Sleep Center Research Articles

Retrospective cohort study of hypersomnias of central origin from two Australian tertiary sleep disorders services.

Hypersomnias of central origin (HOCO) are diverse in origin and symptomatology and remain poorly described in an Australian population. We hypothesised that the rate of human leukocyte antigen (HLA) DQB1*0602 positivity in the Australian cohort would be comparable to international registries. The current study aims to evaluate epidemiological and clinical characteristics of Australian patients with HOCO, including prevalence of HLA DQB1*0602 positivity, the most specific HLA marker associated with narcolepsy. This is a retrospective study. Patients≥ 16 years of age presenting with symptoms of hypersomnolence who attended one of two Australian sleep centres (New South Wales and Queensland) in the preceding 24 months and had undergone both HLA serology and multiple sleep latency tests (MSLTs) were included. Main outcome measures included demographics, HLA DQB1*0602 positivity, MSLT, and clinical parameters (presence of auxiliary narcolepsy symptoms, laboratory tests, relevant prescribed medications). Eighty-eight patients were included. HLA DQB1*0602 positivity was highest in those with type 1 narcolepsy (NT1) (95.7%) and lowest in those without a classifiable disorder (9.1%). Mean sleep latency was lowest and number of sleep-onset rapid eye movement periods (SOREMPs) highest in the NT1 group. Comorbid disorders, particularly depression and overweight/obesity, were prevalent in all cohorts. Across all diagnostic groups, dexamphetamine was the most commonly prescribed agent for excessive daytime sleepiness. Patients with HOCO assessed in two specialised Australian clinics demonstrate comparable clinical characteristics to other published cohorts internationally; however, available pharmacological agents in Australia do not reflect international standards of care.

Associations between abdominal obesity and the risk of stroke in Chinese older patients with obstructive sleep apnea: Is there an obesity paradox?

Background and purposeAbdominal obesity (AO) is a well-known independent risk factor for stroke in the general population although it remains unclear in the case of the elderly, especially in Chinese older patients with obstructive sleep apnea (OSA), considering the obesity paradox. This study aimed to investigate the association between AO and stroke among Chinese older patients with OSA.MethodsData were collected from January 2015 to October 2017, and 1,290 older patients (age 60–96 years) with OSA (apnea–hypopnea index ≥ 5 events/h on polysomnography) were consecutively enrolled from sleep centers at six hospitals, evaluated for AO defined as waist circumference (WC) using the standardized criteria for the Chinese population, and followed up prospectively for a median period of 42 months. Logistic regression and Cox regression analyses were used to determine the cross-sectional and longitudinal associations between AO and stroke risk in these participants and different groups of the severity of OSA.ResultsParticipants with AO had a higher prevalence of stroke at baseline. A higher incidence of stroke during a median follow-up period of 42 months in participants with AO than in participants without AO (12.4% vs. 6.8% and 8.3% vs. 2.4%, respectively; both P < 0.05) was predicted. Cross-sectional analysis revealed an association between AO and stroke (odds ratio [OR]1.96, 95% confidence interval [CI] 1.31–2.91), which was stronger among participants with moderate OSA only (OR 2.16, 95%CI 1.05–4.43). Cox regression analysis showed that, compared to participants without AO, participants with AO had a higher cumulative incidence of stroke (hazard ratio [HR] 2.16, 95% CI 1.12–4.04) during a median follow-up of 42 months, and this association was observed in patients with severe OSA only (HR 3.67, 95% CI 1.41–9.87) but not for individuals with mild OSA (HR = 1.84, 95% CI 0.43–6.23) and moderate OSA (HR = 1.98, 95% CI 0.73–6.45).ConclusionThe risk of stroke is associated with AO among Chinese older patients who have OSA, both at baseline and during follow-up, and the strength of the association varied by OSA severity. Active surveillance for early detection of AO could facilitate the implementation of stroke-preventive interventions in the Chinese older OSA population.

