Between-sexes differences in lumbopelvic muscle mechanical properties of non-climacteric adults: a cross-sectional design.

The lumbopelvic muscle mechanical properties (MMPs) are clinically relevant, but their dependence on sex remains unknown. Therefore, this study aimed to identify if lumbopelvic MMPs depend on the sex in a young adult population. Thirty-five healthy nulliparous women and 35 healthy men were analyzed (age range: 18-50). Lumbopelvic MMPs, that is, tone, stiffness, elasticity, relaxation and creep, assessed with MyotonPRO®, and pelvic floor (PF) health questionnaires were compared between-sexes. Intra-group correlations between sociodemographic and clinical data, and MMPs were also determined. The MMPs of PF were different between healthy non-climacteric adults of both sexes, with women showing higher values of tone and stiffness and lower values of elasticity and viscoelastic properties than men (in all cases, p < 0.03). At lumbar level, tone and stiffness were higher for men at both sides (in all cases, p < 0.04), and relaxation was lower at left side (p = 0.02). The MMPs showed few correlations with sociodemographic data within women. However, within males, there were positive correlations for PF stiffness and viscoelastic parameters with age, BMI and function (0.334 < r < 0.591) and, at lumbar level, negative correlations for tone and stiffness ( - 0.385 < r < -0.590) and positive correlations for viscoelastic properties (0.564 < r < 0.719), with BMI. This indicated that between-sexes differences of lumbopelvic MMPs depend on the specific location of assessment in healthy non-obese young individuals. Women show higher tone and stiffness and lower elasticity and viscoelasticity than men, at PF level.

Reliability of the Modified Ashworth Scale After Stroke for 13 Muscle Groups.

OBJECTIVE: To evaluate the reliability of the protocol for administration of the Modified Ashworth Scale (MAS) for all commonly affected muscle groups after stroke. DESIGN: A repeated-measures design was used in administration of MAS for 13 muscle groups on 2 assessment days. Intrarater reliability and interrater reliability (between 3 raters) was assessed. SETTING: Inpatient rehabilitation. PARTICIPANTS: 30 patients, 1-19 months after stroke (age 55.1±13.5 years; N=30). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Intra- and interrater reliability of the muscle tone assessment protocol with MAS for 7 upper and 6 lower limb muscle groups compiled from previous studies; 1 modified and 4 originally described. The weighted kappa was calculated. RESULTS: The most and the least frequently assigned MAS grades were 0 and 4, respectively. Agreement was the highest for grade 0 (49% within raters, 32% between raters). Intrarater reliability was good to excellent for upper limb (κ=0.71-0.94) and moderate to excellent for lower limb (κ=0.55-0.97) muscles. Interrater reliability was poor to good for upper limb (κ=0.25-0.66) and moderate for lower limb (κ=0.41-0.54) muscles. CONCLUSIONS: The intrarater reliability of MAS was moderate for the hip flexors. The reliability results for the other 4 muscles studied anew after stroke were similar to the predetermined ones. The better intrarater reliability results confirmed previous findings. Because of the low interrater reliability, caution is needed in interpreting the results when reassessment is not possible by the same examiner. A well-described protocol for administering the MAS may lead to its standardization.

Automated Creak Differentiates Adductor Laryngeal Dystonia and Muscle Tension Dysphonia.

OBJECTIVE: The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers with muscle tension dysphonia (MTD) and speakers without voice disorders. METHODS: Sixteen speakers with AdLD, sixteen speakers with MTD, and sixteen speakers without voice disorders were recorded in a quiet environment reading aloud a standard paragraph. An open-source creak detector was used to calculate the percentage of creak (% creak) in each of the speaker's six recorded sentences. RESULTS: A Kruskal-Wallis one-way analysis of variance revealed a statistically significant effect of group on the % creak with a large effect size. Pairwise Wilcoxon tests revealed a statistically significant difference in % creak between speakers with AdLD and controls as well as between speakers with AdLD and MTD. Receiver operating characteristic curve analyses indicated that % creak differentiated AdLD from both controls and speakers with MTD with high sensitivity and specificity (area under the curve statistics of 0.94 and 0.86, respectively). CONCLUSION: Percentage of creak as calculated by an automated creak detector may be useful as a quantitative indicator of AdLD, demonstrating the potential for use as a screening tool or to aid in a differential diagnosis. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:2687-2694, 2023.

Prevalence and Characteristics of Muscle Tightness in Young Adults.

