Network analysis of sleep bruxism in the EPISONO adult general population

Sleep bruxism (SB) has been associated with biological and psychosocial factors. The assessment of SB includes self-report, clinical evaluation, and polysomnography. This study aimed to investigate the associations of self-reported SB with other sleep disorders and demographic, psychological, and lifestyle factors in the adult general population, and to investigate whether self-reported SB and polysomnographically (PSG) confirmed SB provide similar outcomes in terms of their associated factors. We recruited 915 adults from the general population in Sao Paulo, Brazil. All participants underwent a one-night PSG recording and answered questions about sex, age, BMI, insomnia, OSA risk, anxiety, depression, average caffeine consumption, smoking frequency, and alcohol consumption frequency. We investigated the link between SB and the other variables in univariate, multivariate, and network models, and we repeated each model once with self-reported SB and once with PSG-confirmed SB. Self-reported SB was only significantly associated with sex (p = 0.042), anxiety (p = 0.002), and depression (p = 0.03) in the univariate analysis, and was associated with insomnia in the univariate (p < 0.001) and multivariate (β = 1.054, 95%CI 1.018-1.092, p = 0.003) analyses. Network analysis showed that self-reported SB had a direct positive edge to insomnia, while PSG-confirmed SB was not significantly associated with any of the other variables. Thus, sleep bruxism was positively associated with insomnia only when self-reported, while PSG-confirmed SB was not associated with any of the included factors.

Decrypting the putative interrelation between sleep bruxism, masticatory muscle pain and sleep breathing disorders: Nosology and the role of hypoxia

This commentary on sleep medicine explores whether the potential relationship between sleep bruxism (SB), masticatory muscle pain (MMP) and sleep breathing disorders (SBDs)contributes to improving the management of co-occurring conditions.The paper is divided into 2 sections: (1) reviewing the debate on SB nosology; and (2) based on the publications from the Martynowicz & Wieckiewicz research group, exploringthe role of intermittent hypoxia as a putative mechanism endotype that may link such co-occurrence among individuals for whom characteristics are not yet clear.

Clinical Phenotypes Supporting the Relationship Between Sleep Disturbance and Impairment of Placebo Effects

Lack of good sleep or insomnia can lead to many health issues, including an elevated risk of cardiovascular disease, obesity, fatigue, low mood, and pain. While chronic pain negatively impacts sleep quality, the relationship between descending pain modulatory systems like placebo effects and sleep quality is not thoroughly known. We addressed this aspect in a cross-sectional study in participants with chronic pain. Placebo effects were elicited in a laboratory setting using thermal heat stimulations delivered with visual cues using classical conditioning and verbal suggestions. We estimated the levels of insomnia severity with the Insomnia Severity Index and the sleep quality with the Pittsburg Sleep Quality Index. The previous night's sleep continuity was assessed as total sleep time, sleep efficiency, and sleep midpoint the night before the experiment. 277 people with chronic pain and 189 pain-free control individuals participated. Participants with chronic pain and insomnia showed smaller placebo effects than those with chronic pain without insomnia. Similarly, poor sleep quality was associated with reduced placebo effects among participants with chronic pain. Clinical anxiety measured by Depression Anxiety Stress Scales partially mediated these effects. In contrast, placebo effects were not influenced by the presence of insomnia or poor sleep quality in pain-free participants. Sleep continuity the night before the experiment did not influence the placebo effects. Our results indicate that participants who experience insomnia and/or poor sleep quality and chronic pain have smaller placebo effects, and that the previous night sleep continuity does not influence the magnitude of placebo effects. PERSPECTIVE: This study examined the relationship between sleep disturbances and experimentally induced placebo effects. We found that individuals with chronic pain who experience insomnia and poor sleep quality demonstrated reduced placebo effects compared to their counterparts with good sleep quality and no insomnia.

Mandibular Jaw Movement Automated Analysis for Oral Appliance Monitoring in Obstructive Sleep Apnea: A Prospective Cohort Study

RATIONALE

Oral appliances are second-line treatments options after continuous positive airway pressure for obstructive sleep apnea (OSA) management. However, the need for oral appliance titration limits their use due to monitoring challenges to assess the treatment effect.

OBJECTIVES

To assess the validity of mandibular jaw movements (MJM) automated analysis compared to polysomnography/polygraphy (PSG/PG) in evaluating the effect of oral appliance treatment and the effectiveness of MJM monitoring for oral appliance titration at home in OSA patients.

METHODS

This observational, prospective study included 135 OSA patients eligible for oral appliance therapy. The primary outcome was the apnea-hypopnea index (AHI), measured through in-laboratory PSG/PG and MJM-based technology. . Additionally, MJM monitoring at-home was conducted at regular intervals during the titration process. The agreement between PSG/PG and MJM automated analysis was evaluated using Bland-Altman analysis. Change in AHI during the home-based oral appliance titration process was evaluated using GLMM and GEE models.

RESULTS

The automated MJM analysis demonstrated strong agreement with PG in assessing AHI during MAD treatment, with a median bias of 0.24/h (limits of agreement: -11.2 to 12.8/h). The improvement of AHI from baseline in response to oral appliance treatment was consistent across 3 evaluation conditions : in-lab PG (-59.6%; 59.8 to -59.5), in-lab MJM (-59.2%; -65.2 to -52.2) and at-home MJM analysis (-59.7% ; -67.4 to -50).

CONCLUSIONS

Incorporating MJM automated analysis into the oral appliance titration process has the potential to optimize oral appliance therapy outcomes for OSA.

Sleep architecture as a candidate for phenotyping sleep bruxism: A narrative physiological review

BACKGROUND

Sleep bruxism (SB), an oral behaviour in otherwise healthy individuals, is characterised by frequent rhythmic masticatory muscle activity (RMMA) during sleep. RMMA/SB episodes occur over various sleep stages (N1-N3 and rapid eye movement (REM)), sleep cycles (non-REM to REM), and frequently with microarousals. It currently remains unclear whether these characteristics of sleep architecture are phenotype candidates for the genesis of RMMA/SB.