Chronotype and poor sleep quality in young adults – a pilot study on the role of rumination

BackgroundEveningness has been associated with poor sleep quality and depression. However, chronotype has also been shown to be a multidimensional construct, not limited to a merely morningness-eveningness orientation. It has also been proposed that other factors may also mediate the relationship between chronotype and its mental health sequelae. This pilot study explores the role of rumination as a mediator between chronotype and sleep quality, chronotype and depressive symptoms. MethodsA sample of 144 participants completed The Morningness–Eveningness-Stability-Scale Improved (MESSi), Pittsburgh Sleep Quality Index (PSQI), Rumination-Reflection Questionnaire (RRQ) and Center for Epidemiologic Studies Depression Scale (CES-D)). The results were tested using Spearman's rank correlation coefficient, multiple linear regression and the Sobel test. ResultsRumination was linked to poor sleep quality and increased depression. Morning affect and Distinctness (i.e. rigidity, or the subjective amplitude of the circadian rhythm) correlated with rumination. Rumination was a partial mediator of the associations between Morning Affect and sleep quality, Morning Affect and depression. ConclusionsRumination may play a role in the association between chronotype (particularly Morning Affect and Distinction) and sleep quality and depression. The recognition of this association might serve as a basis for clinical psychoeducational and therapeutic programs targeting both adjustment of the circadian rhythm and rumination as a psychopathological sign.

Association of Homocysteine and Risks of Long-Term Cardiovascular Events and All-Cause Death among Older Patients with Obstructive Sleep Apnea: A Prospective Study.

This study aimed to assess whether raised baseline plasma tHcy concentrations increased the risks of major adverse cardiovascular events (MACE) and all-cause death outcomes in older patients with obstructive sleep apnea (OSA). A multicenter, prospective, observational study. Beijing, Shandong Province, Gansu Province of China. A total of 1, 290 OSA patients aged 60 to 96 years from sleep centers of six hospitals in China consecutively recruited between January 2015 and October 2017. Cox proportional models assessed the association between tHcy and the risk of new-onset all events among Chinese older OSA patients. The final analysis (60.1% male; median age, 66 years) used data from 1, 100 subjects during a median follow-up of 42 months, a total of 105 (9.5%) patients developed MACE and 42 (3.8%) patients died. Multivariable Cox regression analysis showed higher adjusted hazard ratios (aHRs) of MACE, myocardial infarction (MI), hospitalization for unstable angina, and composite of all events with tHcy levels in the 4th quartile (HR=5.93, 95% CI: 2.79-12.59; HR=4.72, 95% CI:1.36-4.61; HR=4.26, 95% CI:1.62-5.71; HR=4.17, 95% CI:2.23-7.81) and the 3rd quartile (HR=3.79, 95% CI:1.76-8.20; HR=3.65, 95% CI:1.04-2.98; HR=2.75, 95% CI:1.08-3.76; HR=2.51, 95% CI:1.31-4.83) compared to reference tHcy levels in quartile 1, respectively, while the aHRs (95% CIs) of all-cause death showed significantly higher only in the highest tHcy level quartile than in the lowest quartile (HR=3.20, 95% CI=1.16-8.84, P=0.025) with no significant differences in risks of cardiovascular death and hospitalisation for heart failure among groups (P>0.05). tHcy, a marker of prognosis for older OSA patients, was significantly associated with the increased risk of MACE and all-cause death in this population independent of BMI, smoking status, and other potential risk factors, but not all clinical components events of MACE. New therapeutic approaches for older patients with OSA should mitigate tHcy-associated risks of MACE, and even all-cause death.

