Muscle Tone Physiology and Abnormalities

Effect of modified scooter board therapy on trunk control and hip muscle activation in children with cerebral palsy - A pilot randomised control study

Cerebral palsy (CP), with an incidence rate of 2.95, is one of the leading causes of disability in children. The excessive tone in several muscle groups causes significant movement deficits and secondary impairments, such as hip displacement, affecting quality of life. Although age-related functional positioning treatment is effective, it does not prevent secondary deficits. Literature recommends the use of task-based training with an emphasis on the functional elongation of these spastic muscle groups. Thus, a therapy that is engaging, parent-inclusive, and addresses hip-related deficits is needed. Hence, this study aimed to develop and evaluate a therapy targeting adductor overactivity and trunk control. Modified Scooter Board Therapy (MSBT) is an intervention that uses a specially designed scooter board device, allowing children to propel themselves forward while positioned prone with hip abduction and neutral hip rotation. A convenient sample of eight children with CP were assigned to either the MSBT or conventional exercise group. The intervention lasted eight weeks, and electromyographic (EMG) recordings at rest and during volitional activity were obtained at baseline and after eight weeks. Non-parametric statistical analysis, with a significance level of p < 0.05, showed no statistically significant differences between the groups at the end of the eight weeks. However, volitional hip adductor activity significantly changed in the MSBT group, indicated by a reduction in mean motor unit potential at rest. Additionally, parents preferred MSBT for its ease of use. Thus, MSBT appears to be a clinically promising intervention to reduce adductor hypertonicity and improve active control, highlighting the importance of prone positioning with active elongation for better motor function.

A protocol to evaluate the effect of Modified Scooter Board Therapy on Trunk Control and Hip muscles Activation in children with Cerebral Palsy

Cerebral palsy (CP) is a condition caused due to damage to a developing brain, leading to various motor, sensory and cognitive impairments. Being one of the leading cause of developmental disability among children worldwide, CP warrants a rehabilitation technique which is feasible and engaging for the child, cost effective for the family and based neurophysiological principles. Among the various impairments, the children with CP exhibit difficulty in sitting and ambulation due to abnormal tone and poor control in the muscles around the hip joint and the trunk. The previous literature supports the prone positioning and its effect in improving the girdle and trunk control, however there is lack in the studies which evaluate the type of interventions which consider the child and parent participation in intervention being delivered. Thus, the current double blinded randomized control trial aims to evaluate the effect of exercises done using Modified scooter board device in addition to conventional therapy in improving the hip muscle activation and trunk control in children with CP.•A study evaluating the effectiveness of a novel scooter board device in children with CP.•An intervention which is simple, self-engaging and cost effective to prevent most secondary complications seen in children with CP.•An intervention which is aimed at reducing the hardship experienced by parents of children with CP towards improving their functional outcome.

Cogwheel rigidity in Parkinson's disease: Clinical, biomechanical and neurophysiological features

OBJECTIVES

Cogwheel rigidity in Parkinson's disease has been poorly investigated so far, thus leaving the scientific interpretation of this phenomenon substantially unsolved. A detailed clinical, biomechanical and neurophysiological investigation would clarify the pathophysiological underpinning of cogwheel rigidity.

METHODS

Patients underwent robot-assisted wrist extensions at various angular velocities, when OFF and ON therapies. For each value of angular velocity, several biomechanical (i.e. elastic, viscous and neural components) and neurophysiological measures (i.e. long-latency stretch reflex) were synchronously assessed and correlated with the clinical score of rigidity (i.e. Movement Disorder Society Unified Parkinson's Disease Rating Scale-part III, subitems for the upper limb).

RESULTS

A total of 18 PD patients participated. Patients were divided into two groups according to the presence of cogwheel rigidity at the clinical examination (CWR and No-CWR, respectively). CWR patients had a longer disease duration, greater motor severity and disability scores compared to those who did not. Biomechanical (NC and TF) and neurophysiological data (LLRs amplitude and AUC) also disclosed a more pronounced impairment in patients with cogwheel rigidity. L-DOPA comparably improved rigidity measures in patients with and without cogwheel rigidity.

DISCUSSION

Cogwheel rigidity may be associated with prominent impairment in clinical, biomechanical, and neurophysiological features of rigidity in patients with PD. Future studies in larger cohorts are needed to achieve more firm conclusions.

Clinical efficacy observation of repetitive magnetic stimulation for treating upper limb spasticity after stroke

To investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) for managing upper limb muscular spasticity after stroke, and to examine its therapeutic effects on spasticity and motor function in the upper limb. A total of 110 post-stroke patients with upper limb spasticity were randomly assigned to the experimental or the control group. The experimental group received rTMS in conjunction with conventional rehabilitation therapy. The affected side of the head received daily treatment for 20 min each at Erb's point and the stimulation point, totaling 15 sessions over six days per week. The stimulation frequencies were 10 Hz (high frequency, M1 region) and 1 Hz (low frequency, Erb's point), with an intensity at 120% of the threshold. The control group received sham stimulation alongside conventional rehabilitation therapy. Assessments including the Modified Ashworth Scale (MAS) and Fugl-Meyer Assessment for Upper Extremity (FM-UE), were also conducted before treatment initiation and after 15 rounds of rTMS. Post hoc subgroup analyses were conducted using independent-sample t-tests for FM-UE scores and Mann-Whitney U tests for MAS scores to assess heterogeneity in treatment responses by stroke type (cerebral infarction vs. intracerebral hemorrhage). Among these 110 patients, 25 patients were excluded from the study for various reasons. Hence, 53 patients were included in the control group and 32 patients were included in the experimental group. Following 15 rounds of rTMS, the experimental group exhibited a reductions in MAS score (P = 0.004). FM-UE scores increased significantly in both groups (both P < 0.05), with significant improvement observed in the experimental group (P < 0.05). Subgroup analyses revealed no significant differences in FM-UE or MAS outcomes between stroke types, likely due to the limited sample size of intracerebral hemorrhage participants (experimental group: n = 8; control group: n = 16). rTMS effectively alleviates upper limb spasticity and enhances motor function after stroke by modulating cortical and spinal nerve excitability.

Decoding Autoimmunity: Insights Into Neuromyelitis Optica and Its Relationship With Other Autoimmune Neurological Disorders

Neuromyelitis optica (NMO) is a rare but debilitating autoimmune condition characterized by severe attacks of optic neuritis and transverse myelitis, often resulting in significant neurological disability. Autoantibodies targeting aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) play critical roles in disease pathogenesis, and therapeutic strategies encompassing immunosuppressive therapies and emerging biologics are employed to manage disease activity and prevent relapse. While studies suggest a potential overlap between NMO and other autoimmune neurological conditions, research in this area remains limited. This review explores the commonalities and distinctions between NMO and related autoimmune neurological disorders, hypothesizing that shared autoantibody mechanisms and clinical features may refine diagnostic criteria and therapeutic interventions. Additionally, it addresses tailored management approaches for specific clinical features of NMO and its overlaps. The paper also explores current research on biomarkers and novel treatment modalities, highlighting persistent knowledge gaps, such as understanding the immune mechanisms behind NMO and predicting individual responses to therapies. The review underscores the necessity for collaborative research efforts to improve diagnostic accuracy and therapeutic efficacy. Ultimately, these efforts will enhance personalized care strategies and optimize outcomes and quality of life for patients with NMO and related autoimmune neurological disorders.

A Comprehensive Understanding of Postural Tone Biomechanics: Intrinsic Stiffness, Functional Stiffness, Antagonist Coactivation, and COP Dynamics in Post-Stroke Adults

OBJECTIVE

To analyse the relationship between traditional stiffness and muscle antagonist coactivation in both stroke and healthy participants, using linear and non-linear measures of coactivation and COP during standing, stand-to-sit, and gait initiation.

METHODS

Participants were evaluated through a cross-sectional design. Electromyography, isokinetic dynamometer, and force plate were used to calculate coactivation, intrinsic and functional stiffness, and COP displacement, with both linear and non-linear metrics. Spearman's correlations and Mann-Whitney tests were applied (p < 0.05).

RESULTS

Post-stroke participants showed higher contralesional intrinsic stiffness (p = 0.041) and higher functional stiffness (p = 0.047). Coactivation was higher on the ipsilesional side during standing (p = 0.012) and reduced on the contralesional side during standing and transitions (p < 0.01). Moderate correlations were found between intrinsic and functional stiffness (p = 0.030) and between coactivation and intrinsic stiffness (standing and stand-to-sit: p = 0.048) and functional stiffness (gait initiation: p = 0.045). COP displacement was reduced in post-stroke participants during standing (p < 0.001) and increased during gait initiation (p = 0.001). Post-stroke participants exhibited increased gastrocnemius/tibialis anterior coactivation during gait initiation (p = 0.038) and higher entropy and stability across tasks (p < 0.001).

