The Contribution of Sleep Quality and Psychological Factors to the Experience of Within-Day Pain Fluctuations Among Individuals With Temporomandibular Disorders.

We assessed the impact of day-to-day sleep quality and psychological variables (catastrophizing, negative affect, and positive affect) to within-day pain fluctuations in 42 females with painful temporomandibular disorders (TMD) using electronic diaries. More specifically, we examined the contribution of these variables to the likelihood of experiencing pain exacerbations defined as 1) an increase of 20 points (or more) in pain intensity on a 0 to 100 visual analog scale from morning to evening, and/or 2) a transition from mild-to-moderate pain over the course of the day; and pain decreases defined as 3) a decrease of 20 points (or more) in pain intensity (visual analog scale) from morning to evening, and/or 4) a reduction from moderate-to-mild pain over the day. The results indicated significantly main effects of sleep on both pain exacerbation outcomes (both P's < .05), indicating that nights with better sleep quality were less likely to be followed by clinically meaningful pain exacerbations on the next day. The results also indicated that days characterized by higher levels of catastrophizing were associated with a greater likelihood of pain exacerbations on the same day (both P's < .05). Daily catastrophizing was the only variable significantly associated with within-day pain decrease indices (both P's < .05). None of the other variables were associated with these outcomes (all P's > .05). These results underscore the importance of addressing patients' sleep quality and psychological states in the management of painful TMD. PERSPECTIVES: These findings highlight the significance of sleep quality and pain catastrophizing in the experience of within-day pain fluctuations among individuals with TMD. Addressing these components through tailored interventions may help to alleviate the impact of pain fluctuations and enhance the overall well-being of TMD patients.

One session of repetitive transcranial magnetic stimulation induces mild and transient analgesic effects among female individuals with painful temporomandibular disorders.

OBJECTIVE: Temporomandibular disorders (TMD) are characterised by chronic pain and dysfunction in the jaw joint and masticatory muscles. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a potential non-invasive treatment for chronic pain; however, its effectiveness in individuals with TMD has not been thoroughly investigated. This study aimed to evaluate the immediate and sustained (over seven consecutive days) effects of a single session of active rTMS compared to sham stimulation on pain intensity and pain unpleasantness in individuals with TMD. METHODS: A randomised, double-blind, sham-controlled trial enrolled 41 female participants with chronic TMD. Pain intensity and pain unpleasantness were assessed immediately pre- and post-intervention, as well as twice daily for 21 days using electronic diaries. Secondary outcomes included pain interference, sleep quality, positive and negative affect and pain catastrophizing. Adverse effects were monitored. Repeated measures ANOVA and multilevel modelling regression analyses were employed for data analysis. RESULT: Active rTMS demonstrated a significant immediate mild reduction in pain intensity and pain unpleasantness compared to sham stimulation. However, these effects were not sustained over the 7-day post-intervention period. No significant differences were observed between interventions for pain interference, sleep quality and negative affect. A minority of participants reported minor and transient side effects, including headaches and fatigue. CONCLUSION: A single session of active rTMS was safe and led to immediate mild analgesic effects in individuals with TMD compared to sham stimulation. However, no significant differences were observed between interventions over the 7-day post-intervention period. Based on this study, rTMS stimulation appears to be a promising safe approach to be tested in TMD patients with longer stimulation protocols.

Standardised Tool for the Assessment of Bruxism.