Association between residential greenness and obstructive sleep apnoea among adults in Southern China

BackgroundNo previous study has explored the association of residential greenness with obstructive sleep apnoea (OSA) indexes. ObjectiveTo investigate the association of exposure to residential greenness with OSA indexes in adults in Guangdong Province, Southern China. MethodsFrom January 1, 2005 to December 31, 2015, a total of 3925 participants were recruited from the Sleep Center of Guangdong Provincial People's Hospital. Apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were measured by polysomnography or home sleep test (HST). Participants' daytime sleepiness scores were evaluated using The Epworth Sleeping Scale (ESS). The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were used to assess residential greenness levels. Generalized linear regression models were used to assess the associations of residential greenness with OSA indexes after adjusting for multiple covariates. ResultsThe mean (standard deviation) age of the participants was 63.3 (14.4) years. In adjusted models, an interquartile range (IQR) increase in 3-year average NDVI was significantly associated with 9.8 % (95 % confidence interval [95 % CI]: 17.5 %, 2.1 %); 14.5 % (95 % CI: 24.5 %, 4.4 %) and 6.9 % (95 % CI: 13.7 %, 0.0 %) decreases in AHI, ODI and ESS scores, respectively. Furthermore, an IQR increase in 3-year average EVI was significantly associated with 7.8 % (95 % CI: 13.7 %, 1.9 %); 10.8 % (95 % CI: 18.3 %, 3.2 %) and 7.2 % (95 % CI: 12.5 %, 2.0 %) declines in AHI, ODI and ESS scores, respectively. Significant associations were only observed among males, adults aged ≥65 years old, and in the warm season. ConclusionsOur study indicates that higher residential greenness was significantly associated with lower OSA indexes in adult population in South China, especially in males, in the elderly, and in the warm season.

Sleep and Breathing Disturbances in Children With Leigh Syndrome: A Comparative Study

BackgroundLeigh syndrome (LS) is a progressive neurodegenerative mitochondrial disease characterized by necrotizing lesions affecting different parts of the central nervous system, especially in the brainstem and basal ganglia. Lesions in this area may involve respiratory and sleep centers, resulting in the clinically significant disturbances seen—but poorly characterized—in LS. The purpose of the present study is to characterize and compare the physiologic responses to respiratory disturbances quantified by polysomnography metrics of children with LS with age-sex- and apnea-hypopnea index (AHI)-matched patients with obstructive sleep apnea (OSA), a common clinical population with similar burden of sleep-disordered breathing. MethodsRetrospective comparative study of polysomnographic data from six patients with LS were reviewed and compared with 18 age-sex-AHI-matched patients with OSA, with particular attention to cardiorespiratory and sleep architecture metrics. ResultsSleep architecture and stage duration were conserved in LS and OSA groups, but increased wake after sleep onset was seen among the first group. The LS group exhibited both obstructive and central sleep apnea. The group also had significantly greater values of heart rate, ≥3% oxygen desaturation index, and lower values of sleep efficiency, respiratory arousal index, and total sleep time when compared with the OSA group. ConclusionsPatients with LS exhibited significantly more sleep-related cardiorespiratory disturbances and sleep fragmentation when compared with neurotypical children with OSA. Given that these findings are plausibly detrimental to health and development, sleep evaluation in patients with similar conditions should be encouraged for early management.

Comorbid insomnia and sleep apnea in children: a preliminary explorative study.

Insomnia and sleep-disordered breathing (SDB) are prevalent sleep disorders. These disorders can therefore be concurrently present - comorbid insomnia and sleep apnea (COMISA). The prevalence of COMISA in the paediatric age range is unclear. As such, phenotypic constructs should help better define this comorbid condition if it exists in children and improve both diagnostic sensitivity and ultimately clinical care outcomes. We aimed to evaluate the frequency of insomnia in children and adolescents referred for evaluation of sleep symptoms suggestive of SDB in one initial (Cohort#1) and verify such findings in an independent cohort (Cohort#2) using a retrospective cross-sectional approach in patients aged 9-19 years presenting at a sleep centre to be evaluated for symptoms of SDB. Cohort #1 comprised 50 consecutive children (58% males; mean [SD] age 13.6[3.3]years; median [interquartile range, IQR] Epworth Sleepiness Scale score 10[6-12]) who were evaluated using validated SDB and insomnia questionnaires. Cohort#2 was extracted from electronic medical records and included 384 polysomnographically evaluated children (mean [SD] age 12.9[3.6]years; mean [SD] body mass index z score 1.27[0.28]; median Epworth Sleepiness Scale score 9.7[4-17]). In Cohort #1, 56% were at high risk of SDB, 36% had insomnia alone, and 18% were at high risk of COMISA. The prevalence of COMISA in Cohort #2 was 16%, 72% had SDB alone, and 12% had insomnia alone. In both cohorts, COMISA manifested as increased propensity for sleepiness and fatigue during both waking and daytime. Thus, the presence of COMISA is frequent in the paediatric age range and accompanied by a more prominent symptomatic phenotype.

