID (compared to 63 % and 17 %, respectively, in the FTI group). CONCLUSION: This study confirms prematurity as a risk factor for SUID with no difference in the SUID-specific risk factors studied except for breastfeeding and socioeconomic status of the fathers. VPI and FTI died at similar chronological ages with a high proportion of infants dying in prone position. These results argue for reinforcement of prevention strategies in cases of prematurity.

Positional Treatment of Obstructive Sleep Apnea.

Positional sleep apnea (POSA), a distinctive subtype of obstructive sleep apnea, underscores the critical influence of a patient's sleeping position on the severity of their condition. In the management of POSA, compliance with positional therapy (PT) is paramount, as it wields a profound impact on the treatment's efficacy and the overall alleviation of the disease. The advent of new-generation PT devices offers a promising alternative to conventional methods like the tennis ball technique, boasting higher compliance rates and substantial disease alleviation.

Sleep characteristics, early spontaneous movements, and developmental functioning in preterm infants in the early postnatal period.

OBJECTIVE: This study aimed to investigate the following: (i) sleep characteristics in preterm infants at 9-20 weeks of corrected age, and (ii) differences in early spontaneous movements and developmental functioning results between the groups based on some sleep characteristics. METHODS: Seventy-four preterm infants (36 female) were included. Sleep characteristics were assessed according to the Brief Infant Sleep Questionnaire (BISQ). The infants were divided into two groups based on total sleep duration: less than 12 h (38 infants), and 12 h and more (36 infants). Video recordings were made for the General Movements Assessment (GMA) and evaluated using the Motor Optimality Score for 3- to 5-Month-Old-Infants-Revised (MOS). Cognitive, language, and motor development were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). RESULTS: The total sleep duration of all preterm infants (mean ± SD) was 11.8 ± 3.3 h. Infants who had absent fidgety movements slept less than 12 h, and fidgety movements differed between the groups (p = 0.012). Infants who slept 12 h or more had significantly higher MOS (p = 0.041), cognitive (p = 0.002), language (p < 0.001), and motor (p = 0.002) development results. Infants who snored had lower MOS (p = 0.001), cognitive (p = 0.004), language (p = 0.002), and motor (p = 0.001) development results. Infants with fewer than three nocturnal awakenings had significantly higher Bayley-III cognitive (p = 0.007), language (p = 0.032), and motor (p = 0.005) domain results. Prone and supine sleeping positions showed higher motor domain results than lateral positions (p = 0.001). CONCLUSIONS: Sleep in preterm infants might be a key factor in early developmental functioning processes and nervous system integrity. Even in the first months of life, there are substantial differences in cognitive, language, and motor development in association with sleep characteristics.

Longitudinally assessed maternal sleep position, measures of breathing during sleep, and fetal growth in high-risk pregnancies.

STUDY OBJECTIVES: Subjective recall of supine sleep during pregnancy has been linked to increased risk of stillbirth, but longitudinal, objective data are lacking. We aimed to examine how sleep position and breathing parameters change throughout pregnancy, and investigated associations between maternal supine sleep, assessed objectively in early and late gestation, and fetal growth velocity in high-risk women. METHODS: Women with singleton pregnancies and body mass index (BMI) ≥27 kg/m2 underwent level-III sleep apnea testing. Sleep position was assessed by accelerometry. We derived percentiles of estimated fetal weight and birthweight using FetalGPSR software, then calculated growth velocity as change in percentile/week between the second-trimester anatomy scan and birth. RESULTS: In total, 446 women were included, with N = 126 in the longitudinal sleep pattern analysis and N = 83 in the fetal growth analysis. Sleep-onset position and predominant sleep position were significantly correlated in both early (p = 0.001) and late (p < 0.01) pregnancy. However, supine going-to-bed position predicted predominant supine sleep in only 47% of women. Between early and late pregnancy there was a reduction in predominant supine sleepers (51.6% to 30.2%). Percent of sleep spent supine and oxygen desaturation index, in the third trimester, were significantly associated after BMI adjustment (B = 0.018, p = 0.04). Models did not suggest significant effects of early or late pregnancy supine sleep on growth velocity (p > 0.05). CONCLUSIONS: Going-to-bed position predicts predominant supine sleep in less than half of women with overweight and obesity. Time spent supine throughout pregnancy correlates with measures of sleep-disordered breathing. Maternal sleep position patterns did not affect fetal growth velocity in this high-risk population, but the study was not powered to detect differences.