OBJECTIVE: This paper aims to present and describe the Standardised Tool for the Assessment of Bruxism (STAB), an instrument that was developed to provide a multidimensional evaluation of bruxism status, comorbid conditions, aetiology and consequences. METHODS: The rationale for creating the tool and the road map that led to the selection of items included in the STAB has been discussed in previous publications. RESULTS: The tool consists of two axes, specifically dedicated to the evaluation of bruxism status and consequences (Axis A) and of bruxism risk and etiological factors and comorbid conditions (Axis B). The tool includes 14 domains, accounting for a total of 66 items. Axis A includes the self-reported information on bruxism status and possible consequences (subject-based report) together with the clinical (examiner report) and instrumental (technology report) assessment. The Subject-Based Assessment (SBA) includes domains on Sleep Bruxism (A1), Awake Bruxism (A2) and Patient's Complaints (A3), with information based on patients' self-report. The Clinically Based Assessment (CBA) includes domains on Joints and Muscles (A4), Intra- and Extra-Oral Tissues (A5) and Teeth and Restorations (A6), based on information collected by an examiner. The Instrumentally Based Assessment (IBA) includes domains on Sleep Bruxism (A7), Awake Bruxism (A8) and the use of Additional Instruments (A9), based on the information gathered with the use of technological devices. Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid association with bruxism. It includes domains on Psychosocial Assessment (B1), Concurrent Sleep-related Conditions Assessment (B2), Concurrent Non-Sleep Conditions Assessment (B3), Prescribed Medications and Use of Substances Assessment (B4) and Additional Factors Assessment (B5). As a rule, whenever possible, existing instruments, either in full or partial form (i.e. specific subscales), are included. A user's guide for scoring the different items is also provided to ease administration. CONCLUSIONS: The instrument is now ready for on-field testing and further refinement. It can be anticipated that it will help in collecting data on bruxism in such a comprehensive way to have an impact on several clinical and research fields.

Research routes on awake bruxism metrics: Implications of the updated bruxism definition and evaluation strategies.

BACKGROUND: With time, due to the poor knowledge on it epidemiology, the need to focus on awake bruxism as a complement of sleep studies emerged. OBJECTIVE: In line with a similar recent proposal for sleep bruxism (SB), defining clinically oriented research routes to implement knowledge on awake bruxism (AB) metrics is important for an enhanced comprehension of the full bruxism spectrum, that is better assessment and more efficient management. METHODS: We summarised current strategies for AB assessment and proposed a research route for improving its metrics. RESULTS: Most of the literature focuses on bruxism in general or SB in particular, whilst knowledge on AB is generally fragmental. Assessment can be based on non-instrumental or instrumental approaches. The former include self-report (questionnaires, oral history) and clinical examination, whilst the latter include electromyography (EMG) of jaw muscles during wakefulness as well as the technology-enhanced ecological momentary assesment (EMA). Phenotyping of different AB activities should be the target of a research task force. In the absence of available data on the frequency and intensity of wake-time bruxism-type masticatory muscle activity, any speculation about the identification of thresholds and criteria to identify bruxers is premature. Research routes in the field must focus on the improvement of data reliability and validity. CONCLUSIONS: Probing deeper into the study of AB metrics is a fundamental step to assist clinicians in preventing and managing the putative consequences at the individual level. The present manuscript proposes some possible research routes to advance current knowledge. At different levels, instrumentally based and subject-based information must be gathered in a universally accepted standardised approach.

The Impact of Sleep Disturbances on Endogenous Pain Modulation: A Systematic Review and Meta-Analysis.

The bidirectional relationship between sleep and pain problems has been extensively demonstrated but despite all the accumulating evidence, their shared mechanisms are currently not fully understood. This review examined the association between sleep disturbances, defined as a broad array of sleep-related outcomes (eg, poor quality, short duration, insomnia), and endogenous pain modulation (EPM) in healthy and clinical populations. Our search yielded 6,151 references, and 37 studies met the eligibility criteria. Qualitative results showed mixed findings regarding the association between sleep disturbances and temporal summation of pain (TSP) and conditioned pain modulation (CPM), with poor sleep more commonly associated with decreased pain inhibition in both populations. Quantitative results indicated that such associations were not statistically significant, neither in healthy populations when EPM outcomes were assessed for changes pre-/post-sleep intervention (TSP: .31 [95%CI: -.30 to .92]; P = .321; CPM: .40 [95%CI: -.06 to .85] P = .088) nor in clinical populations when such association was assessed via correlation (TSP: -.00 [95%CI: -.22 to .21] P = .970; CPM: .12 [95%CI: -.05 to .29]; P = .181). For studies that reported results by sex, meta-analysis showed that experimental sleep disturbances impaired pain inhibition in females (1.43 [95%CI: .98-1.88]; P < .001) but not in males (-.30 [95%CI: -2.69 to 1.60]; P = .760). Only one study investigating the association between sleep disturbances and offset analgesia was identified, while no studies assessing spatial summation of pain were found. Overall, this review provides a comprehensive overview of the association between sleep disturbances and EPM function, emphasizing the need for further investigation to clarify specific mechanisms and phenotypic subtypes. PERSPECTIVE: This review shines a light on the association between sleep disturbances and endogenous pain modulation function. Qualitatively, we found a frequent association between reduced sleep quality and impaired pain inhibition. However, quantitatively such an association was not corroborated. Sex-specific effects were observed, with females presenting sleep-related impaired pain inhibition but not males.