OBJECTIVES

This narrative review investigated the relationship between sleep architecture and the occurrence of RMMA as a SB phenotype candidate.

METHODS

PubMed research was performed using keywords related to RMMA/SB and sleep architecture.

RESULTS

In non-SB and SB healthy individuals, RMMA episodes were most frequent in the light non-REM sleep stages N1 and N2, particularly during the ascending phase of sleep cycles. The onset of RMMA/SB episodes in healthy individuals was preceded by a physiological arousal sequence of autonomic cardiovascular to cortical activation. It was not possible to extract a consistent sleep architecture pattern in the presence of sleep comorbidities. The lack of standardisation and variability between subject complexified the search for specific sleep architecture phenotype(s).

CONCLUSION

In otherwise healthy individuals, the genesis of RMMA/SB episodes is largely affected by oscillations in the sleep stage and cycle as well as the occurrence of microarousal. Furthermore, a specific sleep architecture pattern cannot be confirmed in the presence of sleep comorbidity. Further studies are needed to delineate sleep architecture phenotype candidate(s) that contribute to the more accurate diagnosis of SB and treatment approaches using standardised and innovative methodologies.

A case-control study on the effect of rhythmic masticatory muscle activity (RMMA) clusters on sleep fragmentation and severity of orofacial muscle pain in sleep bruxism

Rhythmic masticatory muscle activity (RMMA) is a periodic muscle activity that characterises sleep bruxism (SB) events. These can occur as a single event, in pairs, or in clusters. Since RMMA episodes often occur in clusters and the relevance of this occurrence is unknown, we conducted a study to investigate the effect of RMMA clusters on sleep fragmentation and the severity of orofacial muscle pain. This study involved a secondary analysis using data from 184 adult subjects with orofacial muscle pain who underwent definitive polysomnography (PSG) for sleep bruxism diagnosis. Self-reported orofacial muscle pain (OFMP) was assessed using the numeric rating scale, and additional evaluation of side-to-side equivalence (symmetry) was described using a binary system. Among the 184 participants, 60.8% (n = 112) did not exhibit clusters and among the 72 participants with clusters, 36.1% (n = 26) and 63.9% (n = 46) were in the high and low RMMA frequency groups, respectively. The high SB group had significantly three times more phasic RMMA events than the noncluster group. A total of 89.67% (n = 165) of subjects reported orofacial muscle pain. While there was no difference in the severity of OFMP among groups, a significant decrease in symmetry between the severity of temporal muscle pain on the left and right sides was noted in the cluster group compared with the noncluster group. Clustering of RMMA events is associated with sleep fragmentation. The asymmetry of temporal muscle pain is related to the presence of RMMA clusters in sleep bruxism.

An exploratory study on the association between serotonin and sleep breathing disorders

This exploratory observational study aimed to evaluate whether the blood levels of serotonin and enzymes involved in serotonin synthesis are associated with sleep breathing parameters. A total of 105 patients were included in this study, who were subjected to single-night polysomnography with simultaneous audio-video recordings. Peripheral blood samples were collected to estimate the serum levels of serotonin, tryptophan hydroxylase 1 (TPH1), and aromatic l-amino acid decarboxylase (AADC). Results showed a negative correlation between blood serotonin levels, and oxygen desaturation index (ODI) (p = 0.027), central apnea (p = 0.044) and obstructive apnea (OA) (p = 0.032) scores. Blood TPH1 levels were negatively correlated with average (p = 0.003) and minimal saturation (p = 0.035) and positively correlated with apnea-hypopnea index (p = 0.010), OA (p = 0.049), and hypopnea index (p = 0.007) scores. A tendency to sleep-disordered breathing seemed to co-occur with lower blood serotonin and higher TPH1 levels.Clinical Trial Registration : www.ClinicalTrials.gov , identifier NCT04214561.

Association between night pain and quality of life in women: A general population sleep study

BACKGROUND

Women with pain present decreased sleep duration and quality of life, but little is known about the consequences of nighttime pain on overall health. Our goal was to compare levels of anxiety, depression and fatigue in women with pain during the night with those without pain. We hypothesized that pain perception is associated with the worsening of fatigue and mood.

METHODS

In total, 244 women aged 20-80 years who took part in the Epidemiologic Sleep Study (EPISONO) met the inclusion criteria, 85 in the self-reported pain group and 171 in the control group. Participants were assigned to the pain group if they both responded (i) they generally had pain, according to Pre-Sleep Questionnaire (PSQ) and (ii) their pain generally interfered with their sleep 3 or more times a week, according to Pittsburg Sleep Quality Index (PSQI). Those who answered negatively to both questions were allocated to the control group. All participants underwent a full night laboratory polysomnography, and completed questionnaires related to fatigue, depression, anxiety and quality of life.

RESULTS

Pain group participants had a significantly lower perception of quality of life, and significantly higher levels of fatigue (5.4 times), anxiety and depression. Pain perception was also correlated to levels of anxiety and depression in the psychological (r_s  = -0.463, -0.607, respectively) and social (r_s  = -0.423, -0.438, respectively) quality of life domains.

CONCLUSIONS

Nighttime pain in women was associated with decreased quality of life, worsening mood and fatigue. Our data shows the importance of investigating pain and its deleterious effects on women's health.

SIGNIFICANCE

Our study highlights that women experiencing nighttime pain also reported worse mood outcomes and decreased quality of life, regardless of the level and type of pain. Our data, based on association analysis and not investigating causality, suggest it is important to consider nighttime pain in clinical care to improve quality of life and general health.

