The Central Sensitization Inventory validated and adapted for a Brazilian population: psychometric properties and its relationship with brain-derived neurotrophic factor

Sensory Profiles Predict Symptoms of Central Sensitization in Low Back Pain: A Predictive Model Research Study

Background: Acute low back pain has a high prevalence, and when persisting into chronicity, it results in enormous socio-economic consequences. Sensory preferences may be key factors in predicting central sensitization as the main mechanism of nociplastic pain and chronicity. Objectives: Build a model to predict central sensitization symptoms using sensory profiles based on the PROGRESS framework. Methods: A Prognostic Model Research study was carried out to predict central sensitization symptoms at 12 weeks, using baseline sensory profiles, based on 114 patients with acute low back pain. Independent variables were sensory profiles, state and trait anxiety, age, duration, pain severity, depressive symptoms, and pain catastrophizing. Results: This model, based on continuous data, significantly predicts central sensitization symptoms at 12 weeks. It contains two significantly contributing variables: sensory profile Sensory Sensitive (unstandardized B-value = 0.42; p = 0.01) and trait anxiety (unstandardized B-value = 0.53; p ≤ 0.001). The model has a predictive value of R2 = 0.38. Conclusions: This model significantly predicts central sensitization symptoms based on sensory profile Sensory Sensitive and trait anxiety. This model may be a useful tool to intervene in a bottom-up and top-down approaches to prevent chronicity in clinical practice, including individual sensory preferences and behavioral responses to sensory stimulation in rehabilitation strategies.

Central sensitization inventory is associated with psychological functioning but not with psychophysical assessment of pain amplification

BACKGROUND

The central sensitization inventory (CSI) is a questionnaire that has been widely used as a tool for assessing symptoms associated with sensitization. However, its ability to identify individuals with this phenomenon has recently been questioned. The aim of this study was to assess the correlation of CSI with psychosocial and psychophysical factors in patients with painful TMD diagnosed according to diagnostic criteria for temporomandibular disorders (DC/TMD) and asymptomatic controls, as well as to determine the influence of these variables on the CSI scores variations.

METHODS

This cross-sectional study with 77 patients diagnosed with painful TMD according to DC/TMD and 101 asymptomatic controls realized correlations between CSI, WUR, PPT, CPM and psychosocial questionnaires (HADS, PSQI, PCS and PSS). In cases where significant correlations existed, the potential influence of these variables on CSI variation was explored through linear regression analysis.

RESULTS

It has been found that the CSI correlates with psychosocial variables (anxiety, depression, catastrophizing, sleep and stress) (p < 0.0006) regardless of the presence of TMD, and that 68.9% of the variation in CSI scores can be influenced by all these variables (except stress). On the contrary, the CSI does not correlate with psychophysical parameters indicative of pain amplification (wind-up ratio and conditioned pain modulation) (p > 0.320).

CONCLUSION

CSI is more associated with psychosocial factors than with more robust indicators of probable central sensitization (CS), thus limiting its utility in detecting this phenomenon both in TMD patients and healthy individuals.

SIGNIFICANCE STATEMENT

The research highlights a noteworthy relationship between the central sensitization inventory and psychological factors, emphasizing their substantial influence on inventory values. This correlation offers crucial insights into mental health markers within the questionnaire. Additionally, the lack of connection with pain amplification implies a necessary re-evaluation of the inventory's diagnostic suitability, especially in cases of painful temporomandibular disorders. Thus, caution is urged in its application for identifying CS in these individuals.

Correlations of The Central Sensitization Inventory, conditioned pain modulation, cognitions and psychological factors in individuals with chronic neck pain: A cross-sectional study

INTRODUCTION

Chronic neck pain (CNP) is a global public health problem, with high prevalence and absenteeism rates. Central sensitization (CS) as a basis for chronic pain may play an essential role in its development and progression. It is often comorbid with low conditioned pain modulation (CPM) effects, cognitions, and psychological problems.

OBJECTIVES

The purposes of this study were to (1) explore the relationship between pain-related cognitions and psychological factors, CPM effects, and the central sensitization inventory (CSI) scores; and (2) determine whether cognitions and psychological factors can predict CSI scores and CPM effects in individuals with CNP.

METHODS

Fifty-four individuals with CNP were recruited for this cross-sectional study. The following outcome measures were evaluated: The CSI (screening tool) was compared with the cold pressor test (CPT), which was the psychophysical test used to assess the CPM; neck pain intensity using the visual analogue scale (VAS), as well as pain-related cognitions (including kinesiophobia and pain catastrophization) and psychological states (including anxiety and depression) using self-report questionnaires.

RESULTS

CSI score was not associated with the CPM effect (r = 0.257, p > 0.05), and no cognitions or psychological factors were associated with CPM (p > 0.05), but CSI score was moderately positively correlated with kinesiophobia (r = 0.554, p < 0.01), lowly positively correlated with pain catastrophization (r = 0.332, p = 0.017) and anxiety (r = 0.492, p < 0.01), but not depression (r = 0.207, p = 0.132). Multiple linear regression analysis showed that kinesiophobia (B = 1.308, p < 0.01) and anxiety (B = 1.806, p = 0.02) were significant positive predictors of CSI score.

CONCLUSIONS

The findings confirm some of our hypotheses. Accordingly, the findings inferred that the CSI does not seem to respond to CPM effect in patients with CNP effectively. In addition, CSI score was associated with cognitions and psychological factors, of which kinesiophobia and anxiety were effective predictors. In clinical practice, pain-related cognitions and psychological factors should be fully considered to manage neck pain efficiently.

How do the mindfulness and sensory-behavioural-emotional aspects influence the painful experience related to temporomandibular disorder?

BACKGROUND

Chronic pain is persistent or recurrent pain lasting longer than 3 months. The experience of temporomandibular disorder (TMD)-related pain is modulated by emotional and social factors, with mindfulness encapsulating these aspects.

OBJECTIVE

To investigate the association between cognitive-behavioural-emotional characteristics, mindfulness and the painful experience in women with chronic pain-related TMD.

METHODS

A cross-sectional study was conducted, including 90 women aged between 18 and 61 years old, diagnosed with chronic pain-related TMD according to the Diagnostic Criteria for Temporomandibular Disorder, considering both temporomandibular joint and muscle pain. Specific instruments were employed to assess cognitive-behavioural-emotional aspects. The Mindful Attention Awareness Scale and the Five Facets of Mindfulness Questionnaire scales evaluated the level and construct of mindfulness. The relationship between variables was analysed using bivariate association tests (.05 > p < .20), followed by multiple regression tests (p < .05).

RESULTS

The heightened experience of pain correlated with increasing age, a low level of education, the attribution of the locus of control by chance, and lower levels of mindfulness (p < .05). The heightened experience of pain was negatively influenced by mindfulness levels (p < .05). On the other hand, the painful experience was mainly influenced by facets describing negative formulation, distraction, non-reactivity and non-judgement (p < .05).

CONCLUSION

Demographic, cognitive-behavioural-emotional data and levels of mindfulness and its facets presented different influence weights on the painful experience. These findings provide support for future studies focusing on mindfulness strategies, education and pain management in women with chronic pain-related TMD.

Is the Central Sensitization Inventory (CSI) associated with quantitative sensory testing (QST)? A systematic review and meta-analysis

Central sensitization (CS) involves an amplification of neural processing within the central nervous system that can result in widespread pain patterns and hypersensitivity to stimuli. The Central Sensitization Inventory (CSI) and various quantitative sensory testing (QST) methods purport to assess clinical markers of CS. The purpose of this systematic review and meta-analysis was to summarize and quantify the associations between total CSI scores and QST measures from previous studies. A systematic search identified 39 unique studies that were deemed eligible for the systematic review and 33 studies for meta-analyses (with 3314 subjects and 154 effect sizes), including five QST modalities: conditioned pain modulation, temporal summation, pressure pain threshold, heat pain threshold, and cold pain threshold. The meta-analysis yielded statistically significant CSI-QST correlations in total subject samples for all five QST modalities. The strongest associations were identified between CSI scores and pain threshold testing, especially pressure pain threshold, in which 51% of effects sizes, from 29 studies and 3071 subjects, were determined to be in a medium to large range.

Sensory profiles and their role in the persistence of central sensitization symptoms in low back pain. A prospective cohort study

INTRODUCTION

Acute lower back pain can lead to neuroplastic changes in the central nervous system, and symptoms of central sensitization after 12 weeks. While sensory sensitivity has been shown to predict symptoms of central sensitization, trait sensory profiles may be prognostic in the persistence of central sensitization symptoms in low back pain over time.

OBJECTIVE

To examine sensory profiles as prognostic symptoms of central sensitization in people with acute low back pain.

METHODS

A longitudinal type 2 prognostic factor research study was performed according to the PROGRESS framework. Baseline and 12-week follow-up measures were taken using the Adolescent/Adult Sensory Profile and the Central Sensitization Inventory measures. Study participants were consecutively included from primary care physiotherapy practices. Univariable, and multivariable regression analyses were performed to adjust sensory profiles based on previous history of low back pain, baseline Central Sensitization Inventory scores, level of pain, disability, age, and duration of low back pain.

RESULTS

After adjustment, the sensory profiles of Low Registration B = 0.44, 95%CI (0.18, 0.70), Sensation Seeking B = 0.38, 95%CI (0.19, 0.57), Sensory Sensitive B = 0.49, 95%CI (0.25, 0.74), Sensation Avoiding B = 0.40, 95% CI (0.15, 0.65) was significantly associated with the persistence of central sensitization symptoms (N = 103).

CONCLUSION

Sensory profiles may predict symptoms of central sensitization after 12 weeks in people with acute low back pain.

Impact of multiple-session home-based transcranial direct current stimulation (M-HB-tDCS) on eating behavior in fibromyalgia: A factorial randomized clinical trial

BACKGROUND

Multiple-session home-based self-applied transcranial direct current stimulation (M-HB-self-applied-tDCS) has previously been found to effectively reduce chronic pain and enhance cognitive function. However, the effectiveness of this method for disordered eating behavior still needs to be studied.

OBJECTIVE

This study aimed to assess whether 20 sessions of M-HB-self-applied-tDCS, administered over four weeks to either the left dorsolateral prefrontal cortex (L-DLPFC) or primary motor cortex (M1), could improve various aspects of eating behavior, anthropometric measures, and adherence.

METHODS

We randomly assigned 102 fibromyalgia patients between the ages of 30 and 65 to one of four tDCS groups: L-DLPFC (anodal-(a)-tDCS, n = 34; sham-(s)-tDCS, n = 17) or M1 (a-tDCS, n = 34; s-tDCS, n = 17). Patients self-administered 20-min tDCS sessions daily with 2 mA under remote supervision following in-person training.