Females with painful temporomandibular disorders present higher intracortical facilitation relative to pain-free controls.

OBJECTIVES: This study aimed to investigate cortical excitability differences in the primary motor cortex (M1) hand representation between individuals with temporomandibular disorders (TMD) and healthy controls. We assessed resting motor thresholds, motor-evoked potentials (MEPs), intracortical inhibition, and intracortical facilitation and explored potential associations with clinical and psychosocial characteristics in the TMD group. MATERIALS AND METHODS: We recruited 36 female participants with TMD and 17 pain-free controls. Transcranial magnetic stimulation (TMS) was used to assess M1 cortical excitability. Correlations between clinical and psychosocial factors and cortical excitability measures were also evaluated. RESULTS: Patients with TMD showed significantly higher intracortical facilitation at 12 ms (z = 1.98, p = 0.048) and 15 ms (z = 2.65, p = 0.008) when compared to controls. Correlations revealed associations between intracortical facilitation and pain interference, sleep quality, depressive symptoms, and pain catastrophizing in the TMD group. CONCLUSIONS: Females with TMD exhibit heightened motor cortex intracortical facilitation in the hand representation, potentially indicating altered cortical excitability beyond the motor face area. This suggests a role for cortical excitability in TMD pathophysiology, influenced by psychosocial factors. CLINICAL RELEVANCE: Understanding cortical excitability in TMD may inform targeted interventions. Psychosocial variables may play a role in cortical excitability, emphasizing the multidimensional nature of TMD-related pain. Further research is needed to confirm and expand upon these findings, with potential implications for the management of TMD and related pain conditions.

The Role of Emotion Regulation, Affect, and Sleep in Individuals With Sleep Bruxism and Those Without: Protocol for a Remote Longitudinal Observational Study.

BACKGROUND: Sleep bruxism (SB) is an oral behavior characterized by high levels of repetitive jaw muscle activity during sleep, leading to teeth grinding and clenching, and may develop into a disorder. Despite its prevalence and negative outcomes on oral health and quality of life, there is currently no cure for SB. The etiology of SB remains poorly understood, but recent research suggests a potential role of negative emotions and maladaptive emotion regulation (ER). OBJECTIVE: This study's primary aim investigates whether ER is impaired in individuals with SB, while controlling for affective and sleep disturbances. The secondary aim tests for the presence of cross-sectional and longitudinal mediation pathways in the bidirectional relationships among SB, ER, affect, and sleep. METHODS: The study used a nonrandomized repeated-measures observational design and was conducted remotely. Participants aged 18-49 years underwent a 14-day ambulatory assessment. Data collection was carried out using electronic platforms. We assessed trait and state SB and ER alongside affect and sleep variables. We measured SB using self-reported trait questionnaires, ecological momentary assessment (EMA) for real-time reports of SB behavior, and portable electromyography for multinight assessment of rhythmic masticatory muscle activity. We assessed ER through self-reported trait questionnaires, EMA for real-time reports of ER strategies, and heart rate variability derived from an electrocardiography wireless physiological sensor as an objective physiological measure. Participants' trait affect and real-time emotional experiences were obtained using self-reported trait questionnaires and EMA. Sleep patterns and quality were evaluated using self-reported trait questionnaires and sleep diaries, as well as actigraphy as a physiological measure. For the primary objective, analyses will test for maladaptive ER in terms of strategy use frequency and effectiveness as a function of SB using targeted contrasts in the general linear model. Control analyses will be conducted to examine the persistence of the SB-ER relationship after adjusting for affective and sleep measures, as well as demographic variables. For the secondary objective, cross-sectional and longitudinal mediation analyses will test various competing models of directional effects among self-reported and physiological measures of SB, ER, affect, and sleep. RESULTS: This research received funding in April 2017. Data collection took place from August 2020 to March 2022. In all, 237 participants were eligible and completed the study. Data analysis has not yet started. CONCLUSIONS: We hope that the effort to thoroughly measure SB and ER using gold standard methods and cutting-edge technology will advance the knowledge of SB. The findings of this study may contribute to a better understanding of the relationship among SB, ER, affect, and sleep disturbances. By identifying the role of ER in SB, the results may pave the way for the development of targeted interventions for SB management to alleviate the pain and distress of those affected. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/41719.

