Assessment of forearm muscle spasticity with sonoelastography in patients with stroke

Neuromusculoskeletal modeling of spasticity: A scoping review

INTRODUCTION

This scoping review aimed to provide an overview of neuromusculoskeletal models used to investigate the mechanisms underlying spasticity and identify issues to be addressed in future models.

MATERIALS AND METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews (PRISMA-ScR) guidelines and searched four bibliographic databases (PubMed, Compendex Engineering Village, IEEE Xplore, and Science Direct). Inclusion criteria were original studies written in English that investigated the underlying mechanisms of spasticity in humans with no age restrictions. Two independent reviewers selected studies.

RESULTS

Eighteen studies met the inclusion criteria. Stroke was the neurological condition addressed by most studies, followed by cerebral palsy. The studies focused mainly on passive tasks with the knee joint as the primary target. All studies considered that spasticity was associated with alterations in the stretch reflex loop. Among the parameters tested by the studies, the reflex gains and thresholds were the parameters that could better represent levels of severity or effects of botulinum toxin type-A treatment. Recent studies proposed that stretching acceleration, muscle force, and force rate could be fed back into the feedback loop besides the muscle length and stretching velocity. However, no consensus was found among them. Finally, it has been that stiffness and viscosity of muscle-tendon-unit are also relevant for describing resistance to passive movement.

CONCLUSION

In order to provide relevant clinical and physiological information, future modeling should include supraspinal mechanisms in-depth, use image-based data to personalize non-neural parameters, specify models according to etiology and tasks, especially the active tasks of daily life activities.

Feasibility of shear wave elastography to assess upper limb spasticity in patients after brain injury

PURPOSE

To assess the feasibility of Shear Wave Elastography (SWE) for quantifying upper limb spasticity in people after brain injury.

METHODS

This observational study included 52 patients with upper limb spasticity after brain injury. Participants underwent a two-week rehabilitation treatment. The modified Ashworth scale (MAS), upper extremity section of the Fugl-Meyer motor scale (FMMS-UE), Barthel index (BI) and SWE were assessed before and after a two-week rehabilitation. The shear modulus was used to evaluate the stiffness of the biceps brachii at the transverse and longitudinal plane of 0°and 90°elbow flexion.

RESULTS

In our study, paretic side shear modulus values were significantly larger than non-paretic sides (all p-values < 0.05), with significant reductions only on the paretic side (all p-values < 0.001) after 2-week rehabilitation treatment. At baseline, MAS and shear modulus had a significant positive correlation. After rehabilitation, only the longitudinal plane shear modulus showed a correlation with MAS. No significant correlations were found between shear modulus and FMMS-UE or BI scores, except for a negative correlation between shear modulus and BI at 0° transverse plane flexion.

CONCLUSIONS

Our findings indicate that SWE effectively quantifies upper limb spasticity and can assess the impact of rehabilitation treatment.

Shear wave elastography in the assessment of gastrocnemius spastic muscle elasticity: influences of ankle position and muscle contraction

BACKGROUND

Following upper motor neuron syndromes (UMNS), intrinsic viscoelastic muscle properties such as elastic stiffness may be altered, which leads to muscle hyper-resistance to passive mobilization. So far, no gold standard assessment of hyper-resistance, whether clinical or instrumental, is available. Shear wave elastography (SWE) has been increasingly used for non-invasive evaluation of elastic stiffness of skeletal muscles in people with hyper-resistance.

AIM

Our study aimed to evaluate the validity of SWE at ankle neutral resting position (ANRP). Additional objectives included assessing the influence of ankle position, muscle contraction, and laterality on elastic stiffness, and evaluating the reproducibility and responsiveness of SWE.

DESIGN

Observational cohort study.

SETTING

Outpatients of the physical and rehabilitation medicine department of a university hospital in Brussels.

POPULATION

Thirty hemiparetic patients following UMNS with hyper-resistance in gastrocnemii muscles.