RESULTS

Generalized linear models revealed significant effects of M-HB-self-applied-tDCS compared to s-tDCS on uncontrolled eating (UE) (Wald χ2 = 5.62; df = 1; P = 0.018; effect size, ES = 0.55), and food craving (Wald χ2 = 5.62; df = 1; P = 0.018; ES = 0.57). Regarding fibromyalgia symptoms, we found a differentiated impact of a-tDCS on M1 compared to DLPFC in reducing food cravings. Additionally, M-HB-a-tDCS significantly reduced emotional eating and waist size. In contrast, M1 stimulation was more effective in improving fibromyalgia symptoms. The global adherence rate was high, at 88.94%.

CONCLUSION

These findings demonstrate that M-HB-self-applied-tDCS is a suitable approach for reducing uncontrolled and emotional eating, with greater efficacy in L-DLPFC. Furthermore, these results revealed the influence of fibromyalgia symptoms on M-HB-self-applied-tDCS's, with M1 being particularly effective in mitigating food cravings and reducing fibromyalgia symptoms.

Botulinum toxin-A effects on pain, somatosensory and psychosocial features of patients with refractory masticatory myofascial pain: a randomized double-blind clinical trial

The antinociceptive effect of BoNT-A have been well documented in animal studies; however, results of few but well-designed randomized placebo-controlled clinical trials about BoNT-A efficacy in masticatory myofascial pain (MFP) are inconsistent. Therefore, the present randomized, double-blind, placebo-controlled clinical trial evaluated the efficacy of BoNT-A in patients with refractory MFP. Twenty-eight patients with pain reduction of less than 30% despite conservative treatment and with an average pain intensity of > 50 mm on the visual analogue scale (VAS) participated. Patients were randomly assigned to receive a total of 80 U of BoNT-A or saline solution (SS) injected into the masseter and anterior temporalis muscles. Pain intensity (VAS), quantitative sensory testing (QST), conditioned pain modulation (CPM), and psychosocial status were examined. Follow-up was performed at 1 and 6 months. For repeated-measure comparisons between evaluation times, Friedman test with Bonferroni correction was used for pain and somatosensory variables and the Wilcoxon test for the psychosocial variables. The Mann-Whitney test was used for all comparisons between groups. The BoNT-A group had a significant decrease in pain intensity at follow-ups compared with the SS group (p < 0.001). QST assessment revealed higher pressure pain threshold values in the masseter muscle for BoNT-A group compared to SS (p < 0.03) at all follow-ups. No differences were found for mechanical pain threshold and wind-up ratio values (p > 0.05) in the entire study. The BoNT-A group presented the most efficient CPM effect (p < 0.03) only at the 1 month follow-up in the masseter muscle. There was a significant time effect for BoNT-A in all psychosocial variables (p < 0.05) and a drug effect in the Central Sensitization Inventory (p < 0.01), Pittsburgh Sleep Quality Index (p < 0.004), and Healthy Survey 36 (p < 0.05) at 6 months follow-up. The study demonstrates that a single injection-session of BoNT-A has positive effects on the hall pain spectrum of patients with refractory masticatory myofascial pain.

Clinical features of chronic primary pain in individuals presenting painful temporomandibular disorder and comorbidities

BACKGROUND

The diagnosis of chronic primary pain (CPP), according to the recently released International Classification of Disease (ICD-11) criteria, refers to conditions with complex aetiologies. CPP is characterized by specific clinical features such as generalized sensory hypersensitivity and widespread pain, and is associated with functional disability and emotional distress.

OBJECTIVE

This study investigated clinical features of CPP in individuals with painful temporomandibular disorders (TMD) and comorbidities (fibromyalgia, migraine and/or tension-type headache).

METHODS

This cross-sectional study was conducted with a sample of 129 individuals. Painful TMD, fibromyalgia and primary headaches were evaluated based on well-established international criteria. Generalized sensory hypersensitivity was assessed using psychophysical tests. Symptoms of anxiety and depression were assessed by the Generalized Anxiety Disorder-7 and Patient Health Questionnaire-9. The Central Sensitization Inventory was applied to assess central sensitization-related symptoms and the Pittsburg Sleep Quality Index to evaluate the quality of sleep. The presence of widespread pain was assessed using a body map. The sample was stratified into three groups: control (n = 25), TMD-painful TMD only (n = 35) and TMD + Cm-painful TMD and comorbidities (n = 69). Statistical analysis was performed using one-way ANOVA, chi-squared test and ANCOVA, considering gender as a covariate (α = .05).

RESULTS

Compared to controls, individuals presenting painful TMD and comorbidities showed lower pressure pain thresholds in all evaluated areas (p ≤ .012) and a higher number of painful areas in the body (p = .001). They presented more symptoms of anxiety (p = .040) and depression (p = .018), and a higher score in the Central Sensitization Inventory (p ≤ .006) than the other groups.

CONCLUSION

Individuals with painful TMD and comorbidities presented more clinical features of CPP compared to those affected by TMD only.

Effectiveness of pain neuroscience education on somatosensory functioning after surgery for breast cancer: A double-blinded randomized controlled trial

Pain is one of the most prevalent and long-term adverse effects described by people who have undergone breast cancer surgery. Non-helpful perceptions and thoughts about pain may contribute to the transition of acute to persistent pain. Adding educational interventions to the current physical therapy program in this population may help to improve or prevent persistent pain. Pain neuroscience education (PNE) is a type of educational intervention that addresses the experience of pain in a broader sense by explaining pain not only from a biomedical perspective, but also from a psychological and social perspective. A double-blinded randomized controlled trial (EduCan trial) investigated whether PNE, in addition to a standard physiotherapy program immediately after surgery for breast cancer, was more effective on somatosensory functioning in the short (4 months postoperatively) and long term (18 months postoperatively), than providing a biomedical explanation for pain. Somatosensory functioning was evaluated using a self-reported questionnaire as well as a comprehensive quantitative sensory testing evaluation. The findings of this study revealed that adding six sessions of PNE to a standard physical therapy program (n = 184) did not result in a significantly different course of somatosensory functioning up to 18 months postoperatively as compared to biomedical pain education. These findings provide an interesting basis for future research into who should receive PNE after surgery for breast cancer (e.g., patient profiling or phenotyping) and how we can tailor it to the individual to increase its effectiveness.

Efficacy of Home-Based Transcranial Direct Current Stimulation Over the Primary Motor Cortex and Dorsolateral Prefrontal Cortex in the Disability Due to Pain in Fibromyalgia: A Factorial Sham-Randomized Clinical Study

This randomized, double-blind, controlled clinical trial compared the effectiveness of home-based-(HB) active transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (l-DLPFC) or primary motor cortex (M1) with their respective sham-(s)-tDCS to determine whether a-tDCS would be more effective than s-tDCS in reducing pain and improving disability due to pain. The study included 102 patients with fibromyalgia aged 30 to 65 years old randomly assigned to 1 of 4 tDCS groups using a ratio of 2:1:2:1. The groups included l-DLPFC (a-tDCS, n = 34) and (s-tDCS, n = 17), or tDCS on the M1 (a-tDCS, n = 34) or (s-tDCS, n = 17). Patients self-administered 20 sessions of tDCS, with 2 mA for 20 minutes each day under remote supervision after in-person training. The Mixed Model for Repeated Measurements revealed that a-tDCS on DLPFC significantly reduced pain scores by 36.53% compared to 25.79% in s-tDCS. From baseline to the fourth week of treatment, a-tDCS on M1 reduced pain scores by 45.89% compared to 22.92% over s-tDCS. A generalized linear model showed a significant improvement in the disability scale in the groups that received a-tDCS compared to s-tDCS over M1 20.54% versus 2.49% (χ2 = 11.06, df = 1, P < .001]), while on DLPFC the improvement was 14.29% and 5.77%, with a borderline significance (χ2 = 3.19, df = 1, P = .06]), respectively. A higher reduction in serum brain-derived neurotrophic factor from baseline to treatment end was positively correlated with decreased pain scores regardless of the treatment group. The application of a-tDCS over M1 increased the heat pain threshold and the function of the descending pain inhibitory system. PERSPECTIVE: These findings provide important insights: (1) HB-tDCS has effectively reduced pain scores and improved disability due to fibromyalgia. (2) The study provides evidence that HB-a-tDCS is a viable and effective therapeutic approach. (3) HB-a-tDCS over M1 improved the function of the descending pain inhibitory system and increased the heat pain threshold. Finally, our findings also emphasize that brain-derived neurotrophic factor, as an index of neuroplasticity, may serve as a valuable marker associated with changes in clinical pain measures. TRIAL REGISTRATION: Number NCT03843203.

Cross-cultural adaptation and validation for central sensitization inventory: based on Chinese patients undergoing total knee arthroplasty for knee osteoarthritis

BACKGROUND

This study was conducted to develop a simplified Chinese version of the central sensitization inventory (CSI-CV) and to evaluate its reliability and validity.

METHODS

The CSI-CV was developed through a process involving the translation and back translation of the original CSI. Subsequently, experts reviewed and revised the content of the items to ensure their appropriateness. A total of 325 patients with knee osteoarthritis (KOA), who were scheduled to undergo total knee arthroplasty (TKA), completed the CSI-CV at a prominent orthopedic center in Xi'an, China. Afterward, a random selection of 100 participants was chosen for retesting after one week. The reliability and validity of the inventory were evaluated through exploratory factor analysis, correlation coefficient calculation and other methods.

RESULTS

The CSI-CV consists of 25 items in five dimensions (emotional distress, headache and jaw symptoms, physical symptoms, urological symptoms, and fatigue and sleep problems). The cumulative variance contribution rate was 75.3%, the Cronbach's α coefficient was 0.83, the Guttman split-half reliability coefficient was 0.88 and the intraclass correlation coefficient was 0.965. The CSI-CV scores correlated moderately with the total scores of the brief pain inventory (r = 0.506), Western Ontario and McMaster Universities Osteoarthritis Index (r = 0.466) and EuroQoL Group's five-dimension questionnaire (r = 0.576).

CONCLUSIONS

The findings demonstrate that the CSI was successfully trans-culturally adapted into a simplified Chinese version (CSI-CV) that was reliable and valid for Chinese-speaking patients who awaiting TKA for KOA.