Multimodal Telemonitoring for Weight Reduction in Patients With Sleep Apnea: A Randomized Controlled Trial

Telemonitoring the use of CPAP devices and remote feedback on device data effectively optimizes CPAP adherence in patients with OSA. Can expanding the scope of telemonitoring and remote feedback to body weight (BW), BP, and physical activity enhance efforts for BW reduction in Patients with OSA receiving CPAP? Participants were recruited from patients at 16 sleep centers in Japan with OSA and obesity who were receiving CPAP therapy. Obesity was defined as a BMI of≥ 25kg/m2, based on Japanese obesity guidelines. Implementation of CPAP telemonitoring was enhanced with electronic scales, BP monitors, and pedometers that could transmit data from devices wirelessly. Participants were randomized to the multimodal telemonitoring group or the usual CPAP telemonitoring group and were followed up for 6months. Attending physicians provided monthly telephone feedback calls to the usual CPAP telemonitoring group on CPAP data obtained remotely. In the multimodal telemonitoring group, physicians additionally encouraged participants to reduce their BW, after sharing the remotely obtained data on BW, BP, and step count. The primary outcome was set as≥ 3%BW reduction from baseline. One hundred sixty-eight participants (BMI, 31.7 ± 4.9kg/m2) completed the study, and≥ 3%BW reduction occurred in 33 of 84 participants (39.3%) and 21 of 84 participants (25.0%) in the multimodal telemonitoring and usual CPAP telemonitoring groups, respectively (P= .047). Whereas no significant differences were found between the two groups in the change in office and home BP, daily step counts during the study period were significantly higher in the multimodal telemonitoring group than in the usual CPAP telemonitoring group (4,767 steps/d [interquartile range (IQR), 2,864-6,617 steps/d] vs3,592 steps/d [IQR, 2,117-5,383 steps/d]; P= .02) INTERPRETATION: Multimodal telemonitoring may enhance BW reduction efforts in patients with OSA and obesity. UMIN Clinical Trials Registry; No.: UMIN000033607; URL: www.umin.ac.jp/ctr/index.htm.

Adherence to Auto-CPAP and Age: A Stable Condition? Comment on Barroso et al. Influence of Age on Adherence to Auto-CPAP: Experience from a Sleep Center in Portugal. Adv. Respir. Med. 2022, 90, 143-147.

We have read with great interest the recent paper published by Barroso et al. [...].

Sleep telemedicine lacks immunity to Continuous Positive Airway Pressure device shortages

In this issue of SLEEP, Kosky et al. [1] take a real-world approach to explore a particular application of sleep telemedicine. Their manuscript, “Telemedicine compared to standard face-to-face care for CPAP treatment: real-world Australian experience,” shows that the former is both feasible and noninferior to the latter in terms of CPAP adherence, efficacy, and sleepiness/functional outcome improvement. While the standard care arm participants reported slightly higher satisfaction than the telemedicine arm participants, there were significant cost savings in the telemedicine arm. The study is particularly notable for several reasons, including its pragmatic design. Participants were not randomized into standard- and telemedicine-based care, a common paradigm among similar trials. Individuals living more than 100 km from the sleep center became the telemedicine arm as they likely would in usual clinical practice. As Table 1 of the article demonstrates, demographic imbalances introduced by such a recruitment model were relatively minor. Another notable feature in the study’s design was its emphasis on CPAP treatment follow-up as opposed to initial evaluation or testing. That is, initial evaluations were not constrained to video consultation if the participant chose to have that initial visit face to face in Perth. Furthermore, all participants—standard and telemedicine arm—underwent in-laboratory sleep testing and face-to-face CPAP set-up (if indicated) at the same Perth sleep center. It was at this point that the treatment models diverged most consistently; telemedicine arm participants received CPAP follow-up via telephone and remote telemonitoring via built-in CPAP device modem, while standard arm participants received CPAP follow-up via face-to-face visits and physical device downloads. The results, summarized above, revealed that the technologic blend of video teleconferencing, telephone, and remote CPAP device downloading had delivered clinically rigorous, well-accepted, and cost-effective care. Participant enrollment concluded in June 2019, just as sleep telemedicine was about to face significant disruption.

