To Combine or Not to Combine Physical Therapy With tDCS for Stroke With Shoulder Pain? Analysis From a Combination Randomized Clinical Trial for Rehabilitation of Painful Shoulder in Stroke.

Purpose: Transcranial Direct Current Stimulation (tDCS) is an intervention that seems to be an ideal tool to enhance the effects of rehabilitation therapies given it facilitates generation of plasticity in the stimulated brain area. In stroke this strategy has been highly utilized; however, the results have been mixed. In this trial we have evaluated the analgesic and functional effects of Transcranial Direct Current Stimulation (tDCS) combined with physiotherapy in stroke survivors with shoulder pain. Methods: Twenty-six stroke surviving adults with shoulder pain received 10 sessions of passive mobilization and performed upper limb exercises using a cycle ergometer, combined with active or sham tDCS. The intensity of pain in the hemiplegic shoulder was measured using the Visual Analog Scale (VAS); secondary outcomes were the level of motor impairment, handgrip strength, range of motion, motor function of the upper limbs, and quality of life (QOL) assessed before and after 10 sessions and 1 month after the end of the treatment. Results: A clinically important pain reduction (3 points) was found in both groups and was maintained at follow-up; there was no significant difference between groups (p = 0.3). Similarly, the shoulder range of motion improved, motor function and quality of life improved showed no significant differences between groups. One result that needs to be underscored is that both groups had a significant effect size toward improvement in all of these outcomes. Conclusions: We discuss in this study that tDCS is not a useful combination strategy when the physical therapy has a large effect by itself and we also review other negative trials of combined therapy under this framework of ceiling effect of the main physical therapy. Trial registry: Trial registration: Brazilian Registry of Clinical Trials, RBR-8F5MNY (http://www.ensaiosclinicos.gov.br/rg/RBR-8f5mny/). Registered on June 2, 2017. Beginning of the recruitment of the volunteers: august, 2017.

Repetitive transcranial magnetic stimulation increases the corticospinal inhibition and the brain-derived neurotrophic factor in chronic myofascial pain syndrome: an explanatory double-blinded, randomized, sham-controlled trial.

UNLABELLED: Chronic myofascial pain syndrome has been related to defective descending inhibitory systems. Twenty-four females aged 19 to 65 years with chronic myofascial pain syndrome were randomized to receive 10 sessions of repetitive transcranial magnetic stimulation (rTMS) (n = 12) at 10 Hz or a sham intervention (n = 12). We tested if pain (quantitative sensory testing), descending inhibitory systems (conditioned pain modulation [quantitative sensory testing + conditioned pain modulation]), cortical excitability (TMS parameters), and the brain-derived neurotrophic factor (BDNF) would be modified. There was a significant interaction (time vs group) regarding the main outcomes of the pain scores as indexed by the visual analog scale on pain (analysis of variance, P < .01). Post hoc analysis showed that compared with placebo-sham, the treatment reduced daily pain scores by -30.21% (95% confidence interval = -39.23 to -21.20) and analgesic use by -44.56 (-57.46 to -31.67). Compared to sham, rTMS enhanced the corticospinal inhibitory system (41.74% reduction in quantitative sensory testing + conditioned pain modulation, P < .05), reduced the intracortical facilitation in 23.94% (P = .03), increased the motor evoked potential in 52.02% (P = .02), and presented 12.38 ng/mL higher serum BDNF (95% confidence interval = 2.32-22.38). No adverse events were observed. rTMS analgesic effects in chronic myofascial pain syndrome were mediated by top-down regulation mechanisms, enhancing the corticospinal inhibitory system possibly via BDNF secretion modulation. PERSPECTIVE: High-frequency rTMS analgesic effects were mediated by top-down regulation mechanisms enhancing the corticospinal inhibitory, and this effect involved an increase in BDNF secretion.

Association of anxiety with intracortical inhibition and descending pain modulation in chronic myofascial pain syndrome.

BACKGROUND: This study aimed to answer three questions related to chronic myofascial pain syndrome (MPS): 1) Is the motor cortex excitability, as assessed by transcranial magnetic stimulation parameters (TMS), related to state-trait anxiety? 2) Does anxiety modulate corticospinal excitability changes after evoked pain by Quantitative Sensory Testing (QST)? 3) Does the state-trait anxiety predict the response to pain evoked by QST if simultaneously receiving a heterotopic stimulus [Conditional Pain Modulation (CPM)]? We included females with chronic MPS (n = 47) and healthy controls (n = 11), aged 19 to 65 years. Motor cortex excitability was assessed by TMS, and anxiety was assessed based on the State-Trait Anxiety Inventory. The disability related to pain (DRP) was assessed by the Profile of Chronic Pain scale for the Brazilian population (B:PCP:S), and the psychophysical pain measurements were measured by the QST and CPM. RESULTS: In patients, trait-anxiety was positively correlated to intracortical facilitation (ICF) at baseline and after QST evoked pain (ß = 0.05 and ß = 0.04, respectively) and negatively correlated to the cortical silent period (CSP) (ß = -1.17 and ß = -1.23, respectively) (P <0.05 for all comparisons). After QST evoked pain, the DRP was positively correlated to ICF (ß = 0.02) (P < 0.05). Pain scores during CPM were positively correlated with trait-anxiety when it was concurrently with high DRP (ß = 0.39; P = 0.02). Controls' cortical excitability remained unchanged after QST. CONCLUSIONS: These findings suggest that, in chronic MPS, the imbalance between excitatory and inhibitory descending systems of the corticospinal tract is associated with higher trait-anxiety concurrent with higher DRP.