Increased Delta and Theta Power Density in Sickle Cell Disease Individuals with Chronic Pain Secondary to Hip Osteonecrosis: A Resting-State Eeg Study

PURPOSE

Identify the presence of a dysfunctional electroencephalographic (EEG) pattern in individuals with sickle cell disease (SCD) and hip osteonecrosis, and assess its potential associations with depression, anxiety, pain severity, and serum levels of brain-derived neurotrophic factor (BDNF).

METHODS

In this cross-sectional investigation, 24 SCD patients with hip osteonecrosis and chronic pain were matched by age and sex with 19 healthy controls. Resting-state EEG data were recorded using 32 electrodes for both groups. Power spectral density (PSD) and peak alpha frequency (PAF) were computed for each electrode across Delta, Theta, Alpha, and Beta frequency bands. Current Source Density (CSD) measures were performed utilizing the built-in Statistical nonparametric Mapping Method of the LORETA-KEY software.

RESULTS

Our findings demonstrated that SCD individuals exhibited higher PSD in delta and theta frequency bands when compared to healthy controls. Moreover, SCD individuals displayed increased CSD in delta and theta frequencies, coupled with decreased CSD in the alpha frequency within brain regions linked to pain processing, motor function, emotion, and attention. In comparison to the control group, depression symptoms, and pain intensity during hip abduction were positively correlated with PSD and CSD in the delta frequency within the parietal region. Depression symptoms also exhibited a positive association with PSD and CSD in the theta frequency within the same region, while serum BDNF levels showed a negative correlation with CSD in the alpha frequency within the left insula.

CONCLUSION

This study indicates that individuals with SCD experiencing hip osteonecrosis and chronic pain manifest a dysfunctional EEG pattern characterized by the persistence of low-frequency PSD during a resting state. This dysfunctional EEG pattern may be linked to clinical and biochemical outcomes, including depression symptoms, pain severity during movement, and serum BDNF levels.

Central Sensitisation Inventory-Thai version: translation, cross-cultural adaptation, and psychometric evaluation in chronic non-specific neck pain

PURPOSE

To translate and cross-culturally adapt the English version of the Central Sensitisation Inventory (CSI) into Thai (CSI-Thai) and to evaluate its psychometric properties in individuals with chronic non-specific neck pain.

MATERIALS AND METHODS

Cross-cultural translation and adaptation of the CSI were performed according to standard guidelines. A total of 340 participants were invited to complete the CSI-Thai, Visual Analogue Scale (pain intensity), Neck Disability Index, Fear-Avoidance Beliefs Questionnaire, Pain Catastrophising Scale (PCS), and Short Form-36. Psychometric evaluation included confirmatory factor analysis, internal consistency, test-retest reliability, agreement, and construct validity.

RESULTS

Dimensionality analyses indicated that a bifactor model, comprising one general factor plus four orthogonal factors, fit the CSI structure better than unidimensional and the four-factor models. The general factor showed substantial reliability (Cronbach α = 0.91, Omega ω = 0.94, and omega hierarchical ω-h = 0.91). The intraclass correlation coefficient was 0.90, representing excellent stability over a 48 h interval. Moderate-to-strong correlations and acceptable-to-excellent discriminations were found between the CSI-Thai and all questionnaires. The exception was the PCS (no correlation and discrimination). The standard error of measurement and minimal detectable change of the CSI-Thai were 2.33 and 6.47, respectively.

CONCLUSIONS

The translation and cross-cultural adaptation of the CSI-Thai were successful, with satisfactory reliability and construct validity.Implications for rehabilitationCentral Sensitisation Inventory-Thai version (CSI-Thai) is successfully adapted and demonstrated satisfactory reliability and construct validity.The CSI-Thai can be applicable to assess central sensitisation-related signs and symptoms in Thai-speaking patients with chronic non-specific neck pain (CNSNP) both clinical and research purposes.The CSI-Thai correlated to pain, disability and quality of life among patients with CNSNP.

Impact of central sensitization on pain, disability and psychological distress in patients with knee osteoarthritis and chronic low back pain

BACKGROUND

Central sensitization (CS) is becoming increasingly recognized as a significant factor in many chronic pain conditions, including knee osteoarthritis (KOA) and chronic low back pain (CLBP). Yet it presently remains unclear how strong is the involvement of CS in KOA and CLBP and which factors are involved in CS in these two chronic disabling diseases.

METHODS

This is a cross-sectional study in which included a total of 178 patients with KOA and 118 patients with CLBP. Inclusion criteria for eligible participants for the KOA group were a confirmed diagnosis of KOA according to the American College of Rheumatology criteria, and for the CLBP group a chronic low back pain for more than 3 months. Subjects were excluded if they presented with a diagnosed psychiatric disorder or if they lacked the capacity to provide informed consent, understand study questionnaires or perform physical performance tests. In each group, were assessed; CS-related symptoms using the Central Sentization Inventory (CSI); demographic and clinical characteristics such as disease duration, pain intensity on a visual analog scale, self-reported function using the Lequesne index for KOA patients and the Oswestry Disability index for CLBP patients, and physical performance with the 6 minutes' walk test; as well as psychosocial risk factors using the Patient Health Questionnaire for depression (PHQ-9), the Generalized Anxiety Disorder (GAD-7) and the Pain Catastrophizing Scale (PCS).

RESULTS

CSI scores significantly correlated with pain intensity and disability in KOA and CLBP patients, and were highly correlated with self-reported symptoms of depression, anxiety and pain catastrophizing. Depression significantly predicted the CSI score in both groups.

CONCLUSION

These findings provide further evidence for the impact of CS on pain, function and physical performance in KOA and CLBP patients. Psychosocial symptoms such as pain catastrophizing, anxiety and depression should also be considered as they are also associated with CS.

Short-term heart rate variability at rest in individuals with temporomandibular disorder: a comparative analysis

OBJECTIVE

Compare heart rate variability (HRV) indices in participants with and without myogenic temporomandibular disorder (TMD). Secondarily, we correlated HRV indices with pain and quality of life variables.

METHODS

This is a comparative observational cross-sectional study. Individuals of both genders with and without a history of TMD were included. Short-term heart rate variability was assessed using a Polar V800. Central sensitization was assessed using the Central Sensitization Inventory. Pain through the numeric pain scale and the impact of oral health on quality of life using the OHIP-14 questionnaire.

RESULTS

A total of 80 participants were enrolled in the study: most individuals included in both groups were young adults, women and slightly overweight. We observed a decrease in HRV in the TMD group (p < 0.01) when compared to the control group. In addition, we observed a greater impact of oral health on quality of life, central sensitization in addition to high resting pain scores (p < 0.01). We observed significant correlation between the LF index of HRV and the FAI score (r = 0.311; p = 0.05). The NPS, CSI and OHIP-14 scores did not correlate with any of the HRV indices (p > 0.05).

CONCLUSION

The short-term HRV in individuals with TMD is significantly lower when compared to a control group. Furthermore, there seems to be a relationship between the severity of the dysfunction and the HRV variables.

CLINICAL RELEVANCE

Using portable and low-cost devices, the HRV can be easily collected and analyzed, without the need for an arsenal of equipment such as the conventional electrocardiogram. This measure can contribute to the therapy adopted and identify individuals prone to unfavorable outcomes involving ANS modulation.

Women with fibromyalgia (ACR criteria) compared with women diagnosed by doctors and women with osteoarthritis: Cross-sectional study using functional and clinical variables

PURPOSE

To compare functional and clinical variables of women with fibromyalgia (American College of Rheumatology [ACR] criteria) vs women diagnosed by doctors and women with knee osteoarthritis (KOA).

METHODS

This is a cross-sectional study. We used clinical measures, namely, Widespread Pain Index (WPI), Symptom Severity Scale (SSS), Fibromyalgia Impact Questionnaire-Revised (FIQ-R), Numerical Pain Rating Scale (NPRS), Central Sensitization Inventory (CSI), Pain-Related Catastrophizing Thoughts Scale (PCTS), and functional measures, such as Sit-to-Stand (STS) test, and Timed Up and Go (TUG) test.

RESULTS

The sample consisted of 91 participants divided into 3 groups: participants with KOA (n = 30), fibromyalgia diagnosed according to the ACR (FM-ACR, n = 31), and fibromyalgia according to the medical diagnosis (FM-Med, n = 30). In the comparisons, we observed a significant difference (P < 0.05) and a large effect size (d ≥ 0.8), between all groups, in the WPI, WPI + SSS, FIQ-R domains, CSI, and PCTS. We did not observe significant values in the correlations between the clinical variables, SST, and TUG test.

CONCLUSION

People with fibromyalgia according, to the ACR, have higher levels of widespread pain, symptom severity, global impact on quality of life, central sensitization, and catastrophizing compared with people with knee OA and people with clinical fibromyalgia diagnosis not confirmed by the ACR diagnostic criteria.

Insomnia is associated with symptoms of central sensitization in patients with painful temporomandibular disorders

BACKGROUND

Central sensitization (CS) and temporomandibular disorder (TMD) are both associated with insomnia. Therefore, the authors aimed to investigate whether insomnia was associated with more symptoms of CS in patients with TMD.

METHODS

In 82 volunteers with TMD, insomnia was clinically assessed, allowing sample stratification according to its presence. The Central Sensitization Inventory questionnaire was self-applied to assess the clinical symptoms of CS.

RESULTS

Participants with insomnia had significantly higher mean (SD) scores of CS according to the Central Sensitization Inventory than participants without insomnia (43.10 [12.57] vs 26.59 [13.66]; P = < .001).

CONCLUSIONS

Insomnia was associated with higher scores of CS symptoms in patients with TMD.

PRACTICAL IMPLICATIONS

Insomnia influences TMD as well as its relationship with CS, and, therefore, it is critical to the clinical management of TMD.

Patients with neuropathic pain from lumbosacral radiculopathy demonstrate similar pressure pain thresholds and conditioned pain modulation to those with fibromyalgia

OBJECTIVE

The purpose of the study was to evaluate pain thresholds, impairment of the endogenous pain modulatory system, and self-reported cognitive-emotional and central sensitization-related symptoms among three subject groups: a rarely studied patient cohort with neuropathic pain from lumbosacral radiculopathy (NPLSR), patients with fibromyalgia (FM) and healthy controls (HC).

METHODS

Patient-reported pain-related symptomology was evaluated with psychometricallyvalidated questionnaires. Pressure pain threshold (PPT), heat pain threshold (HPT), and cold pain threshold (CPT) were assessed in the low back and contralateral forearm. Conditioned pain modulation (CPM) was evaluated with a recently introduced methodology that accounts for a standard error of measurement.

