Sleep bruxism in children and adolescents-A scoping review

BACKGROUND AND OBJECTIVE

This review paper focuses on sleep bruxism (SB) in children and adolescents. It aims to assess the landscape of knowledge published in the last 20 years.

METHODS

A total of 144 relevant publications from 386 previously identified through Medline were included, of which 83 were on possible SB, 37 on probable SB, 20 on definite SB and 4 were non-applicable. The review places emphasis on the recent evidence on prevalence, pathophysiology, diagnosis and management of SB in children and adolescents, with special focus on probable and definitive SB.

RESULTS

The prevalence ranges from 5% to 50% depending on the age range and on the SB diagnosis (possible, probable or definitive). The pathophysiology is multifactorial, arousal associated and with behavioural problems and sleep disorders (obstructive sleep apnoea, snoring, nightmares) as risk factors, as well as respiratory conditions (allergies, oral breathing). Screening should include questionnaires and dental assessment. Instrumental recording is helpful to confirm diagnosis although more studies are needed to validate this approach in children. SB management includes controlling orofacial and dental consequences and assessing for any other comorbidity. Management options include occlusal splints, oral appliances (advancement mandibular), rapid maxillary expansion and some medications, although this last option is supported by limited evidences in children.

CONCLUSION

Suggestions of future topics in research are delivered to better understand comorbidities, diagnosis and management with improved outcomes compared to what is currently available.

Prevalence, Severity, and Description of Dental Anomalies in Children Treated for Acute Lymphoblastic Leukemia

Purpose: To assess the prevalence and severity of and describe dental anomalies in children treated for acute lymphoblastic leukemia (ALL) under recent Dana-Farber Cancer Institute (DFCI) protocols. Methods: Patients aged between 14 and 25 years old having received a diag- nosis of ALL before the age of 11 years and after September 2000 received clinical and radiographic oral examinations. Results: Dental anomalies were observed in 26 (51.0 percent) of 51 subjects. Microdontia was the most prevalent dental defect (39.2 percent). Impacted permanent second molars were observed in five (9.8 percent) patients. Being age five years or younger at diagnosis significantly increased the prevalence and severity of dental anomalies (P<0.001). Conclusions: Recent DFCI protocols showed a decreased prevalence of dental disturbances. The anomalies observed may still alter the development of the dental arches and occlusion in pediatric ALL survivors. Further research is needed to confirm the association between ALL treatment and permanent second molar impaction.

Reliability and accuracy of a semi-automatic segmentation protocol of the nasal cavity using cone beam computed tomography in patients with sleep apnea

OBJECTIVES

The objectives of this study included using the cone beam computed tomography (CBCT) technology to assess: (1) intra- and inter-observer reliability of the volume measurement of the nasal cavity; (2) the accuracy of the segmentation protocol for evaluation of the nasal cavity.

MATERIALS AND METHODS

This study used test-retest reliability and accuracy methods within two different population sample groups, from Eastern Asia and North America. Thirty obstructive sleep apnea (OSA) patients were randomly selected from administrative and research oral health data archived at two dental faculties in China and Canada. To assess the reliability of the protocol, two observers performed nasal cavity volume measurement twice with a 10-day interval, using Amira software (v4.1, Visage Imaging Inc., Carlsbad, CA). The accuracy study used a computerized tomography (CT) scan of an OSA patient, who was not included in the study sample, to fabricate an anthropomorphic phantom of the nasal cavity volume with known dimensions (18.9 ml, gold standard). This phantom was scanned using one NewTom 5G (QR systems, Verona, Italy) CBCT scanner. The nasal cavity was segmented based on CBCT images and converted into standard tessellation language (STL) models. The volume of the nasal cavity was measured on the acquired STL models (18.99 ± 0.066 ml).

RESULTS

The intra-observer and inter-observer intraclass correlation coefficients for the volume measurement of the nasal cavity were 0.980-0.997 and 0.948-0.992 consecutively. The nasal cavity volume measurement was overestimated by 1.1%-3.1%, compared to the gold standard.

CONCLUSIONS

The semi-automatic segmentation protocol of the nasal cavity in patients with sleep apnea and by using cone beam computed tomography is reliable and accurate.

CLINICAL RELEVANCE

This study provides a reliable and accurate protocol for segmentation of nasal cavity, which will facilitate the clinician to analyze the images within nasoethmoidal region.

Orthodontic and Facial Characteristics of Craniofacial Syndromic Children with Obstructive Sleep Apnea

Introduction: Obstructive sleep apnea (OSA) is a disorder in which ventilation becomes disrupted due to a complete or partial upper airway obstruction Altered craniofacial morphology is one of the most important anatomical factors associated with obstructive sleep apnea (OSA). Studies have assessed craniofacial features in the non-syndromic pediatric population. The aim of this study was to analyze the orthodontic and facial characteristic of craniofacial syndromic children referred for polysomnography (PSG) and to assess the correlation with the apnea-hypopnea index (AHI). Methods: In the current cross-sectional study, consecutive syndromic patients referred for PSG were invited to participate. A systematic clinical examination including extra- and intra-oral orthodontic examination was performed by calibrated orthodontists. Standardized frontal and profile photographs with reference points were taken and analyzed using ImageJ^® software to study the craniofacial morphology. PSG data were analyzed for correlation with craniofacial features. STROBE guidelines were strictly adopted during the research presentation. Results: The sample included 52 syndromic patients (50% females, mean age 9.38 ± 3.36 years) diagnosed with 17 different syndromes, of which 24 patients had craniofacial photography analysis carried out. Most of the sample (40%) had severe OSA, while only 5.8% had no OSA. Down's syndrome (DS) was the most common syndrome (40%) followed by Goldenhar syndrome (5%), Pierre Robin Sequence (5%), and other syndromes. The severity of AHI was significantly correlated with decreased midfacial height. increased thyromental angle and cervicomental angle, decreased mandibular angle, and decreased upper facial height. All patients with DS were diagnosed with OSA (57% severe OSA), and their ODI was significantly correlated with increased intercanthal distance. Obesity was not correlated to the severity of AHI for syndromic patients. Conclusions: Decreased midfacial height and obtuse thyromental angle were correlated with increased AHI for syndromic patients. Increased intercanthal distance of DS patients could be a major predictor of OSA severity. Obesity does not seem to play a major role in the severity of OSA for syndromic patients. Further studies with larger samples are necessary to confirm these findings.

