Motor Imagery Performance and Tactile Spatial Acuity: Are They Altered in People with Frozen Shoulder?

Exploration of the clinical course and longitudinal correlations in frozen shoulder: The role of autonomic function, central pain processing, and psychological variables. A longitudinal multicenter prospective observational study

BACKGROUND

Altered central pain processing (CPP) and dysautonomia might play a role in the clinical course of frozen shoulder and psychological factors, like pain catastrophizing and hypervigilance, might influence clinical variables in frozen shoulder.

OBJECTIVES

To explore the clinical course of frozen shoulder regarding CPP, dysautonomia, pain catastrophizing, and hypervigilance and to explore whether longitudinal correlations between these outcomes and pain intensity were present.

DESIGN

prospective longitudinal observational study.

METHOD

Participants with frozen shoulder were recruited at hospitals and general practitioner practices and followed for 9 months. They completed six questionnaires (about demographics, shoulder pain and disability, pain intensity, pain catastrophizing, pain hypervigilance, and autonomic symptoms) and underwent tactile sensitivity (allodynia), pressure pain thresholds (hyperalgesia), temporal summation, and conditioned pain modulation during four timeframes (3-month intervals).

RESULTS

Initially, 149 participants with frozen shoulder were recruited and 88 completed all the measurements. An improvement from baseline to at least one follow-up measurement was found for shoulder pain and disability, pain intensity, pain catastrophizing, hypervigilance, and dysautonomia. A fair longitudinal correlation was found between pain intensity and catastrophizing and hypervigilance (r = 0.301-0.397). Poor longitudinal correlations were found between pain intensity and allodynia and hyperalgesia (r = -0.180-0.193), between pain catastrophizing and dysautonomia (r = 0.209) and between hypervigilance and hyperalgesia (r = -0.159).

CONCLUSION

Patients with frozen shoulder showed an early improvement that flattened with time in several pain and psychological variables over the course of 9 months. However, autonomic symptoms rather showed a late improvement over 9 months.

Is there any benefit of adding a central nervous system-focused intervention to a manual therapy and home stretching program for people with frozen shoulder? A randomized controlled trial

BACKGROUND

Frozen shoulder (FS) is a highly disabling pathology of poorly understood etiology, which is characterized by the presence of intense pain and progressive loss of range of motion. The aim of this study was to evaluate the effect of adding a central nervous system (CNS)-focused approach to a manual therapy and home stretching program in people with FS.

METHODS

A total of 34 patients with a diagnosis of primary FS were randomly allocated to receive a 12-week manual therapy and home stretching program or manual therapy and home stretching program plus a CNS-focused approach including graded motor imagery and sensory discrimination training. The Shoulder Pain and Disability Index score, self-perceived shoulder pain (visual analog scale score), shoulder range of motion, and the Patient-Specific Functional Scale score were measured at baseline, after a 2-week washout period just before starting treatment, after treatment, and at 3 months' follow-up.

RESULTS

No significant between-group differences in any outcome were found either after treatment or at 3 months' follow-up.

CONCLUSION

A CNS-focused approach provided no additional benefit to a manual therapy and home stretching program in terms of shoulder pain and function in people with FS.

Reliability and validity of the Shoulder Pain and Disability Index in a sample of patients with frozen shoulder

BACKGROUND

The Shoulder and Pain Disability Index (SPADI) is a widely used outcome measure. The aim of this study is to explore the reliability and validity of SPADI in a sample of patients with idiopathic frozen shoulder.

METHODS

The SPADI was administered to 124 patients with idiopathic frozen shoulder. A sub-group of 29 patients were retested after 7 days. SPADI scores were correlated with other outcome measures (i.e., Disabilities of the Arm, Shoulder and Hand Questionnaire - DASH; Numerical Pain Rating Scale-NPRS; and 36-item Short Form Health Survey-SF-36) to examine construct validity. Structural validity was assessed by a Two-Factors Confirmatory Factor Analysis (CFA). Internal consistency, test-retest reliability, and measurement error were also analyzed.

