Deficient Pain Modulation in Patients with Chronic Hemiplegic Shoulder Pain

Hemiplegic shoulder pain affects ipsilesional aiming movements after stroke: a cross-sectional study

BACKGROUND

Hemiplegic shoulder pain (HSP) is common after stroke. The pain perception may exacerbate changes in the motor behavior of the ipsi-lesional upper limb, contributing to the functional decline of an individual's motor performance.

OBJECTIVE

This study evaluates the influence of pain perception on the aiming movements performed with the ipsilesional upper limb in individuals with unilateral chronic stroke.

METHODS

A cross-sectional study was conducted with 41 participants divided into three groups: 1) stroke with contralesional shoulder pain ≥ 3 by the Visual Numerical Pain Scale (SPSG; n = 13); 2) stroke no shoulder pain (nSPSG; n = 14); and 3) healthy control (CTG; n = 14) matched by sex and age. Individuals with stroke were matched for the severity of sensorimotor impairment by the Fugl-Meyer upper limb subscale and the injured hemisphere side. Stroke groups performed aiming movements with the ipsilesional upper limb and the CTG with the corresponding limb using a pen tip on the sensitive surface of a digitizing tablet. Performance across groups was compared by one-way analysis of variance, considering the time since injury as a covariate. The planning and execution variables of the movement trajectory were analyzed, and the significance was set at 5%.

RESULTS

Trajectories of the SPSG were slower (p = .010; η2 = 0.22), were less smooth (p = .002; η2 = 0.30), had more directional error (p = .002; η2 = 0.28), and were less accurate (p = .034; η2 = 0.17) than the CTG. The nSPSG and CTG showed similar performance.

CONCLUSIONS

The perception of pain impairs aiming movements performed with the ipsilesional upper limb in individuals with unilateral chronic stroke.

Prevalence, risk factor and outcome in middle-aged and elderly population affected by hemiplegic shoulder pain: An observational study

Background

Hemiplegic shoulder pain is the most common complication after stroke. It usually occurs during the critical period of stroke recovery and hinders the rehabilitation of upper extremity motor function. However, there are few studies on the risk factors, the development and prognosis of shoulder pain after stroke.

Objectives

This study aimed to observe the prevalence of post-stroke shoulder pain in the middle-aged and elderly population, find out the risk factors for post-stroke shoulder pain, and explore its effect on stroke outcome.

Methods

Eligible patients with hemiplegic shoulder pain in the rehabilitation unit were recruited and followed up at 2 and 4 months. The basic clinical information including age, gender, hypertension and atrial fibrillation history, stroke types, stroke location was recorded. Range of motion for shoulder, glenohumeral subluxation, muscle tension, activity of daily living of upper limb were measured. Data from blood test and shoulder ultrasonography were collected.

Results

480 stroke patients were screened within 1 year, and 239 patients were included in the statistical analysis. The prevalence of hemiplegic shoulder pain was 55.6% (133/239) at admission, 59.4% (142/239) after 2 months, and 55.1% (130/236) after 4 months. We found that shoulder pain was more likely to occur in women, patients with large-area stroke, increased tension of biceps brachii or triceps brachii, subluxation and limited passive range of motion of the shoulder. And the ability of daily living of patients with shoulder pain was significantly lower than that of patients without shoulder pain. Shoulder ultrasonography showed that the most common lesion in patients with shoulder pain was supraspinatus tendon thickening, and the thickness of supraspinatus tendon in the hemiplegic side of patients with shoulder pain was significantly higher than that of unaffected side. In addition, the hospitalization rate of patients with shoulder pain after 2 months and 4 months was significantly higher than that without shoulder pain.

Conclusions

Hemiplegic shoulder pain has a high prevalence and can last for several months. Multiple risk factors are involved. Moreover, hemiplegic shoulder pain affects the readmission rate of patients. Therefore, we should pay more attention to this problem in our clinical work. The application of various means to relieve shoulder pain will be conducive to the recovery of upper limb motor function and shorten the in-hospital rehabilitation time.

Comparative Effectiveness of Injection Therapies for Hemiplegic Shoulder Pain in Stroke: A Systematic Review and Network Meta-Analysis

Hemiplegic shoulder pain (HSP) hampers post-stroke functional recovery and is not well managed with conservative treatments. This systematic review aimed to examine the various injection therapies for HSP and investigate their effectiveness at different time points. The protocol of this meta-analysis was registered on INPLASY with a registration number of INPLASY202180010. PubMed, EMBASE, and Scopus were searched from their inception to 4 August 2021 for the clinical studies investigating comparative effectiveness of different injection regimens for treating hemiplegic shoulder pain in patients with stroke. The primary outcome was the weighted mean difference (WMD) on the visual analog scale (VAS) of pain reduction in the fourth-week and between the fourth and twenty-fourth weeks. Ranking probabilities of the WMD for each treatment were obtained using simulations. Seventeen studies with 595 participants were included. The network meta-analysis showed that at the fourth-week, intra-muscular botulinum toxin (BoNT) injections and suprascapular nerve blocks (SSNB) were superior to a placebo, with WMDs of 1.55 (95% CI, 0.09 to 3.01) and 1.44 (95% CI, 0.07 to 2.80), respectively. SSNB possessed the highest probability (53.3%) and appeared to be the best treatment in the fourth-week, followed by intra-muscular BoNT injections (42.6%). Intramuscular BoNT injections were better than the placebo, with a WMD of 1.57 (95% CI, 0.30 to 2.84) between the 4th and 24th weeks. Intramuscular BoNT injections had the highest probability (79.8%) as the best treatment between the 4th and 24th weeks. SSNB was likely to rank first in relieving HSP at the fourth post-treatment week, whereas intra-muscular BoNT injections had the highest probability to achieve the best treatment effectiveness in the post-injection period between the fourth and twenty-fourth weeks. However, as some of the included studies used a non-randomized controlled design, more randomized controlled trials are needed in the future to validate and better understand the short- and long-term efficacy of different injection therapies for management of HSP.