The influence of obstructive sleep apnea syndrome on orthodontic treatment decisions in children and adolescents. Part 1: OSA phenotypes, treatment temporality and reciprocal effects on growth

Introduction

Pediatric OSAS is a complex condition, comprising a plurality of clinical signs, complicated by the phenomena of growth. Its etiology is dominated by the hypertrophy of lymphoid organs, but obesity and certain craniofacial and neuromuscular tone abnormalities also contribute.

Material and Method

The authors summarize the interrelations between pediatric OSAS endotypes, phenotypes and orthodontic anomalies. They report clinical practice recommendations on the multidisciplinary management of pediatric OSAS and define the place and timing of orthodontics.

Results

There is an indication for treatment of pediatric OSAS for an OAHI greater than 5/h, regardless of comorbidity, as well as for symptomatic children, whose OAHI is between 1-5/h. The first line of treatment is adenotonsillectomy, but it does not always normalize the OAHI. Complementary treatments are often necessary: early orthodontics (rapid maxillary expansion, myofunctional appliances), oral reeducation, as well as the management of obesity and allergies. Careful watching, without treatment is possible for mild cases with few symptoms, as pediatric OSAS tends to resolve naturally with growth.

Discussion

The therapeutic approach is stratified, depending on the severity of OSAS and the child's age. In terms of orthodontic repercussions, obesity is associated with earlier maturation and some facial morphological differences, while oral hypotonia and nasal obstruction can alter facial growth, promoting mandibular hyperdivergence and maxillary deficiency.

Conclusion

Orthodontists are in a privileged position for the detection, follow-up and certain treatments of OSAS.

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.

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.

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 (OSA).

METHODS

10 individuals with OSA (4 males; age = 50.1 ± 8.1 years) were included in this study. RMMA was scored using one 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 [ICC] = 0.751, 0.976, 0.815, and 0.950, respectively), while 1C and 2C presented fair agreement (ICC= 0.662 and 0.657). Besides, 2M and 2T displayed good sensitivity (87.8% and 72.0%) and positive predictive value (PPV; 83.1% and 76.0%). In contrast, 1M and 1T had good sensitivity (88.4% and 87.8%) but fair PPV (60.1% and 53.2%). 1C and 2C showed poor sensitivity (41.1% and 40.3%) and fair PPV (62.9% and 60.6%).

CONCLUSIONS

Polysomnography with bilateral masseter or temporalis muscle EMG traces is regarded valid in RMMA scoring in individuals with OSA. 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 OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: The Effects of Oral Appliance Therapy on Masseter Muscle Activity in Obstructive Sleep Apnea; Identifier: NCT02011425.

Prevalence of malocclusions and oral dysfunctions in children with persistent sleep-disordered breathing after adenotonsillectomy in the long term

STUDY OBJECTIVES

To evaluate the prevalence of craniofacial/orthodontic abnormalities and oral dysfunctions in a population of children with persistent sleep-disordered breathing despite adenotonsillectomy.

METHODS

Medical charts of 4,000 children with sleep-disordered breathing operated on in a tertiary hospital were retrospectively reviewed. Patients reporting persistent sleep-disordered breathing symptoms were invited to an orthodontic/myofunctional evaluation following the Sleep Clinical Score), followed by a 1-night ambulatory type III sleep study.

RESULTS

One hundred nonsyndromic symptomatic patients were examined (mean age 8.8 ± 3.5 years), from 1 to 12 years after surgery (mean 4.6 ± 3.1 years); 24% were overweight/obese; 69 had a sleep study. Although prevalent, oronasal abnormalities and malocclusions were not specifically associated with pathological sleep parameters (cartilage hypotonia 18%, septal deviation 5%, short lingual frenulum 40%). Malocclusions were associated with a higher respiratory event index in children under 8 years only, whereas an impaired nasal dilator reflex and tongue immaturity were associated with an increased obstructive respiratory event index in all patients (1.72 ± 2.29 vs 0.72 ± 1.22 events/h, P = .011) and Respiratory Event Index, respectively (3.63 ± 3.63 vs 1.19 ± 1.19 events/h). Male sex, phenotype, nasal obstruction, oral breathing, and young age at surgery (< 3 years) were significantly related to higher respiratory event index. Using the Sleep Clinical Score > 6.5 cut-off, patients with persistent sleep apnea were significantly distinct from chronic snoring (2.72 ± 2.67 vs 0.58 ± 0.55, P < .01).