RESULTS

The construct validity was satisfactory as seven out of eight of the expected correlations formulated (≥ 75%) for the subscales were satisfied. The CFA showed good values of all indicators for both Pain and Disability subscales (Comparative Fit Index = 0.999; Tucker-Lewis Index = 0.997; Root Mean Square Error of Approximation = 0.030). Internal consistency was good for pain (α = 0.859) and disability (α = 0.895) subscales. High test-retest reliability (Intraclass correlation coefficient [ICC]) was found for pain (ICC = 0.989 [95% Confidence Interval (CI = 0.975-0.995]) and disability (ICC = 0.990 [95% CI = 0.988-0.998]). Standard Error of Measurement values of 2.27 and 2.32 and Minimal Detectable Change values of 6.27 and 6.25 were calculated for pain and disability subscales, respectively.

CONCLUSION

The SPADI demonstrated satisfactory reliability and validity properties in a sample of patients with idiopathic frozen shoulder.

Positive effects of neuromuscular exercises on pain and active range of motion in idiopathic frozen shoulder: a randomized controlled trial

BACKGROUND AND OBJECTIVES

Frozen shoulder (FS) is characterized by pain and significant loss of active and passive shoulder motion. Strengthening exercises are among the standard exercises used for FS. Neuromuscular exercise (NME) effectively improved pain and the range of motion in shoulder. However, no prior research has looked into the effects of NME compared to strengthening exercises in FS rehabilitation. The aim of the present study was to evaluate the effects of NME compared to strengthening exercises on pain and active range of motion (AROM) in individuals with idiopathic frozen shoulder.

METHODS

Forty individuals with idiopathic frozen shoulder were randomly assigned to either the experimental group (NME with regular physical therapy, n = 20) or the control group (strengthening exercises with regular physical therapy, n = 20). In both groups, the interventions were performed once a day, 5 days a week for 8 weeks. Pain scores on the visual analogue scale (VAS) and AROM of the shoulder were assessed at baseline and after the 8-week treatment. The primary analysis was the group × time interaction.

RESULTS

Two-by-two mixed analysis of variance (ANOVA) revealed a significant group × time interaction for VAS (F = 29.67; p < 0.01); AROM in flexion (F = 12.05; p < 0.01), internal rotation (F = 6.62; p < 0.05) and external rotation (F = 16.93; p < 0.01) in favor of the experimental group. The two-by-two mixed ANOVA revealed a significant main effect of time for VAS (F = 1648.47; p < 0.01); AROM in flexion (F = 591.70; p < 0.01), extension (F = 114.57; p < 0.01), abduction (F = 1602.04; p < 0.01), internal rotation (F = 664.14; p < 0.01) and external rotation (F = 1096.92; p < 0.01). No other significant differences were found.

CONCLUSIONS

NME is superior to strengthening exercises in terms of pain and AROM of shoulder flexion, internal rotation and external rotation in individuals with idiopathic FS. NME could be used to treat individuals with FS.

TRIAL REGISTRATION

Trial registration number: ChiCTR2100054453. Registration date: 17/12/2021.

Body Schema as Assessed by Upper Limb Left/Right Judgment Tasks Is Altered in Stroke: Implications for Motor Imagery Training

BACKGROUND AND PURPOSE

Individuals with stroke often experience significant impairment of the upper limb. Rehabilitation interventions targeting the upper limb are typically associated with only small to moderate gains. The knowledge that body schema can be altered in other upper limb conditions has contributed to the development of tailored rehabilitation approaches. This study investigated whether individuals with stroke experienced alterations in body schema of the upper limb. If so, this knowledge may have implications for rehabilitation approaches such as motor imagery.

METHODS

An observational study performed online consisting of left/right judgment tasks assessed by response time and accuracy of: (i) left/right direction recognition; (ii) left/right shoulder laterality recognition; (iii) left/right hand laterality recognition; (iv) mental rotation of nonembodied objects. Comparisons were made between individuals with and without stroke. Secondary comparisons were made in the stroke population according to side of stroke and side of pain if experienced.

