Muscle activity and acute stress in fibromyalgia.

BACKGROUND: Fibromyalgia (FM) patients are likely to differ from healthy controls in muscle activity and in reactivity to experimental stress. METHODS: We compared psychophysiological reactivity to cognitive stress between 51 female FM patients aged 18 to 65 years and 31 age- and sex-matched healthy controls. They underwent a 20-minute protocol consisting of three phases of relaxation and two phases of cognitive stress. We recorded surface electromyography normalized to maximum voluntary muscle contraction (%EMG), the percentage of time with no muscle activity (EMG rest time), and subjective pain and stress intensities. We compared group reactivity using linear modelling and adjusted for psychological and life-style factors. RESULTS: The FM patients had a significantly higher mean %EMG (2.2 % vs. 1.0 %, p < 0.001), pain intensity (3.6 vs. 0.2, p < 0.001), and perceived stress (3.5 vs. 1.4, p < 0.001) and lower mean EMG rest time (26.7 % vs. 47.2 %, p < 0.001). In the FM patients, compared with controls, the pain intensity increased more during the second stress phase (0.71, p = 0.028), and the %EMG decreased more during the final relaxation phase (-0.29, p = 0.036). Within the FM patients, higher BMI predicted higher %EMG but lower stress. Leisure time physical activity predicted lower %EMG and stress and higher EMG rest time. Higher perceived stress predicted lower EMG rest time, and higher trait anxiety predicted higher pain and stress overall. CONCLUSIONS: Our results suggest that repeated cognitive stress increases pain intensity in FM patients. FM patients also had higher resting muscle activity, but their muscle activity did not increase with pain. Management of stress and anxiety might help control FM flare-ups. TRIAL REGISTRATION: Retrospectively registered on ClinicalTrials.gov ( NCT03300635 ).

Symptom severity in burning mouth syndrome associates with psychological factors.

Burning mouth syndrome (BMS) patients are psychologically distressed, but whether this associates with symptom severity is unclear. The aim was to investigate the association of psychological factors with pain intensity and interference in BMS. Fifty-two women (mean age 63.1, SD 10.9) with BMS participated. Pain intensity and interference data were collected using 2-week pain diaries. Psychological factors were evaluated using Depression Scale (DEPS), Pain Anxiety Symptom Scale (PASS) and Pain Vigilance and Awareness Questionnaire (PVAQ). The local ethical committee approved the study. Patients were divided into groups based on pain severity distribution tertiles: low intensity (NRS ≤ 3.7) or interference (NRS ≤ 2.9) (tertiles 1-2, n = 35) and moderate to intense intensity (NRS > 3.7) or interference (>2.9) (tertile 3, n = 17). T test, Wilcoxon's test and Pearson's correlation coefficient were used in the analyses. Patients in the highest intensity and interference tertiles reported more depression (P = .0247 and P = .0169) and pain anxiety symptoms (P = .0359 and P = .0293), and were more preoccupied with pain (P = .0004 and P = .0003) than patients in the low intensity and interference groups. The score of the pain vigilance questionnaire correlated significantly with pain intensity (r = .366, P = .009) and interference (r = .482, P = .009). Depression (r = .399, P = .003) and pain anxiety symptoms (r = .452, P = .001) correlated with pain interference. Symptom severity in BMS associates with symptoms of psychological distress emphasising the need to develop multidimensional diagnostics for the assessment of BMS pain.

The relationship between anger regulation, mood, pain, and pain-related disability in women treated for breast cancer.

