Watch-PAT versus level III device in diagnosing sleep disordered breathing in first myocardial infarction

Circadian timing, melatonin and hippocampal volume in later-life adults

Hippocampal atrophy is a prominent neurodegenerative feature of Alzheimer's disease and related dementias. Alterations in circadian rhythms can exacerbate cognitive aging and neurodegeneration. This study aimed to examine how dim light melatonin onset and melatonin levels are associated with hippocampal volume in cognitively healthy individuals. We studied data from 52 later-life adults (mean age ± SD = 70.0 ± 6.3 years). T1-weighted anatomical images from 3.0 T magnetic resonance imaging data were collected and processed using the BRAINSTools toolbox. Dim light melatonin onset was used to assess circadian timing. The area under the curve was calculated to quantify melatonin concentration levels 6 hr before bedtime, and 14-day wrist actigraphy data were used to assess habitual bedtime. Multiple linear regression modelling with hippocampal volume as the dependent variable was used to analyse the data adjusting for age and sex. The average dim light melatonin onset was 19:45 hours (SD = 84 min), and area under the curve of melatonin levels 6 hr before habitual bedtime was 38.4 pg ml-1 × hr (SD = 29.3). We found that later dim light melatonin onset time (b = 0.16, p = 0.005) and greater area under the curve of melatonin levels 6 hr before habitual bedtime (b = 0.05, p = 0.046) were associated with greater adjusted hippocampal volume. The time between dim light melatonin onset and the midpoint of sleep timing was not associated with hippocampal volume. The findings suggest that earlier circadian timing (dim light melatonin onset) and reduced melatonin may be associated with reduced hippocampal volume in older adults. Future research will help researchers utilize circadian rhythm information to delay brain aging.

Sleep, circadian rhythm characteristics, and melatonin levels in later life adults with and without coronary artery disease

STUDY OBJECTIVES

The purpose of this study was to conduct a comprehensive assessment of sleep and circadian rhythms in individuals with and without coronary artery disease (CAD).

METHODS

This was a cross-sectional study. Participants were 32 individuals, mean age = 70.9, female 46.9%, 19 with CAD, and 13 without CAD. We assessed sleep quality and 24-hour rest-activity rhythms for 14 days using wrist actigraphy and self-report measures, and circadian rhythm using dim light melatonin onset.

RESULTS

Melatonin levels prior to habitual bedtime were significantly lower in individuals with CAD than in those without CAD (median area under the curve = 12.88 vs 26.33 pg/ml × h, P = .049). The median circadian timing measured by dim light melatonin onset was the same for the 2 groups with 20:26 [hours:minutes] for individuals with CAD and 19:53 for the control group (P = .64, r = .14). Compared to the control group, the CAD group had significantly lower amplitude (P = .03, r =-.48), and lower overall rhythmicity (pseudo-F-statistic P = .004, r = -.65) in their 24-hour rest-activity rhythms.

CONCLUSIONS

This is one of the first studies to comprehensively assess both sleep and circadian rhythm in individuals with CAD. Compared to non-CAD controls, individuals with CAD had lower levels of melatonin prior to habitual bedtime and a lower 24-hour rest-activity rhythm amplitude and overall rhythmicity. Future studies using larger sample sizes should further investigate the possibility of suppressed circadian rhythmicity in individuals with CAD.

CITATION

Moon C, Benson CJ, Albashayreh A, Perkhounkova Y, Burgess HJ. Sleep, circadian rhythm characteristics, and melatonin levels in later life adults with and without coronary artery disease. J Clin Sleep Med. 2023;19(2):283-292.

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

Does Scoliosis Affect Sleep Breathing?

OBJECTIVE

Scoliosis, especially thoracic curves, causes poor pulmonary function. As a result, scoliosis may impair sleep breathing. The literature regarding the relationship between scoliosis and sleep breathing is sparse.

METHODS

Fifty-seven patients with adolescent idiopathic scoliosis or congenital scoliosis and 25 healthy control subjects were included. The wrist sleep monitors was used. Sleep breathing was evaluated with the following parameters: 1) Respiratory Disorders Index (pRDI), indicating mean respiratory events per hour of sleep including apnea, hypoxia, and respiratory effort-related arousal; 2) Apnea and Hypopnea Index (pAHI), expressing the number of apnea and hypopnea events per hour of sleep; and 3) mean and minimal oxygen saturation (Sao₂) during sleep.

RESULTS

No differences in age, sex distribution, and body mass index were found between the two groups. Patients with scoliosis had statistically significant higher pRDI (median, 10.10 vs. 8.65; P = 0.039) and pAHI (median, 1.60 vs. 0.72; P = 0.029) scores than the control group. The minimal SaO₂ value in patients with scoliosis was lower (median, 93% vs. 94%, respectively; P = 0.005), whereas no difference was found in the mean SaO₂ value during sleep. In patients with scoliosis, pAHI scores were higher when lying on the convex side of the thoracic curve compared with the concave side (2.34 vs. 2.28, respectively; P = 0.044), whereas no such difference was observed in the control group.

CONCLUSIONS

Patients with scoliosis have more respiratory events of apnea and hypopnea during sleep than the control group. The minimal SaO₂ value in patients with scoliosis is lower than the normal population. Sleeping on the convex side of the thoracic curve results in higher pAHI scores than on the concave side.