CONCLUSIONS

Oronasal anatomical and functional abnormalities were quite prevalent and various in persistent sleep-disordered breathing after adenotonsillectomy. Nasal disuse and tongue motor immaturity were associated with a higher obstructive respiratory event index in the long term, whereas craniofacial risk factors might have a more pronounced impact at younger age.

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.

The effects of mandibular advancement appliance therapy on jaw-closing muscle activity during sleep in patients with obstructive sleep apnea: a 3-6 months follow-up

STUDY OBJECTIVES

The main aim of this study was to investigate the effects of mandibular advancement appliance (MAA) therapy on jaw-closing muscle activity (JCMA) time-related to respiratory arousals, and on JCMA time-related to nonrespiratory arousals in patients with obstructive sleep apnea.

METHODS

Eighteen patients with OSA (mean ± standard deviation = 49.4 ± 9.8 years) with a mean ± standard deviation apnea-hypopnea index of 22.0 ± 16.0 events/h of sleep participated in a randomized controlled crossover trial in which two ambulatory polysomnographic recordings, 1 with an MAA in situ and another without the MAA in situ, were performed. JCMA was quantified as the sum of rhythmic masticatory muscle activities and other orofacial activities.

RESULTS

Significant reductions in the apnea-hypopnea index (Z = -2.984; P = .003), in the respiratory arousal index (Z = -2.896; P = .004), and in the JCMA time-related to respiratory arousal index (Z = -3.434; P = .001) were found with MAA in situ. On the nonrespiratory arousal index, and on the JCMA time-related to nonrespiratory arousal index, MAA had no significant effect (T = 2.23; P = .82; and Z = -0.66; P = .51, respectively).

CONCLUSIONS

This study shows that effective mandibular advancement appliance therapy significantly reduces jaw-closing muscle activities time-related to respiratory arousals in OSA patients. Future studies are needed to confirm these findings in obstructive sleep apnea patients with comorbid sleep bruxism.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: The Effects of Oral Appliance Therapy on Masseter Muscle Activity in Obstructive Sleep Apnea; Identifier: NCT02011425.

Dental sleep medicine: Time to incorporate sleep apnoea education in the dental curriculum

Dental sleep medicine is a discipline that includes conditions such as sleep breathing disorders (eg snoring and sleep apnoea), sleep bruxism, orofacial pain and sleep-related complaints, and to some extent gastro-oesophageal reflux disorder and/or insomnia. Obstructive sleep apnoea (OSA) is a life-threatening condition that dentists need to identify and manage when indicated in order to increase patient well-being and to be taken in consideration in the dental curriculum. The main objective of this paper is to highlight the relevance of dental sleep medicine in the context of dental education, and to discuss potential educational content for integration in the dental curriculum with a focus on OSA, a condition that is not yet integrated in many dental training curricula around the world.

High separation anxiety trajectory in early childhood is a risk factor for sleep bruxism at age 7

STUDY OBJECTIVES

The evolution of sleep bruxism manifestations and their co-occurrence with separation anxiety in early childhood remain unclear. Our threefold aim was to: (1) describe developmental sleep bruxism trajectories in early childhood, (2) investigate co-occurrences between trajectories of sleep bruxism and separation anxiety, and (3) determine whether distinct trajectories of separation anxiety increase the risk of presenting sleep bruxism during the first year of elementary school.

METHODS

This study is part of the Québec Longitudinal Study of Child Development. Sleep bruxism scores were assessed from age 1.5 to 7 years with the Self-Administered Questionnaire for Mother (n = 1946). Separation anxiety scores were measured from age 1.5 to 6 years with the Interviewer-Completed Computerized Questionnaire (n = 2045).

RESULTS

We identified four sleep bruxism trajectories from age 1.5 to 6 years: High-Increasing sleep bruxism at age 1.5 (14.1%), High-Increasing sleep bruxism at age 4 (18.3%), Low-Persistent sleep bruxism (12.1%), and Never-Persistent sleep bruxism (55.5%); and four separation anxiety trajectories from age 1.5 to 6 years: Low-Persistent separation anxiety (60.2%), High-Increasing separation anxiety (6.9%), High-Decreasing separation anxiety (10.8%), and Low-Increasing separation anxiety (22.1%). Sleep bruxism and separation anxiety trajectories were weakly associated (X2 = 37.84, p < 0.001). Compared with preschoolers belonging to the Low-Persistent separation anxiety trajectory, preschoolers in the High-Increasing separation anxiety trajectory had almost double the risk of presenting sleep bruxism at age 7 (95% CI = 1.25-3.22, p = 0.04).

CONCLUSION

When separation anxiety issues are detected in early childhood, it would be useful to target sleep bruxism during the first year of elementary school.

Critical Issues in Dental and Medical Management of Obstructive Sleep Apnea

This critical review focuses on obstructive sleep apnea (OSA) and its management from a dental medicine perspective. OSA is characterized by ≥10-s cessation of breathing (apnea) or reduction in airflow (hypopnea) ≥5 times per hour with a drop in oxygen and/or rise in carbon dioxide. It can be associated with sleepiness and fatigue, impaired mood and cognition, cardiometabolic complications, and risk for transportation and work accidents. Although sleep apnea is diagnosed by a sleep physician, its management is interdisciplinary. The dentist’s role includes 1) screening patients for OSA risk factors (e.g., retrognathia, high arched palate, enlarged tonsils or tongue, enlarged tori, high Mallampati score, poor sleep, supine sleep position, obesity, hypertension, morning headache or orofacial pain, bruxism); 2) referring to an appropriate health professional as indicated; and 3) providing oral appliance therapy followed by regular dental and sleep medical follow-up. In addition to the device features and provider expertise, anatomic, behavioral, demographic, and neurophysiologic characteristics can influence oral appliance effectiveness in managing OSA. Therefore, OSA treatment should be tailored to each patient individually. This review highlights some of the putative action mechanisms related to oral appliance effectiveness and proposes future research directions.