Obstructive sleep apnea is position dependent in young infants

BackgroundObstructive sleep apnea in infants with Pierre Robin sequence is sleep-position dependent. The influence of sleep position on obstructive events is not established in other infants.MethodsWe re-evaluated ten-year pediatric sleep center data in infants aged less than six months, with polysomnography performed in different sleep positions. We excluded infants with syndromes, genetic defects, or structural anomalies.ResultsComparison of breathing between supine and side sleeping positions was performed for 72 infants at the median corrected age of 4 weeks (interquartile range (IQR) 2-8 weeks). Of the infants, 74% were male, 35% were born prematurely, and 35% underwent study because of a life-threatening event or for being a SIDS sibling. Upper airway obstruction was more frequent (obstructive apnea-hypopnea index (OAHI), p < 0.001), 95th-percentile end-tidal carbon dioxide levels were higher (p = 0.004), and the work of breathing was heavier (p = 0.002) in the supine than in the side position. Median OAHI in the supine position was 8 h−1 (IQR 4–20 h−1), and in the side position was 4 h−1 (IQR 0-10 h−1).ConclusionsObstructive upper airway events in young infants are more frequent when supine than when sleeping on the side.ImpactThe effect of sleep position on obstructive sleep apnea is not well established in infants other than in those with Pierre Robin sequence.A tendency for upper airway obstruction is position dependent in most infants aged less than 6 months. Upper airway obstruction is more common, end-tidal carbon dioxide 95th-percentile values higher, and breathing more laborious in the supine than in the side-sleeping position.Upper airway obstruction and obstructive events have high REM sleep predominance.As part of obstructive sleep apnea treatment in young infants, side-sleeping positioning may prove useful.

Dopamine and GPCR-mediated modulation of DN1 clock neurons gates the circadian timing of sleep

The metronome-like circadian regulation of sleep timing must still adapt to an uncertain environment. Recent studies in Drosophila indicate that neuromodulation not only plays a key role in clock neuron synchronization but also affects interactions between the clock network and brain sleep centers. We show here that the targets of neuromodulators, G Protein Coupled Receptors (GPCRs), are highly enriched in the fly brain circadian clock network. Single-cell sequencing indicates that they are not only enriched but also differentially expressed and contribute to clock neuron identity. We generated a comprehensive guide library to mutagenize individual GPCRs in specific neurons and verified the strategy by introducing a targeted sequencing approach. Combined with a behavioral screen, the mutagenesis strategy revealed a role of dopamine in sleep regulation by identifying two dopamine receptors and a clock neuron subpopulation that gate the timing of sleep.

Does unconscious socioeconomic bias influence tele-evaluation of obstructive sleep apnea? An exploratory analysis

Study objectivesWe examined the association between a patient's income and a provider's ability to identify risk for obstructive sleep apnea (OSA) when assessed in-person versus via telemedicine. MethodsWe utilized data from a randomized interrater reliability study of 58 patients who were referred to a university sleep center. Participants volunteered their annual income bracket as part of data collection, although raters were blinded to these data. We assessed the inter-method reliability between the clinical impressions of a telemedicine rater and those of an in-person rater for pretest probability of OSA, stratified by income levels. ResultsInter-method reliabilities, assessed using weighted kappa, were 0.83, 0.24, and 0.66 for subjects with low (<$50,000/year), moderate ($50,000-$100,000/year) and high (>$100,000) incomes, respectively. The kappa statistics were significantly different (p = 0.005) between the low and moderate income groups. ConclusionsThere was a significant difference in the reliability values of telemedicine versus in-person assessments between the low and middle income brackets. This is despite the raters being unaware of the patients' income levels. This association might suggest possible unconscious bias in evaluating for OSA. With telemedicine in early development, it is important to create processes that will minimize bias that might result from patients’ economic disparities.