Nocturnal behavioral patterns of African ungulates in zoos.

Currently, most studies on ungulates' behavior are conducted during the daylight hours, but their nocturnal behavior patterns differ from those shown during day. Therefore, it is necessary to observe ungulates' behavior also overnight. Detailed analyses of nocturnal behavior have only been conducted for very prominent ungulates such as Giraffes (Giraffa camelopardalis), African Elephants (Loxodonta africana), or livestock (e.g., domesticated cattle, sheep, or pigs), and the nocturnal rhythms exhibited by many ungulates remain unknown. In the present study, the nocturnal rhythms of 192 individuals of 18 ungulate species from 20 European zoos are studied with respect to the behavioral positions standing, lying-head up, and lying-head down (the typical REM sleep position). Differences between individuals of different age were found, but no differences with respect to the sex were seen. Most species showed a significant increase in the proportion of lying during the night. In addition, the time between two events of "lying down" was studied in detail. A high degree of rhythmicity with respect to this quantity was found in all species. The proportion of lying in such a period was greater in Artiodactyla than in Perissodactyla, and greater in juveniles than in adults.

Left lateral decubitus sleeping position is associated with improved gastroesophageal reflux disease symptoms: A systematic review and meta-analysis.

BACKGROUND: A limited number of studies have demonstrated that sleeping in the left lateral decubitus (LLD) decreases nocturnal reflux in patients with gastroesophageal reflux disease (GERD) compared to right lateral decubitus (RLD) and supine. AIM: This systematic review summarizes the association between sleeping in the LLD position and nocturnal reflux in patients with GERD. METHODS: Studies published up to July 17, 2023, in MEDLINE, EMBASE, and CENTRAL were searched. Eligible studies were randomized and nonrandomized studies assessing the effect of sleeping in LLD compared to RLD and supine in reducing nocturnal reflux in GERD patients. Outcomes include the acid exposure time (AET) (% time in pH<4), acid clearance time (ACT) (in sec/episode), number of reflux episodes, and improvement in N-GSSIQ scores. RESULTS: Two nonrandomized studies showed decreased AET and ACT in LLD sleep position in comparison to RLD (mean difference [MD] -2.03 [95%CI: -3.62 to -0.45]; -81.84 [95%CI: -127.48 to -36.20], respectively) and supine position (MD -2.71 [95%CI: -4.34 to -1.09]; -74.47 [95%CI: -116.26 to -32.69], respectively). There was no difference in AET and ACT between RLD sleep position and supine. Furthermore, one randomized controlled trial investigating the use of electronic sleep positional therapy, which increased the duration of LLD sleep and decreased the duration of RLD sleep compared to sham, showed nocturnal symptoms improvement (improved N-GSSIQ score, increased reflux-free nights, and resolution of nocturnal reflux symptoms). CONCLUSION: Current evidence suggests that sleeping on the left side could reduce nocturnal reflux and improve GERD-related quality of life, therefore warranting interventions that promote LLD sleep position.

The joint association of ambient air pollution and different sleep posture with mild obstructive sleep apnea: A study conducted at Taipei Sleep Center.

BACKGROUND: Growing evidence suggests the detrimental impact of supine position and air pollution on obstructive sleep apnea (OSA), as well as the potential benefits of nonsupine positions. However, their interaction effects on OSA remain unclear. OBJECTIVES: To evaluate the interaction effects of air pollution (NO2/PM2.5) and sleep position on OSA on additive and multiplicative scales. METHODS: This study included 3330 individuals. Personal exposure to air pollution was assessed using a spatiotemporal model. OSA was diagnosed through polysomnography. The associations of supine and nonsupine positions and air pollutants with mild-OSA and their interaction effects on mild-OSA. were explored through generalized logistic regression. RESULTS: Supine position and high NO2 level independently increased the risk of mild-OSA, while PM2.5 was not associated with mild-OSA. Significant interactions were observed between supine position and NO2 at different lag periods (0-7 days, 0-1 year, and 0-2 years) (P = 0.042, 0.013, and 0.010, respectively). The relative excess risks due to interactions on the additive scale for 1-week, 1-year, and 2-year NO2 exposure and supine position were 0.63 (95 % CI: 0.10-1.16), 0.56 (95 % CI: 0.13-0.99), and 0.64 (95 % CI: 0.18-1.10); the corresponding odds ratios for interactions on the multiplicative scale were 1.45 (95 % CI: 1.01-2.07), 1.55 (95 % CI: 1.09-2.22), and 1.60 (95 % CI: 1.12-2.28). The positive interactions persisted in men and participants with obesity. No interaction was observed between nonsupine position and NO2 levels; nevertheless, significant interactions were noted on both the negative additive and multiplicative scales in men. CONCLUSION: Prolonged supine sleep significantly increased the risk of mild-OSA, particularly in men and individuals with obesity. Although the benefits of nonsupine position are considerably less than the risks of NO2 exposure, avoiding prolonged supine sleep may reduce the risk of mild-OSA caused by high levels of NO2 in men.