Persistent sleep disordered breathing after adenoidectomy and/or tonsillectomy: a long-term survey in a tertiary pediatric hospital

PURPOSE

To determine the long-term prevalence of persistent sleep disordered breathing (SDB) in children, after adenoidectomy, tonsillectomy or adenotonsillectomy, and to assess the relationship between baseline characteristics and persistent nocturnal symptoms.

METHODS

The clinical charts of children operated for adenoidectomy and/or tonsillectomy in a tertiary hospital, between January 2000 and March 2016, were retrospectively reviewed. All patients who had signs of SDB prior to surgery received a six-question validated pediatric questionnaire, the Hierarchic Severity Clinical Scale (HSCS).

RESULTS

A total of 4000 children showing SDB prior to surgery were selected out of 5809 (68.9%); 1176 parents returned the questionnaire (29.4%), with a mean age at surgery of 4.3 ± 2.2 and age at survey of 9.6 ± 3.6. Complete resolution of SDB was subjectively reported in 798 patients (67.9%), and mild SDB was suspected in 301 children (25.6%, HSCS > 0 with chronic snoring), while 77 (6.5%) had a HSCS > 2.72, suggesting persistent obstructive sleep apnea. In non-syndromic children, male sex, history of sole adenoidectomy, or sole tonsillectomy, and early age of surgery (< 2 years-old) were associated with higher HSCS scores (p < 0.05). Moreover, symptoms had a tendency to decrease from 1 to 6 years, re-occur at age 7-8, and also after 13, with boys reporting more severe symptoms, at a younger age.

CONCLUSIONS

Surgical excision of lymphoid tissue to treat SDB in childhood seems to be effective in the long term in two-thirds of subjects, while partial surgeries, specific age groups and early surgery are more likely to have persistent or recurrent symptoms.

Review of modelling air pollution from traffic at street-level - The state of the science

Traffic emissions are a complex and variable cocktail of toxic chemicals. They are the major source of atmospheric pollution in the parts of cities where people live, commute and work. Reducing exposure requires information about the distribution and nature of emissions. Spatially and temporally detailed data are required, because both the rate of production and the composition of emissions vary significantly with time of day and with local changes in wind, traffic composition and flow. Increasing computer processing power means that models can accept highly detailed inputs of fleet, fuels and road networks. The state of the science models can simulate the behaviour and emissions of all the individual vehicles on a road network, with resolution of a second and tens of metres. The chemistry of the simulated emissions is also highly resolved, due to consideration of multiple engine processes, fuel evaporation and tyre wear. Good results can be achieved with both commercially available and open source models. The extent of a simulation is usually limited by processing capacity; the accuracy by the quality of traffic data. Recent studies have generated real time, detailed emissions data by using inputs from novel traffic sensing technologies and data from intelligent traffic systems (ITS). Increasingly, detailed pollution data is being combined with spatially resolved demographic or epidemiological data for targeted risk analyses.

Sleep Bruxism-Tooth Grinding Prevalence, Characteristics and Familial Aggregation: A Large Cross-Sectional Survey and Polysomnographic Validation

STUDY OBJECTIVES

Sleep bruxism (SB) is characterized by tooth grinding and jaw clenching during sleep. Familial factors may contribute to the occurrence of SB. This study aims are: (1) revisit the prevalence and characteristics of SB in a large cross-sectional survey and assess familial aggregation of SB, (2) assess comorbidity such as insomnia and pain, (3) compare survey data in a subset of subjects diagnosed using polysomnography research criteria.

METHODS

A sample of 6,357 individuals from the general population in Quebec, Canada, undertook an online survey to assess the prevalence of SB, comorbidities, and familial aggregation. Data on familial aggregation were compared to 111 SB subjects diagnosed using polysomnography.

RESULTS

Regularly occurring SB was reported by 8.6% of the general population, decreases with age, without any gender difference. SB awareness is concomitant with complaints of difficulties maintaining sleep in 47.6% of the cases. A third of SB positive probands reported pain. A 2.5 risk ratio of having a first-degree family member with SB was found in SB positive probands. The risk of reporting SB in first-degree family ranges from 1.4 to 2.9 with increasing severity of reported SB. Polysomnographic data shows that 37% of SB subjects had at least one first-degree relative with reported SB with a relative risk ratio of 4.625.

CONCLUSIONS

Our results support the heritability of SB-tooth grinding and that sleep quality and pain are concomitant in a significant number of SB subjects.