Airway Phenotypes and Nocturnal Wearing of Dentures in Elders with Sleep Apnea

The objective of this study was to examine to what extent the anatomic characteristics of the upper airway can influence the effect of nocturnal wearing of dentures on the sleep of edentulous elders with untreated sleep apnea. This study used the data from a randomized crossover clinical trial and an exploratory approach to address its objectives. Cone beam computed tomography scans of 65 edentulous individuals (female, n = 37; male, n = 28; mean ± SD age, 74.54 ± 6.42 y) with untreated obstructive sleep apnea (OSA) were used to identify anatomic variables. Polysomnography data were collected by means of one portable overnight recording. The respiratory variable values, including apnea-hypopnea index (AHI), with and without denture worn during sleep were used to calculate the change. Statistical analyses included multiple linear regressions, cluster analysis, and binary logistic regressions. A receiver operator characteristic curve was used to illustrate the accuracy of the statistical model. The regression model explained 15.8% (R²) of AHI change. An increase in the lateral dimension of the minimum cross-sectional area was associated with a decrease in AHI, oxygen desaturation index, and respiratory arousal index changes (P ≤ 0.041). Furthermore, an increase in the length of the hypopharynx was associated with an increase in AHI and oxygen desaturation index changes (P ≤ 0.027). An increase in the lateral dimension of the minimum cross-sectional area of the upper airway was associated with a decreased likelihood of being in the group having a worsened AHI (odds ratio = 0.85; 95% CI, 0.76 to 0.95; P = 0.006). An increase in the length of the oropharynx was associated with an increased likelihood of having increased AHI (odds ratio = 1.10; 95% CI, 1.01 to 1.20; P = 0.026). The nocturnal aggravation of respiratory variables in edentulous individuals with OSA who wear dentures at night can be linked to certain anatomic characteristics of the upper airway. Replication of these findings may open novel avenues for personalized advice regarding nocturnal wearing of dentures in edentulous individuals with OSA (ClinicalTrials.gov: NCT01868295).

The effects of mandibular advancement appliance therapy on jaw-closing muscle activity time-related to oxygen desaturations: A randomised controlled trial

BACKGROUND

Previous study showed that in individuals with obstructive sleep apnea (OSA), the contractions of masseter muscles after respiratory events can be nonspecific motor phenomena, dependent on the duration of respiratory arousals rather than the occurrence of the respiratory events. However, the role of intermittent hypoxia in the occurrence of jaw-closing muscle activities (JCMAs) was not taken into consideration. An exposure to intermittent hypoxia has been shown to initiate a series of activities, including muscular sympathetic activity in patients with OSA.

OBJECTIVE

To determine the effects of mandibular advancement appliance (MAA) therapy on JCMA time-related to oxygen desaturation with and without arousal in individuals with OSA.

METHODS

Eighteen individuals with OSA (age: 49.4 ± 9.8 years, apnea-hypopnea index (AHI): 10.0|18.4|30.3, JCMA index: 1.7|4.3|5.6), participated in a randomised controlled crossover clinical trial, in which two ambulatory polysomnographic recordings were performed: one with MAA in situ and the other without MAA in situ. JCMAs were recorded bilaterally from both masseter and temporalis muscles.

RESULTS

There was no significant effect of the MAA on the overall JCMA index (Z = -1.372, p = .170). With the MAA in situ, JCMA index time-related to oxygen desaturation with arousal significantly decreased (Z = -2.657, p = .008), while there was no significant effect of the MAA on the JCMA index time-related to oxygen desaturation without arousal (Z = -0.680, p = .496).

CONCLUSION

Effective mandibular advancement appliance therapy significantly reduces jaw-closing muscle activities time-related to oxygen desaturation with arousal in individuals with OSA.

Nurses’ perception of integrating an innovative clinical hypnosis–derived intervention into outpatient chemotherapy treatments

Introduction: Conversational hypnosis (CH) is known to optimize the management of symptoms resulting from antineoplastic treatment. However, the perception of nurses who have been called upon to integrate this practice into their care has yet to be documented. Goal: Describe how nurses perceive the integration of CH into chemotherapy-related care. Methods: Individual interviews and an iterative analysis were conducted with six nurses who had previous experience in CH in an outpatient oncology clinic. Findings: Six themes emerged: 1) the outpatient oncology clinic, a saturated care setting; 2) the key elements supporting the integration of CH into care; 3) an added value for patients; 4) a positive and rewarding experience for nurses; 5) collateral benefits; and 6) CH, an approach that warrants consideration amid the pandemic. Conclusion: These findings shed light on nurses’ unique point of view regarding the challenges and benefits of integrating CH into oncology care. Keywords: cancer, outpatient chemotherapy, conversational hypnosis, nursing

La perception des infirmières quant à l’intégration d’une intervention novatrice inspirée de l’hypnose clinique aux traitements de chimiothérapie à la clinique externe d’oncologie

Introduction : L’hypnose conversationnelle (HC) est connue pour optimiser la gestion des symptômes liés aux traitements antinéoplasiques. Toutefois, la perception des infirmières qui ont dû intégrer cette pratique dans leurs soins n’a encore jamais été documentée. But : Décrire la perception des infirmières quant à l’intégration de l’HC aux soins entourant la chimiothérapie. Méthodes : Des entrevues individuelles et une analyse itérative ont été réalisées auprès de 6 infirmières possédant une expérience préalable de l’HC à la clinique externe d’oncologie. Résultats : 6 thèmes ont émergé : 1) la clinique externe d’oncologie, un contexte de soins saturé; 2) les clés de voûte qui soutiennent l’intégration de l’HC dans les soins; 3) une valeur ajoutée pour les patients; 4) une expérience positive et valorisante pour les infirmières; 5) des bénéfices collatéraux; et 6) l’HC, une approche à considérer pendant la pandémie. Conclusions : Ces résultats révèlent le point de vue unique des infirmières sur les défis et avantages de l’intégration de l’HC aux soins en oncologie. Mots-clés : cancer, chimiothérapie ambulatoire, hypnose conversationnelle, pratique infirmière

Sleep bruxism and obstructive sleep apnea: association, causality or spurious finding? A scoping review

Study Objectives

To evaluate the available evidence on the putative relationships between sleep bruxism (SB) and, obstructive sleep apnea (OSA) to assess the extent of research on this topic, and to formulate suggestions for future research.