CONCLUSION

Post-stroke participants showed higher contralesional intrinsic and functional stiffness, reduced coactivation in static tasks, and increased coactivation in dynamic tasks. COP and coactivation analyses revealed impaired stability and random control, highlighting the importance of multidimensional evaluations of postural tone.

Clinical and brain functional correlates of instrumental rigidity measurement in Parkinson's disease

Rigidity, a cardinal symptom of Parkinson's disease (PD), remains challenging to assess objectively. A torque-angle instrument was developed to quantify muscle tone, providing two parameters: bias difference and elastic coefficient. This study aimed to investigate the association of the instrument-measured rigidity with clinical assessments and brain function. In 30 patients with PD, the muscle tone in both arms was evaluated. Ten with wearing-off phenomenon were assessed twice, off and on condition. Twentynine patients underwent brain perfusion single-photon emission computed tomography (SPECT), and expression of PD-related covariance pattern (PDRP) was computed. Bias difference and elastic coefficient showed positive correlations with physician-rated rigidity (P < 0.002). Bias difference decreased after dopaminergic medication (P = 0.022) and was associated with lower body mass index (P = 0.012). Elastic coefficient positively correlated with the Unified PD Rating Scale Part III and PDRP scores (P < 0.044). Furthermore, the higher bias difference correlated with decreased sensory-motor cortex and increased substantia nigra perfusion (P < 0.001). The Torque-angle instrument is a viable tool for quantifying rigidity in PD. The bias difference reflects treatment responsiveness and is associated with the function in the sensory-motor cortex and substantia nigra. The elastic coefficient is indicative of overall Parkinsonism severity.

Pedal Reaction Forces and Electromyography Responses Indicate Eccentric Contractions During Motorized Cycling in a Rat Model of Incomplete Spinal Cord Injury

Motorized cycling (MC) is utilized as an alternative to traditional exercise in individuals who are unable to perform voluntary movements post-spinal cord injury. Although rodent models of MC often show more positive outcomes when compared with clinical studies, the cause of this difference is unknown. We postulate that biomechanical differences between rats and humans may contribute to this discrepancy. To begin to test this theory, we examined pedal reaction forces and electromyography (EMG) of hindlimb muscles as a function of cycle phase and cadence in a rat model of MC. We found that higher cadences (≥30 RPM) increased EMG and force, with higher forces observed in animals with contusion injuries as compared with transections. To further investigate the forces, we developed a technique to separate rhythmic (developed with the motion of the pedals) from nonrhythmic forces. Rhythmic forces resulted from induced eccentric muscle contractions that increased (amplitude and prevalence) at higher cadences, whereas nonrhythmic forces showed the opposite pattern. Our results suggest that muscle activity during MC in rats depends on the stretch reflex, which, in turn, depends on the rate of muscle lengthening that is modulated by cadence. Additionally, we provide a framework for understanding MC that may help translate results from rat models to clinical use in the future.

Comparison of gait and architecture of the medial gastrocnemius in developmentally delayed children with different muscle tone: A preliminary pilot study

BACKGROUND

Muscle tone alteration reduces gait and motor function in children with developmental delays. We aimed to determine differences in gait and structure of the medial gastrocnemius muscle between typically developing children and children with developmental delays with different muscle tone.

METHODS

Forty-nine participants were divided into typically developing children (n = 22), children with spastic hemiplegia (n = 6), children with spastic diplegia (n = 9), and children with central hypotonia (n = 12). A wearable gait analysis system was used to measure spatiotemporal variables and pelvic movement, and ultrasonography was used to measure the pennation angle, thickness, and fascicle length of the medial gastrocnemius.

FINDING

Children with spastic hemiplegia had significantly smaller total symmetric index and pelvic tilt symmetric index than typically developing children (P < 0.050). Children with spastic diplegia had smaller pennation angle than typically developing children (P < 0.050), and children with central hypotonia had lower velocity than typically developing children (P < 0.050). Children with spastic diplegia had a greater pelvic rotation range than children with central hypotonia (P < 0.050).

INTERPRETATION

This study helps to understand gait and muscle structure in central hypotonia and spastic cerebral palsy.

Mastication and electrical activation in the masseter and anterior temporalis muscles of children and adolescents with osteogenesis imperfecta

PURPOSE

to characterize mastication and electrical activation of the masseter and anterior temporalis muscles in children and adolescents with osteogenesis imperfecta (OI), and relate results to guided occlusion and occlusal interference.

METHODS

This observational, analytical cross-sectional study included 22 subjects divided into mild OI (MOI) (type 1) (n=15) and moderate-to-severe OI (MSOI) (types 3, 4, and 5) (n=7) groups. The Orofacial Myofunctional Evaluation with Scores (OMES) form was used to evaluate the clinical aspects of mastication. Surface electromyography was performed on the masseter and anterior temporalis muscles at rest for 10 seconds and during maximum intercuspation, spontaneous chewing, and instructed chewing on the right and left sides. Additionally, the activation index and muscle symmetry were measured.

RESULTS

a preferentially unilateral chewing pattern was observed in 12 (54.5%) participants. Masticatory patterns did not influence electrical activation during any of the tasks, nor did occlusal guidance during maximum intercuspation or mastication. The percentage of muscle activation during maximal intercuspation approached half of the total activation during spontaneous chewing. In muscle activation indices, the MSOI group presented more atypical scores, while the MOI group scores seemed to be in line with reference values. The symmetry indices seemed to correspond to reference values, but the standard deviation and minimum and maximum values pointed to asymmetric results.

CONCLUSION

This study found that the OI population presented muscle imbalances, but the results did not allow us to define one pattern of change.

Influence of pain, sequential movement or short-term rest performance on the evaluation results of neck muscle mechanical properties: a case-control study

INTRODUCTION

Individuals with neck pain (NP) often experience altered muscle mechanical properties (MMPs), such as increased tone and stiffness. Myotonometry has become a reliable, noninvasive tool for measuring MMPs. However, the effect of movement and rest on MMPs in acute neck pain (ANP) individuals remains insufficiently explored.

OBJECTIVE

This study aimed to evaluate how sequential movement and short-term rest influence the MMPs of neck muscles in subjects with ANP.

METHODS

A case-control study was conducted with 37 subjects with APN and 37 matched healthy controls. Muscle mechanical properties were assessed by myotonometry at baseline, post-movement (after a motion assessment sequence), and post-rest. The outcome measures of MMPs were frequency or tone, stiffness, decrement, which is the inverse of elasticity, relaxation, and creep.

RESULTS

Subjects with ANP showed higher muscle tone, stiffness and decrement, and lower relaxation than controls, all with p < .05. In the ANP group, decrement was the only property that showed a significant change after movement and rest, both with p < .05. Reduced means values (m) with its standard deviation (SD) were observed post-movement (m = 1.35 Ø, SD = 0.03) and post-rest (m = 1.33 Ø, SD = 0.03) compared to baseline values (m = 1.43 Ø, SD = 0.04). The other MMPs remained stable across evaluation times (p > .05).

CONCLUSION

The evaluation of MMPs should be conducted prior to any mobility protocol to ensure that the results reflect the basal tissue characteristics in individuals with ANP, highlighting decrement as a sensitive marker of these changes.

Pathophysiology and Management Strategies for Post-Stroke Spasticity: An Update Review

Post-stroke spasticity (PSS), characterized by a velocity-dependent increase in muscle tone and exaggerated reflexes, affects a significant portion of stroke patients and presents a substantial obstacle to post-stroke rehabilitation. Effective management and treatment for PSS remains a significant clinical challenge in the interdisciplinary aspect depending on the understanding of its etiologies and pathophysiology. We systematically review the relevant literature and provide the main pathogenic hypotheses: alterations in the balance of excitatory and inhibitory inputs to the descending pathway or the spinal circuit, which are secondary to cortical and subcortical ischemic or hemorrhagic injury, lead to disinhibition of the stretch reflex and increased muscle tone. Prolongation of motoneuron responses to synaptic excitation by persistent inward currents and secondary changes in muscle contribute to hypertonia. The guidelines for PSS treatment advocate for a variety of therapeutic approaches, yet they are hindered by constraints such as dose-dependent adverse effects, high cost, and limited therapeutic efficacy. Taken together, we highlight key processes of PSS pathophysiology and summarize many interventions, including neuroprotective agents, gene therapy, targeted therapy, physiotherapy, NexTGen therapy and complementary and alternative medicine. We aim to confer additional clinical benefits to patients and lay the foundation for the development of new potential therapies against PSS.