The relationship between cortical excitability and pain catastrophizing in myofascial pain.

UNLABELLED: Pain catastrophizing regularly occurs in chronic pain patients. It has been suggested that pain catastrophizing is a stable, person-based construct. These findings highlight the importance of investigating catastrophizing in conceptualizing specific approaches for pain management. One important area of investigation is the mechanism underlying pain catastrophizing. Therefore, this study explored the relationship between a neurophysiological marker of cortical excitability, as assessed by transcranial magnetic stimulation, and catastrophizing, as assessed by the Brazilian Portuguese Pain Catastrophizing Scale, in patients with chronic myofascial pain syndrome. The Pain Catastrophizing Scale is a robust questionnaire used to examine rumination, magnification and helplessness that are associated with the experience of pain. We include 24 women with myofascial pain syndrome. The Brazilian Portuguese Pain Catastrophizing Scale and cortical excitability were assessed. Functional and behavioral aspects of pain were evaluated with a version of the Profile of Chronic Pain scale and by multiple pain measurements (eg, pain intensity, pressure pain threshold, and other quantitative sensory measurements). Intracortical facilitation was found to be significantly associated with pain catastrophizing (ß = .63, P = .001). Our results did not suggest that these findings were influenced by other factors, such as age or medication use. Furthermore, short intracortical inhibition showed a significant association with pressure pain threshold (ß = .44, P = .04). This study elaborates on previous findings indicating a relationship between cortical excitability and catastrophizing. The present findings suggest that glutamatergic activity may be associated with mechanisms underlying pain catastrophizing; thus, the results highlight the need to further investigate the neurophysiological mechanisms associated with pain and catastrophizing. PERSPECTIVE: This study highlights the relationship between cortical excitability and catastrophizing. Cortical measures may illuminate how catastrophizing responses may be related to neurophysiological mechanisms associated with chronic pain.

Cross-cultural adaptation and validation of the profile of chronic pain: screen for a Brazilian population.

OBJECTIVE: To translate the original English version of the Profile of Chronic Pain: Screen (PCP:S) into Brazilian Portuguese and examine basic psychometric properties of the translated version. We investigated ceiling and floor effects, internal consistency, factor structure, convergent validity, and the ability of the Brazilian PCP:S (B-PCP:S) to discriminate persons with pain who were either employed or not working, or in treatment or not in treatment. METHODS: The Brazilian Portuguese version of the Profile of Chronic Pain: Screen (B-PCP:S) was administered to a sample of 414 adults (men = 67). Pain catastrophizing was also assessed. Subsamples with special conditions (working despite pain [N = 116] vs not working due to pain [N = 122], and not receiving treatment for pain [N = 119] vs receiving treatment [N = 119]) were identified to investigate the discriminative properties of B-PCP:S. RESULTS: For the B-PCP:S, Cronbach's α values were 0.76 (severity), 0.88 (interference), and 0.87 (emotional burden). Confirmatory factor analysis supported the original, English language three-factor structure, with the comparative fit index = 0.93, root mean square error of approximation = 0.075, and normed fit index = 0.93. Significant correlations were found between pain intensity, pain interference, and emotional burden, and a criterion measure of catastrophizing (correlation coefficients ranged from 0.48 to 0.66, P < 0.01). B-PCP:S scores (severity, interference, and emotional burden) were higher in subjects under a doctor's care for pain and in those not working due to pain. CONCLUSION: This B-PCP:S version was found to be a reliable instrument, with basic evidence of validity for the evaluation of pain severity, interference, and emotional burden in Brazilian Portuguese adults. The profile of B-PCP:S scores was similar to that observed in the original version.

Cross-cultural adaptation and validation of the Brazilian Portuguese version of the pain catastrophizing scale.