METHODS

Elastic stiffness was quantified by shear wave velocity (SWV) measurements of gastrocnemii muscles. A higher SWV corresponds to a higher elastic stiffness. Measurements were performed on the affected and less-affected limbs in ANRP, in passive dorsiflexion and during isometric contraction. Assessments were performed 3 times. Criterion validity, reproducibility, and responsiveness were evaluated. A linear mixed model was used to study position and laterality effect.

RESULTS

In ANRP, reproducibility was excellent and SWV was significantly higher in the affected limb than in the less-affected limb. This laterality effect disappeared in passive dorsiflexion and was even reversed during isometric contraction. SWV was significantly higher on both sides in passive dorsiflexion and during contraction than in ANRP.

CONCLUSIONS

Our results suggest that SWE measurements in ANRP are reliable and may provide a more valid measurement of gastrocnemii elastic stiffness following UMNS.

CLINICAL REHABILITATION IMPACT

SWE may be a useful clinical tool as an extension of the physical exam for longitudinal monitoring of passive muscle elastic stiffness, to assist with treatment decisions and to better quantify the therapeutic effect of procedures to reduce muscle overactivity. However, a standardized protocol should be used. ANRP seems to be the most valid position for assessing gastrocnemius elastic stiffness in neurological populations. This should be kept in mind for the choice of positioning in further studies.

The relationship between rubrospinal tract structure and ankle plantarflexor muscle stiffness in children with Cerebral Palsy

We aimed to study the structure of the rubrospinal tract (RuST) and stiffness of muscles of lower extremities in Cerebral Palsy (CP) children and understand the contribution of the structure of the RuST to spasticity of these muscles.Twenty-six spastic CP children of age 4-15 years old participated. The structure of this tract was characterized using the parameters extracted from diffusion tensor imaging (DTI). These parameters included fractional anisotropy (FA), and mean diffusivity (MD). To quantify the stiffness of the tibialis anterior (TA) and the gastrocnemius (Gs) muscles, some features of the texture analysis of the region of interest (ROI) in real-time sonoelastography (RTSE) images, including shear wave velocity (SWV), contrast, autocorrelation, correlation, energy, and entropy were extracted.We used Pearson correlation coefficients to find the relationships between the texture of muscles and RuST structure. The results showed some significant relationships between autocorrelation, entropy, and energy of Gs muscle and FA and MD of RuST. It means that RuST may have a role in the Gs muscle function which is an extensor muscle.

Assessing muscle architecture with ultrasound: implications for spasticity

Botulinum Neurotoxin Type A (BoNT-A) injections using Ultrasound (US) guidance have led to research evaluating changes in muscle architecture. Controversy remains as to what constitutes increased Echo-Intensity (EI) in spastic muscles and whether this may affect outcomes. We aim to provide a narrative review of US muscle architecture changes following Central Nervous System (CNS) lesions and explore their relationship to spasticity. Medline, CINAHL, and Embase databases were searched with keywords: ultrasonography, hypertonia, spasticity, fibrosis, and Heckmatt. Three physicians reviewed the results of the search to select relevant papers. Reviews identified in the search were used as a resource to identify additional studies. A total of 68 papers were included. Four themes were identified, including histopathological changes in spastic muscle, effects of BoNT-A on the muscle structure, available US modalities to assess the muscle, and utility of US assessment in clinical spasticity. Histopathological studies revealed atrophic and fibro-fatty changes after CNS lesions. Several papers described BoNT-A injections contributing to those modifications. These changes translated to increased EI. The exact significance of increased muscle EI remains unclear. The Modified Heckmatt Scale (MHS) is a validated tool for grading muscle EI in spasticity. The use of the US may be an important tool to assess muscle architecture changes in spasticity and improve spasticity management. Treatment algorithms may be developed based on the degree of EI. Further research is needed to determine the incidence and impact of these EI changes in spastic muscles.

Effects of neurorehabilitation with and without dry needling technique on muscle thickness, reflex torque, spasticity and functional performance in chronic ischemic stroke patients with spastic upper extremity muscles: a blinded randomized sham-controlled clinical trial

PURPOSE

Evaluation the effects of dry needling on sonographic, biomechanical and functional parameters of spastic upper extremity muscles.

