Aberrant occlusal sensitivity in adults with increased somatosensory amplification: a case-control study.

OBJECTIVES: Occlusal sensitivity (OS)-the ability to detect fine objects between opposing teeth-mainly relies on the activity of mechanoreceptors located in the periodontal ligament. We tested whether somatosensory amplification (SSA)-the tendency to perceive normal somatic sensations as being intense, noxious, and disturbing, which plays a critical role in hypervigilance-affects OS. MATERIALS AND METHODS: We measured OS in 66 adults divided into three groups based on their SSA scores (LowSSA, Intermediate - IntSSA, HighSSA) by asking them to bite on aluminum foils (8 to 72 µm thick) and a sham foil, and report whether they felt each foil. We performed 20 trials for each thickness and sham condition (each participant was tested 120 times), and compared the frequency of correct answers (%correct) among groups after adjusting for participants' trait anxiety, depression, self-reported oral behaviors, and masseter cross-sectional area. RESULTS: %correct was affected by the interaction Foil Thickness-by-SSA (p = 0.007). When tested with the 8 µm foil, the HighSSA group had a lower %correct than the IntSSA (contrast estimate [95% CI]: -14.2 [-25.8 - -2.6]; p = 0.012) and the LowSSA groups (-19.1 [-31.5 - -6.6]; p = 0.001). Similarly, with the 24 µm foil, the HighSSA group had a lower %correct compared to the IntSSA (-12.4 [-24.8-0.1]; p = 0.048) and the LowSSA groups (-10.8 [-22.5-0.8]; p = 0.073). CONCLUSION: Individuals with high SSA present with an aberrant occlusal sensitivity. CLINICAL RELEVANCE: Our findings provide novel insights into the relationship between occlusal perception and psychological factors, which may influence an individual's ability to adapt to dental work.

Positive airway pressure therapy for chronic pain in patients with obstructive sleep apnea-a systematic review.

PURPOSE: Obstructive sleep apnea (OSA) is prevalent in patients with chronic non-cancer pain. OSA may lead to low sleep quality and an increase in pain sensitivity. Patients reporting greater sleep impairment tend to experience higher pain intensity and vice versa. Positive airway pressure (PAP) is the current gold standard treatment for OSA. This review aims to evaluate the efficacy of PAP therapy in patients with comorbid chronic pain and OSA in influencing pain outcomes like pain intensity, tolerance, threshold, and sensitivity. METHODS: We performed a systematic literature search for studies published after 1990, utilizing the following databases: Medline, Medline In-Process/ePubs, Embase, Cochrane CENTRAL, and the Cochrane Database of Systematic Reviews. Search terms included "chronic pain," "sleep disorders," and "positive airway pressure." RESULTS: Of 1982 initial studies, ten studies met the study inclusion criteria. Seven of these studies examined the effect of PAP therapy on chronic pain, of which five demonstrated improved pain outcomes, specifically, headache pain. The effect of PAP therapy on chronic non-headache pain was found to be inconclusive. When examining the three studies that did not involve chronic pain patients, PAP therapy effectively increased pain threshold and tolerance in two studies (p = 0.03 and p = 0.01). CONCLUSION: An association exists between PAP therapy and decreased chronic headache outcomes in patients with OSA. Additionally, research shows that PAP therapy may increase pain tolerance and threshold. Future high-quality evidence is required to further investigate the association between PAP and non-headache chronic pain.

Simple screening model for identifying the risk of sleep apnea in patients on opioids for chronic pain.

BACKGROUND: There is an increased risk of sleep apnea in patients using opioids for chronic pain. We hypothesized that a simple model comprizing of: (1) STOP-Bang questionnaire and resting daytime oxyhemoglobin saturation (SpO2); and (2) overnight oximetry will identify those at risk of moderate-to-severe sleep apnea in patients with chronic pain. METHOD: Adults on opioids for chronic pain were recruited from pain clinics. Participants completed the STOP-Bang questionnaire, resting daytime SpO2, and in-laboratory polysomnography. Overnight oximetry was performed at home to derive the Oxygen Desaturation Index. A STOP-Bang score ≥3 or resting daytime SpO2 ≤95% were used as thresholds for the first step, and for those identified at risk, overnight oximetry was used for further screening. The Oxygen Desaturation Index from overnight oximetry was validated against the Apnea-Hypopnea Index (≥15 events/hour) from polysomnography. RESULTS: Of 199 participants (52.5±12.8 years, 58% women), 159 (79.9%) had a STOP-Bang score ≥3 or resting SpO2 ≤95% and entered the second step (overnight oximetry). Using an Oxygen Desaturation Index ≥5 events/hour, the model had a sensitivity of 86.4% and specificity of 52% for identifying moderate-to-severe sleep apnea. The number of participants who would require diagnostic sleep studies was decreased by 38% from Step 1 to Step 2 of the model. CONCLUSION: A simple model using STOP-Bang questionnaire and resting daytime SpO2, followed by overnight oximetry, can identify those at high risk of moderate-to-severe sleep apnea in patients using opioids for chronic pain. TRIAL REGISTRATION NUMBER: NCT02513836.

Prevalence of sleep disturbances in patients with chronic non-cancer pain: A systematic review and meta-analysis.