Qualitative assessment of infant sleep practices and other risk factors of sudden infant death syndrome (SIDS) among mothers in Lusaka, Zambia.

BACKGROUND: There is very little information on the beliefs and perceptions of mothers about SIDS and its related risk factors in Africa. To better understand parental decisions about infant sleep practices and other risk factors for SIDS, we conducted focus group discussions (FGDs) with mothers of infants in Lusaka, Zambia. METHODS: FGDs involved 35 purposively sampled mothers aged 18-49 years. FGDs were conducted using a semi-structured interview guide in the local language, Nyanja. These were translated, transcribed verbatim into English, and then coded and analyzed using thematic analysis in NVivo 12. RESULTS: Six FGDs were conducted with 35 mothers in April-May 2021 across two study sites. FGD Participants were generally aware of sudden unexplained infant deaths, with several describing stories of apparent SIDS in the community. The side sleeping position was preferred and perceived to be safer for the infant with most believing the supine position posed an aspiration or choking risk to the infant. Bedsharing was also preferred and perceived to be convenient for breastfeeding and monitoring of the infant. Experienced family members such as grandmothers and mothers-in-law, and health care workers were frequently cited as sources of information on infant sleep position. A heightened awareness of the infant's sleeping environment was suggested as a mechanism to prevent SIDS and smothering. CONCLUSIONS: Decisions about bedsharing and infant sleep position were guided by maternal beliefs and perceptions about what is convenient for breastfeeding and safer for the infant. These concerns are vital to designing tailored interventions to address sleep-related sudden infant losses in Zambia. Public health campaigns with tailored messages that address these concerns are likely to be effective at ensuring optimal uptake of safe sleep recommendations.

Dietary factors involved in GERD management.

Gastroesophageal reflux disease (GERD) is extremely common, and even modest weight gain has been associated with higher symptom burden as well as objective evidence of reflux on endoscopy and physiological measurement. Certain trigger foods, especially citrus, coffee, chocolate, fried food, spicy food and red sauces are frequently reported to worsen reflux symptoms, although hard evidence linking these items to objective GERD is lacking. There is better evidence that large meal volume and high calorie content can increase esophageal reflux burden. Conversely, sleeping with the head end of the bed raised, avoiding lying down close to meals, sleeping on the left side and weight loss can improve reflux symptoms and objective reflux evidence, especially when the esophagogastric junction 'reflux barrier' is compromised (e.g., in the presence of a hiatus hernia). Consequently, attention to diet and weight loss are both important elements of management of GERD, and need to be incorporated into management plans.

Effects of demographic and sleep-related factors on snoring sound parameters.

OBJECTIVE: To investigate the effect of frequently reported between-individual (viz., age, gender, body mass index [BMI], and apnea-hypopnea index [AHI]) and within-individual (viz., sleep stage and sleep position) snoring sound-related factors on snoring sound parameters in temporal, intensity, and frequency domains. METHODS: This study included 83 adult snorers (mean ± SD age: 42.2 ± 11.3 yrs; male gender: 59%) who underwent an overnight polysomnography (PSG) and simultaneous sound recording, from which a total of 131,745 snoring events were extracted and analyzed. Data on both between-individual and within-individual factors were extracted from the participants' PSG reports. RESULTS: Gender did not have any significant effect on snoring sound parameters. The fundamental frequency (FF; coefficient = -0.31; P = 0.02) and dominant frequency (DF; coefficient = -12.43; P < 0.01) of snoring sounds decreased with the increase of age, and the second formant increased (coefficient = 22.91; P = 0.02) with the increase of BMI. Severe obstructive sleep apnea (OSA; AHI ≥30 events/hour), non-rapid eye movement sleep stage 3 (N3), and supine position were all associated with more, longer, and louder snoring events (P < 0.05). Supine position was associated with higher FF and DF, and lateral decubitus positions were associated with higher formants. CONCLUSIONS: Within the limitations of the current patient profile and included factors, AHI was found to have greater effects on snoring sound parameters than the other between-individual factors. The included within-individual factors were found to have greater effects on snoring sound parameters than the between-individual factors under study.