Muscle Tone and Stiffness Comparison in Ambulatory Children With Unilateral Spastic Cerebral Palsy: Implications for Postural Balance and Functional Mobility

OBJECTIVES

To compare muscle tone and stiffness in ambulatory children with unilateral spastic cerebral palsy (UCP) with typically developing peers and explore their relationship with postural balance and functional mobility.

METHODS

Forty ambulatory children with UCP and age-matched typically developing peers were assessed for tone and stiffness of lumbar spinal extensors, gastrocnemius, and hamstring muscles using a myotonometer. Functional mobility was evaluated with the 2-Minute Walk Test, and the Timed Up and Go Test, while postural balance was evaluated using the Pediatric Balance Scale and the Trunk Control Measurement Scale (TCMS).

RESULTS

The gastrocnemius muscle tone and stiffness were higher on the affected side in UCP compared with the less affected side and typically developing peers (P < .05). Lumbar spinal extensor tone correlated with improved Trunk Control Measurement Scale scores (P = .003). The gastrocnemius and hamstring muscles' tone and stiffness did not significantly affect functional mobility measures in UCP (P > .05).

CONCLUSIONS

Our study highlights the importance of achieving muscle symmetry, particularly in the plantar flexors, for functional mobility in UCP children. While differences in ankle and knee muscle biomechanics were observed, they didn't significantly impact functional mobility or postural balance. Symmetry in lumbar spinal extensor biomechanics correlated with better outcomes, emphasizing the crucial role of trunk control in rehabilitation strategies for ambulatory children with UCP.

EMG-assessed paratonia: A novel approach to investigating motor response inhibition in healthy subjects

Paratonia is an involuntary muscle activity that occurs during passive joint mobilization and is common in people with dementia. It includes oppositional paratonia, in which muscle activity resists passive movement, and facilitatory paratonia, in which it assists movement. This phenomenon reflects a defect in motor response inhibition. In a recently published paper, we demonstrated that paratonia can be detected using surface electromyography (EMG) not only in patients with dementia but also in healthy individuals, the majority of whom do not exhibit clinically observable paratonia. This finding suggests that EMG-assessed paratonia may provide a novel approach to studying motor response inhibition in healthy subjects. The present study investigates this possibility for the first time. We recruited 120 healthy subjects under the age of 30, divided equally into three groups: sedentary, amateur, and professional athletes with low, moderate, and high levels of physical activity, respectively. Paratonia was assessed in the triceps and biceps brachii muscles during passive forearm movements performed manually. The results indicate that paratonia is more pronounced during fast and continuous passive movements, with facilitatory paratonia being more prevalent than oppositional paratonia. It is also more pronounced in the biceps than in the triceps. These findings, which mirror those previously observed in patients with dementia, suggest a similarity between paratonia in healthy subjects and those with cognitive impairment, supporting the hypothesis that paratonia in healthy individuals represents a form of impaired motor response inhibition. Furthermore, the comparison between groups showed that paratonia decreased with increasing physical activity, being least evident in athletes, more noticeable in amateurs, and most pronounced in sedentary individuals. This pattern confirms a key feature of motor response inhibition that has been shown in studies using traditional methods. Overall, our findings suggest that EMG-assessed paratonia provides a new method for studying motor response inhibition in healthy individuals.

Defects in Exosome Biogenesis Are Associated with Sensorimotor Defects in Zebrafish vps4a Mutants

Mutations in human VPS4A are associated with neurodevelopmental defects, including motor delays and defective muscle tone. VPS4A encodes a AAA-ATPase required for membrane scission, but how mutations in VPS4A lead to impaired control of motor function is not known. Here we identified a mutation in zebrafish vps4a, T248I, that affects sensorimotor transformation. Biochemical analyses indicate that the T248I mutation reduces the ATPase activity of Vps4a and disassembly of ESCRT filaments, which mediate membrane scission. Consistent with the role for Vps4a in exosome biogenesis, vps4aT248I larvae have enlarged endosomal compartments in the CNS and decreased numbers of circulating exosomes in brain ventricles. Resembling the central form of hypotonia in VPS4A patients, motor neurons and muscle cells are functional in mutant zebrafish. Both somatosensory and vestibular inputs robustly evoke tail and eye movements, respectively. In contrast, optomotor responses, vestibulospinal, and acoustic startle reflexes are absent or strongly impaired in vps4aT248I larvae, indicating a greater sensitivity of these circuits to the T248I mutation. ERG recordings revealed intensity-dependent deficits in the retina, and in vivo calcium imaging of the auditory pathway identified a moderate reduction in afferent neuron activity, partially accounting for the severe motor impairments in mutant larvae. Further investigation of central pathways in vps4aT248I mutants showed that activation of descending vestibulospinal and midbrain motor command neurons by sensory cues is strongly reduced. Our results suggest that defects in sensorimotor transformation underlie the profound yet selective effects on motor reflexes resulting from the loss of membrane scission mediated by Vps4a.

The Impact of Low-Level Laser Therapy on Spasticity in Children with Spastic Cerebral Palsy: A Systematic Review

CONTEXT

Spastic cerebral palsy (SCP) is a condition characterized by muscle stiffness and involuntary movements, which greatly affect movement abilities and overall well-being. Low-level laser therapy (LLLT) has emerged as a treatment option for managing spasticity, though the current evidence varies.

OBJECTIVE

This systematic review seeks to assess the efficacy of LLLT on spasticity in children with cerebral palsy. We hope it will pinpoint areas where more research is needed and suggest directions for future studies.

METHOD

A search of the literature was performed across databases, such as PubMed, Google Scholar, Scopus, and Elicit. The search utilized keywords and the Medical Subject Headings (MeSH) terms. Only studies conducted in English that focused on children with cerebral palsy (CP) and explored the effects of LLLT on spasticity were considered. The quality of the selected studies was evaluated using assessment tools.

RESULTS

The search identified 534 references, out of which eight studies met the screening criteria for inclusion. All cited papers indicated reductions in spasticity with further mention of reduced pain and greater muscle strength by some authors.

CONCLUSIONS

This review indicates that LLLT shows promise in decreasing spasticity in children with cerebral palsy. Nevertheless, a lack of treatment parameters, heterogeneity in research methods, and a lack of objective outcome measures weaken the results. This review underscores the importance of standardized procedures and carefully planned randomized controlled trials to establish conclusive findings on the effectiveness of LLLT in this population.

Intersession Intra-Rater and Inter-Rater Reliability of Myotonometer for Upper and Lower Extremity Muscles in Children with Spinal Muscular Atrophy

Background/Objectives: This study aimed to examine intra- and inter-rater reliability of a myotonometer (MyotonPRO) in measuring upper and lower extremity mechanical properties in children with spinal muscular atrophy types I and II. Methods: Biceps brachii, triceps brachii, rectus femoris, and gastrocnemius muscle tone and stiffness in children (n = 21) were measured using the MyotonPRO device. Examiner 1 performed two sets of measurements in 60 min to determine intra-rater reliability. Examiner 2 performed measurements between Examiner 1's sets. Intra-interclass correlation coefficient, minimal detectable change, and standard error of measurement values were calculated to assess intra- and inter-rater reliabilities in this cross-sectional study. Results: The results showed excellent intra- and inter-rater reliability analyses for frequency and stiffness values except for the stiffness value of the gastrocnemius muscle, which presented good reliability (ICC = 0.71). Minimal detectable change values ranged from 0.59 to 1.98 Hz for muscle tone and 16.08 to 124.74 N/m for stiffness (for both intra- and inter-rater reliabilities). Conclusions: Our findings indicate that MyotonPRO is a reliable tool for quantifying upper and lower extremity mechanical properties within one session in children with spinal muscular atrophy types I and II. Mechanical properties of the extremity muscle can be determined using this easily applied tool in future studies.

Impact of Virtual Reality on Pain, ROM, Muscle Strength and Quality of Life among Breast Cancer Patients: An Integrative Review of Literature

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among women globally, with significant impacts on physical, emotional, and functional well-being. Traditional rehabilitation methods may not fully address the multifaceted challenges faced by breast cancer survivors (BCSs), prompting exploration into innovative approaches such as Virtual Reality (VR) technology.