The prevalence of persistent post-traumatic headache in adult civilian traumatic brain injury: a systematic review and meta-analysis on the past 14 years.

ABSTRACT: The most recent prevalence estimate of post-traumatic headache (PTH) after traumatic brain injury (TBI) in veterans and civilians dates back to 2008. The prevalence was found to be 57.8%, with surprising higher rates (75.3%) in mild TBI when compared with those with moderate/severe TBI (32.1%). However, the revision of mild TBI diagnostic criteria and an historic peak of TBI in the elderly individuals attributed to the ageing population may lead to different results. Thus, we conducted a systematic review and meta-analysis to assess the updated prevalence of PTH during the past 14 years only in civilians. A literature search was conducted following PRISMA guidelines guided by a librarian. Screening, full-text assessment, data extraction, and risk of bias assessment were performed blindly by 2 raters. Meta-analysis of proportions using the Freeman and Tukey double arcsine method of transformation was conducted. Heterogeneity, sensitivity analysis, and meta-regressions were performed with the predictors: year of publication, mean age, sex, TBI severity, and study design. Sixteen studies were selected for the qualitative analysis and 10 for the meta-analysis. The overall prevalence estimate of PTH was 47.1%, (confidence interval = 34.6, 59.8, prediction intervals = 10.8, 85.4), being similar at different time points (3, 6, 12, and 36+ months). Heterogeneity was high, and none of the meta-regressions were significant. The overall prevalence of PTH after TBI over the past 14 years remains high even if assessed only in civilians. However, the prevalence rates attributed to mild and moderate/severe TBI were similar, differing significantly from previous reports. Efforts are needed to improve TBI outcomes.

The interplay between symptoms of insomnia and pain in people with osteoarthritis: A narrative review of the current evidence.

Osteoarthritis (OA) is a leading cause of disability worldwide and clinical pain is the major symptom of OA. This clinical OA-related pain is firmly associated with symptoms of insomnia, which are reported in up to 81% of people with OA. Since understanding the association between both symptoms is critical for their appropriate management, this narrative review synthesizes the existing evidence in people with OA on i) the mechanisms underlying the association between insomnia symptoms and clinical OA-related pain, and ii) the effectiveness of conservative non-pharmacological treatments on insomnia symptoms and clinical OA-related pain. The evidence available identifies depressive symptoms, pain catastrophizing and pain self-efficacy as mechanisms partially explaining the cross-sectional association between insomnia symptoms and pain in people with OA. Furthermore, in comparison to treatments without a specific insomnia intervention, the ones including an insomnia intervention appear more effective for improving insomnia symptoms, but not for reducing clinical OA-related pain. However, at a within-person level, treatment-related positive effects on insomnia symptoms are associated with a long-term pain reduction. Future longitudinal prospective studies offering fundamental insights into neurobiological and psychosocial mechanisms explaining the association between insomnia symptoms and clinical OA-related pain will enable the development of effective treatments targeting both symptoms.

The Putative Role of Neuroinflammation in the Interaction between Traumatic Brain Injuries, Sleep, Pain and Other Neuropsychiatric Outcomes: A State-of-the-Art Review.