OBJECTIVE: Catastrophizing is a maladaptive response to pain and is one of the factors that contribute to the chronicity of some pain syndromes. The Pain Catastrophizing Scale (PCS) assists both treatment planning and outcome assessment. Its use is limited in Portuguese-speaking countries because of the lack of a validated translated version. We conducted the validation of the Brazilian Portuguese (BP)-PCS and explored its psychometric properties. This study reports the internal consistency, factor structure, and its capability to discriminate pain reported by patients with specific chronic pain conditions. METHODS: Three hundred eighty-four patients, 317 women (82.55%), aged 18-79 years with chronic nonmalignant pain attending an outpatient multidisciplinary pain center participated in this cross-sectional study. The instruments were the BP-PCS, pain intensity, pain interference in functional capacity, and a sociodemographic questionnaire. One subsample with chronic tensional headache (CTH) according to the criteria of the International Headache Society (N = 19), and another with a diagnosis of fibromyalgia according to the American College of Rheumatology criteria (N = 50) were selected to assess the discriminative properties of BP-PCS. RESULTS: We observed good internal consistency (Cronbach's α values of 0.91 for the total BP-PCS, and 0.93 [helplessness], 0.88 [magnification], and 0.86 [rumination] for the respective subdomains). The item-total correlation coefficients ranged from 0.91 to 0.94. Confirmatory factor analysis (CFA) supported the three factors structure, with the comparative fit index = 0.98, root mean square error of approximation = 0.09, and normed fit index = 0.98. Significant correlations were found for pain intensity, pain interference, and patient's mood (correlation coefficients ranged from 0.48 to 0.66, P < 0.01). No significant gender difference was observed for BP-PCS scores. When comparing scores of BP-PCS scale and subscales between the selected control group (patients with pain scores on visual analog scale equal or lower than 40 mm in the most part of the day in the last 6 months) and patients with fibromyalgia or CTH, we observed lower scores for the former group. CONCLUSION: Our findings support the validity and reliability of the BP-PCS. The scale showed satisfactory psychometric properties. CFA provides support for the three-factor structure reported in previous studies. This factor structure presented good discriminative properties to identify catastrophizers who present with mild chronic pain, fibromyalgia, and CTH. The BP-PCS is a valuable tool for use in scientific studies and in the clinical setting in patients with chronic pain in Brazilian Portuguese-speaking countries.

Validation of a Brazilian quantitative sensory testing (QST) device for the diagnosis of small fiber neuropathies / Validação de um aparelho brasileiro de teste de quantificação sensitiva brasileiro para o diagnóstico de neuropatia de fibras finas

Quantitative sensory testing (QST) is defined as the determination of thresholds for sensory perception under controlled stimulus. Our aim was to validate a new QST device for Brazilian sample. In 20 healthy adults, thermoalgesic thresholds were assessed using a QST prototype (Heat Pain Stimulator-1.1.10; Brazil). A 30 × 30 mm² thermode with a 1°C/s stimulus change rate were applied. Thresholds of three consecutive stimuli were averaged in two different sessions separated by at least two weeks. Additionally long thermal heat pain stimulus was performed. To evaluate the consistency of our method we also analyzed 11 patients with small fiber neuropathy. Results showed good reproducibility of thermal perception thresholds in normal individuals and plausible abnormal thresholds in patients. We conclude that our QST device is reliable when analyzing the nociceptive pathway in controls and patients.

Teste de quantificação sensitiva (TQS) significa determinação de limiares de percepção sensitiva frente a um estímulo de intensidade controlada. Nosso objetivo foi validar um novo equipamento de TQS adaptado à população brasileira. Em 20 adultos saudáveis, limiares termoalgésicos foram avaliados, utilizando um aparelho protótipo do TQS (Heat Pain Stimulator-1.1.10; Brazil). Foi utilizado um termodo de 30 × 30 mm², com estímulo térmico de 1°C/s. A média dos limiares de três estímulos consecutivos foi obtida em duas sessões diferentes, separadas por pelo menos 2 semanas. Adicionalmente, foram aplicados estímulos térmicos dolorosos de longa duração. Para avaliar a consistência do nosso método, foram também analisados 11 pacientes com neuropatia de fibras finas. Os resultados mostraram boa reprodutibilidade dos limiares de percepção nos indivíduos saudáveis, assim como limiares anormais nos pacientes. Em conclusão, nosso aparelho de TQS apresentou boa confiabilidade ao analisar a via nociceptiva de controles e pacientes.

Validation of a Brazilian quantitative sensory testing (QST) device for the diagnosis of small fiber neuropathies.

Quantitative sensory testing (QST) is defined as the determination of thresholds for sensory perception under controlled stimulus. Our aim was to validate a new QST device for Brazilian sample. In 20 healthy adults, thermoalgesic thresholds were assessed using a QST prototype (Heat Pain Stimulator-1.1.10; Brazil). A 30 × 30 mm(2) thermode with a 1°C/s stimulus change rate were applied. Thresholds of three consecutive stimuli were averaged in two different sessions separated by at least two weeks. Additionally long thermal heat pain stimulus was performed. To evaluate the consistency of our method we also analyzed 11 patients with small fiber neuropathy. Results showed good reproducibility of thermal perception thresholds in normal individuals and plausible abnormal thresholds in patients. We conclude that our QST device is reliable when analyzing the nociceptive pathway in controls and patients.