Methods

A scoping review including studies examining temporal and overall association and prevalence of SB and OSA was performed. Six main databases and gray literature were searched. The studies selection was conducted by three independent reviewers. A narrative synthesis of the results was carried out.

Results

Thirteen studies in adults and eight studies in children were finally included. The median of concomitant conditions prevalence was 39.3% in adults and 26.1% in children. Marked methodological variability was identified among studies in adults and even more when we compared detection methods in children. No significant association between OSA and SB emerged in most studies in adults, while an association may be possible in children.

Conclusions

Based on the current literature, it is not possible to confirm that there is a relationship between SB and OSA in adults. In patients under pediatric care, although this association seems plausible, there is currently insufficient supportive evidence. Standardized validated methodologies for identifying SB should be consistently used in both populations before reaching any conclusion regarding such association. Furthermore, assessment of shared phenotypes between patients with SB and patients with OSA may reveal new insights that will contribute to personalized approaches aiming to optimize the management of such comorbidities.

Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults

STUDY OBJECTIVES

First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals.

METHODS

NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway.

RESULTS

Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038).

CONCLUSIONS

The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://clinicaltrials.gov/ct2/show/NCT01868295; Identifier: NCT01868295.

CITATION

Chen H, Elham E, Li Y, et al. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.

Orofacial Pain and Snoring/Obstructive Sleep Apnea in Individuals with Head and Neck Cancer: A Critical Review

AIMS

(1) To summarize current knowledge on the prevalence, intensity, and descriptors of orofacial pain and snoring/obstructive sleep apnea (OSA) before and after head and neck cancer (HNC) treatment; and (2) to propose future directions for research.

METHODS

The median prevalence for each condition was estimated from the most recent systematic reviews (SRs) and updated with new findings retrieved from the PubMed, Web of Science, Embase, and Cochrane databases up to December 2021.

RESULTS

The prevalence of HNC pain seems relatively stable over time, with a median of 31% before treatment in three studies to a median of 39% at 1 month to 16 years after treatment in six studies. HNC pain intensity remains mild to moderate. There was a threefold increase in temporomandibular pain prevalence after surgery (median 7.25% before to 21.3% after). The data for snoring prevalence are unreliable. The OSA/HNC prevalence seems relatively stable over time, with a median of 72% before treatment in three studies to 77% after treatment in 14 studies.

CONCLUSION

With the exception of temporomandibular pain, the prevalence of HNC pain and OSA seems to be stable over time. Future studies should: (1) compare the trajectory of change over time according to each treatment; (2) compare individuals with HNC to healthy subjects; (3) use a standardized and comparable method of data collection; and (4) assess tolerance to oral or breathing devices, since HNC individuals may have mucosal sensitivity or pain.

Association between fentanyl treatment for acute pain in the emergency department and opioid use two weeks after discharge

BACKGROUND

Analgesia with fentanyl can be associated with hyperalgesia (higher sensitivity to pain) and can contribute to escalating opioid use. Our objective was to assess the relationship between emergency department (ED) acute pain management with fentanyl compared to other opioids, and the quantity of opioids consumed two-week after discharge. We hypothesized that the quantity of opioids consumed would be higher for patients treated with fentanyl compared to those treated with other opioids.

METHODS

Patients were selected from two prospective cohorts assessing opioids consumed after ED discharge. Patients ≥18 years treated with an opioid in the ED for an acute pain condition (≤2 weeks) and discharged with an opioid prescription were included. Patients completed a 14-day paper or electronic diary of pain medication use. Quantity of 5 mg morphine equivalent tablets consumed during a 14-day follow-up by patients treated with fentanyl compared to those treated with other opioids during their ED stay were analyzed using a multiple linear regression and propensity scores.

RESULTS

We included 707 patients (mean age ± SD: 50 ± 15 years, 47% women) in this study. During follow-up, patients treated with fentanyl (N = 91) during their ED stay consumed a median (IQR) of 5.8 (14) 5 mg morphine equivalent pills compared to 7.0 (14) for those treated with other opioids (p = 0.05). Results were similar using propensity score sensitivity analysis. However, after adjusting for confounding variables, ED fentanyl treatment showed a trend, but not a statistically significant association with a decreased opioid consumption during the 14-day follow-up (B = -2.4; 95%CI = -5.3 to 0.4; p = 0.09).

CONCLUSIONS

Patients treated with fentanyl during ED stay did not consume more opioids after ED discharge, compared to those treated with other opioids. If fentanyl does cause more hyperalgesia compared to other opioids, it does not seem to have a significant impact on opioid consumption after ED discharge.

Effects of nocturnal wearing of dentures on the quality of sleep and oral-health-related quality in edentate elders with untreated sleep apnea: a randomized cross-over trial

STUDY OBJECTIVES

This study aims to assess whether the nocturnal wear of dentures has an effect on the quality of sleep and oral-health-related quality of life of the edentulous elderly with untreated sleep apnea.

METHODS

A single-blind randomized cross-over design with two sequences and two periods was used. Participants (n = 77) were randomly assigned either to sequence 1 (nocturnal wear followed by nocturnal nonwear of the denture for 30-30 days) or sequence 2 (nocturnal nonwear followed by nocturnal wear of denture for 30-30 days). The primary sleep outcome was the quality of sleep, assessed through sleep fragmentation measured as Apnea-Hypopnea Index (AHI) and respiratory arousal from portable polysomnography. Secondary outcomes were daytime sleepiness, sleep quality (Pittsburgh Sleep Quality Index, PSQI) and oral-health-related quality of life measured by validated questionnaires.

RESULTS

The mean paired difference in AHI scores for the period of wearing versus not wearing dentures at night was small 1.0 event per hour (p = 0.50; 95% confidence interval (CI) = -2.0 to 4.1). The mean respiratory arousal index was higher when wearing dentures at night than when not wearing dentures at night, with a mean paired difference of 2.3 events per hour (p = 0.05; 95% CI = 0.0 to 4.6). No difference in sleepiness and PSQI were noted. Wearing dentures at night resulted in a statistically significantly higher mean score of psychological discomfort when compared to not wearing dentures at night.