Sleep disturbances are widely prevalent following a traumatic brain injury (TBI) and have the potential to contribute to numerous post-traumatic physiological, psychological, and cognitive difficulties developing chronically, including chronic pain. An important pathophysiological mechanism involved in the recovery of TBI is neuroinflammation, which leads to many downstream consequences. While neuroinflammation is a process that can be both beneficial and detrimental to individuals' recovery after sustaining a TBI, recent evidence suggests that neuroinflammation may worsen outcomes in traumatically injured patients, as well as exacerbate the deleterious consequences of sleep disturbances. Additionally, a bidirectional relationship between neuroinflammation and sleep has been described, where neuroinflammation plays a role in sleep regulation and, in turn, poor sleep promotes neuroinflammation. Given the complexity of this interplay, this review aims to clarify the role of neuroinflammation in the relationship between sleep and TBI, with an emphasis on long-term outcomes such as pain, mood disorders, cognitive dysfunctions, and elevated risk of Alzheimer's disease and dementia. In addition, some management strategies and novel treatment targeting sleep and neuroinflammation will be discussed in order to establish an effective approach to mitigate long-term outcomes after TBI.

The effects of mandibular advancement appliance therapy on the sequence of jaw-closing muscle activity and respiratory events in individuals with obstructive sleep apnea.

PURPOSE: To determine the effects of a mandibular advancement appliance (MAA) on sequences of jaw-closing muscle activity (JCMA) and apneic or hypopneic event (AHE) in individuals with obstructive sleep apnea (OSA). METHODS: Individuals with OSA were included in a secondary analysis of a randomized controlled crossover trial, in which two ambulatory polysomnographic recordings were performed: one with MAA in situ and the other without MAA. A time span of 16 s between JCMA and AHE was applied to classify JCMAs into four sequences: (1) JCMA occurs before AHE (B-type); (2) both events occur simultaneously (S-type); (3) JCMA occurs after AHE (A-type); and (4) JCMA is time-unrelated to AHE (U-type). The effects of MAA on the distribution of these sequences were analyzed by Wilcoxon signed-rank test. RESULTS: Among 16 individuals (10 men, mean age 51.3 ± 8.5 years) baseline apnea-hypopnea index and JCMA index were 23.8 ± 16.0 events/h and 10.8 ± 10.3 events/h, respectively. In both conditions, i.e., without and with MAA, most JCMAs were U-type (48% and 65%, respectively), followed by A-type (41% and 22%), B-type (25% and 21%), and S-type (2% and 1%). With MAA in situ, only the A-type JCMA index decreased significantly (P = 0.005), while B-type, S-type, and U-type JCMA indices did not change significantly (all P > 0.05). CONCLUSION: MAA therapy only significantly reduces the jaw-closing muscle activities that occur after apneic or hypopneic events in individuals with OSA. TRIAL REGISTRATION: www. CLINICALTRIALS: gov (NCT02011425); December 13, 2013.

Dental sleep-related conditions and the role of oral healthcare providers: A scoping review.

Dental sleep medicine as a discipline was first described about a quarter of a century ago. Snoring, obstructive sleep apnea, sleep bruxism, xerostomia, hypersalivation, gastroesophageal reflux disease, and orofacial pain were identified as dental sleep-related conditions. This scoping review aimed to: i) identify previously unidentified dental sleep-related conditions; and ii) identify the role of oral healthcare providers in the prevention, assessment, and management of dental sleep-related conditions in adults. A systematic literature search was conducted in PubMed, Embase.com, Web of Science, and Cochrane. Studies that reported an actual or likely role of oral healthcare providers in the prevention, assessment, and/or management of sleep-related conditions were included. Of the 273 included studies, 260 were on previously listed dental sleep-related conditions; the other 13 were on burning mouth syndrome. Burning mouth syndrome was therefore added to the list of dental sleep-related conditions for the first aim and categorized into sleep-related orofacial pain. For the second aim, the role of oral healthcare providers was found to be significant in the prevention, assessment, and management of obstructive sleep apnea and sleep bruxism; in the assessment and management of snoring, sleep-related orofacial pain, and oral dryness; and in the assessment of sleep-related gastroesophageal reflux condition.

Sleep Quality and Comfort Reported by Sleep Bruxism Individuals Wearing the Occlusal Splint and Mandibular Advancement Splint: Revisiting Two Crossover Studies.