METHODS

Twenty-four patients (35-65 years) with spastic hand were randomly allocated into two equal groups: intervention and sham-controlled groups. The treatment protocol was 12-sessions neurorehabilitation for both groups and 4-sessions dry needling or sham-needling for the intervention group and sham-controlled group respectively on wrist and fingers flexor muscles. The outcomes were muscle thickness, spasticity, upper extremity motor function, hand dexterity and reflex torque which were assessed before, after the 12th session, and after one-month follow-up by a blinded assessor.

RESULTS

The analysis showed that there was a significant reduction in muscle thickness, spasticity and reflex torque and a significant increment in motor function and dexterity in both groups after treatment (p < 0.01). However, these changes were significantly higher in the intervention group (p < 0.01) except for spasticity. Moreover, a significant improvement was seen in all outcomes measured one-month after the end of the treatment in the intervention group (p < 0.01).

CONCLUSIONS

Dry needling plus neurorehabilitation could decrease muscle thickness, spasticity and reflex torque and improve upper-extremity motor performance and dexterity in chronic stroke patients. These changes were lasted one-month after treatment.Trial Registration Number: IRCT20200904048609N1IMPLICATION FOR REHABILITATIONUpper extremity spasticity is one of the stroke consequences which interfere with motor function and dexterity of patient hand in activity of daily livingApplying the dry needling accompanied with neurorehabilitation program in post-stroke patients with muscle spasticity can reduce the muscle thickness, spasticity and reflex torque and improve upper extremity functions.

Utility of Ultrasound Elastography to Evaluate Poststroke Spasticity and Therapeutic Efficacy: A Narrative Review

Poststroke spasticity (PSS) is a common complication that affects function and daily self-care. Conservative PSS treatments include traditional rehabilitation, botulinum toxin injection, and extracorporeal shock wave therapy. Currently, the Modified Ashworth Scale and Modified Tardieu Scale are widely used tools to clinically evaluate spasticity, but the best tool for PSS assessment remained controversial. Ultrasound elastography (UE), including shear wave and strain image as the emerging method to evaluate soft tissue elasticity, became popular in clinical applications. Spastic biceps and gastrocnemius muscles were reported to be significantly stiffer compared to nonparetic muscles or healthy control using shear wave or strain elastography. More studies investigated the utility, reliability, and validity of UE in patients with PSS, but the contemporary consensus for the utility of UE in the measurement and therapeutic follow-up of PSS remained lacking. Therefore, this narrative review aimed to appraise the literature on the shear wave and strain elastography on PSS and summarize the roles of UE in assessing the therapeutic efficacy of different PSS interventions.

The Sonoelastography and Functional Outcome of Upper Extremity after Kinesiotaping on the Spastic Forearm in Patients with Subacute Stroke

Objectives

This study is aimed at exploring the feasibility of sonoelastography on muscle stiffness of spastic forearm and evaluating the improvement of functional performance in patients with poststroke spasticity (PSS) after receiving kinesiotaping (KT) and rehabilitation.

Methods

According to the spastic levels (using modified Ashworth scale (MAS)) of the affected upper extremity, 59 patients with stroke were allocated into two groups, group A (MAS 0-1): 31 patients (14 men and 17 women; mean age: 60 years) and group B (MAS 1+-2): 28 patients (22 men and 6 women; mean age: 51 years). The Brunnstrom motor recovery stage at the wrist/distal parts in groups A and B was stage 3/3.5 and stage 2.75/3. We evaluated the Brunnstrom stage, spastic levels by MAS and modified Tardieu scale (MTS), and Fugl-Meyer Assessment for upper extremity (FMA-UE). We also evaluated the muscle spasticity of flexor carpi radialis (FCR), flexor carpi ulnaris (FCU), and flexor digitorum superficialis (FDS) muscles using sonoelastography with shear wave velocity (SWV). We applied KT for 20 patients in group B, comparing the changes in sonoelastography and functional outcomes between KT and without KT interventions.