OBJECTIVE

The present review aims to assess the effectiveness of VR in alleviating pain, improving Range of Motion (ROM), enhancing muscle strength, and augmenting the overall quality of life in patients undergoing breast cancer rehabilitation.

METHODS

A comprehensive review of existing literature was conducted, focusing on studies investigating the use of VR in breast cancer rehabilitation. PubMed, Scopus, PEDro and Google scholar were searched for articles addressing VR interventions targeting pain management, ROM improvement, muscle strength enhancement, and quality of life enhancement in breast cancer patients.

RESULTS

Findings yielded total 12 articles matching the selection criteria. VR technology has shown promising results in addressing the multifaceted needs of breast cancer patients. VR also serves as a distraction tool, positively impacting psychological well-being and mitigating negative psychological symptoms associated with the disease.

CONCLUSION

VR represents a non-pharmacological approach to pain management and rehabilitation in breast cancer patients. Its ability to engage emotional, cognitive, and attention processes contributes to its effectiveness in enhancing overall quality of life. Further research is warranted to elucidate the long-term benefits and optimal utilization of VR technology in breast cancer rehabilitation programs.

A spectrum of cognitive-behavioral-movement disorders in adrenoleukodystrophy: A case series from a tertiary care centre in the eastern part of India

Background

Adrenoleukodystrophy (ALD) is an intriguing disease with a heterogeneous clinico-radiological profile. Behavioral and cognitive impairments are often the initial and predominant manifestations, yet their patterns are frequently overlooked. This study aims to elaborate on the patterns of cognitive dysfunction, behavioral changes, and movement disorders in ALD to facilitate its earlier diagnosis.

Methods

In this case series, 12 cases of ALD were assessed and evaluated for cognitive, behavioral, and movement abnormalities to identify patterns of involvement.

Results

All patients were male, with an age range of 5-46 years. 75% presented with cerebral ALD (CALD), and 25% had an adrenomyeloneuropathy phenotype. Cognitive dysfunction, behavioral changes, and seizures were observed in 75%, 66.7%, and 33.3% of ALD patients. An initial posterior to anterior pattern of progression of cognitive impairment dominated by higher-order visual dysfunction and language regression was observed in 66.7% of CALD patients, while a frontal pattern was noted in 22.2% of CALD patients. While cognitive impairment typically indicated dysfunction of occipito-parieto-temporal networks, behavioral changes predominantly suggested dysfunctional fronto-temporal-subcortical connections. A novel observation was the occurrence of tics and stereotypies in 33.3% of ALD patients.

Conclusion

This study describes the patterns of cognitive, behavioral, and movement abnormalities in ALD and highlights the contributory role of dysfunctional white matter networks. Cognitive patterns predominantly reflect a posterior-to-anterior gradient of impairment of white matter connections, while behavioral markers indicate involvement of fronto-temporal-subcortical networks. Adding to this spectrum, the occurrence of tics and stereotypies is a unique observation in ALD.

Reliability of MyotonPro in measuring the biomechanical properties of the quadriceps femoris muscle in people with different levels and types of motor preparation

The aim of this research was to evaluate the reliability of the measurements of biomechanical parameters of the muscles of athletes representing different disciplines as well as untrained people. Ninety-four young, healthy male individuals participated in the study and were divided into five subgroups: footballers (n = 25), volleyballers (n = 14), handballers (n = 19), MMA fighters (n = 16), and undrained group (n = 20). All of the participants underwent measurements of stiffness (S), muscle tone (T) and elasticity (E) by two independent measurers using MyotonPro equipment. Analysis was conducted on two different parts of the quadriceps femoris: rectus femoris (RF) and vastus medialis (VM. Consequently, the comprehensive analysis comprised 564 measurements (94 participants * 3 parameters = 282 * 2 measurers = 564). The results proves high reliability of the myotonometry (Pearson's CC over 0.8208-0.8871 for different parameters, ICC from to 0.74 to 0.99 for different muscles and parameters) excluding only stiffness for the VM which was characterized withlow ICC of 0.08 and relatively highest between the examined parameters MAE% of 8.7% which still remains low value. The most significant differences between the parameters in examined groups were observed between MMA fighters and volleyballers in terms of muscle tone and elasticity of the VM (correlation of 0.14842 and 0.15083 respecitively). These results confirm the usability of myotonometry in measuring the biomechanical properties of the muscles in different sports groups and confirm the independence of the results obtained from the person performing the measurement.

[Applied anatomy study and preliminary clinical application of hyper selective neurectomy of triceps branches combined with partial neurotomy of S 2 nerve root to relieve spastic equinus foot]

Objective

To observe the possibility of hyper selective neurectomy (HSN) of triceps branches combined with partial neurotomy of S 2 nerve root for relieving spastic equinus foot.

Methods

Anatomical studies were performed on 12 adult cadaveric specimens. The S 2 nerve root and its branches were exposed through the posterior approach. Located the site where S 2 joined the sciatic nerve and measured the distance to the median line and the vertical distance to the posterior superior iliac spine plane, and the S 2 nerve root here was confirmed to have given off branches of the pelvic splanchnic nerve, the pudendal nerve, and the posterior femoral cutaneous nerve. Between February 2023 and November 2023, 4 patients with spastic equinus foot were treated with HSN of muscle branches of soleus, gastrocnemius medial head and lateral head, and cut the branch where S 2 joined the sciatic nerve. There were 3 males and 1 female, the age ranged from 5 to 46 years, with a median of 26 years. The causes included traumatic brain injury in 2 cases, cerebral hemorrhage in 1 case, and cerebral palsy in 1 case. The disease duration ranged from 15 to 84 months, with a median of 40 months. The triceps muscle tone measured by modified Ashworth scale (MAC) before operation was grade 3 in 2 cases and grade 4 in 2 cases. The muscle strength measured by Daniels-Worthingham manual muscle test (MMT) was grade 2 in 1 case, grade 3 in 1 case, and 2 cases could not be accurately measured due to grade 4 muscle tone. The Holden walking function grading was used to evaluate lower limb function and all 4 patients were grade 2. After operation, triceps muscle tone, muscle strength, and lower limb function were evaluated by the above grading.

Results

The distance between the location where S 2 joined the sciatic nerve and median line was (5.71±0.53) cm and the vertical distance between the location and posterior superior iliac spine plane was (6.66±0.86) cm. Before joining the sciatic nerve, the S 2 nerve root had given off branches of the pelvic splanchnic nerve, the pudendal nerve, and the posterior femoral cutaneous nerve. All the 4 patients successfully completed the operation, and the follow-up time was 4-13 months, with a median of 7.5 months. At last follow-up, the muscle tone of the patients decreased by 2-3 grades when compared with that before operation, and the muscle strength did not decrease when compared with that before operation. Holden walking function grading improved by 1-2 grades, and there was no postoperative hypoesthesia in the lower limbs.

Conclusion

HSN of triceps branches combined with partial neurotomy of S 2 nerve root can relieve spastic equinus foot without damaging other sacral plexus nerves.

The tail segments are required by the performance but not the accomplishment of various modes of Drosophila larval locomotion

The tail plays important roles in locomotion control in many animals. But in animals with multiple body segments, the roles of the hind body segments and corresponding innervating neurons in locomotion control are not clear. Here, using the Drosophila larva as the model animal, we investigated the roles of the posterior terminal segments in various modes of locomotion and found that they participate in all of them. In forward crawling, paralysis of the larval tail by blocking the Abdb-Gal4 labeled neurons in the posterior segments of VNC led to a slower locomotion speed but did not prevent the initiation of forward peristalsis. In backward crawling, larvae with the Abdb-Gal4 neurons inhibited were unable to generate effective displacement although waves of backward peristalsis could be initiated and persist. In head swing where the movement of the tail is not obvious, disabling the larval tail by blocking Abdb-Gal4 neurons led to increased bending amplitude upon touching the head. In the case of larval lateral rolling, larval tail paralysis by inhibition of Abdb-Gal4 neurons did not prevent the accomplishment of rolling, but resulted in slower rolling speed. Our work reveals that the contribution of Drosophila larval posterior VNC segments and corresponding body segments in the tail to locomotion is comprehensive but could be compensated at least partially by other body segments. We suggest that the decentralization in locomotion control with respect to animal body parts helps to maintain the robustness of locomotion in multi-segment animals.