Characterization of Regulatory Extracellular Vesicles from Osteoclasts

Extracellular vesicles (EVs), which include exosomes and ectosomes/microvesicles, have emerged as important intercellular regulators. EVs can interact with surface receptors of target cells and can transport luminal components, including messenger RNAs (mRNAs), microRNAs, and enzymes, to the cytosol of the target cell. Here, we show that hematopoietic cells grown in culture shed exosome-like EVs as they differentiate from preosteoclasts into osteoclasts. These EVs were between 25 and 120 nm (mean, 40 nm) in diameter determined by transmission electron microscopy. The exosome-associated markers CD63 and EpCAM were enriched in the isolated EVs while markers of Golgi and endoplasmic reticulum were not detected. Treatment of isolated hematopoietic cells with EVs did not affect their receptor activator of nuclear factor κB-ligand (RANKL)-stimulated differentiation into osteoclasts. However, EVs from osteoclast precursors promoted 1,25-dihydroxyvitamin D3-dependent osteoclast formation in whole mouse marrow cultures, and EVs from osteoclast-enriched cultures inhibited osteoclastogenesis in the same cultures. These data suggested that osteoclast-derived EVs are paracrine regulators of osteoclastogenesis. EVs from mature osteoclasts contained receptor activator of nuclear factor κB (RANK). Immunogold labeling showed RANK was enriched in 1 in every 32 EVs isolated from osteoclast-enriched cultures. Depletion of RANK-rich EVs relieved the ability of osteoclast-derived EVs to inhibit osteoclast formation in 1,25-dihydroxyvitamin D3-stimulated marrow cultures. In summary, we show for the first time that EVs released by osteoclasts are novel regulators of osteoclastogenesis. Our data suggest that RANK in EVs may be mechanistically linked to the inhibition of osteoclast formation. RANK present in EVs may function by competitively inhibiting the stimulation of RANK on osteoclast surfaces by RANKL similar to osteoprotegerin. RANK-rich EVs may also take advantage of the RANK/RANKL interaction to target RANK-rich EVs to RANKL-bearing cells for the delivery of other regulatory molecules.

The effect of nocturnal wear of complete dentures on sleep and oral health related quality of life: study protocol for a randomized controlled trial

Background

Edentulism and sleep disturbance are chronic conditions that are common in older people and have serious adverse consequences for their functioning and quality of life. Edentulism can disturb sleep through the alteration of the craniofacial structure and surrounding soft tissue. However, the effect of prosthetic rehabilitation of edentulism on sleep quality is still not well understood. The objectives of this study are to test whether nocturnal denture wear affects sleep quality, daytime sleepiness, and the oral health related quality of life of edentate older people with moderate to severe sleep apnea, and to identify modifiers of effect of nocturnal denture wear.

Methods/design

We will carry out a single-blind randomized cross-over trial. Seventy edentate older people with moderate to severe obstructive sleep apnea will be enrolled. The study participants will be assigned to wear and not wear their dentures on alternate periods of 30 days. The outcome measures will be sleep quality (assessed by portable polysomnography), daytime sleepiness (assessed by the Epworth Sleepiness Scale), and oral health related quality of life (assessed by validated questionnaire). A number of characteristics (sociodemographic, oropharyngeal morphology, oral and prosthesis characteristics, and perceived general health quality of life) will be assessed by means of clinical examination, 3D imaging of the craniofacial structure, and validated questionnaires at baseline. Linear mixed effects regression models for repeated measures will be fitted to test the study hypotheses. The main analyses will be based on the intention-to-treat principle. To assess the robustness of the findings to potential incomplete adherence, sensitivity analyses will be conducted while applying the per-protocol principle.

Discussion

This practice-relevant evidence could represent a preventive approach to improve sleep characteristics of the older population and improve their well-being and quality of life.

Trial registration

ClinicalTrials.gov NCT01868295.

An fMRI study of cerebrovascular reactivity and perfusion in obstructive sleep apnea patients before and after CPAP treatment

OBJECTIVE

Cerebrovascular reactivity is impaired in patients suffering from obstructive sleep apnea syndrome (OSAS) as demonstrated by transcranial Doppler studies. We use magnetic resonance imaging techniques to investigate the anatomical distribution of cerebrovascular reactivity changes in patients with OSAS, as well as their evolution after therapeutic and sham continuous positive airway pressure (CPAP) treatment.

METHODS

Twenty-three men with moderate or severe obstructive sleep apnea were compared to a healthy control group (n=7) using a breath-holding functional magnetic resonance imaging task and the flow-sensitive alternating inversion recovery (FAIR) imaging before and after 2 months of therapeutic (active) or sub-therapeutic (sham) CPAP treatment.

RESULTS

Significantly higher cerebrovascular reactivity was found in healthy controls as compared to patients in bilateral cortical and subcortical brain regions. Cerebrovascular reactivity increased with therapeutic CPAP in the thalamus and decreased with sham CPAP in medial frontal regions in OSAS patients. Duration of nocturnal hypoxemia and body mass index negatively correlated with cerebrovascular reactivity, particularly in the medial temporal lobe structures, suggesting a possible pathophysiological mechanism for hippocampal injury. There was no difference in perfusion between patients and control group, and no effect of CPAP or sham-CPAP treatment on perfusion in patients.

CONCLUSIONS

Observed cerebrovascular reactivity changes were neither homogeneous throughout the brain nor followed vascular territories, but rather corresponded to underlying neuronal networks, establishing a relationship between cerebrovascular reactivity and surrounding neuronal activity.

Is there a first night effect on sleep bruxism? A sleep laboratory study

STUDY OBJECTIVES

Sleep bruxism (SB) is reported to vary in frequency over time. The aim of this study was to assess the first night effect on SB.