Results

Both the MAS and MTS scales were moderately correlated with the SWV in forearm muscles on hemiplegic side (r = 0.336-0.554) After KT intervention, the SWV in FCR decreased (p = 0.028). Muscle spasticity was reduced (p < 0.01), and distal part of the Brunnstrom stage and FMA-UE were increased (p = 0.045 and p = 0.001). In patients without KT intervention, only the MTS degree reduced (p = 0.026).

Conclusions

The SWV of sonoelastography could objectively assess the reduction of muscle stiffness of the affected forearms in patients with PSS after KT intervention. Advances in Knowledge. Sonoelastography could be a quantitative method to follow up for therapeutic effect of the spastic forearm.

High elasticity of the flexor carpi ulnaris and pronator teres muscles is associated with medial elbow injuries in youth baseball players

OBJECTIVES

The purpose of the present study was to measure the elasticities of the forearm flexor-pronator muscles in youth baseball players and examine their relationships with medial elbow injuries.

METHODS

We examined the strain ratios (SR) of the flexor digitorum superficialis (FDS), flexor carpi ulnaris (FCU), and pronator teres (PT) in 89 youth baseball players with medial epicondylar fragmentation (injury group) and in 142 healthy baseball players (control group). An index of muscle elasticity was determined using ultrasound strain elastography. The SR of each muscles was compared between the injury and control groups, and the SR of the both side arms was compared within group. Moreover, multivariable logistic regression analyses were conducted to examine the association of forearm muscle elasticity with medial elbow injuries.

RESULTS

The SR of the FCU and PT of the throwing arm were significantly higher in the injury group than in the control group (both P < .001). In the injury group, the SR of the FCU was higher in the throwing arm than in the non-throwing arm (P < .001), but no difference was noted for the PT. Multivariable logistic regression analyses showed that a 0.1 increase of the SR of the FCU of the throwing arm (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.14-1.48) and PT of the throwing arm (OR 1.41, 95% CI 1.19-1.67) and the non-throwing arm (OR 1.31, 95% CI 1.12-1.54) was significantly associated with an increased prevalence of medial elbow injuries.

CONCLUSION

High elasticities of the FCU of the throwing arm and PT of both the arms were observed in individuals with medial elbow injuries, and were associated with increased prevalence of medial elbow injuries. These findings may be characteristic of medial elbow injuries in youth baseball players.

Ultrasound elastography in the assessment of post-stroke muscle stiffness: a systematic review

Background

Post-stroke muscle stiffness is a major challenge in the rehabilitation of stroke survivors, with no gold standard in clinical assessment. Muscle stiffness is typically evaluated by the Modified Ashworth Scale or the Tardieu Scale; however, these can have low reliability and sensitivity. Ultrasound elastography is an advanced imaging technology that can quantitatively measure the stiffness of a tissue and has been shown to have good construct validity when compared to clinically assessed muscle stiffness and functional motor recovery.

Objective

The purpose of this article is to systematically review the literature regarding the change in muscle stiffness as measured by ultrasound elastography in stroke survivors.

Methods

Scopus, PubMed, Embase, CINAHL, MEDLINE and Cochrane Library were searched for relevant studies that assessed the change in stiffness of post-stroke muscle stiffness measured by ultrasound elastography following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.

Results

In total, 29 articles were identified, using either strain elastography and shear wave elastography to measure the stiffness of muscles in stroke survivors, most frequently in the biceps and medial gastrocnemius muscles. The stiffness was typically higher in the paretic compared to the non-paretic or healthy control. Other variations that increased the stiffness include increasing the joint angle and introducing a passive stretch or muscle activation. The paretic muscle has also been assessed pre- and post-treatment demonstrating a decrease in stiffness.

Conclusion

Ultrasound elastography is a promising imaging technology for determining the muscle stiffness in stroke survivors with need for a standardized imaging protocol.

Reliability and diagnostic accuracy of corrected slack angle derived from 2D-SWE in quantitating muscle spasticity of stroke patients

BACKGROUND

To explore the feasibility of corrected slack angle acquired from two-dimensional shear wave elastography (2D-SWE) for quantitating the spasticity of medial gastrocnemius (MG) in stroke patients.