CONCLUSIONS

The results provide some support to usual practice guidelines to remove dentures at night in edentulous elders suffering from sleep apnea.

CLINICAL TRIAL REGISTRATION

NCT01868295.

Feasibility and acceptability of hypnosis-derived communication administered by trained nurses to improve patient well-being during outpatient chemotherapy: a pilot-controlled trial

Purpose

This pilot-controlled trial aimed to examine the feasibility and acceptability of hypnosis-derived communication (HC) administered by trained nurses during outpatient chemotherapy to optimize symptom management and emotional support — two important aspects of patient well-being in oncology.

Methods

The trial was conducted in two outpatient oncology units: (1) intervention site (usual care with HC), and (2) control site (usual care). Nurses at the intervention site were invited to take part in an 8-h training in HC. Participants’ self-ratings of symptoms and emotional support were gathered at predetermined time points during three consecutive outpatient visits using the Edmonton Symptom Assessment Scale and the Emotional Support Scale.

Results

Forty-nine patients (24 in the intervention group, 25 in the control group) with different cancer types/stages were recruited over a period of 3 weeks and completed the study. All nurses (N = 10) at the intervention site volunteered to complete the training and were able to include HC into their chemotherapy protocols (about ± 5 min/intervention). Compared to usual care, patients exposed to HC showed a significant reduction in physical symptoms during chemotherapy. In contrast, perception of emotional support did not show any significant effect of the intervention. Participants exposed to HC report that the intervention helped them relax and connect on a more personal level with the nurse during chemotherapy infusion.

Conclusions

Our results suggest that HC is feasible, acceptable, and beneficial for symptom management during outpatient chemotherapy. While future studies are needed, hypnosis techniques could facilitate meaningful contacts between cancer patients and clinicians in oncology.

Trial registration

Clinical Trial Identifier: NCT04173195, first posted on November 19, 2019

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-021-06481-6.

Opioid and non-opioid pain relief after an emergency department acute pain visit

OBJECTIVES

Treatment of acute pain after emergency department (ED) discharge remains a challenge in the opioid crisis context. Our objective was to determine the proportion of patients using opioid vs non-opioid pain medication following discharge from the ED with acute pain, and the association of type of pain medication with average pain intensity before pain medication intake and report of pain relief.

METHODS

This was a prospective cohort study of ED patients aged ≥ 18 years with an acute pain (≤ 2 weeks) who were discharged with an opioid prescription. Patients completed a 14-day diary assessing daily pain intensity level before each pain medication intake (0-10 numeric rating scale), type of pain medication use (opioid vs non-opioid), and if pain was relieved by the medication used that day. Multilevel analyses were used to compare the effect of type of analgesic used on pain intensity and relief.

RESULTS

A total of 381 participants completed the 14-day diary; 50% were women and median age was 54 years (IQR = 43-66). Average daily pain intensity before pain medication intake was significantly higher for patients who used opioids (5.9; 95% CI 5.7-6.2) as compared to non-opioid analgesics (4.2; 95% CI 4.0-4.5) or no pain medication (2.2; 95% CI 1.9-2.5). Controlling for pain intensity, patients using opioids were more likely to report a pain relief (OR = 1.3; 95% CI 1.1-1.8) as compared to those who used non-opioid analgesics.

CONCLUSION

Overall, opioids appear to be effective and used as intended by the prescribing physician.

Signal acquisition and analysis of ambulatory electromyographic recordings for the assessment of sleep bruxism: A scoping review

Background

Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients.

Objectives

(a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited‐channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices.

Method

A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes.

Results

Seventy‐eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA).

Conclusion

Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA.

Research routes on improved sleep bruxism metrics: Toward a standardised approach

A recent report from the European Sleep Research Society's task force "Beyond AHI" discussed an issue that has been a long-term subject of debate - what are the best metrics for obstructive sleep apnoea (OSA) diagnosis and treatment outcome assessments? In a similar way, sleep bruxism (SB) metrics have also been a recurrent issue for >30 years and there is still uncertainty in dentistry regarding their optimisation and clinical relevance. SB can occur alone or with comorbidities such as OSA, gastroesophageal reflux disorder, insomnia, headache, orofacial pain, periodic limb movement, rapid eye movement behaviour disorder, and sleep epilepsy. Classically, the diagnosis of SB is based on the patient's dental and medical history and clinical manifestations; electromyography is used in research and for complex cases. The emergence of new technologies, such as sensors and artificial intelligence, has opened new opportunities. The main objective of the present review is to stimulate the creation of a collaborative taskforce on SB metrics. Several examples are available in sleep medicine. The development of more homogenised metrics could improve the accuracy and refinement of SB assessment, while moving forward toward a personalised approach. It is time to develop SB metrics that are relevant to clinical outcomes and benefit patients who suffer from one or more possible negative consequences of SB.

Artificial Intelligence Analysis of Mandibular Movements Enables Accurate Detection of Phasic Sleep Bruxism in OSA Patients: A Pilot Study

PURPOSE

Sleep bruxism (SBx) activity is classically identified by capturing masseter and/or temporalis masticatory muscles electromyographic activity (EMG-MMA) during in-laboratory polysomnography (PSG). We aimed to identify stereotypical mandibular jaw movements (MJM) in patients with SBx and to develop rhythmic masticatory muscles activities (RMMA) automatic detection using an artificial intelligence (AI) based approach.

PATIENTS AND METHODS

This was a prospective, observational study of 67 suspected obstructive sleep apnea (OSA) patients in whom PSG with masseter EMG was performed with simultaneous MJM recordings. The system used to collect MJM consisted of a small hardware device attached on the chin that communicates to a cloud-based infrastructure. An extreme gradient boosting (XGB) multiclass classifier was trained on 79,650 10-second epochs of MJM data from the 39 subjects with a history of SBx targeting 3 labels: RMMA episodes (n=1072), micro-arousals (n=1311), and MJM occurring at the breathing frequency (n=77,267).