OBJECTIVE: Anger, depressive symptoms, and anxiety are known reactions to cancer and suggested to modulate pain experience. We examined the association between anger regulation, mood, and pain in 952 breast cancer patients followed for 3 years. METHODS: Preoperatively, the patients completed questionnaires about depressive symptoms (BDI), state anxiety (STAI), anger regulation (STAXI-2), and pains in the surgical and other areas. Experimental pain sensitivity was tested. In the follow-up, BDI and STAI were assessed at 1 and at 6 months and at 1, 2, and 3 years after surgery. Pain in the surgical area was evaluated during the first 7 days and at 1 and 3 years after surgery. Pain-related disability was assessed at 3 years after surgery. Latent profile analyses were performed to identify mood profiles, and regression analyses to find independent predictors for mood and pain variables. RESULTS: Anger inhibition and pain had associations with ongoing depressive symptoms and anxiety. Pain-related disability was associated with high anxiety at a hazard ratio (HR) of 2.24 (95% CI, 1.17-4.27), with older age (HR 1.07, 95% CI, 1.01-1.13), and with pain in the surgical area (HR 3.04, 95% CI, 2.41-3.85), but not with anger variables. Any relationship between anger regulation and pain intensity disappeared after controlling for age and mood. CONCLUSIONS: Different forms of pain are important to recognize and treat to support breast cancer patients' psychological well-being. Anger inhibition could be a target for psychotherapeutic intervention, to help with ongoing mood symptoms. The relationship between anger regulation and pain is not straightforward.

Machine-learning-derived classifier predicts absence of persistent pain after breast cancer surgery with high accuracy.

BACKGROUND: Prevention of persistent pain following breast cancer surgery, via early identification of patients at high risk, is a clinical need. Supervised machine-learning was used to identify parameters that predict persistence of significant pain. METHODS: Over 500 demographic, clinical and psychological parameters were acquired up to 6 months after surgery from 1,000 women (aged 28-75 years) who were treated for breast cancer. Pain was assessed using an 11-point numerical rating scale before surgery and at months 1, 6, 12, 24, and 36. The ratings at months 12, 24, and 36 were used to allocate patents to either "persisting pain" or "non-persisting pain" groups. Unsupervised machine learning was applied to map the parameters to these diagnoses. RESULTS: A symbolic rule-based classifier tool was created that comprised 21 single or aggregated parameters, including demographic features, psychological and pain-related parameters, forming a questionnaire with "yes/no" items (decision rules). If at least 10 of the 21 rules applied, persisting pain was predicted at a cross-validated accuracy of 86% and a negative predictive value of approximately 95%. CONCLUSIONS: The present machine-learned analysis showed that, even with a large set of parameters acquired from a large cohort, early identification of these patients is only partly successful. This indicates that more parameters are needed for accurate prediction of persisting pain. However, with the current parameters it is possible, with a certainty of almost 95%, to exclude the possibility of persistent pain developing in a woman being treated for breast cancer.

Does expecting more pain make it more intense? Factors associated with the first week pain trajectories after breast cancer surgery.

The aim of this study was to identify clinical risk factors for unfavorable pain trajectories after breast cancer surgery, to better understand the association between pain expectation, psychological distress, and acute postoperative pain. This prospective study included 563 women treated for breast cancer. Psychological data included questionnaires for depressive symptoms and anxiety. Experimental pain tests for heat and cold were performed before surgery. The amount of oxycodone needed for satisfactory pain relief after surgery was recorded. Pain intensity in the area of operation before surgery and during the first postoperative week and expected intensity of postoperative pain were recorded using the Numerical Rating Scale (NRS 0-10). Pain trajectories were formed to describe both initial intensity (the intercept) and the direction of the pain path (the slope). Factors associated with higher initial pain intensity (the intercept) were the amount of oxycodone needed for adequate analgesia, psychological distress, type of axillary surgery, preoperative pain in the area of the operation, and expectation of postoperative pain. The higher the pain initially was, the faster it resolved over the week. Expectation of severe postoperative pain was associated with higher scores of both experimental and clinical pain intensity and psychological factors. The results confirm that acute pain after breast cancer surgery is a multidimensional phenomenon. Psychological distress, pain expectation, and the patients' report of preoperative pain in the area to be operated should be recognized before surgery. Patients having axillary clearance need more efficient analgesic approaches.

Diagnosing Depression in Chronic Pain Patients: DSM-IV Major Depressive Disorder vs. Beck Depression Inventory (BDI).