METHODS

Consecutive stroke patients with spastic MG and matched healthy controls were recruited. Intra- and interobserver reliability of 2D-SWE measurement were evaluated, and the correlation between corrected slack angle and modified Ashworth scale (MAS) score was examined. The corrected slack angle before and after botulinum toxin A (BoNT-A) injection was compared and its diagnostic performance in classifying the severity of spasticity were assessed with receiver operating characteristic (ROC) curve analysis.

RESULTS

The intra- (0.791 95% CI 0.432-0.932) and interobserver (0.751 95% CI 0.382-0.916) reliability of slack angle acquired with 2D-SWE were good. Significant correlation was found between corrected slack angle and MAS score (R = - 0.849, p < 0.001). The corrected slack angle increased after BoNT-A injection. The cutoff value of MAS ≥ 3 had the highest sensitivity (100%) and specificity (93.33%). The positive predictive value (PPV) for classification of MAS ≥ 1+ and the negative predictive value (NPV) for classification of MAS ≥ 3 were greater than 90%.

CONCLUSION

2D-SWE was a reliable method to quantitate the post-stroke spasticity. The corrected slack angle had advantage in classifying the severity of spasticity, especially in early identification of mild spasticity and confirmation of severe spasticity.

Elasticity of the Flexor Carpi Ulnaris Muscle After an Increased Number of Pitches Correlates With Increased Medial Elbow Joint Space Suppression

ABSTRACT

Saito, A, Namiki, Y, and Okada, K. Elasticity of the flexor carpi ulnaris muscle after an increased number of pitches correlates with increased medial elbow joint space suppression. J Strength Cond Res 35(9): 2564-2571, 2021-This study aimed to measure the medial elbow joint space and elasticity of the forearm flexor-pronator muscles in repetitive pitching and to determine which of the forearm flexor-pronator muscles contribute to elbow valgus stability during pitching. Twenty-six collegiate baseball players performed 7 sets of 15 pitches. The medial elbow joint space and elasticity of the pronator teres, flexor carpi radialis, flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU) were measured using ultrasonography before pitching and after every 15 pitches. Correlations among the rate of change of these parameters were analyzed using Pearson's correlation coefficients. The medial elbow joint space increased after 60 or more pitches compared with that before pitching (all p < 0.001; effect size [ES]: 0.44-1.22). FDS and FCU elasticity increased after 45 and 60 pitches or more in contrast to that before pitching, respectively (FDS: p = 0.047 and p < 0.001, respectively; ES: 1.05-1.42, FCU: p = 0.011 and p < 0.001, respectively; ES: 1.11-1.48). After 75 or more pitches, the rate of change of FCU elasticity correlated negatively with that of the medial elbow joint space (r = -0.395, r = -0.454, and r = -0.404, after 75, 90, and 105 pitches, respectively). Increased FCU elasticity after repetitive pitching correlated with suppression of the increase of the medial elbow joint space. The FCU may be the primary dynamic stabilizer against the elbow valgus force, and evaluation of the FCU elasticity may be important for preventing elbow injuries.

Ultrasound Elastography in the Assessment of the Stiffness of Spastic Muscles: A Systematic Review