Referrals of pediatric patients to a sleep center during its first 5years.

Referrals of pediatric patients to a sleep center during its first 5years.

External proficiency testing improves inter-scorer reliability of polysomnography scoring.

This study evaluated whether or notpolysomnography (PSG) inter-scorer reliability (ISR) across sleep centres could be improved by external proficiency testing (EPT), or by EPT combined with method alignment training. Experienced scorers form 15 sleep centres were randomised to the following: (1) a control group, (2) a group that received a self-directed intervention of EPT reports (EPTPassive) or (3) a group that received an active intervention of method alignment training and EPT reports (EPTActive). Respiratory, arousal and sleep scoring ISR from sixteen PSG fragments were compared between groups across time. Among 30 scorers, there were no ISR changes in controls between baseline (BL) and 6months (6m). Both EPT groups showed ISR improvement from BL to 6m for respiratory, arousal and sleep scoring (p < 0.05). Respiratory scoring back-transformed mean (95CI) proportion of specific agreement (PSA) for the EPTPassive group improved from 0.78 (0.72-0.84) to 0.80 (0.74-0.86) and for the EPTActive group from 0.80 (0.74-0.85) to 0.82 (0.76-0.88). Arousal scoring PSA for the EPTPassive group improved from 0.72 (0.66-0.77) to 0.74 (0.69-0.79) and for the EPTActive group from 0.71 (0.65-0.76) to 0.77 (0.72-0.82). Sleep scoring kappa for the EPTPassive group improved from 0.64 (0.58-0.69) to 0.73 (0.68-0.77) and for the EPTActive group from = 0.75 (0.71-0.80) to 0.80 (0.76-0.85). Overall, poorer performers achieved greater improvement. External proficiency testing produced modest, statistically significant PSG inter-scorer reliability improvements among experienced scorers across sleep centres, with potential to improve clinical management of individual patients and increase research study statistical power.

Manual versus computer-aided scoring of sleep studies: preliminary results on inter-rater agreement and analysis of scoring time differences in one sleep center

Manual versus computer-aided scoring of sleep studies: preliminary results on inter-rater agreement and analysis of scoring time differences in one sleep center

What is the best way to assess the severity of Rhythmic Movement Disorder? Experience from a specialist paediatric sleep centre

What is the best way to assess the severity of Rhythmic Movement Disorder? Experience from a specialist paediatric sleep centre

Central disorders of hypersomnolence: diagnostic discrepancies between military and civilian sleep centers.

The majority of active-duty service members obtain insufficient sleep, which can influence diagnostic evaluations for sleep disorders, including disorders of hypersomnolence. An incorrect diagnosis of hypersomnia may be career ending for military service or lead to inappropriate medical care. This study was conducted to assess the rates at which narcolepsy (Nc) and idiopathic hypersomnia (IH) are diagnosed by military vs civilian sleep disorders centers. This retrospective study utilized claims data from the Military Health System Data Repository. The analyses compared diagnostic rates of military personnel by provider type-either civilian provider or military provider-from January 1, 2016 to December 31, 2019. Three diagnostic categories for Nc and IH: Nc or IH, Nc only, and IH only, were assessed with multivariate logistic regression models. We found that among service members evaluated for a sleep disorder, the odds ratios of a positive diagnosis at a civilian facility vs a military facility for Nc or IH was 2.1, for Nc only was 2.1, and IH only was 2.0 over the 4-year period. Civilian sleep specialists were twice as likely to diagnose central disorders of hypersomnolence compared to military specialists. Raising awareness about this discrepancy is critical given the occupational and patient care-related implications of misdiagnoses. Thomas CL, Vattikuti S, Shaha D, etal. Central disorders of hypersomnolence: diagnostic discrepancies between military and civilian sleep centers. J Clin Sleep Med. 2022;18(10):2433-2441.