Effects of the combination of novel eye mask sleep position therapy device and oral appliance on positional OSA: A multi-arm, parallel-group randomized controlled trial.

OBJECTIVES: We explored whether a new combination of eye mask sleep position therapy (SPT) and oral appliance therapy (OAT) was more effective at treating positional obstructive sleep apnea (POSA) than was the use of either device alone. METHODS: In this randomized controlled trial, 60 POSA subjects diagnosed by standard polysomnography (PSG) were divided into three groups (ratio 1:1:1): SPT, OAT, and SPT combined with OAT (SOT). Participants underwent hospital-based follow-ups during months 1 and 6 after beginning treatment. The primary outcome was the decline in the apnea hypopnea index (AHI) at month 6. The secondary outcomes were changes in oxygen-derived parameters and the curative effect at month 6. RESULTS: After 6 months of treatment, PSG showed that SPT, OAT, and SOT all improved the AHI and oxygen-derived parameters. The AHI decline was significantly better in the SOT group than in the OAT or SPT group (71.58% [50.56-84.84%] for SOT, 44.42% [21.23-67.52%] for OAT, and 33.24% [19.03-54.62%] for SPT at 6 months) (P = 0.018 and P < 0.001 for the comparisons of SOT with OAT and SOT with SPT, respectively). In terms of oxygen-derived parameters, only the sleep apnea-specific hypoxic burden (SASHB) improved more in the SOT group (76.89% [57.43-85.91%]) than in the other groups (44.73% [32.38-72.69%] for OAT and 41.82% [15.40-65.24%] for SPT, P = 0.002 and P < 0.001 for the comparisons of SOT with OAT and SOT with SPT, respectively). The efficacies of SPT, OAT, and SOT were 36.84%, 50%, and 80% at 6 months; the SOT group evidenced the highest value (rate ratio [95% confidence interval] 1.78 (1.05-3.03), P = 0.048 and 2.17 (1.16-4.07), P = 0.010, for the comparisons of SOT with OAT and SOT with SPT, respectively). CONCLUSION: The combination of SPT and OAT was better than either treatment alone and may represent a good option for the treatment of POSA. TRIAL REGISTRATION: Chinese Clinical Trial Registry; URL: http://www.chictr.org.cn/showproj.aspx?proj=42,852; No. ChiCTR1900025584.

Residual OSA in Down syndrome: does body position matter?

STUDY OBJECTIVES: To examine children with Down syndrome with residual obstructive sleep apnea (OSA) to determine if they are more likely to have positional OSA. METHODS: A retrospective chart review of children with Down syndrome who underwent adenotonsillectomy at a single tertiary children's hospital was conducted. Children with Down syndrome who had a postoperative polysomnogram with obstructive apnea-hypopnea index (OAHI) > 1 event/h, following adenotonsillectomy with at least 60 minutes of total sleep time were included. Patients were categorized as mixed sleep (presence of ≥ 30 minutes of both nonsupine and supine sleep), nonsupine sleep, and supine sleep. Positional OSA was defined as an overall OAHI > 1 event/h and a supine OAHI to nonsupine OAHI ratio of ≥ 2. Group differences are tested via Kruskal-Wallis test for continuous variables and Fisher's exact tests for categorical. RESULTS: There were 165 children with Down syndrome who met inclusion criteria, of which 130 individuals had mixed sleep. Patients who predominately slept supine had a greater OAHI than mixed and nonsupine sleep (P = .002). Sixty (46%) of the mixed-sleep individuals had positional OSA, of which 29 (48%) had moderate/severe OSA. Sleeping off their backs converted 14 (48%) of these 29 children from moderate/severe OSA to mild OSA. CONCLUSIONS: Sleep physicians and otolaryngologists should be cognizant that the OAHI may be an underestimate if it does not include supine sleep. Positional therapy is a potential treatment option for children with residual OSA following adenotonsillectomy and warrants further investigation. CITATION: Lackey TG, Tholen K, Pickett K, Friedman N. Residual OSA in Down syndrome: does body position matter? J Clin Sleep Med. 2023;19(1):171-177.