The incidence of muscle spasticity is high in patients with diseases of the central nervous system. This condition leads to significant limitations in movement and impaired functional capacities. Muscle spasticity manifests as changes in the mechanical properties of the muscles. This muscle disorder is generally assessed using qualitative methods, whose validity, reliability and sensitivity are questionable. In recent years, ultrasound elastography (USE) has been used as a non-invasive technique for characterizing the stress response and mechanical properties of individual muscles in the evaluation of spasticity. This article presents a systematic review of the USE techniques, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration guidelines, used for the evaluation of muscle stiffness caused by spasticity. The articles selected in this study were evaluated using the Quality Appraisal of Diagnostic Reliability (QAREL) tool. Mainly, studies on the assessment of spasticity involving the evaluation of muscle stiffness with USE techniques (i.e., shear-wave elastography [SWE] or compression elastography [CE]) were selected. Then, common topics related to the assessment of spastic muscles and the statistical results of these studies were classified. Of 21 articles, nine used only CE, 10 used only SWE and two used both techniques. In the studies, statistically significant differences were observed in the measurements of muscle stiffness between the paretic and non-paretic sides as well as between patients and healthy patients. The clinical measurements obtained, devices used and assessment and probe positions for both techniques were discussed. The most frequently studied muscles were the biceps (n = 7) and gastrocnemius (n = 11). On applying the QAREL tool, we found that only two studies showed compliance at 80%-90%, seven studies at 50%-70% and the remaining 12 at 10%-40%. The results showed that USE techniques have limitations in spasticity assessment, such as subjectivity because of the lack of standardized protocols. A deficit of studies on intra-operator and inter-operator measurements indicates that this technique is not yet mature for spasticity diagnosis, although it is a promising diagnostic tool for designing treatment plans and monitoring the effectiveness of therapeutic modalities.

Contribution of Single-Fiber Evaluation on Monitoring Outcomes Following Injection of Botulinum Toxin-A: A Narrative Review of the Literature

Botulinum toxin-A (BoNT-A) blocks acetylcholine release at the neuromuscular junction (NMJ) and is widely used for neuromuscular disorders (involuntary spasms, dystonic disorders and spasticity). However, its therapeutic effects are usually measured by clinical scales of questionable validity. Single-fiber electromyography (SFEMG) is a sensitive, validated diagnostic technique for NMJ impairment such as myasthenia. The jitter parameter (µs) represents the variability of interpotential intervals of two muscle fibers from the same motor unit. This narrative review reports SFEMG use in BoNT-A treatment. Twenty-four articles were selected from 175 eligible articles searched in Medline/Pubmed and Cochrane Library from their creation until May 2020. The results showed that jitter is sensitive to early NMJ modifications following BoNT-A injection, with an increase in the early days’ post-injection and a peak between Day 15 and 30, when symptoms diminish or disappear. The reappearance of symptoms accompanies a tendency for a decrease in jitter, but always precedes its normalization, either delayed or nonexistent. Increased jitter is observed in distant muscles from the injection site. No dose effect relationship was demonstrated. SFEMG could help physicians in their therapeutic evaluation according to the pathology considered. More data are needed to consider jitter as a predictor of BoNT-A clinical efficacy.

Respiratory and peripheral muscle involvement in patients with pulmonary arterial hypertension due to congenital heart diseases

Skeletal and respiratory muscle dysfunction has been previously described in patients with other etiologic subgroups of pulmonary arterial hypertension (PAH) but has never been investigated in patients with PAH due to congenital heart diseases (CHD). This study aims to show the involvement of skeletal and respiratory muscles in these patients. This cross-sectional study included patients with PAH due to CHD and healthy controls. Patients' demographic properties, six-minute walk tests; shoulder abduction, handgrip, knee extension, and ankle dorsiflexion muscle strength, maximum inspiratory (MIP) and expiratory pressures (MEP) were measured. Deltoid, flexor digitorum superficialis, and profundus, tibialis anterior and rectus femoris muscles were visualized with ultrasonography and their cross-sectional areas (CSA) were also measured in both groups. 12 patients and 12 controls were included. Mean MIP was 104.22±32.57 cm H2O for healthy participants while 61.33±29.74 cm H2O for patients (p<0.001). For mean MEP, it was 100.08±26.05 cm H2O in healthy participants and 69.75±39.79 cmH2O in controls (p=0.004). When the strength of skeletal muscles was compared, there were significant differences between the groups in all measurements except for bilateral grip strength. In the correlation analysis, MIP and MEP values showed no significant correlations with clinical parameters. They showed significant moderate correlations with skeletal muscle strength. When CSAs of the muscles were compared, there were significant differences in all measurements except for left FDS and FDP and bilateral rectus femoris. This study showed that in patients with pulmonary arterial hypertension due to CHD, respiratory muscle strength is significantly worse than healthy participants. Patients had also significantly worse skeletal muscle strength except for grip strength.