Antiferromagnetic artificial neuron modeling of the withdrawal reflex

Replicating neural responses observed in biological systems using artificial neural networks holds significant promise in the fields of medicine and engineering. In this study, we employ ultra-fast artificial neurons based on antiferromagnetic (AFM) spin Hall oscillators to emulate the biological withdrawal reflex responsible for self-preservation against noxious stimuli, such as pain or temperature. As a result of utilizing the dynamics of AFM neurons, we are able to construct an artificial neural network that can mimic the functionality and organization of the biological neural network responsible for this reflex. The unique features of AFM neurons, such as inhibition that stems from an effective AFM inertia, allow for the creation of biologically realistic neural network components, like the interneurons in the spinal cord and antagonist motor neurons. To showcase the effectiveness of AFM neuron modeling, we conduct simulations of various scenarios that define the withdrawal reflex, including responses to both weak and strong sensory stimuli, as well as voluntary suppression of the reflex.

Quantity and Distribution of Muscle Spindles in Animal and Human Muscles

Muscle spindles have unique anatomical characteristics that can be directly affected by the surrounding tissues under physiological and pathological conditions. Understanding their spatial distribution and density in different muscles is imperative to unravel the complexity of motor function. In the present study, the distribution and number/density of muscle spindles in human and animal muscles were reviewed. We identified 56 articles focusing on muscle spindle distribution; 13 articles focused on human muscles and 43 focused on animal muscles. The results demonstrate that spindles are located at the nerve entry points and along distributed vessels and they relate to the intramuscular connective tissue. Muscles' deep layers and middle segments are the main topographic distribution areas. Eleven articles on humans and thirty-three articles on animals (totaling forty-four articles) focusing on muscle spindle quantity and density were identified. Hand and head muscles, such as the pronator teres/medial pterygoid muscle/masseter/flexor digitorum, were most commonly studied in the human studies. For animals, whole-body musculature was studied. The present study summarized the spindle quantity in 77 human and 189 animal muscles. We identified well-studied muscles and any as-yet unfound data. The current data fail to clarify the relationship between quantity/density and muscle characteristics. The intricate distribution of the muscle spindles and their density and quantity throughout the body present some unique patterns or correlations, according to the current data. However, it remains unclear whether muscles with fine motor control have more muscle spindles since the study standards are inconsistent and data on numerous muscles are missing. This study provides a comprehensive and exhaustive approach for clinicians and researchers to determine muscle spindle status.

Neurofascialvascular training for carpal tunnel syndrome as an evolution of neurodynamic treatment: A case report

INTRODUCTION

In this case report a new approach called neurofascialvascular training (NFVT) is described. NFVT consists of two mechanisms which improve mechanosensitivity in carpal tunnel syndrome (CTS). The first involves increased blood flow in the nerve microcirculation, while the second stimulates the reciprocal sliding between the thin sheets of connective tissue inside the nerve. The goal of these two actions is to squeeze, mobilize and reduce intraneural edema. The novelty of this approach is the simultaneous involvement of multiple physiological systems to reduce nerve mechanosensitivity. This case report describes the rehabilitation progress achieved by NFVT in a patient with CTS.

MAIN SYMPTOMS AND/OR IMPORTANT CLINICAL FINDINGS

A 64-year-old woman complaining of nocturnal pain and tingling with severe impairment of sleep quality for two years was diagnosed at CTS.

THERAPEUTIC INTERVENTIONS

The patient underwent nine 30-min exercise sessions of NFVT.

OUTCOMES

At each session and at the last follow-up 3 months after the end of treatment the following tests were performed: the upper limb neurodynamic test1 (ULNT1), the Hand Grip Meter and the Phdurkan test. Furthermore ultrasound, numerical rating scale and the Boston Carpal Tunnel Questionnaire (BCTQ) were also adopted.

CONCLUSION

NFVT can improve symptoms and motor dysfunction in a patient with CTS.

TAKE-AWAY LESSON

In the presence of mild carpal tunnel syndrome, active neurofascialvascular training that increases peripheral blood flow and targets fascial tissue within the peripheral nervous system can resolve symptoms and produce significant improvement within a few months of starting treatment.

Myofascial release for adults with chronic neck pain and depression

BACKGROUND

Depression affects a significant portion of the global adult population, with chronic pain patients being particularly susceptible to severe depression. Pain and mental illness contribute to an imbalance in the autonomic nervous system, affecting heart function. Myofascial release promises to improve mental and physical health by addressing fascial dysfunctions.

OBJECTIVE

This study aims to investigate the influence of myofascial release on emotional states and autonomic nervous system functioning in individuals with chronic neck pain and depression. Additionally, it seeks to evaluate the myofascial release effect on fascial properties, pain intensity and sensitivity, and cervical spine range of motion.

METHOD

Experimental Study.

RESULT

The study revealed significant enhancements in the myofascial release group, such as a substantial reduction in pain perception and stiffness, increased range of motion of the cervical spine, heart rate variability, positive affect, and pressure pain threshold. The effect sizes of these improvements ranged from small to large. No significant differences were observed in elasticity and tone.

CONCLUSION

The findings suggest that myofascial release has a positive impact on individuals with chronic neck pain and depression, particularly in reducing pain intensity. Integrating myofascial release into treatment approaches may be beneficial. However, further research is needed to confirm and expand upon these findings, explore long-term effects, and better understand the clinical significance of certain outcomes.

TRIAL REGISTRATION

http://www.osf.io, doi.org/10.17605/OSF.IO/6F5RS.

[A case of suspected IgG4-related hypophysitis presented with panhypopituitarism and central diabetes insipidus]

A 78-year-old man complained of subacute general fatigue and anorexia, following diplopia and gait disturbance. He demonstrated wide-based and small-stepped gait without objectively abnormal ocular movements. Brain ‍MRI showed enlargement of the pituitary stalk and gland with uniform contrast enhancement. PET-CT showed FDG ‍uptake in the pituitary gland, mediastinal lymph nodes, and left hilar lymph nodes. Blood investigations revealed panhypopituitarism and high serum IgG4 levels up to 265 ‍mg/dl. Histopathological examination revealed no IgG4-positive cell infiltration in the biopsied mediastinal lymph nodes. However, we suspected IgG4-associated hypophysitis based on the clinical symptoms and MRI findings, which were markedly resolved with steroid. Central masked diabetes insipidus was manifested, but was improved with oral desmopressin. We should pay close attention to the fact that IgG4-related hypophysitis may present with various symptoms regarded as indefinite complaints related to aging or underlying diseases, especially in elderly patients with multimorbidity.

Unraveling the threads of stability: A review of the neurophysiology of postural control in Parkinson's disease

Postural instability is a detrimental and often treatment-refractory symptom of Parkinson's disease. While many existing studies quantify the biomechanical deficits among various postural domains (static, anticipatory, and reactive) in this population, less is known regarding the neural network dysfunctions underlying these phenomena. This review will summarize current studies on the cortical and subcortical neural activities during postural responses in healthy subjects and those with Parkinson's disease. We will also review the effects of current therapies, including neuromodulation and feedback-based wearable devices, on postural instability symptoms. With recent advances in implantable devices that allow chronic, ambulatory neural data collection from patients with Parkinson's disease, combined with sensors that can quantify biomechanical measurements of postural responses, future work using these devices will enable better understanding of the neural mechanisms of postural control. Bridging this knowledge gap will be the critical first step towards developing novel neuromodulatory interventions to enhance the treatment of postural instability in Parkinson's disease.

Identifying and Evaluating Young Children with Developmental Central Hypotonia: An Overview of Systematic Reviews and Tools

Children with developmental central hypotonia have reduced muscle tone secondary to non-progressive damage to the brain or brainstem. Children may have transient delays, mild or global functional impairments, and the lack of a clear understanding of this diagnosis makes evaluating appropriate interventions challenging. This overview aimed to systematically describe the best available evidence for tools to identify and evaluate children with developmental central hypotonia aged 2 months to 6 years. A systematic review of systematic reviews or syntheses was conducted with electronic searches in PubMed, Medline, CINAHL, Scopus, Cochrane Database of Systematic Reviews, Google Scholar, and PEDro and supplemented with hand-searching. Methodological quality and risk-of-bias were evaluated, and included reviews and tools were compared and contrasted. Three systematic reviews, an evidence-based clinical assessment algorithm, three measurement protocols, and two additional measurement tools were identified. For children aged 2 months to 2 years, the Hammersmith Infant Neurological Examination has the strongest measurement properties and contains a subset of items that may be useful for quantifying the severity of hypotonia. For children aged 2-6 years, a clinical algorithm and individual tools provide guidance. Further research is required to develop and validate all evaluative tools for children with developmental central hypotonia.