PURPOSE: To assess (1) whether an occlusal splint (OS) or mandibular advancement splint (MAS) allowed better sleep quality and was more comfortable in individuals with sleep bruxism (SB); and (2) the relationship between sleep quality, comfort, and reduction in RMMA related to SB. MATERIALS AND METHODS: Polysomnographic data from 21 SB subjects (mean ± SD age 25.6 ± 4.5 years) collected in two previous studies were compared. Morning self-reports on sleep quality and comfort of the oral device, polysomnographic data, and RMMA index data from no-device nights were compared to nights using an OS or MAS. The reduction ratio of the RMMA index was calculated for both devices. A responder to the oral device was identified when the RMMA index was less than 2 and when it showed a reduction of at least 50% from the no-device control night. RESULTS: Self-reports for sleep quality and comfort of the oral device showed a mild advantage of the OS when compared to the MAS (r2 = 0.47, r2 = 0.32; P ≤ .01). In responders, the MAS induced a greater reduction in the RMMA index (P = .03) than the OS. CONCLUSIONS: In the short term, the comfort of the oral device seemed to influence sleep quality in SB individuals. However, despite the slightly higher degree of comfort offered by the OS, the MAS induced a greater effect on the RMMA index. Int J Prosthodont 2022;36:138-147. doi: 10.11607/ijp.7525.

The influence of age on the frequency of rhythmic masticatory muscle activity during sleep in general population differs from that in clinical research samples.

BACKGROUND: During sleep, limb and jaw muscle motor activity can be quantified by electromyography (EMG). The frequency of periodic limb activity during sleep increases with age in both the general and clinical research populations. The literature is controversial regarding stability, over age, of the frequency of rhythmic masticatory muscle activity (RMMA), which is one biomarker of sleep bruxism (SB). OBJECTIVES: The purpose of this retrospective sleep laboratory study was to assess if any change in RMMA frequency occurs over age in the general population (GP) and two clinical research (CR) samples. METHODS: RMMA signals from polysomnography (PSG) recordings of 465 individuals, irrespective of SB awareness, were analysed. The sample comprised 164 individuals from the GP of Sao Paulo, and 301 individuals from Montreal and Osaka CR samples. Data were divided into two subgroups, younger (15-39) and older (40-80) participants. RMMA was classified as low frequency (<2 events/h) or high (≥2 events/h). Pearson correlation (R) and B (slope) analyses were performed with power estimations. RESULTS: In the GP sample, no significant change over age was noted in the RMMA index/year. In the CR samples, a significant reduction was observed in the RMMA index/year (-0.05) with age (R2  = .042; p < .001; 3.5 to 1.5 RMMA/h from 20 to 60 years old). CONCLUSIONS: In the GP, the RMMA index remained stable over age. In the CR samples, a significant, reduction was observed. Prospective studies with multiple home sleep recordings, in both general and clinical research populations, are needed before extrapolating from the present findings.

Oral appliances reduce masticatory muscle activity-sleep bruxism metrics independently of changes in heart rate variability.

OBJECTIVES: Sleep bruxism (SB) is associated with physiological activities including sympathetic autonomic system dominance and sleep micro-arousal. While oral appliances (OA) are used to prevent SB harmful effects, the influence of OAs physiological mechanisms during sleep is unknown. The aim of this study is to assess whether heart rate variability (HRV) changes, as a marker of autonomic nervous system activity, would be associated with the OA mechanism of action on SB using occlusal splint (OS) and mandibular advancement splint (MAS). MATERIALS AND METHODS: A retrospective analysis, from data previously collected in 21 participants with SB (25.6 ± 4.5 years) with polysomnographic recordings, was done. HRV data were compared between a reference night (no-device) and ones during which OS or MAS was used in a crossover study design. Rhythmic masticatory muscle activity (RMMA) index was compared between nights. HRV was evaluated using autoregressive model analysis for three sections: baseline (distance from RMMA), immediately before, and after RMMA period. RESULTS: A significant reduction in RMMA index, when wearing OA during sleep, was observed (P < 0.01), but was not associated with HRV parameters change. HRV significantly changed after RMMA onset for nights with OA during non-REM sleep in comparison with baseline (P < 0.02). CONCLUSIONS: The usage of OAs for SB participants reduced RMMA, but most likely independently of changes in HRV linked to the mechanism associated with SB genesis. CLINICAL RELEVANCE: Wearing OA seems to reduce grinding noise and protect from dental injuries but does not seem to influence SB genesis.

Conditioning to Enhance the Effects of Repetitive Transcranial Magnetic Stimulation on Experimental Pain in Healthy Volunteers.