In young adults, muscle sprains and strains leading to muscle tightness are considered short-term and believed to have no ill effects on quality of life. However, recent advances in the science indicate that muscle tightness is an invisible condition that can limit life activities. The objective of this study was to identify the prevalence and characteristics of muscle tightness in young adults. The study used descriptive quantitative design. One hundred individuals aged between 18 and 27 years completed a survey based upon a validated muscle tightness measurement tool. Seventy-two percent of participants reported experiencing muscle tightness that limited their daily living and recreational activities. Fifty-six percent reported experiencing pain with muscle tightness. Women were more likely than men to experience muscle tightness. Awareness, prompt evaluation, and treatment of this condition are key to preventing negative consequences associated with chronic muscle tightness.

Integrative Review and Framework of Suggested Mechanisms in Primary Muscle Tension Dysphonia.

PURPOSE: Despite the high prevalence of primary muscle tension dysphonia (MTD-1), its underlying mechanisms and their interrelationships have yet to be fully identified. The objectives of this integrative review were (a) to describe and classify the suggested underlying mechanisms for MTD-1, (b) to appraise the empirical evidence supporting each of the proposed mechanisms, and (c) to summarize the information in an integrative model. METHOD: PubMed, Scopus, and CINAHL were searched for all publications pertaining to muscle tension dysphonia. Papers were retained if they included theoretical or empirical data pertaining to underlying mechanisms of MTD-1. A total of 921 papers initially qualified for screening, of which 100 remained for consideration in this review. Underlying mechanisms of MTD-1 were extracted using a consensus approach. RESULTS: Seven broad categories of putative mechanisms involved in MTD-1 were identified: psychosocial, autonomic, sensorimotor, respiratory, postural, inflammatory, and neuromuscular. These categories were further divided into 19 subcategories detailed in the body of this review article. Based on the reviewed evidence, our proposed integrative model presents MTD-1 as an idiosyncratic motor adaptation to physiological perturbation or perceived threat. Under this model, physiologically or psychologically aversive stimuli can instigate a series of motor adaptations at multiple levels of the nervous system, ultimately disturbing muscle activation patterns and their biomechanical outcomes. Importantly, these adaptations appear to have the potential to become chronic even after threatening stimuli are withdrawn. CONCLUSIONS: The proposed model highlights the importance of personalized rehabilitation in MTD-1 treatment. Limitations of the literature are discussed to provide guidance for future research aimed at improving our understanding of MTD-1. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.19586065.

[Feeling stiff but what does it mean objectively? : Can you measure muscle tension?] / Gefühlt steif und objektiv? : Kann man Muskelverspannungen messen?

Almost everyone is familiar with "tense muscles", but what is muscle tension physiologically behind? Are tense muscles more active; do they have problems relaxing? Are they harder or stiffer than asymptomatic muscles? In this work, current evidence regarding the activity and stiffness of tense neck muscles is presented. Further, measurement methods and their limitations are explained. These limitations reveal the shortcomings of the current knowledge and the need for further research. Finally, a recently funded research project on the measurement of tense muscles is presented.

A Novel and Clinically Feasible Instrument for Quantifying Upper Limb Muscle Tone and Motor Function via Indirect Measure Methods.

OBJECTIVE: Quantifying muscle tone is often based on a tester's subjective judgment in clinical settings. There is, however, a lack of suitable tools that can be used to objectively assess muscle tone. This study thus introduces a reliable, clinically-feasible device, called the Arm Circumference Motor Evaluation System (ACMES), for quantifying the muscle tone of upper limbs without using mechanical torque transducers. METHODS: While the ACMES conducts continuously passive arm circumduction motions, the voltage and current of the driving motor is transduced into torque values via a least square approximation. A torque sensor and springs with different spring constants were used for the validity and reliability test in the first part of this study. Fifteen healthy adults and two patients who had experienced a stroke participated in the second part, which was a clinical experiment used to examine the in-vivo test-retest reliability and to explore the inspection differences between healthy and patient participants. RESULTS: The results showed that the ACMES has high validity (R2: ~0.99) and reliability (R2: 0.96~0.99). The reliability of the ACMES used on human subjects was acceptable (R2: 0.83~0.85). The various muscle tone patterns could be found among healthy and stroke subjects via the ACMES. CONCLUSION: Clinically, abnormal muscle tone, which seriously affects motion performance, will be found in many diagnoses, such as stroke or cerebral palsy. However, objectively and feasibly measuring abnormal tone in modern clinical settings is still a challenging task. Thus, the ACMES was developed and tested to verify its feasibility as a measurement system for detecting the mechanical torque associated with muscle tone.

Feasibility of Using a Portable MyotonPRO Device to Quantify the Elastic Properties of Skeletal Muscle.