BACKGROUND: Diagnosing depression in chronic pain is challenging due to overlapping somatic symptoms. In questionnaires, such as the Beck Depression Inventory (BDI), responses may be influenced more by pain than by the severity of depression. In addition, previous studies have suggested that symptoms of negative self-image, a key element in depression, are uncommon in chronic pain-related depression. The object of this study is to assess the relationship of the somatic and cognitive-emotional items of BDI with the diagnosis of depression, pain intensity, and disability. METHODS: One hundred consecutive chronic pain patients completed the Structured Clinical Interview for DSM Disorders (SCID) for the diagnosis of major depressive disorder (MDD) according to DSM-IV. Two subscales of BDI (negative view of self and somatic-physical function) were created according to the factor model presented by Morley. RESULTS: In the regression analysis, the somatic-physical function factor associated with MDD, while the negative view of self factor did not. Patients with MDD had higher scores in several of the BDI items when analysed separately. Insomnia and weight loss were not dependent on the depression diagnosis. LIMITATIONS: The relatively small sample size and the selected patient sample limit the generalisability of the results. CONCLUSIONS: Somatic symptoms of depression are also common in chronic pain and should not be excluded when diagnosing depression in pain patients. Regardless of the assessment method, diagnosing depression in chronic pain remains a challenge and requires careful interpretation of symptoms.

Pain in 1,000 women treated for breast cancer: a prospective study of pain sensitivity and postoperative pain.

BACKGROUND: This article describes the methods and results of the early part (experimental pain tests and postoperative analgesia) of a study that assesses genetic and other factors related to acute pain and persistent pain after treatment of breast cancer in a prospective cohort of 1,000 women. METHODS: One thousand consenting patients were recruited to the study. Before surgery (breast resection or mastectomy with axillary surgery), the patients filled in questionnaires about health, life style, depression (Beck Depression Inventory), and anxiety (State-Trait Anxiety Inventory). They were also exposed to experimental tests measuring heat (43° and 48°C, 5 s) and cold (2-4°C) pain intensity and tolerance. Anesthesia was standardized with propofol and remifentanil, and postoperative analgesia was optimized with i.v. oxycodone. RESULTS: The patients showed significant interindividual variation in heat and cold pain sensitivity and cold pain tolerance. There was a strong correlation between the experimental pain measures across the tests. Presence of chronic pain, the number of previous operations, and particularly state anxiety were related to increased pain sensitivity. Previous smoking correlated with decreased heat pain sensitivity. These factors explained 4-5% of the total variance in pain sensitivity in these tests. Oxycodone consumption during 20 h was significantly higher in patients who had axillary clearance. Oxycodone consumption had only a weak correlation with the experimental pain measures. CONCLUSIONS: Contact heat and cold pressure tests identify variability in pain sensitivity which is modified by factors such as anxiety, chronic pain, previous surgery, and smoking. High levels of anxiety are connected to increased pain sensitivity in experimental and acute postoperative pain.

Temperament traits and chronic pain: the association of harm avoidance and pain-related anxiety.

OBJECTIVE: Anxiety symptoms are common in chronic pain patients. High levels of anxiety are associated with increased pain experience and disability. Proneness to anxiety has a large interindividual variation. The aim of the study was to determine whether the anxiety-related temperament trait Harm Avoidance (HA), is associated with pain-related anxiety. METHODS: One hundred chronic pain patients in a multidisciplinary pain clinic participated in the study. The patients were assessed using the HA scale of the Temperament and Character Inventory (TCI) of Cloninger and Pain Anxiety Symptoms Scale-20 (PASS-20). Both the HA total score and the four subscales of HA were analyzed. Current pain intensity was measured using the Visual Analogue Scale (VAS). The Beck Depression Inventory (BDI) was used to control for the influence of depression on the personality measurement. RESULTS: The HA total score was associated with PASS-20, but the association became non-significant after controlling for depression. The HA4 Fatigability subscale was associated with the PASS scales. Depression did not influence this association. Pain intensity was not correlated with HA or the PASS scales. However, the association between HA4 Fatigability and PASS was influenced by pain intensity. Higher pain intensity was associated with stronger association between the scales. CONCLUSION: Harm Avoidance, representing temperament and trait-related anxiety, has relevance in pain-related anxiety. Assessing personality and temperament may deepen the clinician's understanding of the pain experience and behavior in chronic pain patients.