Reliability of quantitative ultrasound measurement of flexor digitorum superficialis and profundus muscles in stroke

Aim: This study aims to investigate reliability of quantitative ultrasound measurement of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) muscles in stroke. Materials & methods: Patients with a history of stroke were recruited. FDP and FDS muscles on both upper extremities were investigated with ultrasound. Two independent assessors acquired images and analyzed them using a program and Heckmatt scale. Results: Forty-eight patients were included. The inter-rater intraclass correlation coefficient for echo intensities was calculated as 0.91 while intrarater intraclass correlation coefficient as 0.80. For Heckmatt scale, the inter-rater reliability for FDS was Kw = 0.74 (p < 0.0005) and for FDP it was Kw = 0.73 (p < 0.0005). Mean echo intensity values showed significant strong correlations with Heckmatt scores (r = 0.663 and r = 0.633 with both p values <0.001). Conclusion: Quantitative ultrasound imaging of FDS and FDP is a reliable method to demonstrate echo intensity changes of muscles in stroke.

Muscle and tendon properties of the spastic lower leg after stroke defined by ultrasonography: a systematic review

INTRODUCTION

Peripheral muscle and tendon changes after stroke can influence the functional outcome of patients. The aim of this systematic review was to summarize the evidence of ultrasonographic changes in morphological muscle and tendon properties of the spastic hemiparetic lower leg in patients with first ever stroke.

EVIDENCE ACQUISITION

A systematic search was conducted through PubMed, Embase, Scopus, Cinahl, Cochrane Library, and manual searches from inception until May 1, 2020. Observational case control or cohort studies were included. Risk of bias was evaluated by using the Newcastle-Ottawa Quality Assessment Scale. Outcome parameters of interest included muscle thickness, muscle and tendon length, fascicle length, pennation angle and echo-intensity.

EVIDENCE SYNTHESIS

Nine studies investigated outcome parameters beyond one-month after stroke. We are unable to make a comprehensive statement. Nevertheless, there are some arguments for reduced muscle thickness and reduced fascicle length of the hemiplegic, spastic leg.

CONCLUSIONS

Despite the fact that objective assessment by ultrasonography holds promise for diagnosis and follow-up of spastic hemiparesis after stroke, more evidence is needed to determine how changes in morphological muscle and tendon properties are related to muscle weakness, severity of spasticity and compensation strategies such as disuse or overuse in longitudinal studies starting early after stroke.

Effects of spasticity and hemiplegic posture on median nerve and carpal tunnel in stroke patients: Electrophysiological and ultrasonographic evaluation

This study aims to evaluate whether the upper extremity spasticity and hemiplegic posture have any effect on the morphology of the carpal tunnel and median nerve in stroke patients. Nerve conduction studies (NCS) were performed in 46 stroke patients and compared to those of 30 healthy controls. The cross-sectional area (CSA) of the carpal tunnel (CT) and median nerve (wrist/mid-forearm levels) was assessed by ultrasonography. The mean ages of the stroke and control group were 55.6 ± 13.5 and 56 ± 12.1 years, respectively. The median spasticity score of the forearm pronators and wrist flexor muscles was 2 (0-4) according to the Modified Ashworth Scale (MAS). The compound muscle action potential (CMAP) of the median nerve was reduced (10,093 ± 4,451 mV) when compared to non-paretic side (11,615 ± 4,397 mV) (p:0.02) and the CSA of the CT was thinner on the paretic side (1.9 ± 0.3 cm² vs 2.08 ± 0.2 cm²) (p:0.03). Pronator spasticity had no significant effect on the CSA of the median nerve and NCS at the forearm level. The CSA of the median nerve at the wrist was significantly thicker in patients with the wrist flexor spasticity graded II (MAS) and above compared to those with spasticity graded I and below (9.5 ± 1.7 mm² and 8.7 ± 1.7 mm² respectively) (p:0.03). However, the thickening of the median nerve didn't cause significant abnormalities in NCS. This study shows that in stroke patients, wrist flexor spasticity and hemiplegic wrist posture can cause explicit morphological changes in the CT and median nerve albeit normal findings on NCS.