RESULTS

Validated on unseen data from 28 patients, the model showed a very good epoch-by-epoch agreement (Kappa = 0.799) and balanced accuracy of 86.6% was found for the MJM events when using RMMA standards. The RMMA episodes were detected with a sensitivity of 84.3%. Class-wise receiver operating characteristic (ROC) curve analysis confirmed the well-balanced performance of the classifier for RMMA (ROC area under the curve: 0.98, 95% confidence interval [CI] 0.97-0.99). There was good agreement between the MJM analytic model and manual EMG signal scoring of RMMA (median bias -0.80 events/h, 95% CI -9.77 to 2.85).

CONCLUSION

SBx can be reliably identified, quantified, and characterized with MJM when subjected to automated analysis supported by AI technology.

Relationship between acute pain trajectories after an emergency department visit and chronic pain: a Canadian prospective cohort study

OBJECTIVES

Inadequate acute pain management can reduce the quality of life, cause unnecessary suffering and can often lead to the development of chronic pain. Using group-based trajectory modelling, we previously identified six distinct pain intensity trajectories for the first 14-day postemergency department (ED) discharge; two linear ones with moderate or severe pain during follow-up (~40% of the patients) and four cubic polynomial order trajectories with mild or no pain at the end of the 14 days (low final pain trajectories). We assessed if previously described acute pain intensity trajectories over 14 days after ED discharge are predictive of chronic pain 3 months later.

DESIGN

Prospective cohort study.

SETTING

Tertiary care trauma centre academic hospital.

PARTICIPANTS

This study included 18 years and older ED patients who consulted for acute (≤2 weeks) pain conditions that were discharged with an opioid prescription. Patients completed a 14-day diary in which they listed their daily pain intensity (0-10 numeric rating scale).

OUTCOMES

Three months after ED visit, participants were questioned by phone about their current pain intensity (0-10 numeric rating scale). Chronic pain was defined as patients with current pain intensity ≥4 at 3 months.

RESULTS

A total of 305 participants remained in the study at 3 months, 49% were women and a mean age of 55±15 years. Twelve per cent (11.9; 95% CI 8.2 to 15.4) of patients had chronic pain at the 3-month follow-up. Controlling for age, sex and pain condition, patients with moderate or severe pain trajectories and those with only a severe pain trajectory were respectively 5.1 (95% CI 2.2 to 11.8) and 8.2 (95% CI 3.4 to 20.0) times more likely to develop chronic pain 3 months later compared with patients in the low final pain trajectories.

CONCLUSION

Specific acute pain trajectories following an ED visit are closely related to the development of chronic pain 3 months later.

TRIAL REGISTRATION NUMBER

NCT02799004; Results.

The Canadian Pain Society: A historical perspective

This article reviews the major features and events that have characterized the 40-year history of the Canadian Pain Society/Société canadienne de la douleur, which is a chapter of the International Association for the Study of Pain (IASP). The review first describes its early formative years in the 1970s as eastern and western chapters of IASP and then its evolution as a Canada-wide chapter and society. Also highlighted is the formulation in this period of its purpose to foster pain research, education, and management and the many activities in which the Society has been engaged to reinforce this purpose over the ensuing decades. These include its annual scientific meetings and the establishment of publications, guidelines, and other educational material as well as awards to support research and trainees. Many of these activities have included engagement with key partners who have also collaborated with the Society in national and international advocacy for pain. The review also outlines some of the features and factors underpinning the Society’s national and international reputation and impact resulting from the many contributions that its members have made to the advances in pain research, education, and management over the past 40 years. The review concludes by noting that by way of its rich history and its past and present experiences, the Society is well positioned to continue its many activities and contributions to address the many challenges still facing the pain field in Canada and around the world.

Update on the prevalence of persistent post-traumatic headache in adult civilian traumatic brain injury: protocol for a systematic review and meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) is a major public health concern. Persistent post-traumatic headache (PTH) is a common consequence of TBI affecting productivity and quality of life. The only review providing information about headache prevalence after TBI was published in 2008, combined data from civilian and military TBI, and was strictly derived from Medline database. Due to recent changes in TBI diagnosis and trauma epidemiology, the aim of the current study is to perform a systematic review and meta-analysis to derive updated prevalence estimates of persistent PTH in adult civilian TBI.

METHODS AND ANALYSIS

The methods have been defined following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies published from 2008 to 2019 will be identified searching the electronic databases Medline, Embase, Cochrane, Google Scholar, Directory of Open Access Journals and Web of Science. Retrieved records will be independently screened by two authors and relevant data will be extracted from studies reporting data on persistent PTH prevalence among civilian TBI individuals (≥16 years). The pooled prevalence estimates of any form of headache will be computed applying random-effects meta-analysis. Heterogeneity will be assessed using the I2 statistic and explored through subgroup analyses considering TBI severity (mild vs moderate/severe). Estimations of risk of bias will be performed using the Risk of Bias Tool for Prevalence Studies.

ETHICS AND DISSEMINATION

The result of this systematic review will be published in a peer-reviewed journal and disseminated at relevant conferences presentations. Formal ethical approval is not required because we will search and evaluate only existing sources of literature. By focusing on studies conducted in the last decade, this review will provide the most up-to-date information about the global prevalence of persistent PTH after TBI. Considering the economical and social burden of persistent PTH after TBI, accurate estimates of this problematic disorder is of utmost importance for planning, implementing and evaluating prevention interventions.

PROSPERO REGISTRATION NUMBER

CRD42018094138.

Recent opioid use and fall-related injury among older patients with trauma

BACKGROUND

Evidence for an association between opioid use and risk of falls or fractures in older adults is inconsistent. We examine the association between recent opioid use and the risk, as well as the clinical outcomes, of fall-related injuries in a large trauma population of older adults.