RESULTS

Compared to the HC subjects, the FM and NPLSR subjects had significantly lower pain thresholds and more CPM impairment. No significant differences in PPT and CPM were observed between the FM and NPLSR groups. Significant group differences were found in self-reported symptoms of depression, anxiety, stress, and central sensitization. Self-reported symptom severity increased in a stair-step fashion, with the HC group scoring lowest and FM group scoring highest.

CONCLUSION

The NPLSR group manifested CPM dysfunction and pressure hyperalgesia at similar levels to the FM group, indicating that these two chronic pain syndromes, likely based on different pathophysiological mechanisms, in fact share some common pain processing features. However, though both patient groups demonstrated similarities in pain processing, self-reported cognitive-emotional and central sensitization-related symptom severity was significantly higher in the FM cohort, which distinguished them from the chronic NPLSR cohort.

Do "central sensitization" questionnaires reflect measures of nociceptive sensitization or psychological constructs? A systematic review and meta-analyses

ABSTRACT

Central sensitization (CS) is defined as an increased nociceptive responsiveness due to sensitization of neurons in the central nervous system, usually the result of prolonged nociceptive input or a disease state associated with noxious inputs (eg, polyarthritis). The concept of CS has recently been adopted in clinical assessments of chronic pain, but its diagnosis in humans may now include a wide range of hypervigilant responses. The purpose of this review is to ascertain whether self-report questionnaires linked with CS are associated with enhanced nociceptive responses or whether they measure sensitivity in a broader sense (ie, emotional responses). According to our published, PROSPERO-registered review protocol (CRD42021208731), a predefined search of studies that involve the Central Sensitization Inventory (CSI) or Pain Sensitivity Questionnaire (PSQ), correlated with either nociceptive sensory tests or emotional hypervigilance was conducted on MEDLINE, PsycINFO, and Web of Science. Correlations between the CSI or PSQ with our primary outcomes were extracted and meta-analysed. A review of 66 studies totalling 13,284 participants found that the CSI (but not the PSQ) strongly correlated with psychological constructs: depression, anxiety, stress, pain catastrophising, sleep, and kinesiophobia. The CSI and PSQ showed weak or no correlations with experimental measures of nociceptive sensitivity: pain thresholds, temporal summation, or conditioned pain modulation. The PSQ did, however, correlate strongly with phasic heat and tonic cold pain tests. The studies reviewed did not provide sufficient evidence that self-report measures reflect a canonical understanding of CS. The CSI more closely reflects psychological hypervigilance than increased responsiveness of nociceptive neurons.

Neuropathic-like symptoms and central sensitization related signs and symptoms negatively affect the functional performance of patients with knee osteoarthritis – a cross-sectional study

Objective

This study aimed to compare the functional performance among participants with a neuropathic-like symptoms (NS) and central sensitization related signs and symptoms (CS), and their knee osteoarthritis (OA) counterparts.

Methods

A cross-sectional observational study was conducted with 125 participants with knee OA (94 females, mean age 63.1 ​± ​7.4 years). Participants completed a self-reported questionnaire with personal and clinical features and musculoskeletal pain characteristics, including NS (PainDETECT), CS (Central Sensitization Inventory, CSI), and conditioned pain modulation. Self-reported functional disability (Western Ontario and McMaster Universities Osteoarthritis Index, WOMAC) and functional mobility (Timed Up and Go, TUG) were compared among patients with NS, CS, and their knee OA counterparts using the one-way analysis of variance (ANOVA).

Results

Thirty-three (26.4%) participants had NS and CS, eighteen (14.4%) had NS, twenty-seven (21.6%) participants had CS, and 47 (37.6%) had knee OA with no NS or CS. A one-way ANOVA revealed greater functional limitation in the group with NS and CS (mean ​= ​67.5 ​± ​12.0) or NS (mean ​= ​56.7 ​± ​17.5) than the group without these symptoms (mean ​= ​32.0 ​± ​20.7) with a statistical significance difference [F(3, 121) ​= ​29.434, p ​< ​0.001] in the WOMAC Total score. The group with NS and CS (mean ​= ​19.2 ​± ​7.4) or NS (mean ​= ​16.3 ​± ​6.3) had slower velocity than the group without these symptoms (mean ​= ​11.6 ​± ​3.5) with a statistical significance difference [F(3,121) ​= ​10.045, p ​< ​0.001] in the TUG test.

Conclusion

Participants with knee osteoarthritis and NS or CS pain phenotype have greater functional limitations than their counterparts.

Peripheral body temperature rhythm as a marker of the severity of depression symptoms in fibromyalgia

BACKGROUND

Circadian rhythm alterations have been reported in fibromyalgia (FM) and depression. Peripheral body temperature (PBT) is a reliable measure of the circadian system, so we compared the PBT rhythm between persons with FM and controls. We evaluated PBT correlation with depression symptoms and pain severity in women with FM.

METHODS

We included 101 women aged 30-65 with FM diagnosis (FM group, n = 83) and controls (n = 18). Twenty-four-hour PBT was assessed by actigraphy. For the analysis, in the FM group, the PBT measurement was divided into four periods: morning (6 a.m.-noon), afternoon (noon-6 p.m.), evening (6 p.m.-midnight), and night (midnight-6 a.m.). According to their scores on the Hamilton Depression Rating Scale (HDRS), participants were classified as having mild or moderate to severe depression symptoms.

RESULTS

There was no difference in PBT between FM and controls. Subjects with FM and moderate to severe depression symptoms showed a higher PBT (p = .003) during the evening period (p = .004). The analysis of PBT rhythm revealed an interaction between time and group according to mild or moderate to severe depression symptoms (χ2 (3) = 12.79, p < .005). The pain severity was positively correlated with PBT (ß=0.22, [CI 95%, 0.07-0.37], p = .003).

CONCLUSIONS

PBT rhythm was not a sensitive measure for discriminating persons with FM from controls. In FM, PBT is related to the severity of depression symptoms and pain intensity.

Are central sensitization symptoms and psychosocial alterations interfering in the association between painful TMD, migraine, and headache attributed to TMD?

OBJECTIVE

To determine if somatosensory function and symptoms related to central sensitization (CS) differed in individuals with painful temporomandibular disorders (TMD) according to the presence of migraine (MIG) or MIG + headache attributed to TMD (HAT).

MATERIALS AND METHODS

This study evaluated 92 adults (20-65 years), presenting painful TMD. Standard diagnostic criteria were applied to classification of painful TMD, MIG, and HAT. CS was assessed through the central sensitization inventory (CSI), wind-up ratio (WUR), pressure pain thresholds (PPT), and the conditioned pain modulation test (CPM). Psychosocial factors were evaluated by validated instruments.

RESULTS

There was a significant difference regarding gender, with more women in the group TMD + MIG + HAT (p = 0.028). TMD + MIG and TMD + MIG + HAT had significantly lower PPTs than the TMD group. No group differences were found for the WUR, CPM, or CSI. TMD + MIG + HAT had higher chronic pain intensity (p = 0.001), disability points (p = 0.045), graded chronic pain scale (p = 0.007), and higher somatization (NSPS) scores (p = 0.012), compared to the other groups.

CONCLUSION

Mechanical hyperalgesia was more pronounced in the group with the highest pain and somatization scores, while CPM and WUR did not differ between groups. Altered somatosensory function and CS may partially underlie the pathophysiology of overlapping TMD pain conditions, pointing towards additive effects of comorbid head pains.

CLINICAL RELEVANCE

Our results demonstrate the importance of considering the association of primary and secondary headaches during TMD assessment and its implications for maintaining the signs and symptoms of CS. This can influence the conduct of treatment, which must be multidisciplinary, and must include management of mechanisms related to CS.

Effects of Hypnotic Analgesia and Transcranial Direct Current Stimulation on Pain Tolerance and Corticospinal Excitability in Individuals with Fibromyalgia: A Cross-Over Randomized Clinical Trial

Objective

We compare the effect of HAS, a-tDCS on the left dorsolateral prefrontal cortex (l-DLPFC), and rest-testing on pain measures [(cold pressor test (CPT) (primary outcome) and heat pain threshold]. We also compare their effects on the motor evoked potential (MEP) (primary outcome), short intracortical inhibition (SICI), intracortical facilitation (ICF), and cortical silent period (CSP).

Methods

This randomized, blind, crossover trial included 18 women with fibromyalgia, aged from 18 to 65 years old. They received at random and in a crossover order a-tDCS over the l-DLPFC (2mA), HAS, or a rest-testing.

Results

HAS compared to a-tDCS increased the pain tolerance with a moderate effect size (ES) [Cohen's f=-0.78; (CI 95%; -1.48 to -0.12)]. While compared to rest-testing, HAS increased the CPT with a large ES [Cohen's f=-0.87; (CI 95%; -1.84 to -0.09)]. The a-tDCS compared to HAS increased the MEP amplitude with large ES [Cohen's f=-1.73 (CI 95%; -2.17 to -0.17)]. Likewise, its ES compared to rest-testing in the MEP size was large [Cohen's f=-1.03; (CI 95%; -2.06 to -0.08)].

Conclusion

These findings revealed that HAS affects contra-regulating mechanisms involved in perception and pain tolerance, while the a-tDCS increased the excitability of the corticospinal pathways. They give a subsidy to investigate their effect as approaches to counter regulate the maladaptive neuroplasticity involved in fibromyalgia.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier - NCT05066568.

Can high pain intensity and catastrophizing interfere with the cognitive performance of women with chronic pain related TMD? A cross-sectional study

OBJECTIVE

Interventions based on pain education and self-management are dependent on factors such as attention, memory, concentration, and executive function. To explore the relationship between cognitive performance and the variables pain intensity, central sensitization, catastrophizing, and hypervigilance in women diagnosed with chronic pain-related TMD.

METHODOLOGY

This is a cross-sectional study. A total of 33 women (mean age: 38±4.6 years; range: 18 to 66 years) with chronic pain-related TMD (myalgia and/or arthralgia) diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Specific questionnaires were used to evaluate cognitive performance, overall pain intensity, central sensitization, hypervigilance, and pain catastrophizing. The data were analyzed using Pearson's correlation coefficient and backward stepwise multiple linear regression (statistical significance at 5% alpha).

RESULTS

Approximately 53% of the study sample showed decreased cognitive performance. High central sensitization, hypervigilance, and pain catastrophizing were observed. A significant negative correlation was observed between cognitive performance and hypervigilance (p=.003, r=-.49), cognitive performance and catastrophizing (p<.001, r=-.58), and cognitive performance and pain intensity (p<.001, r=-.58). Regarding the partial regression coefficients, only catastrophizing and pain intensity showed statistical significance (t=-2.12, p=.043; t=-2.64, p=.014, respectively), indicating a significant role in explaining cognitive performance at the sample.

