Human Studies

This study evaluated the reliability and validity of a Japanese version of Pain Disability Index (PDI). Analyses were conducted on a 7-item version (PDI-J) and a 5-item (PDI-5-J version of the PDI). Using a web-based survey system, we recruited 300 individuals with chronic low back pain (lasting ≥3 months) and 300 individuals with chronic daily headache (lasting ≥15 days per month for 3 months) aged 20-64 years. Analyses revealed a one-factor with goodness-of-fit indices assessed by confirmatory factor analysis. For concurrent validity, we calculated Pearson's correlation coefficients among the PDI-J, PDI-5-J, Pain Disability Assessment Scale, Pain numerical rating scale, and revised version of Short-Form McGill Pain Questionnaire. Internal consistency was evaluated by Cronbach's α, and test-retest reliability was assessed with intraclass correlations (ICCs) in 100 of 600 participants a week after the first response. Both Japanese adaptations of the PDI demonstrated good concurrent validity and reliability (Cronbach's α was 0.89 for PDI-J in chronic low back pain or chronic daily headache, and 0.94 and 0.93 for PDI-5-J in chronic low back pain and chronic daily headache, respectively). The PDI-J and PDI-5-J showed were highly correlated (r = 0.98). ICCs were 0.67 and 0.59 for the PDI-J and 0.59 and 0.63 for the PDI-5-J in chronic low back pain and chronic daily headache, respectively. In conclusion, these two PDI versions can be potentially used for evaluating pain-related interference with daily activities among the Japanese general population.

Psychological acceptance has emerged as an important construct to explain low psychological distress in different clinical samples. However, the incremental validity of psychological acceptance to explain adjustment to medical conditions over other related and well-established constructs, such as coping, is relatively unclear. This study explored whether psychological acceptance significantly contributes to explain adjustment above and beyond coping in females with endometriosis. A total of 169 females ( = 34.95 years; = 6.07 years) with endometriosis and pain symptoms completed the Acceptance and Action Questionnaire-II, the Brief-COPE, the Hospital Anxiety and Depression Scale, the Psychological Wellbeing Scale, and the Endometriosis Health Profile-5. We conducted Hierarchical Regression Analyses to determine the contribution of psychological acceptance to explaining adjustment. The results showed that the contribution of psychological acceptance ranged from 11 to 20% when controlling for coping, while coping explained from 1 to 8% when the model was reversed. The findings suggest that psychological acceptance is a more useful construct than coping for predicting PD and other psychological outcomes in females with endometriosis.

The purpose of this study is to assess the efficacy of transcranial direct current stimulation (tDCS) in patients with treatment-refractory trigeminal neuralgia (TN) and examine the utility of neuroimaging methods in identifying markers of such efficacy. Six patients with classical TN refractory to maximal medical treatment, underwent tDCS (three cases inhibitory/cathodic and three cases excitatory/anodic stimulation). All patients underwent pre- and posttreatment functional magnetic resonance imaging (fMRI) during block-design tasks (i.e., Pain, Pain + tDCS, tDCS) as well as single-shell diffusion MRI (dMRI) acquisition. The precise locations of tDCS electrodes were identified by neuronavigation. Five therapeutic tDCS sessions were carried out for each patient with either anodic or cathodic applications. The Numeric Rating Scale of pain (NRS) and the Headache Disability Index (HDI) were used to score the subjective efficacy of treatment. Altered activity of regional sites was identified by fMRI and associated changes in the spinothalamocortical sensory tract (STCT) were measured by the dMRI indices of fractional anisotropy (FA) and mean diffusivity (MD). Fiber counts of the bilateral trigeminal root entry zone (REZ) were performed as an added measure of fiber loss or recovery. All patients experienced a significant reduction in pain scores with a substantial decline in HDI ( value < 0.01). Following a course of anodic tDCS, the ipsilateral caudate, globus pallidus, somatosensory cortex, and the contralateral globus pallidus showed a significantly attenuated activation whereas cathodic tDCS treatment resulted in attenuation of the thalamus and globus pallidus bilaterally, and the somatosensory cortex and anterior cingulate gyrus contralaterally. dMRI analysis identified a substantial increase (>50%) in the number of contralateral sensory fibers in the STCT with either anodic or cathodic tDCS treatment in four of the six patients. A significant reduction in FA (>40%) was observed in the ipsilateral REZ in the posttreatment phase in five of the six patients. Preliminary evidence suggests that navigated tDCS presents a promising method for alleviating the pain of TN. Different patterns of activation manifested by anodic and cathodic stimulation require further elaboration to understand their implication. Activation and attenuation of responses at various sites may provide further avenues for condition treatment.