BACKGROUND The aims of this study were to (1) calculate the correlation between different tensile force levels and corresponding muscle stiffness both in vitro and in vivo; (2) determine whether muscle stiffness assessed using a MyotonPRO myotonometer can be used to accurately estimate muscle activity level; and (3) evaluate the inter-operator reliability of MyotonPRO-based measurement in assessing biceps brachii muscle (BBM) stiffness. MATERIAL AND METHODS In Experiment I, muscle stiffness, as measured using the MyotonPRO, was obtained at 0 N, 2 N, 4 N, 6 N, 8 N, and 10 N of applied force on 6 fresh medial gastrocnemius muscle specimens. In Experiment II, 11 healthy subjects were recruited. BBM stiffness, assessed by the same device, was obtained at different tensile force levels, from 0 to 50% of maximal voluntary contraction (MVC). For the reliability test, the score for each subject was quantified by 2 operators (I and II), thrice, at 30-minute intervals on the same day. RESULTS A strong correlation was found between the different tensile force levels, which corresponded to muscle stiffness in vitro (r=0.71-0.95, all P<0.05). In vivo, muscle stiffness increased linearly with an increase of the tensile force levels from 0 to 50% of MVC (r=0.99, P=0.00) and there was a significant difference in BBM stiffness among the incremental isometric tasks (F [1.76, 17.60]=91.52, P=0.00). The inter-operator reliability for the measurement of BBM stiffness was good (ICC=0.86). CONCLUSIONS Our findings indicate that muscle stiffness measured using the MyotonPRO is strongly related to muscle activity level and that the MyotonPRO is a feasible tool for quantifying BBM stiffness as well as for quantifying changes in MVC levels.

Smooth muscle tone alters arterial stiffness: the importance of the extracellular matrix to vascular smooth muscle stiffness ratio.

BACKGROUND: Recent studies show that vascular smooth muscle (VSM) is more important to elastic artery mechanics than previously believed. It remains unclear whether increased VSM tone increases or decreases arterial stiffness. METHODS AND RESULTS: We developed a novel arterial mechanics model based on pressure-diameter relationships that incorporates the contributions of extracellular matrix (ECM) and VSM to arterial stiffness measures. This model is advantageous because it simple enough to use with limited clinical data but has biologically relevant parameters which include ECM stiffness, VSM stiffness, and VSM tone. The model was used to retrospectively analyze the effects of nitroglycerin-induced vasodilation in four clinical studies. Stiffness parameters were modeled for five arterial regions including both elastic and muscular arteries. The model describes complex experimental data with changing VSM tone and blood pressure. Our analysis found that when ECM is less stiff than VSM, increasing VSM tone increases arterial stiffness. The opposite is seen when ECM is stiffer than VSM, increasing VSM tone decreases stiffness. Our results also suggest that VSM tone is a compensatory mechanism for elevated ECM stiffness in hypertensive individuals. CONCLUSION: Based on retrospective analysis of four clinical studies, we propose a simple hypothesis for the role of VSM tone on arterial stiffness: increased VSM tone increases arterial stiffness when VSM is stiffer than ECM and decreases arterial stiffness when ECM is stiffer than VSM. This hypothesis and the methods used in this study could have important implications for understanding arterial physiology in both hypertension and cardiovascular disease and deserve further exploration.

Strain Elastosonography Measurement in Patients with Primary Muscle Tension Dysphonia Compared with Healthy Speakers: A Pilot Study.

OBJECTIVES: The purpose of this study was to investigate real-time elastosonography (RTE) to measure strain of the (para)laryngeal muscles in patients with primary muscle tension dysphonia (MTD) and healthy speakers. STUDY DESIGN: This is a cross-sectional study. METHODS: Ten patients with primary MTD (37.8 ± 10.53 years) and 10 healthy speakers (36.9 ± 9.8 years) participated. Participants were diagnosed as MTD patient or healthy via voice history, voice self-assessment, perceptual voice evaluation, laryngeal palpation, and videostroboscopy. Then, RTE was performed to extract strain index (SI) and strain ratio (SR) for all participants. The RTE was utilized for the suprahyoid, thyrohyoid, and the cricothyroid muscles, both in right and left sides during rest, /a/, and /i/ prolongations. To study the effect of group, task, and interactive effect on the SI and SR, two-way repeated-measures analysis of variance was performed. RESULTS: The effect of group on the SI was significant for the right cricothyroid (P ˂ 0.001). Significant effect of group on the SR obtained for the right suprahyoid, left thyrohyoid, and right cricothyroid (P < 0.05). Moreover, the only muscle whose SR was significantly affected by task was the left suprahyoid (P < 0.05). Compared to healthy speakers, the interactive effect was significantly lower in SI for the left cricothyroid, and higher in SR for both the right suprahyoid and left cricothyroid in patients (P < 0.05). CONCLUSIONS: The RTE can discriminate patients with primary MTD from healthy subjects in some laryngeal muscles, especially suprahyoid and cricothyroid. It may be regarded as a clinical instrument in the assessment of MTD in future. Further studies with bigger sample size are recommended.