CONCLUSION

High pain intensity and the presence of catastrophic thoughts regarding pain can predict impaired cognitive performance in women with chronic pain-related TMD. Management strategies addressing psychosocial dimensions such as reducing catastrophizing and ensuring complete understanding of the condition are important.

Primary somatosensory cortex and periaqueductal gray functional connectivity as a marker of the dysfunction of the descending pain modulatory system in fibromyalgia

Background

Resting-state functional connectivity (rs-FC) may aid in understanding the link between pain-modulating brain regions and the descending pain modulatory system (DPMS) in fibromyalgia (FM). This study investigated whether the differences in rs-FC of the primary somatosensory cortex in responders and non-responders to the conditioned pain modulation test (CPM-test) are related to pain, sleep quality, central sensitization, and the impact of FM on quality of life.

Methods

This cross-sectional study included 33 females with FM. rs-FC was assessed by functional magnetic resonance imaging. Change in the numerical pain scale during the CPM-test assessed the DPMS function. Subjects were classified either as non-responders (i.e., DPMS dysfunction, n = 13) or responders (n = 20) to CPM-test. A generalized linear model (GLM) and a receiver operating characteristic (ROC) curve analysis were performed to check the accuracy of the rs-FC to differentiate each group.

Results

Non-responders showed a decreased rs-FC between the left somatosensory cortex (S1) and the periaqueductal gray (PAG) (P < 0.001). The GLM analysis revealed that the S1-PAG rs-FC in the left-brain hemisphere was positively correlated with a central sensitization symptom and negatively correlated with sleep quality and pain scores. ROC curve analysis showed that left S1-PAG rs-FC offers a sensitivity and specificity of 85% or higher (area under the curve, 0.78, 95% confidence interval, 0.63-0.94) to discriminate who does/does not respond to the CPM-test.

Conclusions

These results support using the rs-FC patterns in the left S1-PAG as a marker for predicting CPM-test response, which may aid in treatment individualization in FM patients.

Impairment on Cardiovascular Autonomic Modulation in Women with Migraine

Autonomic dysfunction, such as reduced vagally mediated heart rate variability, has been suggested in headache patients but is still uncertain when considering primary headache disorders. This study aims to compare the heart rate and blood pressure variability and baroreflex sensitivity between women with migraine and controls. A migraine (n = 20) and a control group (n = 20) of age-matched women without headache were evaluated. Heart rate variability was analyzed through frequency-domain using spectral analysis presenting variance, low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.15-0.4 Hz) bands and by time domain (root mean square of successive R-R interval differences, RMSSD). Blood pressure variability was analyzed with spectral analysis and baroreflex sensitivity with the sequence method. Migraine group had lower heart rate variability characterized by a reduction in total variance, LF oscillations (sympathetic/vagal modulation) and HF oscillations (vagal modulation), and a reduction in SD and RMSSD compared to control group. No difference was found in the blood pressure variability analysis. Regarding baroreflex sensitivity, migraine group had decreased values of total gain, gain down and up compared to control group. Women with migraine exhibited autonomic modulation alterations, expressed by decreased values of heart rate variability and baroreflex sensitivity, but not by differences in blood pressure variability.

Effects of osteopathic manipulative treatment associated with pain education and clinical hypnosis in individuals with chronic low back pain: study protocol for a randomized sham-controlled clinical trial

BACKGROUND

Patients with chronic low back pain (CLBP) suffer with functional, social, and psychological aspects. There is a growing number of studies with multimodal approaches in the management of these patients, combining physical and behavioral therapies such as osteopathic manipulative treatment, associating pain education and clinical hypnosis. The aim of the present study will be to evaluate the effects of osteopathic manipulative treatment (OMT) associated with pain neuroscience education (PNE) and clinical hypnosis (CH) on pain and disability in participants with CLBP compared to PNE, CH, and sham therapy.

METHODS

A randomized controlled clinical trial will be conducted in participants aged 20-60 years with CLBP who will be divided into two groups. Group 1 will receive PNE and CH associated with OMT, and G2 will receive PNE, CH, and sham therapy. In both groups, 4 interventions of a maximum of 50 min and with an interval of 7 days will be performed. As primary outcomes, pain (numerical pain scale), pressure pain threshold (pressure algometer), and disability (Oswestry Disability Questionnaire) will be evaluated and, as a secondary outcome, global impression of improvement (Percent of Improvement Scale), central sensitization (Central Sensitization Questionnaire), biopsychosocial aspects (Start Beck Toll Questionnaire), and behavior of the autonomic nervous system (heart rate variability) will be assessed. Participants will be evaluated in the pre-intervention moments, immediately after the end of the protocol and 4 weeks after the procedures. Randomization will be created through a simple randomized sequence and the evaluator will be blinded to the allocation of intervention groups.

DISCUSSION

The guidelines have been encouraging multimodal, biopsychosocial approaches for patients with CLBP; in this sense, the results of this study can help clinicians and researchers in the implementation of a model of treatment strategy for these patients. In addition, patients may benefit from approaches with minimal risk of deleterious effects and low cost. In addition, it will enable the addition of relevant elements to the literature, with approaches that interact and do not segment the body and brain of patients with CLBP, allowing new studies in this scenario.

TRIALS REGISTRATION

Date: September 4, 2021/Number: NCT05042115 .

Cross cultural adaptation, validity, and reliability of Central Sensitization Inventory in Arabic language

PURPOSE

The Central Sensitization Inventory (CSI) is a tool that aid in identifying symptoms associated with nociplastic pain. The aim of this study is to adapt CSI to Arabic language, and to examine its psychometric properties.

METHODS

Adaptation process followed recommended guidelines. Participants with self-reported chronic pain completed a web-based survey. The internal consistency was calculated. Test-retest reliability was examined by allowing 7-9 day gap between two rounds of measurements. Convergent validity was examined by measuring the correlation with Pain Catastrophizing Scale (PCS), EQ-VAS, and EQ-5D-3L. Discriminant validity was examined by testing four priori hypotheses. Factor analysis with principal components extraction was conducted.

RESULTS

CSI-Arabic (CSI-Ar) was successfully produced. Its internal consistency and test-retest reliability were excellent (Cronbach's α = 0.88 and ICC_2,1=0.94). The standard error of measurement and minimal detectable change 95% were 3.45 and 9.57, respectively. CSI total score correlation with PCS, EQ-5D-3L, and EQ-VAS was moderate. The results lend support to the four hypothesis related to discriminant validity. Factor analysis revealed a four-factor structure of CSI-Ar.

CONCLUSIONS

CSI-Ar showed an internal consistency, test-retest reliability, and validity that are comparable to similar studies. The results support the use of CSI-Ar in assessing chronic pain in Arabic-speaking population.Implications for rehabilitationCentral sensitization (CS) mechanisms are thought to contribute to chronic pain.Identifying the presence of CS would personalize management.The Central Sensitization Inventory (CSI) is a valid and reliable tool to aid in identifying symptoms associated with CS.The Arabic version of the CSI is valid and reliable to use in Arabic speaking patients suffering from chronic pain.

The effect of home-based transcranial direct current stimulation in cognitive performance in fibromyalgia: A randomized, double-blind sham-controlled trial

Background

Transcranial Direct Current Stimulation (tDCS) is a promising approach to improving fibromyalgia (FM) symptoms, including cognitive impairment. So, we evaluated the efficacy and safety of home-based tDCS in treating cognitive impairment. Besides, we explored if the severity of dysfunction of the Descendant Pain Modulation System (DPMS) predicts the tDCS effect and if its effect is linked to changes in neuroplasticity as measured by the brain-derived neurotrophic factor (BDNF).

Methods

This randomized, double-blind, parallel, sham-controlled clinical trial, single-center, included 36 women with FM, aged from 30 to 65 years old, assigned 2:1 to receive a-tDCS (n = 24) and s-tDCS (n = 12). The primary outcome was the Trail Making Test's assessment of executive attention, divided attention, working memory (WM), and cognitive flexibility (TMT-B-A). The secondary outcomes were the Controlled Oral Word Association Test (COWAT), the WM by Digits subtest from the Wechsler Adult Intelligence Scale (WAIS-III), and quality of life. Twenty-minute daily sessions of home-based tDCS for 4 weeks (total of 20 sessions), 2 mA anodal-left (F3) and cathodal-right (F4) prefrontal stimulation with 35 cm² carbon electrodes.

Results

GLM showed a main effect for treatment in the TMT-B-A [Wald χ2 = 6.176; Df = 1; P = 0.03]. The a-tDCS improved cognitive performance. The effect size estimated by Cohen's d at treatment end in the TMT-B-A scores was large [-1.48, confidence interval (CI) 95% = -2.07 to-0.90]. Likewise, the a-tDCS effects compared to s-tDCS improved performance in the WM, verbal and phonemic fluency, and quality-of-life scale. The impact of a-tDCS on the cognitive tests was positively correlated with the reduction in serum BDNF from baseline to treatment end. Besides, the decrease in the serum BDNF was positively associated with improving the quality of life due to FM symptoms.

Conclusion

These findings revealed that daily treatment with a home-based tDCS device over l-DLPFC compared to sham stimulation over 4 weeks improved the cognitive impairment in FM. The a-tDCS at home was well-tolerated, underlining its potential as an alternative treatment for cognitive dysfunction. Besides, the a-tDCS effect is related to the severity of DPMS dysfunction and changes in neuroplasticity state.

Clinical trial registration

[www.ClinicalTrials.gov], identifier [NCT03843203].

Association between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with knee osteoarthritis

Objective

To analyze the association between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with knee osteoarthritis (KOA).

Methods

A cross-sectional study was conducted involving 57 individuals with KOA. Evaluations were performed using the Exercise Adherence Rating Scale (EARS), the numerical rating scale (NRPS), the International Knee Documentation Committee (IKDC), The Central Sensitization Inventory (CSI), and the 30 sec sit and stand test (30SSST). Histograms were created to determine the normality of the data. The Kolmogorov-Smirnov test was used to determine the normality of the data. Thus, Pearson’s (r) and determination (R2) correlation coefficients were calculated to determine the strength of associations between variables.

Results

No significant association was found between adherence behavior or reasons for adherence and central sensitization symptoms, the intensity of pain on rest and movement, knee disability symptoms, and functionality.

Conclusion

No significant association was identified between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with KOA.