METHODS

In a retrospective, observational, multicentre cohort study conducted on registry data, we included all patients aged 65 years and older who were admitted (hospital stay > 2 d) for injury in 57 trauma centres in the province of Quebec, Canada, between 2004 and 2014. We looked at opioid prescriptions filled in the 2 weeks preceding the trauma in patients who sustained a fall, compared with those who sustained an injury through another mechanism.

RESULTS

A total of 67 929 patients were retained for analysis. Mean age was 80.9 (± 8.0) years and 69% were women. The percentage of patients who had filled an opioid prescription in the 2 weeks preceding an injury was 4.9% (95% confidence interval [CI] 4.7%-5.1%) for patients who had had a fall, compared with 1.5% (95% CI 1.2%-1.8%) for those who had had an injury through another mechanism. After we controlled for confounding variables, patients who had filled an opioid prescription within 2 weeks before injury were 2.4 times more likely to have a fall rather than any other type of injury. For patients who had a fall-related injury, those who used opioids were at increased risk of in-hospital death (odds ratio 1.58; 95% CI 1.34-1.86).

INTERPRETATION

Recent opioid use is associated with an increased risk of fall and an increased likelihood of death in older adults.

Opioid Use and Misuse Three Months After Emergency Department Visit for Acute Pain

BACKGROUND

Studies evaluating long-term prescription opioid use are retrospective and based on filled opioid prescriptions from governmental databases. These studies cannot evaluate if opioids were really consumed and are unable to differentiate if they were used for a new pain or chronic pain or were misused. The aim of this study was to assess opioid use rate and reasons for consuming 3 months after being discharged from the emergency department (ED) with an opioid prescription.

METHODS

This is a prospective cohort study conducted in the ED of a tertiary care urban center with a convenience sample of discharged patients ≥ 18 years who consulted for an acute pain condition (≤2 weeks). Three months post-ED visit, participants were interviewed by phone on their past 2-week opioid consumption and their reasons for consuming: a) for pain related to the initial ED visit, b) for a new unrelated pain, or c) for another reason.

RESULTS

Of the 524 participants questioned at 3 months (mean ± SD age = 51 ± 16 years, 47% women), 47 patients (9%, 95% confidence interval [CI] = 7%-12%) reported consuming opioids in the previous 2 weeks. Among those, 34 (72%) reported using opioids for their initial pain, nine (19%) for a new unrelated pain and four (9%) for another reason (0.8%, 95% CI = 0.3%-2.0%, of the whole cohort). Patients who used opioids during the 2 weeks after the ED visit were 3.8 (95% CI = 1.2-12.7) times more likely to consume opioids at 3 months.

CONCLUSION

Opioid use at the 3-month follow-up in ED patients discharged with an opioid prescription for an acute pain condition is not necessarily associated with opioid misuse; 91% of those patients consumed opioids to treat pain. Of the whole cohort, less than 1% reported using opioids for reasons other than pain. The rate of long-term opioid use reported by prescription-filling database studies should not be viewed as a proxy for incidence of opioid misuse.

Multicenter assessment of quantitative sensory testing (QST) for the detection of neuropathic-like pain responses using the topical capsaicin model

Background

The use of quantitative sensory testing (QST) in multicenter studies has been quite limited, due in part to lack of standardized procedures among centers.

Aim

The aim of this study was to assess the application of the capsaicin pain model as a surrogate experimental human model of neuropathic pain in different centers and verify the variation in reports of QST measures across centers.

Methods

A multicenter study conducted by the Quebec Pain Research Network in six laboratories allowed the evaluation of nine QST parameters in 60 healthy subjects treated with topical capsaicin to model unilateral pain and allodynia. The same measurements (without capsaicin) were taken in 20 patients with chronic neuropathic pain recruited from an independent pain clinic.

Results

Results revealed that six parameters detected a significant difference between the capsaicin-treated and the control skin areas: (1) cold detection threshold (CDT) and (2) cold pain threshold (CPT) are lower on the capsaicin-treated side, indicating a decreased in cold sensitivity; (3) heat pain threshold (HPT) was lower on the capsaicin-treated side in healthy subjects, suggesting an increased heat pain sensitivity; (4) dynamic mechanical allodynia (DMA); (5) mechanical pain after two stimulations (MPS2); and (6) mechanical pain summation after ten stimulations (MPS10), are increased on the capsaicin-treated side, suggesting an increased in mechanical pain (P < 0.002). CDT, CPT and HPT showed comparable effects across all six centers, with CPT and HPT demonstrating the best sensitivity. Data from the patients showed significant difference between affected and unaffected body side but only with CDT.

Conclusion

These results provide further support for the application of QST in multicenter studies examining normal and pathological pain responses.

Quantity of opioids consumed following an emergency department visit for acute pain: a Canadian prospective cohort study

OBJECTIVES

Prescription opioid diversion is a significant contributor to the opioid misuse epidemic. We examined the quantity of opioids consumed by emergency department (ED) discharged patients after treatment for an acute pain condition (musculoskeletal, fracture, renal colic, abdominal pain and other), and the percentage of unused opioids available for potential misuse.

DESIGN

Prospective cohort study.

SETTING

Tertiary care trauma centre academic hospital.

PARTICIPANTS

A convenience sample of patients ≥18 years who visited the ED for an acute pain condition (≤2 weeks) and were discharged with an opioid prescription. Patients completed a 14-day paper diary of daily pain medication use. To reduce lost to follow-up, participants also responded to standardised phone interview questions about their previous 14-day pain medication use.

OUTCOMES

Quantity of morphine 5 mg tablets (or equivalent) prescribed, consumed and unused during a 14-day follow-up. Quantity of opioids to adequately supply 80% of patients for 2 weeks and 95% of patients for the first 3 days was also calculated.