RESULTS

A total of 895 individuals (445 with stroke) participated. Individuals with stroke took longer for all tasks compared to those without stroke, and were less accurate in correctly identifying the laterality of shoulder (P < 0.001) and hand (P < 0.001) images, and the orientation of nonembodied objects (P < 0.001). Moreover, the differences observed in the hand and shoulder tasks were greater than what was observed for the control tasks of directional recognition and nonembodied mental rotation. No significant differences were found between left/right judgments of individuals with stroke according to stroke-affected side or side of pain.

DISCUSSION AND CONCLUSIONS

Left/right judgments of upper limb are frequently impaired after stroke, providing evidence of alterations in body schema. The knowledge that body schemas are altered in individuals with longstanding stroke may assist in the development of optimal, well-accepted motor imagery programs for the upper limb.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A394).

Functional cortical changes associated with shoulder instability - a systematic review

BACKGROUND

Glenohumeral joint instability is associated with structural deficits and/or alterations in sensory and motor processing; however, a proportion of patients with glenohumeral joint instability fail to respond to surgical and rehabilitative measures. This systematic review aimed to establish if functional cortical changes occur in patients with glenohumeral joint instability.

METHODS

AMED, CINAHL, Cochrane Central Register of Controlled Trials, Embase, Medline, PEDro, Pubmed, PsychINFO and Scopus were searched from inception to 17 March 2021. Randomised controlled trials and non-randomised trials were included and quality was appraised using the Downs and Black tool.

RESULTS

One thousand two hundred seventy-nine records were identified of which five were included in the review. All studies showed altered cortical function when comparing instability patients with healthy controls and included areas associated with higher cortical functions.

DISCUSSION

The findings of this systematic review offer some insight as to why interventions addressing peripheral pathoanatomical factors in patients with glenohumeral joint instability may fail in some cases due to functional cortical changes. However, data are of moderate to high risk of bias. Further high-quality research is required to ascertain the degree of functional cortical changes associated with the type and duration of glenohumeral joint instability.

The sensorimotor theory of pathological pain revisited

Harris (1999) proposed that pain can arise in the absence of tissue damage because changes in the cortical representation of the painful body part lead to incongruences between motor intention and sensory feedback. This idea, subsequently termed the sensorimotor theory of pain, has formed the basis for novel treatments for pathological pain. Here we review the evidence that people with pathological pain have changes to processes contributing to sensorimotor function: motor function, sensory feedback, cognitive representations of the body and its surrounding space, multisensory processing, and sensorimotor integration. Changes to sensorimotor processing are most evident in the form of motor deficits, sensory changes, and body representations distortions, and for Complex Regional Pain Syndrome (CRPS), fibromyalgia, and low back pain. Many sensorimotor changes are related to cortical processing, pain, and other clinical characteristics. However, there is very limited evidence that changes in sensorimotor processing actually lead to pain. We therefore propose that the theory is more appropriate for understanding why pain persists rather than how it arises.

Correlations between Age, Pain Intensity, Disability, and Tactile Acuity in Patients with Chronic Low Back Pain

Objective

Chronic low back pain is an overwhelming problem for a wide range of people and leads to tactile acuity deficits. We aimed to investigate the correlations among age, pain severity, disability, and tactile acuity in patients with chronic low back pain by using multiple tactile acuity tests.

Methods

A total of 58 participants (36.40 ± 14.95 years) with chronic low back pain were recruited, and two-point discrimination, point-to-point test, and two-point estimation were performed on their painful low back areas. The correlations between age, pain intensity, disability, and tactile acuity were characterized with Pearson's correlation coefficients. Subgroup analyses according to the median values of age, pain intensity, and disability were used to compare the intergroup difference in tactile acuity.

Results

Results illustrated significant negative associations among age, pain intensity, disability, and tactile acuity. Subgroup analyses revealed that patients with below-the-median values of age, pain intensity, and disability had better performance in tactile acuity tests than those with above-the-median values.

Conclusion

This study indicated that tactile acuity was negatively associated with age, pain intensity, and disability in young patients with chronic low back pain.