METHODS

A retrospective polysomnographic (PSG) analysis was performed of data from a sample of SB patients (12 females, 4 males; age range: 17-39 years) recorded in a sleep laboratory over 2 consecutive nights. Sleep parameters and jaw muscle activity variables (i.e., rhythmic masticatory muscle activity [RMMA]) for SB were quantified and compared between the 2 nights. Subjects were classified into groups according to severity of RMMA frequency, such as low frequency (2-4 episodes/h and/or < 25 bursts/h) and moderate-high frequency (≥ 4 episodes/h and ≥ 25 bursts/h).

RESULTS

Overall, no first night effects were found for most sleep variables. However, total sleep time, sleep efficiency, and stage transitions showed significant time and group interactions (repeated measures ANOVAs, p ≤ 0.05). The RMMA episode index did not differ between the 2 nights, whereas the second night showed significantly higher burst index, bruxism time index, and mean burst duration (repeated measure ANOVAs, p ≤ 0.05). Five patients of 8 in the low frequency group were classified into the moderate-high frequency group on the second night, whereas only one patient in the moderate-high frequency group moved to the low frequency group.

CONCLUSIONS

The results showed no overall first night effect on severity of RMMA frequency in young and healthy patients with SB. In clinical practice, one-night sleep recording may be sufficient for moderate-high frequency SB patients. However, low RMMA frequency in the first night could be confirmed by a second night based on the patient's medical and dental history.

The nocturnal use of complete dentures and sleep stability in edentulous elders

OBJECTIVE

To evaluate the stability of sleep quality and the impact of nocturnal use of complete dentures on sleep quality in an elderly edentulous population over a one-year period.

MATERIALS AND METHODS

Written informed consent was obtained from 172 edentulous elders who agreed to enrol in a longitudinal cohort study. A total of 153 participants completed the follow-up after one year. Perceived quality of sleep and daytime sleepiness were measured using the Pittsburgh Sleep Quality Index (PSQI, score 0-21) and the Epworth Sleepiness Scale (ESS, score 0-24) at baseline (T0) and at follow-up (T1). Data on oral health related quality of life, type of mandibular dentures (conventional versus implant-retained mandibular overdenture), nocturnal wear of the dentures and socio-demographic status were obtained by means of the OHIP-20 questionnaire, a clinical examination form and a socio-demographic questionnaire.

RESULTS

No statistically significant differences were detected in the global PSQI mean scores and EES mean scores from baseline (PSQI 4.77 ± 3.32; EES 5.35 ± 3.72) to the follow-up assessment (PSQ1 5.04 ± 3.50; EES 5.53 ± 4.34). Edentate elders wearing prostheses at night had poorer daytime sleepiness scores than those who removed their prostheses at night (p=0.003 unadjusted model; p=0.058 adjusted for age, gender, type of prosthesis and the OHIP-20 total score).

CONCLUSION

Results of this study suggest that wearing complete dentures while sleeping has little effect on sleep quality or daytime sleepiness.

The effects of CPAP treatment on task positive and default mode networks in obstructive sleep apnea patients: an fMRI study

INTRODUCTION

Functional magnetic resonance imaging studies enable the investigation of neural correlates underlying behavioral performance. We investigate the effect of active and sham Continuous Positive Airway Pressure (CPAP) treatment on working memory function of patients with Obstructive Sleep Apnea Syndrome (OSAS) considering Task Positive and Default Mode networks (TPN and DMN).

METHODS

An experiment with 4 levels of visuospatial n-back task was used to investigate the pattern of cortical activation in 17 men with moderate or severe OSAS before and after 2 months of therapeutic (active) or sub-therapeutic (sham) CPAP treatment.

RESULTS

Patients with untreated OSAS had significantly less deactivation in the temporal regions of the DMN as compared to healthy controls, but activation within TPN regions was comparatively relatively preserved. After 2 months of treatment, active and sham CPAP groups exhibited opposite trends of cerebral activation and deactivation. After treatment, the active CPAP group demonstrated an increase of cerebral activation in the TPN at all task levels and of task-related cerebral deactivation in the anterior midline and medial temporal regions of the DMN at the 3-back level, associated with a significant improvement of behavioral performance, whereas the sham CPAP group exhibited less deactivation in the temporal regions of Default Mode Network and less Task Positive Network activation associated to longer response times at the 3-back.

CONCLUSION

OSAS has a significant negative impact primarily on task-related DMN deactivation, particularly in the medial temporal regions, possibly due to nocturnal hypoxemia, as well as TPN activation, particularly in the right ventral fronto-parietal network. After 2 months of active nasal CPAP treatment a positive response was noted in both TPN and DMN but without compete recovery of existing behavioral and neuronal deficits. Initiation of CPAP treatment early in the course of the disease may prevent or slow down the occurrence of irreversible impairment.

Sleep bruxism is associated with a rise in arterial blood pressure

STUDY OBJECTIVES

Sleep bruxism (SB) is a movement disorder identified by grinding of teeth and rhythmic masticatory muscle activity (RMMA). RMMA is associated with body movements and cortical arousals. Increases in autonomic sympathetic activities that characterize sleep cortical arousal precede RMMA/SB. Based on these findings, this study examined whether RMMA/SB episodes are also associated with significant changes in arterial blood pressure (BP).

DESIGN

Participants underwent 3 nights of full polysomnography that included noninvasive beat-to-beat BP recording. Single RMMA/SB episodes and arousal episodes were analyzed in stage 2 sleep and categorized as: (i) RMMA/SB + arousal; (ii) RMMA/SB + body movement; (iii) RMMA/SB + arousal + body movement; or (iv) arousal alone. Sleep and RMMA/SB data were compared to a Non SB group. RMMA/SB clusters (RMMA/SB episodes ≤ 30 sec apart) were also analyzed.

