Evaluation of pain sensitivity by tender point counts and myalgic score in patients with and without obstructive sleep apnea syndrome

Fibromyalgia in obstructive sleep apnea-hypopnea syndrome: a systematic review and meta-analysis

Introduction: Fibromyalgia (FM) is a common condition in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). This meta-analysis aimed to evaluate differences in sleep monitoring indicators between patients with OSAHS and positive FM and patients with OSAHS and negative FM and to determine the incidence of FM in patients with OSAHS. Methods: An exhaustive literature review was conducted to analyze the incidence of FM in patients with OSAHS, using online databases, including PubMed, EMBASE, Web of Science, CNKI, and Wanfang, both in English and Chinese. The quality of the included studies was assessed by two researchers using the Newcastle-Ottawa Scale scores. The acquired data were analyzed using Stata 11.0 software. Continuous variables were combined and analyzed using the weighted mean difference as the effect size. Conjoint analyses were performed using random-effects (I2 > 50%) or fixed-effect (I2 ≤ 50%) models based on I2 values. Results: Fourteen studies met the inclusion criteria. This study showed that 21% of patients with OSAHS experienced FM. Subgroup analyses were performed based on race, age, sex, body mass index, and diagnostic criteria for patients with OSAHS. These findings indicate that obese patients with OSAHS have a higher risk of FM, similar to females with OSAHS. Regarding most sleep monitoring indicators, there were no discernible differences between patients with OSAHS with positive FM and those with negative FM. However, patients with positive FM had marginally lower minimum arterial oxygen saturation levels than those with negative FM. The current literature suggests that patients with OSAHS have a high incidence of FM (21%), and FM has little effect on polysomnographic indicators of OSAHS. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024510786, identifier CRD42024510786.

The impact of fibromyalgia syndrome on obstructive sleep apnea syndrome in terms of pain threshold, daytime symptoms, anxiety, depression, disease severity, and sleep quality: a polysomnographic study

BACKGROUND

Current studies have focused on the association of fibromyalgia syndrome (FMS) and obsctructive sleep apnea syndrome (OSAS). Results of these studies on the effect of this association have been inconsistent. The current study aimed to investigate the effect of FMS on OSAS regarding sleep quality, pressure pain threshold, fatigue, daytime symptoms, anxiety, and depression, and also to determine the relationship between OSAS severity and FMS.

METHODS

In a cross-sectional design, patients diagnosed with OSAS were evaluated in two groups comparing those with and those without FMS. Data on demographics, headache, morning fatigue, and chronic pain duration were collected. Questionnaires including the Fatigue Severity Scale (FSS), Fibromyalgia Impact Questionnaire (FIQ), Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI) were completed. Pressure pain threshold, tender points, and polysomnographic data were recorded.

RESULTS

Of 69 patients, 27 were diagnosed with FMS + OSAS and 42 were diagnosed as OSAS only. Statistically significant differences were found between the two groups in VAS, pain duration, morning fatigue, headache, BAI, tender point count, FIQ and FSS scores, and algometer measurements. All polysomnografic data were compared, and no statistically significant differences were found between the two groups. There were no statistically significant differences in the algometer, BDI, BAI, FIQ, and FSS scores when analyzed according to the severity of OSAS.

CONCLUSION

The findings suggest that FMS has no effect on polysomnographic parameters of OSAS. Headache, daytime fatigue, anxiety, depression, pain duration, and pain intensity are higher while the pressure pain threshold is lower when FMS is present. No correlation was found between OSAS severity and FMS, fatigue, pressure pain threshold, depression, and anxiety.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05367167/date: April 8, 2022.

Modulation of Pain Sensitivity by a Hyperventilatory Breathing Exercise and Cold Exposure Training

Background

Evidence indicates that healthy individuals who follow a training program comprised hyperventilatory breathing exercises and cold exposure can voluntarily activate their sympathetic nervous system and attenuate their systemic inflammatory response during experimental endotoxemia (intravenous administration of bacterial endotoxin). Furthermore, trained participants reported less endotoxemia-induced flu-like symptoms. However, it remained to be determined whether the effects on symptoms are due to the mitigated inflammatory response or involve direct analgesic effects of (elements of) the training program.

Methods

In the present study, we used Nijmegen-Aalborg Screening Quantitative sensory testing (NASQ) to objectively map pain sensitivity using non-invasive stimuli to address this question. First, NASQ parameters were evaluated in 20 healthy volunteers before, during, and after the conduct of the hyperventilatory breathing exercise. Second, NASQ measurements were performed before and after 48 healthy volunteers followed different modalities of the training program: breathing exercise training, cold exposure training, the combination of both, or no training. Lastly, NASQ measurements were performed in these 48 subjects during experimental endotoxemia.

Results

Electrical pain detection thresholds increased during the breathing exercise (p = 0.001) as well as four hours afterwards (p = 0.03). Furthermore, cold exposure training resulted in lower VAS scores during hand immersion in ice water (p < 0.001). Systemic inflammation induced by administration of endotoxin nullified the decreased pain perception during the ice water test in subjects trained in cold exposure.

Conclusion

A hyperventilatory breathing exercise decreases pain perception induced by an electrical stimulus. Furthermore, cold exposure training may decrease pain perception induced by hand immersion in ice water.