Medical, Neurologic, and Neuromusculoskeletal Complications

For patients with disorders of consciousness (DoC), treating the medical, neurologic, and neuromuscular complications not only stabilizes their medical disturbances, but minimizes confounding factors that may obscure the ability to accurately identify the level of consciousness and increase the chance of patients' neurologic and functional recovery. Lack of reliable communication and low-level function of patients with DoC make it challenging to diagnose some of the complications. Skilled clinical observation will be imperative to appropriately care for the patients.

An Approach to the Examination of the Lumbar Plexus for Neurosurgical Residents: A Video Manuscript

The lumbar plexus provides innervation to the lower limbs and is essential in enabling motor movement and sensation in the lower limbs. Some of its branches also innervate the muscles in the pelvic girdle. Compared to the brachial plexus in the upper limbs, the lumbar plexus appears to garner less recognition among physicians and surgeons. However, it is important to understand the anatomy of the lumbar plexus and its branches along with the innervation they enable, as injury to them can cause plexopathies and pathologies that should be recognised by any treating clinician. Lumbar disc herniation, trauma and entrapment by muscles or hypertrophic ligaments are common causes of lumbar plexus or nerve injuries. A video was produced to demonstrate the examination techniques explained in this article. To provide comprehensive examination of the lower limbs, the sciatic nerve and its branches are also included in the examination video.

Functional anatomy of mystacial active sensing in rats

Rats' whisking motion and objects' palpation produce tactile signals sensed by mechanoreceptors at the vibrissal follicles. Rats adjust their whisking patterns to target information type, flow, and resolution, adapting to their behavioral needs and the changing environment. This coordination requires control over the activity of the mystacial pad's intrinsic and extrinsic muscles. Studies have relied on muscle recording and stimulation techniques to describe the roles of individual muscles. However, these methods lack the resolution to isolate the mystacial pad's small and compactly arranged muscles. Thus, we propose functional anatomy as a complementary approach for studying the individual and coordinated effects of the mystacial pad muscles on vibrissae movements. Our functional analysis addresses the kinematic measurements of whisking motion patterns recorded in freely exploring rats. Combined with anatomical descriptions of muscles and fascia elements of the mystacial pad in situ, we found: (1) the contributions of individual mystacial pad muscles to the different whisking motion patterns; (2) active touch by microvibrissae, and its underlying mechanism; and (3) dynamic position changes of the vibrissae pivot point, as determined by the movements of the corium and subcapsular fibrous mat. Finally, we hypothesize that each of the rat mystacial pad muscles is specialized for a particular function in a way that matches the architecture of the fascial structures. Consistent with biotensegrity principles, the muscles and fascia form a network of structural support and continuous tension that determine the arrangement and motion of the embedded individual follicles.

Disinhibition Is an Essential Network Motif Coordinated by GABA Levels and GABA B Receptors

Network dynamics are crucial for action and sensation. Changes in synaptic physiology lead to the reorganization of local microcircuits. Consequently, the functional state of the network impacts the output signal depending on the firing patterns of its units. Networks exhibit steady states in which neurons show various activities, producing many networks with diverse properties. Transitions between network states determine the output signal generated and its functional results. The temporal dynamics of excitation/inhibition allow a shift between states in an operational network. Therefore, a process capable of modulating the dynamics of excitation/inhibition may be functionally important. This process is known as disinhibition. In this review, we describe the effect of GABA levels and GABAB receptors on tonic inhibition, which causes changes (due to disinhibition) in network dynamics, leading to synchronous functional oscillations.

Different Thumb Positions in the Tetraplegic Hand

OBJECTIVE

To analyze factors associated with malposition that affects function of the thumb in individuals with tetraplegia.

DESIGN

Retrospective cross-sectional study.

SETTING

Rehabilitation Center for Spinal Cord Injury.

PARTICIPANTS

Anonymized data from 82 individuals (68 men), mean age 52.9±20.2 (SD) with acute/subacute cervical spinal cord injury C2-C8 AIS A-D recorded during 2018-2020.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Motor point (MP) mapping and manual muscle test (MRC) of 3 extrinsic thumb muscles (flexor pollicis longus (FPL), extensor pollicis longus (EPL), and abductor pollicis longus (APL)).

RESULTS

159 hands in 82 patients with tetraplegia C2-C8 AIS A-D were analyzed and assigned to "key pinch" (40.3%), "slack thumb" (26.4%), and "thumb-in-palm" (7.5%) positions. There was a significant (P<.0001) difference between the 3 thumb positions depicted in lower motor neuron (LMN) integrity tested by MP mapping and muscle strength of the 3 muscles examined. All studied muscles showed a significantly different expression of MP and the MRC values (P<.0001) between the "slack thumb" and "key pinch" position. MRC of FPL was significantly greater in the group "thumb-in-palm" compared with "key pinch" position (P<.0001).

CONCLUSIONS

Malposition of the thumb due to tetraplegia seems to be related to the integrity of LMN and voluntary muscle activity of the extrinsic thumb muscles. Assessments such as MP mapping and MRC of the 3 thumb muscles enable the identification of potential risk factors for the development of thumb malposition in individuals with tetraplegia.

Corticospinal excitability during motor preparation of upper extremity reaches reflects flexor muscle synergies: A novel principal component-based motor evoked potential analyses

Background

Previous research has shown that noninvasive brain stimulation can be used to study how the central nervous system (CNS) prepares the execution of a motor task. However, these previous studies have been limited to a single muscle or single degree of freedom movements (e.g., wrist flexion). It is currently unclear if the findings of these studies generalize to multi-joint movements involving multiple muscles, which may be influenced by kinematic redundancy and muscle synergies.

Objective

The objective of this study was to characterize corticospinal excitability during motor preparation in the cortex prior to functional upper extremity reaches.

Methods

20 participants without neurological impairments volunteered for this study. During the experiment, the participants reached for a cup in response to a visual "Go Cue". Prior to movement onset, we used transcranial magnetic stimulation (TMS) to stimulate the motor cortex and measured the changes in motor evoked potentials (MEPs) in several upper extremity muscles. We varied each participant's initial arm posture and used a novel synergy-based MEP analysis to examine the effect of muscle coordination on MEPs. Additionally, we varied the timing of the stimulation between the Go Cue and movement onset to examine the time course of motor preparation.

Results

We found that synergies with strong proximal muscle (shoulder and elbow) components emerged as the stimulation was delivered closer to movement onset, regardless of arm posture, but MEPs in the distal (wrist and finger) muscles were not facilitated. We also found that synergies varied with arm posture in a manner that reflected the muscle coordination of the reach.

Conclusions

We believe that these findings provide useful insight into the way the CNS plans motor skills.

Central effects of trigeminal electrical stimulation

This is a review of the literature on the main neuromodulation techniques, focusing on the possibility of introducing sensory threshold ULFTENS into them. Electro neuromodulation techniques have been in use for many years as promising methods of therapy for cognitive and emotional disorders. One of the most widely used forms of stimulation for orofacial pain is transcutaneous trigeminal stimulation on three levels: supraorbital area, dorsal surface of the tongue, and anterior skin area of the tragus. The purpose of this review is to trigger interest on using dental ULFTENS as an additional trigeminal neurostimulation and neuromodulation technique in the context of TMD. In particular, we point out the possibility of using ULFTENS at a lower activation level than that required to trigger a muscle contraction that is capable of triggering effects at the level of the autonomic nervous system, with extreme ease of execution and few side effects.

Neck Muscle Vibration Alters Cerebellar Processing Associated with Motor Skill Acquisition of a Proprioceptive-Based Task

Experimentally induced neck fatigue and neck pain have been shown to impact cortico-cerebellar processing and sensorimotor integration, assessed using a motor learning paradigm. Vibration specifically impacts muscle spindle feedback, yet it is unknown whether transient alterations in neck sensory input from vibration impact these neural processing changes following the acquisition of a proprioceptive-based task. Twenty-five right-handed participants had electrical stimulation over the right median nerve to elicit short- and middle-latency somatosensory evoked potentials (SEPs) pre- and post-acquisition of a force matching tracking task. Following the pre-acquisition phase, controls (CONT, n = 13, 6 F) received 10 min of rest and the vibration group (VIB, n = 12, 6 F) received 10 min of 60 Hz vibration on the right sternocleidomastoid and left cervical extensors. Task performance was measured 24 h later to assess retention. Significant time by group interactions occurred for the N18 SEP peak, 21.77% decrease in VIB compared to 58.74% increase in CONT (F(1,23) = 6.475, p = 0.018, np2 = 0.220), and the N24 SEP peak, 16.31% increase in VIB compared to 14.05% decrease in CONT (F(1,23) = 5.787, p = 0.025, np2 = 0.201). Both groups demonstrated improvements in motor performance post-acquisition (F(1,23) = 52.812, p < 0.001, np2 = 0.697) and at retention (F(1,23) = 35.546, p < 0.001, np2 = 0.607). Group-dependent changes in the SEP peaks associated with cerebellar input (N18) and cerebellar processing (N24) suggests that an altered proprioceptive input from neck vibration impacts cerebellar pathways.