SETTING

Sleep Laboratory at l'Hôpital du Sacré-Coeur de Montréal.

PARTICIPANTS

Ten young, healthy participants with SB (mean age = 26 ± 1.8 years) and 9 without SB (mean age = 29 ± 1.2 years).

INTERVENTIONS

N/A MEASUREMENTS AND RESULTS: BP increased with all RMMA/SB and arousal episodes (P ≤ 0.05). The average maximum BP surges (systolic/diastolic ± SE mm Hg) were: 25.6 ± 3.3/12.6 ± 2.0 for RMMA/SB + arousal; 30.1 ± 1.7/19.1 ± 1.9 for RMMA/SB + body movement; 26.0 ± 2.8/15.1 ± 2.0 for RMMA/SB + arousal + body movement; 19.4 ± 2.3/8.9 ± 1.2 for arousal alone; and for RMMA/SB clusters: Episode: 1: 26.2 ± 8.7/16.4 ± 5.7; Episode 2: 21.1 ± 7.9/12.6 ± 6.4.

CONCLUSION

Rhythmic masticatory muscle activity/sleep bruxism (RMMA/SB) is associated with blood pressure fluctuations during sleep. Arousals and body movements often occur with RMMA/SB and can impact the magnitude of this BP surge.

Sleep bruxism: a comprehensive overview for the dental clinician interested in sleep medicine

Sleep bruxism (SB) is a common sleep-related motor disorder characterized by tooth grinding and clenching. SB diagnosis is made on history of tooth grinding and confirmed by polysomnographic recording of electromyographic (EMG) episodes in the masseter and temporalis muscles. The typical EMG activity pattern in patients with SB is known as rhythmic masticatory muscle activity (RMMA). The authors observed that most RMMA episodes occur in association with sleep arousal and are preceded by physiologic activation of the central nervous and sympathetic cardiac systems. This article provides a comprehensive review of the cause, pathophysiology, assessment, and management of SB.

Topical review: sleep bruxism, headaches, and sleep-disordered breathing in children and adolescents

Sleep bruxism, a well-known burden for dentists, is commonly observed in pediatric populations. Dentists are responsible for the detection and prevention of the detrimental consequences on the stomatognathic system that may occur in some patients with sleep bruxism. However, sleep bruxism is much more than tooth wear, since it is frequently associated with orofacial pain, headaches, and other more severe sleep disorders, such as sleep-disordered breathing. Although the mechanisms underlying the possible interactions among sleep bruxism, headaches, and sleep-disordered breathing need further research, these conditions are often concomitant. A literature search was performed to identify relevant publications related to the topic, which have been integrated in this topical review. The aim of this article was to provide a brief overview on sleep bruxism, headaches, and sleep-disordered breathing in pediatric patients and to promote a multispecialist approach (including dentists, sleep specialist physicians, and psychologists) in the diagnosis and management of these frequently associated disorders.

Clonidine has a paradoxical effect on cyclic arousal and sleep bruxism during NREM sleep

STUDY OBJECTIVE

Clonidine disrupts the NREM/REM sleep cycle and reduces the incidence of rhythmic masticatory muscle activity (RMMA) characteristic of sleep bruxism (SB). RMMA/SB is associated with brief and transient sleep arousals. This study investigates the effect of clonidine on the cyclic alternating pattern (CAP) in order to explore the role of cyclic arousal fluctuation in RMMA/SB.

DESIGN

Polysomnographic recordings from a pharmacological study.

SETTING

University sleep research laboratory.

PARTICIPANTS AND INTERVENTIONS

Sixteen SB subjects received a single dose of clonidine or placebo at bedtime in a crossover design.

MEASUREMENTS AND RESULTS

Sleep variables and RMMA/SB index were evaluated. CAP was scored to assess arousal instability between sleep-maintaining processes (phase A1) and stronger arousal processes (phases A2 and A3). Paired t-tests, ANOVAs, and cross-correlations were performed. Under clonidine, CAP time, and particularly the number of A3 phases, increased (P≤0.01). RMMA/SB onset was time correlated with phases A2 and A3 for both placebo and clonidine nights (P≤0.004). However, under clonidine, this positive correlation began up to 40 min before the RMMA/SB episode.

CONCLUSIONS

CAP phase A3 frequency increased under clonidine, but paradoxically, RMMA/SB decreased. RMMA/SB was associated with and facilitated in CAP phase A2 and A3 rhythms. However, SB generation could be influenced by other factors besides sleep arousal pressure. NREM/REM ultradian cyclic arousal fluctuations may be required for RMMA/SB onset.

Task positive and default mode networks during a parametric working memory task in obstructive sleep apnea patients and healthy controls

INTRODUCTION

Functional magnetic resonance imaging (fMRI) studies enable the investigation of neural correlates underlying behavioral performance. We investigate the working memory (WM) function of patients with untreated obstructive sleep apnea (OSA) from the view point of task positive and default mode networks (TPN and DMN, respectively) and compare the results to those of healthy controls (HC).

METHODS

A parametric fMRI experiment with 4 levels of visuospatial N-back task was used to investigate the pattern of cortical activation in 17 men with untreated moderate or severe OSA and 7 age-matched HC. Categorical and parametrical analysis of the data was performed. Multiple regression analysis of fMRI data of OSA patients was performed with AHI, nocturnal desaturation time, and BMI as covariates.