Elasticity of the pronator teres muscle in youth baseball players with elbow injuries: evaluation using ultrasound strain elastography

BACKGROUND

Although the pronator teres muscle, a major dynamic stabilizer of elbow valgus stress during throwing, frequently presents stiffness, its relationship with elbow injuries in youth baseball players is unknown. This study investigated the relationship between the elasticity of the pronator teres muscle and elbow injuries in youth baseball players.

METHODS

The strain ratio (SR) of 15 individuals with osteochondritis dissecans of the humeral capitellum (OCD group), 67 individuals with medial epicondylar fragmentation (medial injury group), and 115 healthy individuals (control group) was measured as the index of the elasticity of the pronator teres muscle using ultrasound strain elastography. In addition, the forearm and glenohumeral joint rotation range of motion was measured.

RESULTS

The SR of the throwing arm was significantly higher in the OCD and medial injury groups than in the control group (both P <.001). In the OCD group, the SR was significantly higher in the throwing arm than in the nonthrowing arm (P <.001), whereas in the medial injury group, there was no significant difference between both arms. The glenohumeral joint external rotation range of motion of the throwing arm was moderately negatively correlated with the SR (r = -0.478, P <.001).

CONCLUSIONS

Stiffness of the pronator teres muscle was exhibited only in the throwing arm of individuals with OCD and in both arms in individuals with medial elbow injury. These findings may contribute to an accurate evaluation and prevention of elbow injuries in youth baseball players.

Quantitative Evaluation of Post-stroke Spasticity Using Neurophysiological and Radiological Tools: A Pilot Study

Objective

To determine the possibility of a new measurement tool using electromyography and ultrasonography for quantitative spasticity assessment in post-stroke patients.

Methods

Eight hemiplegic stroke patients with ankle plantarflexor spasticity confirmed by a Modified Ashworth Scale (MAS) were enrolled. Spasticity was evaluated using the MAS and Modified Tardieu Scale (MTS). Each subject underwent surface electromyography (sEMG) using the Brain Motor Control Assessment (BMCA) protocol and was compared with a healthy control group. Using ultrasonography, muscle architecture and elasticity index were measured from the medial gastrocnemius muscle (GCM) on the affected and unaffected sides.

Results

MAS and MTS revealed significant correlation with sEMG activity. The fascicle length and pennation angle were significantly decreased in the medial GCM on the hemiplegic side compared with the unaffected side. The elasticity index of the spastic medial GCM was significantly increased compared with the unaffected side. The MTS X and R²–R1 values were significantly correlated with the elasticity index in the hemiplegic GCM. The relationship between clinical evaluation tools and both BMCA and sonoelastography was linear, but not statistically significant in the multiple regression analysis.

Conclusion

The BMCA protocol and ultrasonographic evaluation provide objective assessment of post-stroke spasticity. Further studies are necessary to conduct accurate assessment and treatment of spasticity.

Correlation between Pathological Characteristics and Young's Modulus Value of Spastic Gastrocnemius in a Spinal Cord Injury Rat Model

The goal of the present study were (1) to investigate the pathological characteristics of gastrocnemius muscle (GM) and quantitatively assess GM tissue stiffness in rat models with spinal cord injury (SCI) and (2) to explore the correlation between pathological characteristics changes and Young's modulus value of GM. 24 Sprague Dawley male rats were allocated into normal control groups and SCI model subgroups, respectively. GM stiffness was assessed with shear wave sonoelastography technology. All GMs were further analyzed by pathological examinations. GM weights were decreased, the ratio of type I fibers was decreased, and the ratio of type II fibers was increased in the GM in the model group. MyHC-I was decreased, while MyHC-II was increased according to the electrophoretic analysis in model subgroups. The elastic modulus value of GM was increased in the model group. A significant negative correlation was found between Young's modulus value of GM and the ratio of type I fibers of GM in model subgroup. Our studies showed that the stiffness of GM is correlated with pathological characteristics during the initial stages of SCI in rats. We also identified shear wave sonoelastography technology as a useful tool to assess GM stiffness in SCI rat models.