The Role of Inflammation, Hypoxia, and Opioid Receptor Expression in Pain Modulation in Patients Suffering from Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a relatively common disease in the general population. Besides its interaction with many comorbidities, it can also interact with potentially painful conditions and modulate its course. The association between OSA and pain modulation has recently been a topic of concern for many scientists. The mechanism underlying OSA-related pain connection has been linked with different pathophysiological changes in OSA and various pain mechanisms. Furthermore, it may cause both chronic and acute pain aggravation as well as potentially influencing the antinociceptive mechanism. Characteristic changes in OSA such as nocturnal hypoxemia, sleep fragmentation, and systemic inflammation are considered to have a curtailing impact on pain perception. Hypoxemia in OSA has been proven to have a significant impact on increased expression of proinflammatory cytokines influencing the hyperalgesic priming of nociceptors. Moreover, hypoxia markers by themselves are hypothesized to modulate intracellular signal transduction in neurons and have an impact on nociceptive sensitization. Pain management in patients with OSA may create problems arousing from alterations in neuropeptide systems and overexpression of opioid receptors in hypoxia conditions, leading to intensification of side effects, e.g., respiratory depression and increased opioid sensitivity for analgesic effects. In this paper, we summarize the current knowledge regarding pain and pain treatment in OSA with a focus on molecular mechanisms leading to nociceptive modulation.

Subjective Sleep Disruption and Mood Disorders are Associated with the Risk of Chronic Pain in Patients with Obstructive Sleep Apnea

OBJECTIVE

This study aimed to determine the prevalence of chronic pain and its risk factors in patients with obstructive sleep apnea (OSA).

METHODS

A total of 145 patients diagnosed with OSA were consecutively recruited from the Sleep Medicine Center in West China Hospital. All patients were divided into two groups including OSA with and without chronic pain. They were assessed the subjective sleep (Pittsburgh Sleep Quality Index, Insomnia Severity Index), objective sleep (polysomnography), mood symptoms (Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale), and pain characteristics (Short-Form McGill Pain Questionnaire). Demographic, clinical, subjective and objective sleep parameters were compared between OSA patients with and without chronic pain. Binary logistic regression models and linear regression models were used to examine the risk factors of chronic pain in OSA.

RESULTS

Fifty-five (37.9%) patients with OSA were diagnosed with chronic pain. There were more severe subjective sleep disruption and symptoms of anxiety and depression in patients with chronic pain compared to those without chronic pain. After controlling for potential confounders, poor subjective sleep quality and severe insomnia and mood disorders (all ps < 0.05), but not objective sleep fragmentation or nocturnal hypoxemia (all ps > 0.05) were associated with the increased risk of pain and pain intensity, respectively.

CONCLUSION

More than one-third of patients with OSA had chronic pain. Subjective sleep disruption and mood disorders are the risk factors of chronic pain in OSA. Our findings suggest that subjective sleep quality should be valued highly in the relationship between OSA and pain.

The Relationship Between Primary Sleep Disorders and Temporomandibular Disorders: An 8-Year Nationwide Cohort Study in South Korea

Background

While evidence is accumulating to propose a specific contribution of sleep disorders and low quality sleep in the pathogenesis of temporomandibular disorders (TMD), management of primary sleep disorders in the process of preventing and treating TMD still remains scientifically unsupported.

Objective

To investigate the association of primary sleep disorders with TMD risk in South Korea.

Patients and Methods

This study was based on the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) of South Korea with 468,882 participants. After excluding participants diagnosed in 2002, those with a diagnosis of a primary sleep disorder in 2003–2005 were recruited. All participants diagnosed with TMD between January 1, 2006 and December 31, 2013 received follow-up. Cox proportional hazards regression was performed to determine the adjusted hazard ratios (aHR) and 95% confidence interval (CI) for TMD according to the presence or absence of a primary sleep disorder diagnosis.

Results

After adjusting for all covariates, primary sleep disorder patients had a 44% higher risk for TMD compared with non-sleep disorder participants (aHR 1.44, 95% CI 1.02–2.04). The incidence rate of TMD was nearly twice as high in participants with sleep disorders compared with those without (6.08 vs 3.27, per 10⁴ person-years). In subgroup analysis, an association was observed with those over 60 years old or who frequently exercised physically.

Conclusion

Primary sleep disorders could be an important independent risk factor for the initiation and maintenance of TMD. Patients with sleep disorders should be monitored for possible co-occurrence of TMD-related symptoms that could aggravate sleep disorders in turn.

An Examination of Pain's Relationship to Sleep Fragmentation and Disordered Breathing Across Common Sleep Disorders

Objective

Short sleep duration and insomnia have been linked to higher pain and an increased risk of developing chronic pain, but relatively little research has examined the contribution of sleep disordered breathing (SDB) to pain. This study examined the unique contributions of SDB and insomnia to chronic pain.

Subjects

Adult patients referred to an academic sleep center for overnight polysomnography were invited to participate.

Methods

Participants (N = 105) completed questionnaires about their sleep and pain, including the Insomnia Severity Index, Medical College of Virginia Pain Questionnaire, and two weeks of sleep/pain diaries.

Results

Most participants (80.00%) reported chronic pain, and the likelihood of having chronic pain did not differ by sleep disorder. However, there was a significant difference in pain intensity; individuals with comorbid obstructive sleep apnea (OSA)/insomnia reported an average pain intensity that was 20 points (out of 100) higher than individuals with insomnia or no diagnosis and 28 points higher than those with OSA, controlling for participant sex (Ps < 0.05). In a hierarchical regression, pain was unrelated to measures of sleep fragmentation (apnea-hypopnea index, spontaneous arousals, periodic leg movement arousals) and nocturnal hypoxemia (SaO2 nadir, time at or below 88% SaO2).

Conclusions

Polysomnography measures of SDB severity and sleep fragmentation were unrelated to pain intensity. However, comorbid OSA/insomnia was associated with significantly higher pain (compared with either disorder in isolation), a finding that has implications for the treatment of chronic pain and possibly for understanding the mechanisms of chronic pain.