The effect of mindful attention training for pain modulation capacity: Exploring the mindfulness-pain link

OBJECTIVE

Mindfulness has been shown to be beneficial for chronic pain. The underlying mechanisms of the mindfulness-pain link, however, are yet to be established. Particularly, the effects of mindfulness on pain modulation, which is shown to be dysfunctional among chronic pain patients, barely has been tested. This study investigated whether a short mindful attention training based on Langerian mindfulness mitigates reductions in pain modulation.

METHOD

Systemic quantitative-somatosensory testing of conditioned pain modulation (CPM) was conducted in 60 undergraduates, who were randomly assigned to one of three groups: (1) Pain-specific mindful attention training; (2) nonspecific mindful attention training; and (3) no mindful attention training. CPM was tested before and after the intervention.

RESULTS

As hypothesized, a reduction in CPM magnitude was observed only in the control group, whereas this reduction was abolished in the two mindfulness groups.

CONCLUSIONS

Langerian mindfulness may mitigate pain modulation reduction as observed in chronic pain, thus shedding light on its potential advantages.

Individual variability and sex differences in conditioned pain modulation and the impact of resilience, and conditioning stimulus pain unpleasantness and salience

Distinct pain experiences are shaped both by personal attributes and characteristics of noxious stimuli. An Individual's capacity for endogenous pain inhibition (reflected by conditioned pain modulation [CPM]), their resilience, and the pain unpleasantness and salience of painful stimuli can impact their pain perception. Here, we aimed to determine how individual variability in CPM relates to sex and resilience as personal attributes, and pain unpleasantness and salience of the CPM conditioning stimulus (CS). We evaluated CPM in 106 healthy participants (51 female and 55 male) based on the change in test stimulus pain applied concurrently with a painful CS, both delivered by painful heat. The CS reduced test stimulus pain in only half of the participants (CPM subgroup), but did not do so for the other half (no-CPM subgroup), many who exhibited pain facilitation. A regression model explained CPM effects after accounting for sex, resilience, CS pain unpleasantness and salience. In the CPM subgroup regression model, the CPM effect was positively related to CS pain unpleasantness, while the CPM effect was not related to any variable in the no-CPM subgroup model. Correlation analyses revealed that the CPM effect was anticorrelated with resilience in males with no-CPM. The CPM effect was correlated with CS pain unpleasantness in males with CPM and in females with no-CPM. The CPM effect and CS salience were correlated in the whole group more strongly than in the subgroups. These data reveal that the complexity of contributors to CPM variability include both personal attributes and attributes of the CS.

Association between Physiological and Subjective Aspects of Pain and Disability in Post-Stroke Patients with Shoulder Pain: A Cross-Sectional Study

Background: Patients often experience pain as a result of a stroke. However, the mechanism of this pain remains uncertain. Our aim was to investigate the relationship between pressure pain thresholds (PPTs) and disability pain in patients with hemiplegic shoulder pain (HSP). Methods: Twenty-six post-stroke patients (age 53.35 ± 13.09 years) and healthy controls (54.35 ± 12.37 years) participated. We investigated spontaneous shoulder pain, disability pain perception through the shoulder pain and disability index (SPADI), and the PPTs over joint C5–C6, upper trapezius, deltoid, epicondyle, second metacarpal, and tibialis anterior, bilaterally. Results: The analysis of variance (ANOVA) showed significant differences in pain between groups (p < 0.001) and differences in the SPADI (p < 0.001) between groups but not between sides for PPTs over deltoid (group: p = 0.007; side: p = 0.750), epicondyle (group: p = 0.001; side: p = 0.848), and tibialis anterior (group: p < 0.001; side: p = 0.932). Pain in the affected arm was negatively associated with PPTs over the affected epicondyle (p = 0.003) and affected tibialis anterior (p = 0.009). Pain (SPADI) appeared negatively correlated with PPTs over the affected epicondyle (p = 0.047), and disability (SPADI) was negatively associated with PPTs over the affected tibialis anterior (p = 0.041). Conclusions: Post-stroke patients showed a relationship between widespread pressure pain hypersensitivity with lower PPT levels and pain disability perception, suggesting a central sensitization mediated by bilateral and symmetric pain patterns.

A Systematic Review: Mindfulness Intervention for Cancer-Related Pain

Moderate-to-severe pain is a common problem experienced by patients with cancer. Although analgesic drugs are effective, adverse side effects are common and some analgesic drugs are addictive. Nonpharmacological treatment may be a way to treat cancer pain without causing negative side effects. Mindfulness is used as an effective nonpharmacological treatment to improve quality of life (QoL) and to address psychological problems including distress, anxiety, stress, and depression. However, the effect of mindfulness on pain severity has not been sufficiently investigated. Therefore, a systematic review was undertaken to describe the effectiveness of mindfulness interventions for pain and its underlying pathophysiologic mechanisms. The search was conducted in PubMed, Ovid MEDLINE, and CINAHL and included only empirical studies published from 2008 to 2017. Search terms included mindfulness, mindfulness-based intervention, meditation, cancer, pain, and cancer-related pain. Six studies met the search criteria. These studies tested several types of intervention including mindfulness-based stress reduction, mindfulness-based cognitive therapy, meditation with massage, and mindful awareness practices. Study outcomes include improved pain severity, anxiety, stress, depression, and QoL. However, most studies reviewed were conducted in the United States and Denmark. Further research is needed to test culturally appropriate mindfulness interventions to reduce pain.