Keystroke Biometrics as a Tool for the Early Diagnosis and Clinical Assessment of Parkinson's Disease

(1) Background: Parkinson's disease (PD) is the second most common neurodegenerative disease. Early diagnosis and reliable clinical assessments are essential for appropriate therapy and improving patients' quality of life. Keystroke biometrics, which capture unique typing behavior, have shown potential for early PD diagnosis. This study aimed to evaluate keystroke biometric parameters from two datasets to identify indicators that can effectively distinguish de novo PD patients from healthy controls. (2) Methods: Data from natural typing tasks in Physionet were analyzed to estimate keystroke biometric parameters. The parameters investigated included alternating-finger tapping (afTap) and standard deviations of interkey latencies (ILSD) and release latencies (RLSD). Sensitivity rates were calculated to assess the discriminatory ability of these parameters. (3) Results: Significant differences were observed in three parameters, namely afTap, ILSD, and RLSD, between de novo PD patients and healthy controls. The sensitivity rates were high, with values of 83%, 88%, and 96% for afTap, ILSD, and RLSD, respectively. Correlation analysis revealed a significantly negative correlation between typing speed and number of words typed with the standard motor assessment for PD, UPDRS-III, in patients with early PD. (4) Conclusions: Simple algorithms utilizing keystroke biometric parameters can serve as effective screening tests in distinguishing de novo PD patients from healthy controls. Moreover, typing speed and number of words typed were identified as reliable tools for assessing clinical statuses in PD patients. These findings underscore the potential of keystroke biometrics for early PD diagnosis and clinical severity assessment.

Emerging theory of sensitization in post-stroke muscle spasticity

Spasticity, characterized by a velocity-dependent increase in muscle tone and exaggerated reflexes, is a common complication in individuals with upper motor neuron syndrome, such as stroke survivors. Sensitization, the heightened responsiveness of the nervous system to sensory stimuli, has emerged as a potential cause of spasticity. This perspective article explores three emerging treatments targeting sensitization. Recent studies have investigated novel treatment modalities for spasticity, including Extracorporeal Shockwave Therapy (ESWT), repetitive peripheral magnetic stimulation (rPMS), and needling. ESWT has shown promising results in reducing spasticity in both the upper and lower extremities, potentially through mechanisms such as nitric oxide production, rheological property changes, and neuromuscular transmission dysfunction. rPMS offers a non-invasive approach that may reduce spasticity by increasing sensory input, enhancing cortical activation, and exerting tissue-softening effects. Needling has also demonstrated positive effects on spasticity reduction. The high heterogeneity observed indicates the need for more rigorous research to confirm these findings. Recently, mechanical needling and sterile water injection invented by the author is also promising for reducing spasticity through removing sensitization. In conclusion, the emerging treatment options discussed in this perspective article provide promising avenues for addressing sensitization in spasticity and improving motor function. However, further research is needed to validate their findings, optimize treatment protocols, and investigate their long-term effects on motor recovery and overall quality of life in individuals with spasticity.

Rigidity in Parkinson's disease: evidence from biomechanical and neurophysiological measures

Although rigidity is a cardinal motor sign in patients with Parkinson's disease (PD), the instrumental measurement of this clinical phenomenon is largely lacking, and its pathophysiological underpinning remains still unclear. Further advances in the field would require innovative methodological approaches able to measure parkinsonian rigidity objectively, discriminate the different biomechanical sources of muscle tone (neural or visco-elastic components), and finally clarify the contribution to 'objective rigidity' exerted by neurophysiological responses, which have previously been associated with this clinical sign (i.e. the long-latency stretch-induced reflex). Twenty patients with PD (67.3 ± 6.9 years) and 25 age- and sex-matched controls (66.9 ± 7.4 years) were recruited. Rigidity was measured clinically and through a robotic device. Participants underwent robot-assisted wrist extensions at seven different angular velocities randomly applied, when ON therapy. For each value of angular velocity, several biomechanical (i.e. elastic, viscous and neural components) and neurophysiological measures (i.e. short and long-latency reflex and shortening reaction) were synchronously assessed and correlated with the clinical score of rigidity (i.e. Unified Parkinson's Disease Rating Scale-part III, subitems for the upper limb). The biomechanical investigation allowed us to measure 'objective rigidity' in PD and estimate the neuronal source of this phenomenon. In patients, 'objective rigidity' progressively increased along with the rise of angular velocities during robot-assisted wrist extensions. The neurophysiological examination disclosed increased long-latency reflexes, but not short-latency reflexes nor shortening reaction, in PD compared with control subjects. Long-latency reflexes progressively increased according to angular velocities only in patients with PD. Lastly, specific biomechanical and neurophysiological abnormalities correlated with the clinical score of rigidity. 'Objective rigidity' in PD correlates with velocity-dependent abnormal neuronal activity. The observations overall (i.e. the velocity-dependent feature of biomechanical and neurophysiological measures of objective rigidity) would point to a putative subcortical network responsible for 'objective rigidity' in PD, which requires further investigation.

Functional Anatomy of the Spinal Tracts Based on Evolutionary Perspectives

The development of spinal cord represents evolutionary progression. The primitive tract is responsible for functions related to basic survival such as locomotion. In contrast, the developed tracts are involved in perceiving the external environment and controlling conscious movements. There are also differences in the arrangement of spinal tracts between the 2 categories. Tracts serving developed functions are located in the deep layer of the lateral funiculus, whereas primitive tracts occupy other areas. Decussation correlates with tract pathways, with primitive tracts projecting ipsilaterally and developing tracts decussating early. Understanding these principles provides insights into spinal tract organization.

Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.

Effect of virtual running with exercise on functionality in pre-frail and frail elderly people: randomized clinical trial

BACKGROUND

Virtual mirror therapies could increase the results of exercise, since the mirror neuron system produces an activation of motor execution cortical areas by observing actions performed by others. In this way, pre-frail and frail people could use this system to reach an exercise capacity threshold and obtain health benefits.

AIM

The aim of this study is to evaluate the effects of a virtual running (VR) treatment combined with specific physical gait exercise (PE) compared to placebo VR treatment combined with PE on functionality, pain, and muscular tone in pre-frail and frail older persons.

METHODS

A single blinded, two-arm, randomised controlled trial design was employed. Thirty-eight participants were divided into two intervention arms: Experimental Intervention (EI) group, in which VR and gait-specific physical exercises were administered and Control Intervention (CI) group, in which a placebo virtual gait and the same exercise programme was administered. Functionality, pain, and tone were assessed.

RESULTS

EI group improved in aerobic capacity, functional lower-limb strength, reaction time, and pain, while CI group remained the same. Regarding static balance and muscle tone, no differences were found for either group. Further analysis is needed to asses VR effectiveness for improving gait, stand-up and sit-down performance and velocity.

CONCLUSIONS

Virtual running therapy appears to enhance capacities related with voluntary movements (i.e., aerobic capacity, functional lower-limb strength, and reaction time) and reduce pain.

Linking cortex and contraction-Integrating models along the corticomuscular pathway

Computational models of the neuromusculoskeletal system provide a deterministic approach to investigate input-output relationships in the human motor system. Neuromusculoskeletal models are typically used to estimate muscle activations and forces that are consistent with observed motion under healthy and pathological conditions. However, many movement pathologies originate in the brain, including stroke, cerebral palsy, and Parkinson's disease, while most neuromusculoskeletal models deal exclusively with the peripheral nervous system and do not incorporate models of the motor cortex, cerebellum, or spinal cord. An integrated understanding of motor control is necessary to reveal underlying neural-input and motor-output relationships. To facilitate the development of integrated corticomuscular motor pathway models, we provide an overview of the neuromusculoskeletal modelling landscape with a focus on integrating computational models of the motor cortex, spinal cord circuitry, α-motoneurons  and skeletal muscle in regard to their role in generating voluntary muscle contraction. Further, we highlight the challenges and opportunities associated with an integrated corticomuscular pathway model, such as challenges in defining neuron connectivities, modelling standardisation, and opportunities in applying models to study emergent behaviour. Integrated corticomuscular pathway models have applications in brain-machine-interaction, education, and our understanding of neurological disease.