RESULTS

OSA patients demonstrate compensatory spatial recruitment of the TPN (maximal at 3-back) and of the DMN (maximal at 2-back). HC had a different patten of spatial recruitment and deactivation of the DMN at the maximal load of task (3-back). Nocturnal desaturation had significant positive correlation with BOLD signal in bilateral frontal, temporal, and occipital regions, and negative correlations in bilateral frontal and left parietal regions; whereas BMI showed only negative correlations with BOLD signal, predominantly in the PFC. AHI was positively correlated with BOLD signal in bilateral frontal regions.

CONCLUSION

Both TPN and DMN are affected in OSA patients, with nocturnal desaturation affecting both networks; whereas BMI appears to be the major negative factor influencing the TPN and has a significant negative correlation with behavioral performance.

Fractalkine functions as a chemoattractant for osteoarthritis synovial fibroblasts and stimulates phosphorylation of mitogen-activated protein kinases and Akt

Fractalkine (FKN/CX3CL1) has been detected in synovial fluids from osteoarthritis (OA) patients. Additionally, low-level expression of the FKN receptor, CX3CR1, has been demonstrated in OA synovial lining. This study aimed to determine a biological function for this ligand/receptor pair in OA and to assess a potential signalling mechanism for FKN in this predominant synovial lining cell type, using chemotaxis assays, Western blotting and F-actin staining. Chemotaxis assays demonstrate that the chemokine domain of FKN effectively induces migration of OA fibroblasts. Consistent with this finding, visualization of F-actin demonstrates that 1 or 10 nM FKN induces noticeable reorganization of cytoskeletal structure in OA fibroblasts after 30 min stimulation with a maximal enhancement at approximately 2 h. In addition, Western blotting analysis demonstrates that FKN stimulates phosphorylation of the mitogen-activated protein (MAP) kinases p38, c-Jun N-terminal kinase (JNK) and extracellular-regulated kinase (ERK) 1/2 as well as the serine-threonine kinase Akt at Ser 473 and Thr 308. All these phosphorylation events occur in a time-dependent manner, with little or no activation within 1 min, and maximal activation occurring typically between 5 and 30 min. Moreover, inhibition of ERK 1/2 significantly reduces FKN-induced OA fibroblast migration. These results suggest that FKN is a novel chemoattractant for OA fibroblasts, consistent with FKN-induced alterations in cytoskeletal structure. In addition, FKN induces OA fibroblast signalling via the MAP kinases p38, JNK and ERK 1/2, as well as Akt.

Weighing the potential effectiveness of various treatments for sleep bruxism

Sleep bruxism may lead to a variety of problems, but its pathophysiology has not been completely elucidated. As such, there is no definitive treatment, but certain preventive measures and/or drugs may be used in acute cases, particularly those involving pain. This article is intended to guide clinician scientists to the treatment most appropriate for future clinical studies. To determine the best current treatment, 2 measures were used to compare the results of 10 clinical studies on sleep bruxism, 3 involving oral devices and 7 involving pharmacologic therapy. The first measure, the number needed to treat (NNT), allows several randomized clinical studies to be compared and a general conclusion to be drawn. The second measure, effect size, allows evaluation of the impact of treatment relative to a placebo using different studies of similar design. Taking into account the NNT, the effect size and the power of each study, it can be concluded that the following treatments reduce sleep bruxism: mandibular advancement device, clonidine and occlusal splint. However, the first 2 of these have been linked to adverse effects. The occlusal splint is therefore the treatment of choice, as it reduces grinding noise and protects the teeth from premature wear with no reported adverse effects. The NNT could not be calculated for an alternative pharmacologic treatment, short-term clonazepam therapy, which had a large effect size and reduced the average bruxism index. However, the risk of dependency limits its use over long periods. Assessment of efficacy and safety of the most promising treatments will require studies with larger sample sizes over longer periods.

Comparison of sleep variables between chronic widespread musculoskeletal pain, insomnia, periodic leg movements syndrome and control subjects in a clinical sleep medicine practice

BACKGROUND

Between 50% and 89% of chronic pain patients report unrefreshing sleep. The aim of this retrospective analysis was to compare the sleep of normal subjects with the sleep of a clinical population presenting musculoskeletal chronic widespread pain (CWP), psychophysiological insomnia and restless legs syndrome/periodic limb movements during sleep (RLS/PLMS) in order to identify sleep variables that may explain the poor sleep complaints of CWP patients.

METHODS

Sleep data from 10 normal subjects and 37 patients (mean age 55+/-3 yo), matched for age and sex, were retrieved from our sleep data bank. Sub-analysis controlled for the effects of medication.

RESULTS

In comparison to normal subjects, sleep duration was shorter in CWP patients (-71 min; p<0.01); sleep efficiency was significantly lower in CWP and insomnia patients (-10.1% and -11.1%, respectively; p<0.05). CWP and PLMS patients lost one non-rapid eye movement (REM) to REM sleep cycle (p<0.04). An intermediate level of PLM was observed during the sleep of CWP patients in comparison to normal subjects (8.8/h vs. 2.0/h) and PLMS patients (33/h). Regular use of non-narcotic analgesics did not seem to interfere with sleep variables.

CONCLUSIONS

The sleep of middle-aged patients with CWP is comparable to that of insomnia patients. The moderate level of PLM during sleep suggests that such sensory motor activity needs to be evaluated in patients suffering from chronic pain.