Assessing infant sleep practices and other risk factors of SIDS in Zambia: a cross-sectional survey of mothers in Lusaka, Zambia.

BACKGROUND: Having infants sleep with their parents and sleeping face down or on their sides are the two most proximate and modifiable risk factors for sudden infant death syndrome (SIDS). Little is known about the burden of SIDS or the prevalence of these risk factors in Africa. Our primary objective was to determine the prevalence of modifiable risk factors of SIDS in Lusaka, Zambia. METHODS: We conducted cross-sectional surveys with recent mothers of infants aged < 1 year across two busy urban clinic sites in Lusaka, Zambia. We used log-binomial regression analysis to identify factors predictive of bedsharing and prone sleeping. RESULTS: Surveys were conducted with 478 mothers between April-May 2021. The sleep-related risk factors, bedsharing and side sleeping, were widely prevalent. 89.5% of respondents indicated that they share a bed with the infant during sleep, 73.0% preferred putting their baby on its side, and 19.9% preferred the prone position. Only 6.7% of respondents described using the safer, supine position. Age of infant was the only factor which was predictive of prone sleeping. Infants > 2 months old were twice as likely to be put to sleep in a prone position compared to infants aged less than 2 months old. Mothers reported that they rarely (24.1%) received advice from medical caregivers to use the supine position. Maternal use of alcohol (12.0%) and tobacco (0.8%) during pregnancy were uncommon. CONCLUSIONS: Bedsharing and placing the infant to sleep on the side were commonly reported among the mothers we interviewed. Whether this represents an opportunity to reduce SIDS in Zambia is unclear since accurate data on the burden of SIDS in Zambia is not available. There is a need for increased awareness of SIDS and more prospective data collection on its burden and related risk factors in these African populations.

[Investigation of sleep position and triggered movement in patients with benign paroxysmal positional vertigo].

Objective:To investigate the characteristics of habitual sleeping position and triggered movement in patients with benign paroxysmal positional vertigo（BPPV）. Methods:The patients with idiopathic tubulitic BPPV who the symptoms were relieved after repositioning were enrolled in this study. The relationship between the side, the tube of otolith detachment and habitual sleeping position and triggered movement was analyzed. Results:①Among the 446 patients, female gender predominated（319 cases, 71.5%）, 41-60 years old group accounted for the highest proportion（192 cases, 43.0%）, and posterior semicircular canal patients accounted for the highest proportion（289 cases, 64.8%）; ②The affected side was associated with habitual sleep postion（P<0.05, ES=0.392）, ipsilateral ear was more common in left or right decubitus; ③There were statistically significant differences in the triggered movement in different types of BPPV（P<0.05, ES=0.380）, BPPV of multiple semicircular canals. Horizontal semicircular canals and posterior semicircular canals were more likely to induce vertigo and nystagmus. Conclusion:Habitual sleeping position and triggered movement could be collected during the diagnosis of BPPV, to predict the affected side and tube. The combination of Roll test and Dix-Hallpike test is more conducive to accurately distinguish the location of otolith shedding.

Discordant Keratoconus in Monozygotic Twins.

We report a case of discordant keratoconus (KC) in a set of monozygotic twins with contrasting environmental risk factors. Twin one had bilateral, asymmetrical KC. He reported significant eye rubbing using his knuckles during his night-shift work as an emergency doctor. His usual sleeping position on the left side corresponded to the most affected eye. Twin two had normal corneas, with no evidence of KC. He reported mild infrequent eye rubbing, daytime work pattern, and a supine sleeping position. This case report highlights the influence of environmental and behavioural factors in the development of KC, in particular eye rubbing, night work, and sleeping position, in two individuals sharing identical genetic inheritance.

Successful treatment of sleep paralysis with the Sleep Position Trainer: a case report.

Sleep paralysis is a period of paralysis at either sleep onset or upon awakening and is often accompanied by terrifying hallucinations. We report a case of a 32-year-old healthy men with a history of mild positional obstructive sleep apnea and sleep paralysis. The positional sleep apnea was successfully treated with the Sleep Position Trainer. Remarkably, he did no longer experience episodes of sleep paralysis since using the Sleep Position Trainer. This case highlights a possible elegant noninvasive long-term solution for the treatment of sleep paralysis. CITATION: Cui N, van Looij MA, Kasius KM. Successful treatment of sleep paralysis with the Sleep Position Trainer: a case report. J Clin Sleep Med. 2022;18(9):2317-2319.