Pain Empathy and Its Association with the Clinical Pain in Knee Osteoarthritis Patients

Pain catastrophizing in rheumatic diseases: prevalence, origin, and implications

Pain is a crucial factor in rheumatic disorders, and reducing it is a primary goal of successful treatment. Adaptive pain-coping strategies can enhance this improvement, but maladaptive approaches such as pain catastrophizing may worsen overall patient well-being. This narrative review aims to provide a concise overview of the existing knowledge on pain catastrophizing in the most prevalent specific rheumatic disorders. The objective of this study was to improve understanding of this phenomenon and its implications, as well as to pinpoint potential directions for future research. We conducted searches in the MEDLINE/PubMed, SCOPUS, and DOAJ bibliography databases to identify articles related to pain catastrophizing in rheumatoid arthritis, psoriatic arthritis, axial spondylarthritis, systemic sclerosis, systemic lupus erythematosus, Sjögren's syndrome, juvenile idiopathic arthritis, and osteoarthritis (non-surgical treatment). Data extraction was performed on November 1, 2023. The investigators screened the identified articles to determine their relevance and whether they met the inclusion criteria. Following a bibliography search, which was further expanded by screening of citations and references, we included 156 records in the current review. The full-text analysis centred on pain catastrophizing, encompassing its prevalence, pathogenesis, and impact. The review established the role of catastrophizing in amplifying pain and diminishing various aspects of general well-being. Also, potential treatment approaches were discussed and summarised across the examined disorders. Pain catastrophizing is as a significant factor in rheumatic disorders. Its impact warrants further exploration through prospective controlled trials to enhance global patient outcomes.

Limbic system plasticity after electroacupuncture intervention in knee osteoarthritis rats

Knee osteoarthritis (KOA) is characterized by debilitating pain. Electroacupuncture (EA), a traditional Chinese medical therapy, has shown promise in KOA pain management. This study investigated the therapeutic potential of EA in KOA and its impact on limbic system neural plasticity. Sixteen rats were randomly assigned into two groups: EA group and sham-EA group. EA or sham-EA interventions were administered at acupoints ST32 (Futu) and ST36 (Zusanli) for three weeks. Post-intervention resting-state fMRI was scanned, assessing parameters including Amplitude of low frequency fluctuations (ALFF), regional homogeneity (ReHo), functional connectivity (FC) and nodal characterizations of network within limbic system. The results showed that EA was strategically directed towards the limbic system, resulting in discernible alterations in neural activity, FC, and network characteristics. Our findings demonstrate that EA had a significant impact on the limbic system neural plasticity in rats with KOA, presenting a novel nonpharmacological approach for KOA treatment.

Relationship between individual differences in pain empathy and task- and resting-state EEG

Pain empathy is a complex form of psychological inference that enables us to understand how others feel in the context of pain. Since pain empathy may be grounded in our own pain experiences, it exhibits huge inter-individual variability. However, the neural mechanisms behind the individual differences in pain empathy and its association with pain perception are still poorly understood. In this study, we aimed to characterize brain mechanisms associated with individual differences in pain empathy in adult participants (n = 24). The 32-channel electroencephalography (EEG) was recorded at rest and during a pain empathy task, and participants viewed static visual stimuli of the limbs submitted to painful and nonpainful stimulation to solicit empathy. The pain sensitivity of each participant was measured using a series of direct current stimulations. In our results, the N2 of Fz and the LPP of P3 and P4 were affected by painful pictures. We found that both delta and alpha bands in the frontal and parietal cortex were involved in the regulation of pain empathy. For the delta band, a close relationship was found between average power, either in the resting or task state, and individual differences in pain empathy. It suggested that the spectral power in Fz's delta band may reflect subjective pain empathy across individuals. For the alpha band, the functional connectivity between Fz and P3 under painful picture stimulation was correlated to individuals' pain sensitivity. It indicated that the alpha band may reflect individual differences in pain sensitivity and be involved in pain empathy processing. Our results suggested the distinct role of the delta and alpha bands of EEG signals in pain empathy processing and may deepen our understanding of the neural mechanisms underpinning pain empathy.

Validation of the Chinese version of the Brief Pain Inventory in patients with knee osteoarthritis

BACKGROUND

Knee osteoarthritis (KOA) primarily presents with symptoms of pain and compromised functionality. Pain is a subjective manifestation that necessitates the employment of reliable evaluation tools for practical assessment, thereby enabling the formulation of appropriate interventional strategies. The Brief Pain Inventory (BPI) is a widely utilized questionnaire for evaluating the status of chronic pain. The purpose of the present study is to translate the short form of BPI into Chinese version (BPI-CV) and conduct cross-cultural adaptation to evaluate the psychometric characteristics of BPI-CV in KOA patients.

METHODS

BPI-CV was translated and cross-culturally adapted according to internationally recognized guidelines. A cohort comprising 150 patients diagnosed with KOA successfully completed the demographic questionnaire, BPI-CV, Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the EuroQoL Group's five-dimension questionnaire (EQ-5D). Internal consistency and test-retest analysis were used to evaluate the reliability. The internal consistency of the scale items was evaluated by calculating the Cronbach's α value (> 0.7). We chose to employ two scales commonly used in the evaluation of KOA patients: the disease-specific WOMAC scale and the universal EQ-5D scale. Construct validity was determined through Pearson correlation analysis, comparing BPI scores with those obtained from the WOMAC and EQ-5D scales. Exploratory factor analysis was used to structural validity.

RESULTS

The BPI-CV was well accepted with no ceiling or floor effect. Cronbach's α for assessing internal consistency was 0.894. Test-retest reliability was excellent with an ICC of 0.852 (95%CI 0.785-0.905). The BPI-CV showed moderate to strong correlations with the pain dimension (r = 0.496-0.860) and the functional interference dimension (r = 0.517-0.712) of the WOMAC and the EQ-5D (r = 0.527-0.743). Three factors resulted using exploratory factor analysis: pain severity, activity interference, and emotional interference, accounting for 79.0% of the total variance. Standard error of measurement was 0.539.

CONCLUSION

BPI-CV has good feasibility, reliability, and validity. It can be recommended for KOA patients in mainland China.