Changing Effects of Minimally Invasive Surgical Intervention on ALT, AST, and UA in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome.

Background This study aims at exploring the effect of obstructive sleep apnea–hypopnea syndrome (OSAHS) on the liver and kidney function indexes of patients and analyze the changes in these indexes after minimally invasive surgery. Method Patients with OSAHS (n = 51) who were diagnosed via polysomnography (PSG) and received minimally invasive surgery in the sleep disorders diagnosis and treatment center of the West China Fourth Hospital of Sichuan University from January 2017 to January 2019 were selected as test subjects and placed in the OSAHS group. At the same time, 79 healthy people with no snoring or breathing difficulties were selected from the medical examination center of the hospital as the control group (tested as normal by PSG). These two groups were used to compare the differences in the related indexes of serum liver and kidney function and evaluate the changes in sleep monitoring and related liver and kidney function indexes in patients with OSAHS after minimally invasive surgery. Results The alanine aminotransferase (ALT), aspartate aminotransferase (AST), and uric acid (UA) levels were higher in the OSAHS group (48.98 ± 36.34, 28.88 ± 14.80, and 422.30 ± 98.65, respectively) than in the control group (21.91 ± 11.61, 22.18 ± 6.19, and 330.49 ± 64.45 and t = 6.514, 3.549, and 6.373, respectively; p < 0.05). Of the patients with OSAHS, 17 were followed up for one year. After minimally invasive surgery, ALT decreased from 44.29 ± 20.61 to 26.47 ± 9.91 (t = 4.395), AST decreased from 27.71 ± 8.32 to 21.82 ± 4.81 (t = 3.673), and UA decreased from 397.35 ± 92.14 umol/L to 362.94 ± 106.76 umol/L (t = 2.580), and these differences were statistically significant (p < 0.05).The changes in ALT (r = −0.635) and AST (r = −0.504) were related to the difference in the lowest blood oxygen saturation (p < 0.05), and the change in UA was related to the difference in the apnea–hypopnea index (r = −0.532, p < 0.05). Conclusion There are some abnormalities in liver- and kidney-function-related indexes in patients with OSAHS, and minimally invasive surgery can help to improve liver and kidney function in these patients.

Association between early stage N2 sleep spindle burst characteristics and vigilance groups: an observational study on patients from a tertiary sleep centre

Objective. Obstructive sleep apnoea (OSA) is associated with impaired vigilance. This paper examines the hypothesis that sleep spindle (Sp) characteristics during nocturnal sleep can be mapped to vigilance deficits measured by the psychomotor vigilance task (PVT) in patients with OSA. Approach. The PVT was performed prior to In-laboratory Polysomnography for 250 patients. PVT outcomes were clustered into three vigilance groups (VGs). Spindles were scored manually for a Training Cohort of 55 patients, (9491 Sps) across different blocks of NREM sleep (SBs) and validated in a Test Cohort (25 patients, 4867 Sps). We proposed a novel set of Sp features including a spindle burst index (SBI), which quantifies the burst characteristics of spindles and constructed models mapping them to VGs. We also explored the performance of conventional Sp features (such as Sp number and density) in our modelling approach. Main results. In the Training Cohort, we observed statistically significant differences in the SBI across VGs and SBs independent of OSA severity (1st stage N2 SBI; p = <0.001 across VGs). In the Test Cohort, a Model based on the proposed SBI predicted VG membership with 88% accuracy. A model based on conventional Sp features mapped to VGs with 80% accuracy, and a model using mixed burst and conventional features reached an accuracy of 88%. Significance. Spindle features measured during diagnostic In-laboratory polysomnography measurements can be mapped to PVT outcomes. The novel SBI proved useful for exploring the relationship between PVT outcomes and sleep. Further studies in larger populations are needed to verify these conclusions.