Percutaneous cervical cordotomy (PCC), which selectively interrupts ascending nociceptive pathways in the spinal cord, can mitigate severe refractory cancer pain. It has an impressive success rate, with most patients emerging pain-free. Aside from the usual complications of neurosurgical procedures, the risks of PCC include development of contralateral pain, which is less understood.

Acid-sensing ion channels (ASICs) play a critical role in nociception in human sensory neurons. Four genes ( and ) encoding multiple subunits through alternative splicing have been identified in humans. Real time-PCR experiments showed strong expression of three subunits , , and in human dorsal root ganglia; however, their detailed expression pattern in different neuronal populations has not been investigated yet. In the current study, using an hybridization approach (RNAscope), we examined the presence of , , and mRNA in three subpopulations of human dorsal root ganglia neurons. Our results revealed that and were present in the vast majority of dorsal root ganglia neurons, while was only expressed in less than half of dorsal root ganglia neurons. The distribution pattern of the three subunits was the same across the three populations of dorsal root ganglia neurons examined, including neurons expressing the REarranged during Transfection (RET) receptor tyrosine kinase, calcitonin gene-related peptide, and a subpopulation of nociceptors expressing Transient Receptor Potential Cation Channel Subfamily V Member 1. These results strongly contrast the expression pattern of in mice since our previous study demonstrated differential distribution of among the various subpopulation of dorsal root ganglia neurons. Given the distinct acid-sensitivity and activity dynamics among different ASIC channels, the expression differences between human and rodents should be taken under consideration when evaluating the translational potential and efficiency of drugs targeting ASICs in rodent studies.

Data from 255 Thais with chronic pain were collected at Chiang Mai Medical School Hospital. After the patients self-rated their level of pain, a smartphone camera was used to capture faces for 10 s at a one-meter distance. For those unable to self-rate, a video recording was taken immediately after the move that causes the pain. The trained assistant rated each video clip for the pain assessment in advanced dementia (PAINAD). The pain was classified into three levels: mild, moderate, and severe. OpenFace was used to convert the video clips into 18 facial action units (FAUs). Five classification models were used, including logistic regression, multilayer perception, naïve Bayes, decision tree, k-nearest neighbors (KNN), and support vector machine (SVM). Out of the models that only used FAU described in the literature (FAU 4, 6, 7, 9, 10, 25, 26, 27, and 45), multilayer perception is the most accurate, at 50%. The SVM model using FAU 1, 2, 4, 7, 9, 10, 12, 20, 25, and 45, and gender had the best accuracy of 58% among the machine learning selection features. Our open-source experiment for automatically analyzing video clips for FAUs is not robust for classifying pain in the elderly. The consensus method to transform facial recognition algorithm values comparable to the human ratings, and international good practice for reciprocal sharing of data may improve the accuracy and feasibility of the machine learning's facial pain rater.

Magnetic Resonance Image-guided High Intensity Focused Ultrasound (MR-HIFU) is a non-invasive treatment option for palliative patients with painful bone metastases. Early evidence suggests that MR-HIFU is associated with similar overall treatment response, but more rapid pain palliation compared to external beam radiotherapy (EBRT). This modelling study aimed to assess the cost-effectiveness of MR-HIFU as an alternative treatment option for painful bone metastases from the perspective of the German Statutory Health Insurance (SHI).