Pain and pain behavior in burning mouth syndrome: a pain diary study.

AIMS: To characterize pain related to primary burning mouth syndrome (BMS) in terms of intensity, interference, and distress caused by the pain, as well as factors influencing the pain across a period of 2 weeks, and to study the use of coping and management strategies on a daily basis. METHODS: Fifty-two female patients with primary BMS completed a 2-week pain diary. Pain intensity, interference, distress, and mood on a 0 to 10 numeric rating scale (NRS), as well as pain amplifying and alleviating factors, were recorded three times a day. The use of treatments (medication or other means) and coping strategies were recorded at the end of each day. Coefficient of variation, repeated measures analysis of variance, and correlative methods were used to assess the between- and within-subject variation, pain patterns, and associations between various pain scores. RESULTS: The overall mean pain intensity score of the 14 diary days was 3.1 (SD: 1.7); there was considerable variation in pain intensity between patients. Most patients experienced intermittent pain. On average, pain intensity increased from the morning to the evening. Intercorrelations between pain intensity, interference, distress, and mood were high, varying between rs = .75 and rs = .93 (P < .001). Pungent or hot food or beverages, stress, and tiredness were the most frequently mentioned pain-amplifying factors. The corresponding pain-alleviating factors were eating, sucking pastilles, drinking cold beverages, and relaxation. Thirty (58%) patients used pain medication and 35% reported using other means to alleviate their BMS pain. There was large variation in the use of coping strategies -between subjects. CONCLUSION: There were considerable differences in pain, in factors influencing the pain, and in pain behavior across BMS patients. This indicates that patient information and education as well as treatment of BMS pain should be individualized.

Psychiatric disorders as assessed with SCID in chronic pain patients: the anxiety disorders precede the onset of pain.

OBJECTIVE: The aim of the study was to determine the prevalence of psychiatric disorders in patients referred to a tertiary pain clinic. The temporal relationship between the onset of pain and depression and anxiety and the association of psychiatric disorders with pain intensity were also analyzed. METHOD: One hundred consecutive outpatients underwent a psychiatric assessment using the Structured Clinical Interview and Statistical Manual of Mental Disorders Axis I. RESULTS: The psychiatric disorders diagnosed for the past 12 months included major depressive (37%), anxiety (25%) and substance use disorder (12%). The prevalence of any lifetime psychiatric disorder was 75%. Most anxiety disorders (77%) had been present before pain onset, whereas 63% of the depressive disorders appeared after the onset of pain. Psychiatric morbidity was associated with increased pain intensity. CONCLUSIONS: Chronic pain patients have a remarkable psychiatric morbidity. A structured diagnostic interview, covering a large range of psychiatric diagnoses, allows a more comprehensive approach to the assessment of the patient. This should improve the management of chronic pain. However, prospective studies are needed to show this.

Pain intensity influences the relationship between anger management style and depression.

There is an abundance of studies concerning depression and pain, while the mechanisms and the relationships of anger expression and pain are less well known. The validity of commonly used depression questionnaires as measures of depression in pain patients has been questioned, as they include items which can be related to the pain problem as well as to signs of depression. The aim of this study was to investigate the relationships between pain severity, various signs of depression, and anger management style. Subjects were 100 consecutive patients referred to the Helsinki University Pain Clinic. Demographic data and pain intensity (VAS) were collected by a questionnaire. Two subscales (negative view and physical function) from the Beck Depression Inventory, and the Anger Expression Scales (Anger-in and Anger-out) from the Spielberg State Trait Anger Expression Inventory 2 were used to assess depression and anger expression, respectively. The results showed that pain severity modulates the relationship between anger expression and physical signs of depression. In patients with more severe pain, the relationships between anger management style, specifically, inhibition of anger and depression were strong, while no such relationships were found in the group of patients with less severe pain. No correlations were found between pain intensity and depression as measured by the sum score of the BDI. However, analysing separately the two subscales of the BDI, negative view and physical function, significant positive relationships between pain intensity and both subscales appeared.