Evaluating the use of baclofen as adjunct treatment for muscle tension dysphonia.

OBJECTIVE: To explore whether use of baclofen as adjunct treatment to voice therapy (VT) led to improvement in subjective throat symptoms in patients with primary muscle tension dysphonia (MTD). MTD is associated with excessive paralaryngeal muscle contraction, and baclofen is a muscle relaxant. STUDY DESIGN: Cross-sectional, questionnaire-based study. METHODS: An initial pool of patients, who were diagnosed with primary MTD and received 1+ VT session(s) at a single tertiary-care center from 2015 to 2019, were placed into either a baclofen group (prescribed 10 mg baclofen t.i.d. PRN along with VT) based on symptomatology or non-baclofen group (VT alone). They were administered questionnaires via postage mail or phone that included the Voice Handicap Index-10 (VHI-10), Reflux Symptom Index (RSI), and other survey elements. A retrospective chart review collected demographic and other clinical data from recruited participants. RESULTS: A total of 314 non-baclofen and 63 baclofen patients met the inclusion criteria of this study, with 37 non-baclofen patients (mean age = 47.5 years, 62.2% female) and 15 baclofen patients (mean age = 45.5 years, 73.3% female) recruited. There was no significant difference in mean [SD] VHI-10 scores (11.30 [8.20] vs. 12.60 [10.75]; p = 0.638) and RSI scores (13.46 [10.44] vs. 16.20 [10.65]; p = 0.398) between non-baclofen and baclofen groups, respectively. CONCLUSION: There was no significant difference in voice psychometric outcomes between non-baclofen and baclofen groups, measured primarily by the VHI-10 and RSI questionnaire components. Further studies are warranted to assess the efficacy and safety of baclofen as a therapeutic option for MTD.

Muscle Flap Reconstruction Based on Muscle Tension Line Groups to Repair the Philtrum of Patients With Microform Cleft Lip or Secondary Cleft Lip.

ABSTRACT: The muscle flap reconstruction technique was developed based on the concept of muscle tension line groups, which elucidates how nasolabial muscle tension helps maintain the shape of the philtrum. To investigate the operative effect, we reviewed 43 patients with microform cleft lip and 102 patients with secondary cleft lip treated with muscle flap reconstruction between January 2018 and June 2020. The patients were scanned using the digital three-dimensional stereophotogrammetry face system pre- and post-operatively, and comparative analysis of three-dimensional (3D) images was used to highlight variations of the philtrum. Visual analog scales were used to assess surgical outcomes. More than 6 months after the surgery, comparative 3D images of 37 patients (86.04%) with microform cleft lip and 86 patients (84.31%) with secondary cleft lip showed visible improvement in the prominence of the affected column. In addition, visual analog scale scores showed that 38 microform cleft lip patients (88.37%) and 89 secondary cleft lip patients (87.25%) had a good appearance. The postoperative prominence of the philtral column in both groups improved significantly compared to before surgery (P < 0.001 and P < 0.001, respectively). There was no significant difference in scores for philtrum prominence pre- and post-operatively between the 2 groups (P > 0.05). Muscle flap reconstruction is an effective means to create the 3D configuration of the philtrum. The biomechanical properties of muscles play a vital role in the morphological maintenance of the philtrum.

The Effects of Different Exteroceptive Experiences on the Early Motor Repertoire in Infants With Down Syndrome.