Objective: In this proof-of-concept study we sought to explore whether the combination of conditioning procedure based on a surreptitious reduction of a noxious stimulus (SRPS) could enhance rTMS hypoalgesic effects [i.e., increase heat pain threshold (HPT)] and augment intervention expectations in a healthy population. Methods: Forty-two healthy volunteers (19-35 years old) were enrolled in a randomized crossover-controlled study and were assigned to one of two groups: (1) SRPS and (2) No SRPS. Each participant received two consecutive sessions of active or sham rTMS over the M1 area of the right hand on two visits (1) active, (2) sham rTMS separated by at least one-week interval. HPT and the temperature needed to elicit moderate heat pain were measured before and after each rTMS intervention on the right forearm. In the SRPS group, conditioning consisted of deliberately decreasing thermode temperature by 3°C following intervention before reassessing HPT, while thermode temperature was held constant in the No SRPS group. Intervention expectations were measured before each rTMS session. Results: SRPS conditioning procedure did not enhance hypoalgesic effects of rTMS intervention, neither did it modify intervention expectations. Baseline increases in HPT were found on the subsequent intervention session, suggesting variability of this measure over time, habituation or a possible "novelty effect." Conclusion: Using a SRPS procedure in healthy volunteers did not enhance rTMS modulating effects on experimental pain sensation (i.e., HPT). Future studies are therefore needed to come up with a conditioning procedure which allows significant enhancement of rTMS pain modulating effects in healthy volunteers.

Accuracy of sleep bruxism scoring based on electromyography traces of different jaw muscles in individuals with obstructive sleep apnea.

STUDY OBJECTIVES: Sleep bruxism is characterized by rhythmic masticatory muscle activity (RMMA). This study aimed to determine the number and type of jaw muscles needed for a valid RMMA scoring in individuals with obstructive sleep apnea. METHODS: Ten individuals with obstructive sleep apnea (4 males; age, 50.1 ± 8.1 years) were included in this study. RMMA was scored using 1 or more of the following jaw muscles' electromyography (EMG) traces of polysomnography recordings: bilateral masseter and temporalis (4MT; the reference standard), unilateral masseter (1M), bilateral masseter (2M), unilateral temporalis (1T), bilateral temporalis (2T), unilateral chin EMG (1C), and bilateral chin EMG (2C). RESULTS: 1M, 2M, 1T, and 2T showed excellent agreement with 4MT (intraclass correlation coefficient = 0.751, 0.976, 0.815, and 0.950, respectively), while 1C and 2C presented fair agreement (intraclass correlation coefficient = 0.662 and 0.657). In addition, 2M and 2T displayed good sensitivity (87.8% and 72.0%) and positive predictive value (83.1% and 76.0%). In contrast, 1M and 1T had good sensitivity (88.4% and 87.8%) but fair positive predictive value (60.1% and 53.2%). 1C and 2C showed poor sensitivity (41.1% and 40.3%) and fair positive predictive value (62.9% and 60.6%). CONCLUSIONS: Polysomnography with bilateral masseter or temporalis muscle EMG traces is regarded valid in RMMA scoring in individuals with obstructive sleep apnea. In contrast, unilateral masseter or temporalis muscle EMG showed only fair accuracy, and chin EMG had poor accuracy. Consequently, these montages cannot be recommended for RMMA scoring in the presence of obstructive sleep apnea. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: The Effects of Oral Appliance Therapy on Masseter Muscle Activity in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02011425; Identifier: NCT02011425. CITATION: Li D, Aarab G, Lobbezoo F, Arcache P, Lavigne GJ, Huynh N. Accuracy of sleep bruxism scoring based on electromyography traces of different jaw muscles in individuals with obstructive sleep apnea. J Clin Sleep Med. 2022;18(6):1609-1615.

Relevance of Sleep Disturbances to Orthopaedic Surgery: A Current Concepts Narrative and Practical Review.

➤: Sleep disturbances can increase the risk of falls and motor vehicle accidents and may reduce bone density. ➤: Poor sleep can lead to worse outcomes after fracture, such as chronic pain and delayed recovery. ➤: Orthopaedic surgeons can play an important role in the screening of sleep disorders among their patients.