An online method to monitor hand muscle tone during robot-assisted rehabilitation

Introduction: Robot-assisted neurorehabilitation is becoming an established method to complement conventional therapy after stroke and provide intensive therapy regimes in unsupervised settings (e.g., home rehabilitation). Intensive therapies may temporarily contribute to increasing muscle tone and spasticity, especially in stroke patients presenting tone alterations. If sustained without supervision, such an increase in muscle tone could have negative effects (e.g., functional disability, pain). We propose an online perturbation-based method that monitors finger muscle tone during unsupervised robot-assisted hand therapy exercises. Methods: We used the ReHandyBot, a novel 2 degrees of freedom (DOF) haptic device to perform robot-assisted therapy exercises training hand grasping (i.e., flexion-extension of the fingers) and forearm pronosupination. The tone estimation method consisted of fast (150 ms) and slow (250 ms) 20 mm ramp-and-hold perturbations on the grasping DOF, which were applied during the exercises to stretch the finger flexors. The perturbation-induced peak force at the finger pads was used to compute tone. In this work, we evaluated the method performance in a stiffness identification experiment with springs (0.97 and 1.57 N/mm), which simulated the stiffness of a human hand, and in a pilot study with subjects with increased muscle tone after stroke and unimpaired, which performed one active sensorimotor exercise embedding the tone monitoring method. Results: The method accurately estimates forces with root mean square percentage errors of 3.8% and 11.3% for the soft and stiff spring, respectively. In the pilot study, six chronic ischemic stroke patients [141.8 (56.7) months after stroke, 64.3 (9.5) years old, expressed as mean (std)] and ten unimpaired subjects [59.9 (6.1) years old] were tested without adverse events. The average reaction force at the level of the fingertip during slow and fast perturbations in the exercise were respectively 10.7 (5.6) N and 13.7 (5.6) N for the patients and 5.8 (4.2) N and 6.8 (5.1) N for the unimpaired subjects. Discussion: The proposed method estimates reaction forces of physical springs accurately, and captures online increased reaction forces in persons with stroke compared to unimpaired subjects within unsupervised human-robot interactions. In the future, the identified range of muscle tone increase after stroke could be used to customize therapy for each subject and maintain safety during intensive robot-assisted rehabilitation.

The Place of Botulinum Toxin in Spastic Hemiplegic Shoulder Pain after Stroke: A Scoping Review

Stroke is a common pathology worldwide, with an age-standardized global rate of new strokes of 150.5 per 100,000 population in 2017. Stroke causes upper motor neuron impairment leading to a spectrum of muscle weakness around the shoulder joint, changes in muscle tone, and subsequent soft tissue changes. Hemiplegic shoulder pain (HSP) is the most common pain condition in stroke patients and one of the four most common medical complications after stroke. The importance of the appropriate positioning and handling of the hemiplegic shoulder for prevention of HSP is therefore of high clinical relevance. Nevertheless, HSP remains a frequent and disabling problem after stroke, with a 1-year prevalence rate up to 39%. Furthermore, the severity of the motor impairment is one of the most important identified risk factors for HSP in literature. Spasticity is one of these motor impairments that is likely to be modifiable. After ruling out or treating other shoulder pathologies, spasticity must be assessed and treated because it could lead to a cascade of unwanted complications, including spastic HSP. In clinical practice, Botulinum toxin A (BTA) is regarded as the first-choice treatment of focal spasticity in the upper limb, as it gives the opportunity to target specifically selected muscles. It thereby provides the possibility of a unique patient tailored focal and reversible treatment for post stroke spasticity. This scoping review aims to summarize the current evidence of BTA treatment for spastic HSP. First, the clinical manifestation and outcome measures of spastic HSP will be addressed, and second the current evidence of BTA treatment of spastic HSP will be reviewed. We also go in-depth into the elements of BTA application that may optimize the therapeutic effect of BTA. Finally, future considerations for the use of BTA for spastic HSP in clinical practice and research settings will be discussed.

Hypotonia: Is It a Clear Term and an Objective Diagnosis? An Exploratory Systematic Review

BACKGROUND

Hypotonia is considered a determinant factor in multiple developmental disorders and is associated with various characteristics and morbidities. It is necessary to perform a systematic review to know which characteristics are described as associated with hypotonia in children and which methods are used for its diagnosis.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used to develop the systematic review protocol. A search of databases (Pubmed, Cochrane, Web of Knowledge, among others) was performed in May 2021 to identify relevant studies. Those describing characteristics or tests of hypotonia assessment were included, excluding those that exclusively addressed peripheral hypotonia. Two reviewers evaluated the articles and collected the data in a table, noting the authors, date of publication, type of study, and characteristics or tests described in relation to hypotonia. The quality of the studies was also assessed, and data were extracted.

RESULTS

A total of 8778 studies were identified and analyzed, of which 45 met the inclusion criteria. Fifty-three characteristics associated with hypotonia and tests used for its evaluation were located, with pull to sit and vertical suspension being the most frequently referenced.

CONCLUSIONS

The characteristics associated with hypotonia, more highly debated by authors are muscle strength, hypermobility, or the maintenance of antigravity postures. The most used test in the diagnosis of hypotonia is observation, followed by the pull-to-sit test, and adoption of frog posture. A unanimous understanding of the term hypotonia would favor further research.

Treatment of spasticity

Spasticity is characterized by an enhanced size and reduced threshold for activation of stretch reflexes and is associated with "positive signs" such as clonus and spasms, as well as "negative features" such as paresis and a loss of automatic postural responses. Spasticity develops over time after a lesion and can be associated with reduced speed of movement, cocontraction, abnormal synergies, and pain. Spasticity is caused by a combination of damage to descending tracts, reductions in inhibitory activity within spinal cord circuits, and adaptive changes within motoneurons. Increased tone, hypertonia, can also be caused by changes in passive stiffness due to, for example, increase in connective tissue and reduction in muscle fascicle length. Understanding the cause of hypertonia is important for determining the management strategy as nonneural, passive causes of stiffness will be more amenable to physical rather than pharmacological interventions. The management of spasticity is determined by the views and goals of the patient, family, and carers, which should be integral to the multidisciplinary assessment. An assessment, and treatment, of trigger factors such as infection and skin breakdown should be made especially in people with a recent change in tone. The choice of management strategies for an individual will vary depending on the severity of spasticity, the distribution of spasticity (i.e., whether it affects multiple muscle groups or is more prominent in one or two groups), the type of lesion, and the potential for recovery. Management options include physical therapy, oral agents; focal therapies such as botulinum injections; and peripheral nerve blocks. Intrathecal baclofen can lead to a reduction in required oral antispasticity medications. When spasticity is severe intrathecal phenol may be an option. Surgical interventions, largely used in the pediatric population, include muscle transfers and lengthening and selective dorsal root rhizotomy.

Neonatal and infantile hypotonia

The underlying etiology of neonatal and infantile hypotonia can be divided into primary peripheral and central nervous system and acquired or genetic disorders. The approach to identifying the likeliest cause of hypotonia begins with a bedside assessment followed by a careful review of the birth history and early development and family pedigree and obtaining available genetic studies and age- and disease-appropriate laboratory investigations. Until about a decade ago, the main goal was to identify the clinical signs and a battery of basic investigations including electrophysiology to confirm or exclude a given neuromuscular disorder, however the availability of whole-exome sequencing and next generation sequencing and transcriptome sequencing has simplified the identification of specific underlying genetic defect and improved the accuracy of diagnosis in many related Mendelian disorders.

Abdominal and lower extremity muscles activity and thickness in typically developing children and children with developmental delay

We investigated abdominal and lower extremity muscle activity and thickness in typically developing children and children with developmental delays. A total of 35 children participated: typically developing peers (n=13), children with hypotonia (n=10), and children with spasticity (n=12). Muscle activity and thickness were measured at rest and during activity. Electromyography was used to measure abdominal and lower extremity muscle activities, and abdominal muscle thickness was measured using ultrasonography. There was a significant difference between the groups in the activity of the rectus abdominis and quadriceps muscles at rest and during activity (P<0.05). There was a significant difference between the groups in the thickness of the external oblique and transversus abdominis muscles during activity (P<0.05). There was a significant difference between the groups in the thickness of the external oblique and internal oblique muscles in the sitting position (P<0.05). Therefore, the characteristics of muscle tone should be considered when applying interventions to children with developmental delay.