The Spatial Extent of Pain Is Associated with Pain Intensity, Catastrophizing and Some Measures of Central Sensitization in People with Frozen Shoulder

The aim of this cross-sectional study was to explore the spatial extent of pain and its association with clinical symptoms, psychological features, and pain sensitization in people with frozen shoulder (FS). Forty-eight individuals with FS completed pain drawings (PDs) and reported their clinical symptoms including pain intensity (Visual Analogue Scale) and shoulder disability (Shoulder Pain and Disability Index). Moreover, pain sensitization measurements (pressure pain thresholds, temporal summation, conditioned pain modulation, and Central Sensitization Inventory (CSI)) were assessed. Psychological features were assessed by Pain Catastrophizing Scale (PCS) and Pain Vigilance and Awareness Questionnaire. Pain frequency maps were generated, Margolis rating scale was used for pain location, and Spearman correlation coefficients were computed. The mean (SD) pain extent was 12.5% (6.7%) and the most common painful area was the anterolateral shoulder region (100%). Women presented a more widespread pain distribution compared with men. Significant positive associations were obtained between pain extent and current pain intensity (rs = 0.421, p < 0.01), PCS (rs = 0.307, p < 0.05) and CSI (rs = 0.358, p < 0.05). The anterolateral region of the shoulder was the most common painful area in people with FS. Women with FS presented more extended areas of pain; and a more widespread distribution of pain was correlated with higher levels of pain, pain catastrophizing and pain sensitization.

Conditioned Pain Modulation Is Not Impaired in Individuals with Frozen Shoulder: A Case-Control Study

Frozen shoulder (FS) is a poorly understood condition resulting in substantial shoulder pain and mobility deficits. The mechanisms behind FS are not yet fully understood, but, similar to other persistent pain states, central pain mechanisms may contribute to ongoing symptoms in this population. The objective of this research was to investigate conditioned pain modulation (CPM) in people with FS compared with pain-free individuals. A total of 64 individuals with FS and 64 healthy volunteers participated in this cross-sectional study. CPM was assessed by using the pressure pain threshold (PPT) and an occlusion cuff (tourniquet test) as the test and conditioning stimulus, respectively. The absolute and percentage of change in PPT (CPM effect) as well as pain profiles (pro-nociceptive vs. anti-nociceptive) of individuals with FS and healthy controls were calculated. No significant differences in the absolute change in the PPT or CPM effect were found in people with FS compared to pain-free controls. Moreover, no between-group differences in the percentage of subjects with pro-nociceptive and anti-nociceptive pain profiles were observed. These results suggest that endogenous pain inhibition is normally functioning in people with FS. Altered central pain-processing mechanisms may thus not be a characteristic of this population.

Joint position sense, motor imagery and tactile acuity in lateral elbow tendinopathy: A cross-sectional study

BACKGROUND

Impairments of sensorimotor function are evident in individuals with lateral elbow tendinopathy (LET), although understanding of the mechanisms for this is lacking.

OBJECTIVES

To determine if motor imagery, tactile acuity and wrist joint position sense (JPS) are impaired in participants with unilateral LET compared to controls, whether deficits are localised to the affected side, and whether deficits relate to severity of pain.

DESIGN

Cross-sectional study with control group.

METHODS

14 participants with unilateral LET of 6 weeks or longer and 14 matched control participants were assessed bilaterally for motor imagery (left/right hand judgement task), tactile acuity (two-point discrimination test) and wrist JPS (reposition test for flexion and extension). Pain levels were measured using a numeric rating scale.

RESULTS

Significant differences in JPS were observed for wrist extension only, such that participants with LET adopted less extended postures with their affected side when compared to their unaffected side (MD = 2.97°; p = 0.01) and to the matched-affected side of controls (MD = 4.89°; p < 0.01). No differences in tactile acuity or motor imagery were observed.

CONCLUSION

Altered wrist extension JPS, but not motor imagery or tactile acuity, was found in the affected side of patients with unilateral LET when compared to non-injured side and asymptomatic controls.