In individuals with chronic pain, sleep disturbances have been suggested to increase suffering, perception of pain, and to negatively affect long-term prognosis. This systematic review and meta-analysis aims to determine the pooled prevalence of sleep disturbances in chronic non-cancer pain patients with no other sleep disorders, using the patient-rated questionnaires Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI). Multiple databases were searched for studies reporting the prevalence of sleep disturbances in chronic pain patients. The meta-analysis was conducted to examine the pooled prevalence of PSQI and ISI data using the inverse-variance random-effects model and to examine mean differences in PSQI scores. The systematic search resulted in 25,486 articles and 20 were included for analysis. In 12 studies using PSQI, the pooled prevalence of sleep disturbance was 75.3% among 3597 chronic pain patients. In eight studies using ISI, the pooled prevalence was 72.9% among 2578 chronic pain patients. The meta-analysis showed a significant mean difference of 2.75 (p < 0.001) in the global PSQI score between the chronic pain group versus the non-chronic pain group. The relatively high prevalence of sleep disturbances in chronic pain patients emphasizes the importance of further characterizing the relationship between sleep and chronic pain.

Cognitive behavioral therapy for insomnia in patients with chronic pain - A systematic review and meta-analysis of randomized controlled trials.

Several randomized controlled trials have implemented cognitive behavioral therapy for insomnia (CBT-I) for patients with comorbid insomnia and chronic pain. This systematic review and meta-analysis investigated the effectiveness of CBT-I on patient-reported sleep, pain, and other health outcomes (depressive symptoms, anxiety symptoms, and fatigue) in patients with comorbid insomnia and chronic non-cancer pain. A systematic literature search was conducted using eight electronic databases. Upon duplicate removal, 6374 records were screened against the inclusion criteria. Fourteen randomized controlled trials were selected for the review, with twelve (N = 762 participants) included in the meta-analysis. At post-treatment, significant treatment effects were found on global measures of sleep (standardized mean difference = 0.89), pain (0.20), and depressive symptoms (0.44). At follow-up (up to 12 mo), CBT-I significantly improved sleep (0.56). Using global measures of sleep, we found a probability of 81% and 71% for having better sleep after CBT-I at post-treatment and final follow-up, respectively. The probability of having less pain after CBT-I at post-treatment and final follow-up was 58% and 57%, respectively. There were no statistically significant effects on anxiety symptoms and fatigue at either assessment point. Future trials with sufficient power, longer follow-up periods, and inclusion of CBT for pain components are warranted.

Sleep-disordered breathing in patients on opioids for chronic pain.

The past two decades has seen a substantial rise in the use of opioids for chronic pain, along with opioid-related mortality and adverse effects. A contributor to opioid-associated mortality is the high prevalence of moderate/severe sleep-disordered breathing, including central sleep apnea and obstructive sleep apnea, in patients with chronic pain. Although evidence-based treatments are available for sleep-disordered breathing, patients are not frequently assessed for sleep-disordered breathing in pain clinics. To aid healthcare providers in this area of clinical uncertainty, we present evidence on the interaction between opioids and sleep-disordered breathing, and the prevalence and predictive factors for sleep-disordered breathing in patients on opioids for chronic pain. We provide recommendations on how to evaluate patients on opioids for risk of moderate/severe sleep-disordered breathing in clinical care, which could lead to earlier use of therapeutic interventions for opioid-associated sleep-disordered breathing, such as opioid cessation or positive airway pressure therapy. This would improve quality of life and well-being of patients with chronic pain.

Performance Characteristics of Spirometry With Negative Bronchodilator Response and Methacholine Challenge Testing and Implications for Asthma Diagnosis.

BACKGROUND: In patients with a history suggestive of asthma, diagnosis is usually confirmed by spirometry with bronchodilator response (BDR) or confirmatory methacholine challenge testing (MCT). RESEARCH QUESTION: We examined the proportion of participants with negative BDR testing who had a positive MCT (and its predictors) result and characteristics of MCT, including effects of controller medication tapering and temporal variability (and predictors of MCT result change), and concordance between MCT and pulmonologist asthma diagnosis. STUDY DESIGN AND METHODS: Adults with self-reported physician-diagnosed asthma were recruited by random-digit dialing across Canada. Subjects performed spirometry with BDR testing and returned for MCT if testing was nondiagnostic for asthma. Subjects on controllers underwent medication tapering with serial MCTs over 3 to 6 weeks. Subjects with a negative MCT (the provocative concentration of methacholine that results in a 20% drop in FEV1 [PC20] > 8 mg/mL) off medications were examined by a pulmonologist and had serial MCTs after 6 and 12 months. RESULTS: Of 500 subjects (50.5 ± 16.6 years old, 68.0% female) with a negative BDR test for asthma, 215 (43.0%) had a positive MCT. Subjects with prebronchodilator airflow limitation were more likely to have a positive MCT (OR, 1.90; 95% CI, 1.17-3.04). MCT converted from negative to positive, with medication tapering in 18 of 94 (19.1%) participants, and spontaneously over time in 25 of 165 (15.2%) participants. Of 231 subjects with negative MCT, 28 (12.1%) subsequently received an asthma diagnosis from a pulmonologist. INTERPRETATION: In subjects with a self-reported physician diagnosis of asthma, absence of bronchodilator reversibility had a negative predictive value of only 57% to exclude asthma. A finding of spirometric airflow limitation significantly increased chances of asthma. MCT results varied with medication taper and over time, and pulmonologists were sometimes prepared to give a clinical diagnosis of asthma despite negative MCT. Correspondingly, in patients for whom a high clinical suspicion of asthma exists, repeat testing appears to be warranted.