OBJECTIVE: Down syndrome is a chromosomal abnormality in which muscle tone, motor development, and sensory systems are affected. The objectives of this study were to examine the changes in movements and postures of 3- to 5-month-old infants with Down syndrome and infants who were neurotypical controls during exposure to a rough-textured surface and to compare the differences occurring before and during an exteroceptive condition that was different between the 2 groups. METHODS: In this quasi-experimental study, participants were 20 infants with Down syndrome (8 female infants; age range = 10-18 weeks, mean [SD] = 12 weeks 2 days [2 weeks 2 days]) and 20 age-matched infants with typical development (8 female infants; age range = 9-17 weeks, mean (SD) = 12 weeks 6 days [1 week 5 days]). The movements and postures of the infants, including fidgety movements, were assessed according to the General Movements Assessment, which determines the Motor Optimality Score (MOS), on 2 surfaces. RESULTS: The MOS outcomes of the infants with Down syndrome (median = 21.5, range = 6-28) were significantly lower than those of the infants who were neurotypical (median = 28, range = 23-28) on a standard mattress. The postures were found to be significantly better in infants with Down syndrome during exposure to a rough-textured surface. The MOS did not change due to the different exteroceptive experiences in infants with Down syndrome and infants who were neurotypical. CONCLUSION: The different exteroceptive experiences caused only postural alterations, which might play a crucial role in early intervention programs for infants with Down syndrome. IMPACT: This is the first study, to our knowledge, on the effects of different exteroceptive conditions, such as a coco coir mattress covered with muslin fabric, on the early motor repertoire in infants with Down syndrome. The findings showed that infants with Down syndrome had heterogeneity in their fidgety movements and large variability of the MOS, and the MOS results from infants with Down syndrome were lower than those of infants who were neurotypical. Fidgety movements and the MOS did not change due to the different exteroceptive experiences in either group. Significant improvements in posture were observed during exposure to a rough-textured surface. The improvement of posture is essential; clinicians might consider the positive effect of putting an infant with Down syndrome on a rough-textured surface and include this strategy in early intervention programs.

BDNF rescues aging-associated internal anal sphincter dysfunction.

Aging can lead to rectoanal incontinence due to internal anal sphincter (IAS) dysfunction, which is characterized by a decrease in IAS tone and contractility and an increase in nonadrenergic noncholinergic (NANC) relaxation. We aimed to determine whether brain-derived neurotropic factor (BDNF) rescues this aging-associated IAS dysfunction (AAID). To do so, we studied the effects of BDNF on the basal and G protein-coupled receptors (GPCR)-stimulated IAS smooth muscle tone and on NANC relaxation in Fischer 344 rats representing different age groups [26-mo-old (aging) vs. 6-mo-old (young)], before and after tyrosine kinase receptor B (TrkB) antagonist K252a. We also used isolated smooth muscle cells (SMCs) to determine the effects of BDNF before and after different agonists. For some studies, we monitored NO release using smooth muscle perfusates. BDNF reversed AAID by rescuing the basal IAS tone and agonists [thromboxane A2 analog (U46619) and angiotensin II (ANG II)]-induced contractility, and NANC relaxation. These rescue effects of BDNF were selective as K252a attenuated the changes in the IAS without modifying the effects of K+depolarization. Because of the direct association between the basal and GPCR-stimulated IAS tone and RhoA/ROCK activation, we speculate that this pathway in the rescue effects of BDNF. Conversely, our data suggest that aging-associated increased NANC relaxation is reversed by decreased release of NO and decrease in the sensitivity of the released inhibitory neurotransmitter. In summary, BDNF rescue of AAID involves RhoA/ROCK and inhibitory neurotransmission. These data have direct implications for the role of BDNF in the pathophysiology and therapeutic targeting of aging-associated rectoanal motility disorders.NEW & NOTEWORTHY These studies demonstrate that brain-derived neurotropic factor (BDNF) rescues the aging-associated internal anal sphincter (IAS) dysfunction, characterized by a decrease in IAS tone, and increase in non-adrenergic noncholinergic relaxation. We determined the effects of BDNF on the basal and GPCR (TXA2 and ANG II)-stimulated IAS tone, and on NANC relaxation, before and after TrkB inhibitor K252a. BDNF may have an important role in the pathophysiology and therapeutic targeting of certain rectoanal motility disorders.

Increasing muscle activity correlations during spontaneous movements in the first six months of life.

Spontaneous muscle activity in the first months of life is an important prerequisite to developing voluntary motor skills and to adapting sensorimotor circuits and muscle tone to body and environmental changes. Even though high variability is a characteristic of early development, several studies have reported significant correlations of limb movements. These assessments were typically made based on kinematics, while the analysis of lower and upper limb muscle activity may provide additional information about maturation of the neuromuscular control. To this end, we examined the electromyographic activity of 12 muscles of the upper and lower limbs in full-term healthy infants (n = 40) aged from 1 week to six months. An increase of ipsilateral and contralateral limb muscle activity correlations with age was found in both flexors and extensors and may reflect a progressive emergence of elements of coordinative neuromuscular behaviour. Correlations between arm and leg muscle responses also increased during passive leg movements. Overall, the findings are consistent with maturation of physiologically relevant neuromuscular network connections during the course of transition from spontaneous-like to voluntary goal-directed movements during early development.