Functional connectivity response to acute pain assessed by fNIRS is associated with BDNF genotype in fibromyalgia: an exploratory study

Fibromyalgia is a heterogenous primary pain syndrome whose severity has been associated with descending pain modulatory system (DPMS) function and functional connectivity (FC) between pain processing areas. The brain-derived neurotrophic factor (BDNF) Val66Met single nucleotide polymorphism has been linked to vulnerability to chronic pain. In this cross-sectional imaging genetics study, we investigated fibromyalgia, the relationship between BDNF Val66Met heterozygous genotypes (Val/Met), and the functional connectivity (FC) response pattern to acute pain stimulus in the motor (MC) and prefrontal (PFC) cortex assessed by near-infrared spectroscopy (fNIRS) before and after a cold pressor test utilizing water (0-1 °C). Also, we assessed the relationship between this genotype with the DPMS function and quality of life. We included 42 women (Val/Val = 30; Val/Met = 12) with fibromyalgia, ages 18-65. The MANCOVA comparing Val/Met to Val/Val genotypes showed higher ΔFC between left(l)-PFC-l-MC (β = 0.357, p = 0.048), l-PFC-right(r)-PFC (β = 0.249, p = 0.012), l-PFC-r-MC (β = 0.226, p = 0.022), and l-MC-r-PFC (β = 0.260, p = 0.016). Val/Met genotypes showed higher efficiency of the DPMS and lower disability due to pain. Here we show that fibromyalgia patients carrying the Val/Met BDNF genotype presented an increased ΔFC across MC and PFC in response to acute pain associated with differences in acute pain perception and fibromyalgia symptoms.

Autonomic Nervous System Function and Central Pain Processing in People With Frozen Shoulder: A Case-control Study

OBJECTIVES

The pathophysiology of a frozen shoulder (FS) is thought to be related to chronic inflammation. Chronic inflammation may disturb the immune system and consequently the nervous system as part of an overarching system. The aim of this study was to determine the presence of disturbed autonomic nervous system function and altered central pain processing (CPP) in patients with FS. Secondarily, the presence of psychological variables (catastrophizing and hypervigilance) and self-reported associated symptoms of altered CPP in patients with FS were investigated.

METHODS

Patients with FS and healthy controls completed the Composite Autonomic Symptom Score (autonomic function) and underwent quantitative sensory testing to assess tactile sensitivity (ie, allodynia), pressure pain thresholds (PPTs, ie, hyperalgesia), temporal summation of pain, and Conditioned Pain Modulation (CPM). Psychological issues were explored with the Pain Catastrophizing Scale and the Pain Vigilance and Awareness Questionnaire, and self-reported symptoms associated with altered CPP were determined with the Central Sensitization Inventory.

RESULTS

Thirty-two patients with FS and 35 healthy controls were analyzed in the study. Patients with FS showed more self-reported autonomic symptoms and symptoms of altered CPP, higher levels of pain catastrophizing and hypervigilance, and are more sensitive to tactile touches and mechanical pressure compared with controls.

DISCUSSION

On the basis of the effect sizes, between-group differences in allodynia, hyperalgesia, catastrophizing, and hypervigilance were clinically relevant, but only local allodynia, hyperalgesia, catastrophizing, and hypervigilance were statistically different. Therefore, obvious altered CPP was not present at the group level in patients with FS compared with controls.

Association between descending pain modulatory system and cognitive impairment in fibromyalgia: A cross-sectional exploratory study

Background

The successful regulation of sensory input to the central nervous system depends on the descending pain modulatory system (DPMS). For the effective regulation of sensory input to the central nervous system and behavioral responses to pain, the DPMS is required. Its connection to fibromyalgia (FM)-related cognitive dysfunction has not yet been investigated. Therefore, this study tested whether measures of verbal fluency, sustained attention, and short-term and working memory could distinguish FM patients from healthy controls (HC). Additionally, it investigated, using a standardized paradigm, the link between cognitive ability and the function of the DPMS in responders and non-responders to the conditioned pain modulation test (CPM-test).

Materials and methods

We enrolled 21 HC women and 69 FM patients, all of whom ranged in age from 30 to 65. We employed scores from the Trail Making Test (TMTB-A) (sustained and divided attention), the Controlled Oral Word Association Test (COWAT) (orthographic and semantic fluency), and the Digits subtest of the Wechsler Adult Intelligence Scale (WAIS-III) as dependent variables.

Results

A generalized linear model (GLM) adjusted by educational level revealed significantly lower scores in FM than HC on the Span digits forward, COWAT-orthographic, and TMTB-A. For FM patients, multilevel MANCOVA revealed that the cognitive performance of non-responders compared to responders to CPM-test showed lower adjusted scores in Span digits forward (Partial-η² = 0.358, P = 0.001), Span digits backward (Partial-η² = 0.358, P = 0.001), COWAT-orthographic (Partial-η² = 0.551, P = 0.001), COWAR-semantic (Partial-η² = 0.355, P = 0.001), and TMTB-A (Partial-η² = 0.360, P = 0.001). The association between the cognitive tests and the DPMS is moderated by the serum level of brain-derived neurotrophic factor (BDNF). Additionally, these cognitive assessments had a positive correlation with antidepressant use and pain threshold. The cognitive assessments, on the other hand, were conversely associated with a life of quality.

Conclusion

Based on these findings, it can be shown that HC performed substantially better on cognitive exams than FM did. They demonstrated a link between clinical complaints about attention and memory and decreased DPMS effectiveness. Additionally, they demonstrated that the BDNF is a moderating element in a potential relationship between the severity of cognitive impairment and DPMS dysfunction.

Sickle cell disease chronic joint pain: Clinical assessment based on maladaptive central nervous system plasticity

Chronic joint pain (CJP) is among the significant musculoskeletal comorbidities in sickle cell disease (SCD) individuals. However, many healthcare professionals have difficulties in understanding and evaluating it. In addition, most musculoskeletal evaluation procedures do not consider central nervous system (CNS) plasticity associated with CJP, which is frequently maladaptive. This review study highlights the potential mechanisms of CNS maladaptive plasticity related to CJP in SCD and proposes reliable instruments and methods for musculoskeletal assessment adapted to those patients. A review was carried out in the PubMed and SciELO databases, searching for information that could help in the understanding of the mechanisms of CNS maladaptive plasticity related to pain in SCD and that presented assessment instruments/methods that could be used in the clinical setting by healthcare professionals who manage chronic pain in SCD individuals. Some maladaptive CNS plasticity mechanisms seem important in CJP, including the impairment of pain endogenous control systems, central sensitization, motor cortex reorganization, motor control modification, and arthrogenic muscle inhibition. Understanding the link between maladaptive CNS plasticity and CJP mechanisms and its assessment through accurate instruments and methods may help healthcare professionals to increase the quality of treatment offered to SCD patients.

Association of low-dose naltrexone and transcranial direct current stimulation in fibromyalgia: a randomized, double-blinded, parallel clinical trial

INTRODUCTION

Fibromyalgia is a complex, generalized, and diffuse chronic musculoskeletal pain. Pharmacological approaches are widely used to relieve pain and increase quality of life. Low-Dose Naltrexone (LDN) was shown to increase the nociceptive threshold in patients with fibromyalgia. Transcranial Direct Current Stimulation (tDCS) is effective for pain management.

OBJECTIVE

The purpose of this study was to evaluate the analgesic and neuromodulatory effects of a combination of LDN and tDCS in patients with fibromyalgia.

METHODS

This was a randomized, double-blinded, parallel, placebo/sham-controlled trial (NCT04502251; RBR-7HK8N) in which 86 women with fibromyalgia were included, and written informed consent was obtained from them. The patients were allocated into four groups: LDN + tDCS (n = 21), LDN + tDCS Sham (n = 22), placebo + tDCS (n = 22), and placebo+tDCS Sham (n = 21). The LDN or placebo (p.o.) intervention lasted 26 days; in the last five sessions, tDCS was applied (sham or active, 20 min, 2 mA). The following categories were assessed: sociodemographic, Visual Analog Pain Scale (VAS), Pain Catastrophizing Scale (PCS), State-Trait Anxiety Inventory (STAI), Fibromyalgia Impact Questionnaire (FIQ), Beck Depression Inventory (BDI-II), Profile of Chronic Pain Scale (PCP:S), Pain Pressure Threshold (PPT), and Conditioned Pain Modulation (CPM). Blood samples were collected to analyze BDNF serum levels.

RESULTS

At baseline, no significant difference was found regarding all measurements. VAS pain was significantly reduced in the LDN + tDCS (p = 0.010), LDN + tDCS Sham (p = 0.001), and placebo+tDCS Sham (p = 0.009) groups. In the PCP:S, the LDN+tDCS group showed reduced pain frequency and intensity (p = 0.001), effect of pain on activities (p = 0.014) and emotions (p = 0.008). Depressive symptoms reduced after all active interventions (p > 0.001).

CONCLUSION

Combined LDN+tDCS has possible benefits in reducing pain frequency and intensity; however, a placebo effect was observed in pain using VAS, and further studies should be performed to analyze the possible association.

Comparison between pain intensity, functionality, central sensitization, and self-efficacy in individuals with unilateral or bilateral knee osteoarthritis: a cross-sectional study

OBJECTIVE:

This study aimed to compare pain intensity, stiffness, functionality, central sensitization, and self-efficacy, between individuals with bilateral knee osteoarthritis and unilateral knee osteoarthritis.

METHODS:

We included sedentary participants with knee osteoarthritis. The diagnosis was defined by a specialist, in which there was a complaint of pain and/or altered function in the lower limbs (duration ≥3 months); morning stiffness; pain intensity ≥3; Kellgren-Lawrence 2–3° associated with X-ray; persistence of symptoms >3 months. We used the following tools: Western Ontario and McMaster Universities Arthritis Index, Numerical Pain Scale, Central Sensitization Inventory, and Pain Self-Efficacy Questionnaire. Intergroup comparisons were performed using the t-test.

RESULTS:

The sample consisted of 118 adult individuals, divided into two groups: bilateral knee osteoarthritis (n=59) and unilateral knee osteoarthritis (n=59). We observed a significant difference (p<0.05) and a large effect size (d≥0.8), in the comparisons between: stature, body mass index, physical function, central sensitization, and self-efficacy.

CONCLUSION:

Individuals with bilateral knee osteoarthritis have higher levels of central sensitization, impaired functionality, and a lower level of self-efficacy.

Are menstrual symptoms associated with central sensitization inventory? A cross-sectional study

BACKGROUND

Dysmenorrhea is a prevalent pain condition that affects women of reproductive age, who are monthly exposed to this pain, usually until they reach the adult age, or even after that, which can predispose them to Central Sensitization. The present study aimed to observe the association between menstrual characteristics and central sensitivity symptoms in women.