RESULTS

Results for 627 patients were analysed (mean age ±SD: 51±16 years, 48% women). Patients consumed a median of seven tablets of morphine 5 mg (32% of the total prescribed opioids). The quantity of opioids to adequately supply 80% of patients for 2 weeks was 20 tablets of morphine 5 mg for musculoskeletal pain, 30 for fracture, 15 for renal colic or abdominal pain and 20 for other pain conditions. The quantity to adequately supply 95% of patients for the first 3 days was 15 tablets of morphine 5 mg.

CONCLUSIONS

Patients discharged from the ED with an acute pain condition consumed a median of fewer than 10 tablets of morphine 5 mg (or equivalent). ED physicians should consider prescribing a smaller quantity of opioids and asking the pharmacist to dispense them in portions to minimise unused opioids.

TRIAL REGISTRATION NUMBER

NCT02799004; Results.

Non-invasive brain stimulation in chronic orofacial pain: a systematic review

Background

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are non-invasive brain stimulation techniques that are being explored as therapeutic alternatives for the management of various chronic pain conditions.

Objective

The primary objective of this systematic review is to assess the efficacy of TMS and tDCS in reducing clinical pain intensity in chronic orofacial pain (OFP) disorders. The secondary objectives are to describe adverse effects, duration of relief, and TMS/tDCS methodologies used in chronic OFP disorders.

Methods

A search was performed in MEDLINE, Embase, Web of Science, Scopus, and Google Scholar. Inclusion criteria were 1) population: adults diagnosed with chronic OFP including neuropathic and non-neuropathic disorders; 2) intervention: active TMS or tDCS stimulation regardless of the used protocol; 3) comparison: sham TMS or tDCS stimulation; and 4) outcome: primary outcome was patient reported pain intensity. Secondary outcomes were duration of pain relief, adverse effects, and methodological parameters. Risk of bias and quality of study reporting were also assessed.

Results

A total of 556 individual citations were identified by the search strategy, with 14 articles meeting selection criteria (TMS=11; tDCS=3). Data were obtained for a total of 228 patients. Included OFP disorders were trigeminal neuralgia, trigeminal neuropathy, burning mouth syndrome, atypical facial pain, and temporomandibular disorders. Significant pain reductions were obtained in both techniques. More number of sessions yielded to more durable effects. Overall, high risk of bias and poor study quality were found.

Conclusion

TMS and tDCS appear to be safe and promising alternatives to reduce pain intensity in different chronic OFP disorders. Additional research effort is needed to reduce bias, improve quality, and characterize optimal brain stimulation parameters to promote their efficacy.

Reliability of hemostasis biomarkers is affected by time-dependent intra-patient variability

Essentials Nucleosomes and free DNA are two newly described biomarkers in venous thromboembolism (VTE). Reliability of nucleosomes, plasma free DNA and conventional hemostasis markers were studied. Hemostasis biological parameters vary over a short time-frame in VTE patients. Hemostasis biological parameters also vary over a short time-frame in healthy controls.

SUMMARY

Background Previous studies have associated neutrophil-derived circulating nucleosomes and plasma free DNA with venous thromboembolism (VTE). However, there are few data concerning these two biomarkers and no studies have compared the reliability of nucleosomes and plasma free DNA against that of conventional hemostasis markers. Objectives We performed a 3-year prospective study of nucleosomes and plasma free DNA levels in comparison with conventional hemostatic biomarkers and blood cells. Patients/Methods Fifteen healthy controls and 22 randomly selected patients with a history of VTE were followed monthly for 6 months. The reliability of these markers was evaluated by the intraclass correlation coefficient (ICCs). Results and Conclusions In healthy controls and patients, we found a low reliability for nucleosomes and plasma free DNA, with ICCs at 0.538 (95% confidence interval [CI], 0.334-0.764) and 0.091 (95% CI, -0.026-0.328), respectively, in the healthy controls, and at 0.213 (95% CI, 0.042-0.463) and 0.161 (CI 95%, 0.008-0.398) in the patient group. For the conventional hemostasis biomarkers and for blood cells, reliability ranged from poor to good in the healthy volunteers and from poor to acceptable in the patient group. Our study shows for the first time that hemostasis biological parameters spontaneously vary over a short time-frame in VTE patients and, more surprisingly, in normal individuals. The clinical value of such intra-individual variations is currently unknown. This variability might mean reinterpreting diagnostic or prognostic models based on static evaluation of individuals. Studying the intrinsic value of individual patterns of markers' variability is warranted.

Medium Increased Risk for Central Sleep Apnea but Not Obstructive Sleep Apnea in Long-Term Opioid Users: A Systematic Review and Meta-Analysis

STUDY OBJECTIVE

Opioids are associated with higher risk for ataxic breathing and sleep apnea. We conducted a systematic literature review and meta-analysis to assess the influence of long-term opioid use on the apnea-hypopnea and central apnea indices (AHI and CAI, respectively).

METHODS

A systematic review protocol (Cochrane Handbook guidelines) was developed for the search and analysis. We searched Embase, Medline, ACP Journal Club, and Cochrane Database up to November 2014 for three topics: (1) narcotics, (2) sleep apnea, and (3) apnea-hypopnea index. The outcome of interest was the variation in AHI and CAI in opioid users versus non-users. Two reviewers performed the data search and extraction, and disagreements were resolved by discussion. Results were combined by standardized mean difference using a random effect model, and heterogeneity was tested by χ(2) and presented as I(2) statistics.

RESULTS

Seven studies met the inclusion criteria, for a total of 803 patients with obstructive sleep apnea (OSA). We compared 2 outcomes: AHI (320 opioid users and 483 non-users) and 790 patients with CAI (315 opioid users and 475 non-users). The absolute effect size for opioid use was a small increased in apnea measured by AHI = 0.25 (95% CI: 0.02-0.49) and a medium for CAI = 0.45 (95% CI: 0.27-0.63). Effect consistency across studies was calculated, showing moderate heterogeneity at I(2) = 59% and 29% for AHI and CAI, respectively.

CONCLUSIONS

The meta-analysis results suggest that long-term opioid use in OSA patients has a medium effect on central sleep apnea.