METHODS

Cross-sectional study. Brazilian women (n=10,402) answered an online form comprised of questions regarding their gynecological history, the Numerical Rating Scale for pain and the Central Sensitization Inventory, part A. For the analysis, we separated women into two groups: Central Sensitivity Symptoms group (n=5,200) and No-Central Sensitivity Symptoms group (n=5,202). We performed a binary logistic regression with the backward insertion method for the variables with p<0.05 in the bivariate analysis between groups. The significance level was set at 5%.

RESULTS

Prevalence of dysmenorrhea was 67.3%, and 32.2% of women in the Central Sensitivity Symptoms group reported pain >8 during their menstrual period. The logistic regression showed that greater levels of menstrual pain (Odds Ratio 1.12), gynecological diseases (Odds Ratio 1.51), presence of dysmenorrhea since adolescence (Odds Ratio 1.20) and irregular menstrual cycles (Odds Ratio 1.47) increased the likelihood of women presenting with Central Sensitivity Symptoms (p<0.05 for all comparisons).

CONCLUSIONS

The present study shows that Central Sensitivity Symptoms are present in about 50% of women and are associated with menstrual characteristics such as dysmenorrhea-related pain intensity, cycle regularity, presence of dysmenorrhea since adolescence accompanied by gynecological diseases.

SIGNIFICANCE

Central sensitivity symptoms occur in 50% of women, and are more present in women with dysmenorrhea. They are associated with cycle regularity, presence of dysmenorrhea since adolescence, and gynecological diseases.

LIMITATIONS

Women that suffer from dysmenorrhea and of higher socioeconomic and educational levels may have been more propense to respond to the invitation; as such, the findings of the present study should be carefully interpreted.

Motor control exercises versus general exercises for greater trochanteric pain syndrome: A protocol of a randomized controlled trial

Introduction

Greater trochanteric pain syndrome is an overarching term used to define pain and tenderness in the greater trochanteric region of the femur, which is more common in women. Abnormal control of lower limb movements and deficient neuromuscular parameters may lead to greater trochanteric pain syndrome; however, no studies have used neuromuscular training as a treatment strategy. Thus, this study aims to compare the effect of a protocol of general exercises versus a program of motor control training on pain at baseline and after treatment in women with greater trochanteric pain syndrome.

Methods

The study was approved by the Research Ethics Committee (CAAE: 87372318.1.0000.5406) and has been prospectively registered on the Brazilian Registry of Clinical Trials (RBR-37gw2x). Sixty participants will be randomized to receive motor control exercises or general exercises. The application will be performed twice a week for 8 weeks. The participants will be evaluated before the treatment (T0), after 8 weeks of intervention (T8) and after 60 weeks of intervention (T60). The primary outcome measures will be the hip pain intensity, and secondary outcomes will be muscle strength, kinesiophobia, global perceived effect, pain catastrophization, central sensitization and quality of life.

Conclusions

Studies have suggested that greater trochanteric pain syndrome may be related to poor hip and pelvic control, however, no study has investigated an exercise protocol focused on increasing the strength of the abductor and extensor muscles of the hip associated with pelvic control training, especially in positions of unilateral support, such as gait. This study will help determine whether greater trochanteric pain syndrome is related to abnormal control of lower limb movements.

Differences in Quantitative Sensory Testing Outcomes Between Patients With Low Back Pain in Primary Care and Pain-free Controls

OBJECTIVES

Quantitative Sensory Testing (QST) is used to test somatosensory functioning in on people with chronic LBP in secondary/tertiary health care facilities. Studies using QST-testing on LBP populations in primary care are scarce. Central Sensitization Inventory (CSI) measures central sensitization (CS)-related symptoms and studies investigating the differences between QST-testing and participants with LBP with a positive and negative score on the CSI questionnaire are also rare. This case-control study investigates differences of an extensive QST-measurement between patients with acute, chronic LBP, and pain-free controls (PFCs) in primary care. Secondary aim is to investigate differences of an extensive QST-measurement between "CS" and "no-CS" group.

MATERIALS AND METHODS

Participants with LBP were recruited from November 2016 to October 2019. Demographic and clinical information was collected and a standardized QST protocol was taken. Data analysis involved determining differences between groups.

RESULTS

Data of 100 participants with LBP and 50 PFCs were analyzed. Heat pain thresholds, pressure pain threshold, and conditioned pain modulation local and remote were significantly moderately to relatively strongly affected by acute, chronic LBP and PFCs (P<0.001 to 0.001). Lumbar temporal summation was significantly moderately affected by acute, chronic LBP, and PFCs (P=0.001). Only pressure pain threshold showed significant difference between "CS" and "no-CS" group (P=0.001 to 0.002).

DISCUSSION

Signs of enhanced nociceptive processing and disturbed top-down nociceptive modulation are apparent in people with acute and chronic LBP in primary care. Results indicate existence of central mechanisms in LBP in primary care.

Hyper-connectivity between the left motor cortex and prefrontal cortex is associated with the severity of dysfunction of the descending pain modulatory system in fibromyalgia

INTRODUCTION

The association between descending pain modulatory system (DPMS) dysfunction and fibromyalgia has been previously described, but more studies are required on its relationship with aberrant functional connectivity (FC) between the motor and prefrontal cortices.

OBJECTIVES

The objective of this cross-sectional observational study was to compare the intra- and interhemispheric FC between the bilateral motor and prefrontal cortices in women with fibromyalgia, comparing responders and nonresponders to the conditioned pain modulation (CPM) test.

METHODS

A cross-sectional sample of 37 women (23 responders and 14 nonresponders to the CPM test) with fibromyalgia diagnosed according to the American College of Rheumatology criteria underwent a standardized clinical assessment and an FC analysis using functional near-infrared spectroscopy. DPMS function was inferred through responses to the CPM test, which were induced by hand immersion in cold water (0-1°C). A multivariate analysis of covariance for main effects between responders and nonresponders was conducted using the diagnosis of multiple psychiatric disorders and the use of opioid and nonopioid analgesics as covariates. In addition, we analyzed the interaction between the CPM test response and the presence of multiple psychiatric diagnoses.

RESULTS

Nonresponders showed increased FC between the left motor cortex (lMC) and the left prefrontal cortex (lPFC) (t = -2.476, p = 0.01) and right prefrontal cortex (rPFC) (t = -2.363, p = 0.02), even when both were considered as covariates in the regression analysis (lMC-lPFC: β = -0.127, t = -2.425, p = 0.021; lMC-rPFC: β = -0.122, t = -2.222, p = 0.033). Regarding main effects, a significant difference was only observed for lMC-lPFC (p = 0.035). A significant interaction was observed between the psychiatric disorders and nonresponse to the CPM test in lMC-lPFC (β = -0.222, t = -2.275, p = 0.03) and lMC-rPFC (β = -0.211, t = -2.2, p = 0.035). Additionally, a significant interaction was observed between the CPM test and FC in these two region-of-interest combinations, despite the psychiatric diagnoses (lMC-lPFC: β = -0.516, t = -2.447, p = 0.02; lMC-rPFC: β = -0.582, t = -2.805, p = 0.008).

CONCLUSIONS

Higher FC between the lMC and the bilateral PFC may be a neural marker of DPMS dysfunction in women with fibromyalgia, although its interplay with psychiatric diagnoses also seems to influence this association.

Questionnaire-based somatosensory profiling in breast cancer survivors: are we there yet? Associations between questionnaires and quantitative sensory testing

PURPOSE

Pain and sensory disturbances are common side effects of breast cancer treatment. Differential somatosensory functioning may reflect distinct pathophysiological backgrounds and therapeutic needs. Aim was to examine whether questionnaires evaluating signs and symptoms related to somatosensory functioning correlate sufficiently with quantitative sensory testing (QST) in breast cancer survivors to warrant consideration for somatosensory profiling in clinical practice.

METHODS

One year after breast cancer surgery, 147 women underwent QST and completed following questionnaires: Douleur Neuropathique en 4 questions (DN4), Central Sensitization Inventory, Margolis Pain Diagram and Visual Analog Scales (VAS). Associations between the questionnaires and QST were evaluated using Spearman correlation coefficients (rs).

RESULTS

Significant but weak (rs < 0.30) correlations were found between total DN4 score and QST results at the inner upper arm for detection of sharp stimuli (rs = 0.227), cold stimuli (rs = -0.186), and painful heat stimuli (rs = 0.179), as well as between QST evaluating conditioned pain modulation and the Margolis Pain Diagram on one hand (rs = 0.176) and minimum-maximum pain intensity differences (VAS) on the other (rs = -0.170).

CONCLUSION

Questionnaires evaluating signs and symptoms related to somatosensory functioning are insufficient for somatosensory profiling. Although somatosensory profiling may be valuable in a mechanism-based management, more research on the most appropriate clinical tools is needed.IMPLICATIONS FOR REHABILITATIONClinicians should be able to recognize that patients with persistent pain or sensory disturbances following breast cancer surgery may have a component of altered somatosensory processing as a significant contributor to their complaint in order to address it appropriately.Somatosensory profiling has yet to be implemented into clinical practice.No evidence-based recommendations can be made on the use of self-reported questionnaires to assess somatosensory processing in a breast cancer population based on the findings of this study.It is suggested to combine information on how individuals process and experience somatosensory stimulation with information from the patient interview or questionnaires to consider which biological, psychological and/or social factors may drive or sustain these neurophysiological processes.

The Benefits of a Therapeutic Exercise and Educational Intervention Program on Central Sensitization Symptoms and Pain-Related Fear Avoidance in Breast Cancer Survivors

BACKGROUND

Central sensitization symptoms and pain-related fear avoidance are two common problems in breast cancer survivors. Non-pharmacologic interventions such as therapeutic exercise and patient education can be effective in this population.

AIMS

This study aimed to: (1) analyze the benefits of a therapeutic exercise and educational program on central sensitization symptoms and pain-related fear avoidance in breast cancer survivors, and (2) explore the association between pain-related fear avoidance and central sensitization symptoms.

DESIGN

A single group pre-post intervention study was conducted.

METHODS

Patients were recruited from the service of Medical Oncology of the University Clinical Hospital Virgen de la Victoria, in Málaga (Spain). The intervention consisted of a therapeutic exercise and educational program that lasted 12 weeks, twice a week, for 1 hour. Two instruments were used: the Spanish version of the Central Sensitization Inventory and the Spanish Fear Avoidance Components Scale.

RESULTS

A total of 82 breast cancer survivors participated in the study. Pre-post change on Central Sensitization Inventory was statistically significant (p = .007). There was a trend towards a significant difference for the Spanish Fear Avoidance Components Scale (p = .062). There was a statistically significant correlation between pain-related fear avoidance and central sensitization symptoms (r = 0.536, p < .001).

CONCLUSIONS

The current study has provided preliminary evidence on the benefits of this intervention in pain-related fear avoidance and central sensitization symptoms in breast cancer survivors. The Spanish version of the Central Sensitization Inventory and the Spanish Fear Avoidance Components Scale demonstrated responsiveness to change.

Effect of central sensitization on dizziness-related symptoms of persistent postural-perceptual dizziness

Background

Persistent postural-perceptual dizziness (PPPD) is a chronic functional dizziness symptom triggered by psychological stress, but its pathophysiology is unknown. Central sensitization is considered the cause of functional diseases, such as medically unexplained symptoms, and is a psychosocially affected condition. However, the association between dizziness symptoms in PPPD and central sensitization remains unclear. Thus, we conducted a cross-sectional study on the relation between dizziness symptoms and central sensitization in PPPD.

Methods

We recruited 61 outpatients with dizziness who met the PPPD diagnostic criteria. In addition to the evaluation of dizziness symptoms using the Dizziness Handicap Inventory, the participants were evaluated using the Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index, and Central Sensitization Inventory (CSI). A CSI score of 40 or higher was defined as central sensitization syndrome (CSS), and the severity of each condition in CSS and non-CSS participants was compared. We also evaluated the association between dizziness symptoms and central sensitization and coexisting symptoms using linear multiple regression analysis.

Results

We analyzed the data of 50 valid responses (valid response rate of 82.0 percent). Compared with the non-CSS group, the CSS group had a higher degree of disability owing to dizziness and a higher rate of complications of anxiety and depression. The regression analysis results showed that the severity of central sensitization was a related factor that could enhance the dizziness symptoms of PPPD.

Conclusions

Central sensitization may affect the dizziness symptoms of PPPD as an exacerbating factor.

Signs Indicative of Central Sensitization Are Present but Not Associated with the Central Sensitization Inventory in Patients with Focal Nerve Injury

Objective: Carpal tunnel syndrome (CTS) is the most common focal nerve injury. People with CTS may show alterations in central processing of nociceptive information. It remains unclear whether the central sensitization inventory (CSI) is capable of detecting such altered central pain processing. Methods: Thirty healthy volunteers were matched with 30 people with unilateral CTS from the orthopaedic waitlist. Changes to central pain processing were established through psychophysical sensory testing (bilateral pressure pain thresholds (PPT), conditioned pain modulation, temporal summation) and pain distribution on body charts. Patients also completed pain severity and function questionnaires, psychological questionnaires and the CSI. Results: Compared to healthy volunteers, patients with CTS have lower PPTs over the carpal tunnel bilaterally (t = −4.06, p < 0.0001 ipsilateral and t = −4.58, p < 0.0001 contralateral) and reduced conditioned pain modulation efficacy (t = −7.31, p <0.0001) but no differences in temporal summation (t = 0.52, p = 0.60). The CSI was not associated with psychophysical measures or pain distributions indicative of altered central pain processing. However, there was a correlation of the CSI with the Beck Depression Inventory (r = 0.426; p = 0.019). Conclusion: Patients with CTS show signs of altered central pain mechanisms. The CSI seems unsuitable to detect changes in central pain processing but is rather associated with psychological factors in people with focal nerve injuries.

Use of the painDETECT to discriminate musculoskeletal pain phenotypes

Background

Musculoskeletal pain patients present similar pain characteristics regardless of the clinical diagnosis. PainDETECT questionnaire is useful for screening neuropathic-like symptoms in many musculoskeletal conditions. However, no previous studies compared pain phenotypes of patients with musculoskeletal pain using the painDETECT. Therefore, the current study aimed to compare the pain characteristics of patients with musculoskeletal pain classified according to the painDETECT as nociceptive pain, unclear, and neuropathic-like symptoms.

Methods

A cross-sectional study was conducted in 308 participants with musculoskeletal pain. Demographic and clinical characteristics of the participants were examined. Neuropathic-like symptoms, pain intensity, pain area, Central Sensitization-related sign and symptoms, functional limitation, and conditioned pain modulation were assessed in patients with musculoskeletal pain. Independent one-way analysis of variance (ANOVA) was used to test for between-group differences for the outcome measures with continuous variables and Pearson chi-square test verified between-group differences on the efficiency of the conditioned pain modulation.

Results

Participants had a mean age of 52.21 (±15.01) years old and 220 (71.42%) were females. One hundred seventy-three (56.16%) participants present nociceptive pain, 69 (22.40%) unclear, and 66 (21.42%) neuropathic-like symptoms. A one-way ANOVA showed differences for the pain intensity [F (2,305) = 20.097; p < .001], pain area [F (2,305) = 28.525; p < .001], Central Sensitization-related sign and symptoms [F (2,305) = 54.186; p < .001], and functional limitation [F (2,256) = 8.061; p < .001]. However, conditioned pain modulation was similarly impaired among the three groups (X² = 0.333, p = 0.847).

Conclusion

Patients with neuropathic-like symptoms revealed unfavorable pain characteristics compared to their counterparts, including pain intensity, generalized pain, Central Sensitization-related sign and symptoms, and functional limitation.

Noninvasive intracranial pressure monitoring in women with migraine

This cross-sectional study aimed to compare the waveform morphology through noninvasive intracranial pressure (ICP-NI) measurement between patients with migraine and controls, and to analyze the association with clinical variables. Twenty-nine women with migraine, age 32.4 (11.2) years and headache frequency of 12.6 (7.5) days per month and twenty-nine women without headache, age 32.1 (9.0) years, were evaluated. Pain intensity, migraine disability, allodynia, pain catastrophizing, central sensitization and depression were evaluated. The ICP-NI monitoring was performed by a valid method consisting of an extracranial deformation sensor positioned in the patients’ scalp, which allowed registration of intracranial pressure waveforms. Heart rate and blood pressure measurements were simultaneously recorded during 20 min in the supine position. The analyzed parameter was the P2/P1 ratio based on mean pulse per minute which P1 represents the percussion wave related to the arterial blood pression maximum and P2 the tidal wave, middle point between the P1 maximum and the dicrotic notch. There was no between-groups difference in the P2/P1 ratio (mean difference: 0.04, IC95%: -0.07 to 0.16, p = 0.352, F (1,1) = 0.881) adjusted by body mass index covariable. The Multiple Linear Regression showed non-statistical significance [F (5,44) = 1.104; p = 0.372; R² = 0.11)] between the P2/P1 ratio and body mass index, presence of migraine, central sensitization, pain catastrophizing and depression. We found no correlation (p > 0.05) between P2/P1 ratio and migraine frequency, migraine onset, pain intensity, pain intensity at day of examination, disability, allodynia. Migraine patients did not present alterations in the waveform morphology through ICP-NI compared to women without headache and no association with clinical variables was found.

Characteristics of clusters with contrasting relationships between central sensitization-related symptoms and pain

The central sensitization inventory (CSI) evaluates the central sensitization (CS)-related symptoms associated with increased pain sensitivity. However, the CSI includes items that are not directly related to pain. In this study, 146 patients with pain were classified into subgroups by k-means cluster analysis based on the short form of the central sensitization inventory (CSI9) and pain scores. In addition, inter-group and multiple comparisons were performed to examine the characteristics of each group. As a result of this study, there were three subgroups (clusters 1, 2, and 3) in which the CSI9 and pain intensity were both low, moderate, and high, and one subgroup (cluster 4) in which only CSI9 was high and pain intensity was low. Two subgroups with high CSI9 scores but contrasting pain intensities (clusters 3 and 4) were extracted; the pattern of CS-related symptoms in these two groups was very similar, with no differences in most of the non-pain factors. It is necessary to consider these points when interpreting the clinical condition of a patient with pain when using the assessment of CS-related symptoms.

Measuring emotional preoperative stress by an app approach and its applicability to predict postoperative pain

BACKGROUND

The Brief Measure of Emotional Preoperative Stress (B-MEPS) was developed to evaluate the preoperative individual vulnerability to emotional stress. To obtain a refined version of B-MEPS suitable for an app approach, this study aimed: (i) to identify items with more discriminant properties; (ii) to classify the level of preoperative emotional stress based on cut-off points; (iii) to assess concurrent validity through correlation with the Central Sensitization Inventory (CSI) score; (iv) to confirm whether the refined version of B-MEPS is an adequate predictive measure for identification of patients prone to intense postoperative pain.

METHODS

We include 1016 patients who had undergone surgical procedures in a teaching hospital. The generalized partial credit model of item response theory and latent class model were employed, respectively, to reduce the number of items and to create cut-off points. We applied the CSI and assessed pain by Visual Analog Scale (0-10) and by the amount of postoperative morphine consumption.

RESULTS

The refined B-MEPS shows satisfactory reliability (Cronbach's alpha 0.79). Preoperative emotional stress, according to the cut-off points, is classified into categories: low, intermediate or high stress. The refined B-MEPS exhibited a linear association with the CSI scores (r2 = 0.53, p < 0.01). Patients with higher levels of emotional stress displayed a positive association with moderate to severe pain and greater morphine consumption.

CONCLUSION

The refined version of B-MEPS, along with an interface of easy applicability, assess emotional vulnerability at the bedside before surgery. This app may support studies focused on intervening with perioperative stress levels.

The Definition, Assessment, and Prevalence of (Human Assumed) Central Sensitisation in Patients with Chronic Low Back Pain: A Systematic Review

Central sensitisation is assumed to be one of the underlying mechanisms for chronic low back pain. Because central sensitisation is not directly assessable in humans, the term 'human assumed central sensitisation' (HACS) is suggested. The objectives were to investigate what definitions for HACS have been used, to evaluate the methods to assess HACS, to assess the validity of those methods, and to estimate the prevalence of HACS. Database search resulted in 34 included studies. Forty different definition references were used to define HACS. This review uncovered twenty quantitative methods to assess HACS, including four questionnaires and sixteen quantitative sensory testing measures. The prevalence of HACS in patients with chronic low back pain was estimated in three studies. The current systematic review highlights that multiple definitions, assessment methods, and prevalence estimates are stated in the literature regarding HACS in patients with chronic low back pain. Most of the assessment methods of HACS are not validated but have been tested for reliability and repeatability. Given the lack of a gold standard to assess HACS, an initial grading system is proposed to standardize clinical and research assessments of HACS in patients with a chronic low back.