Focal Movement Research Articles

Impact of muscle fatigue on anticipatory postural adjustments during gait initiation

IntroductionProlonged or strenuous exercise leads to a temporary decrease in muscle function and performance, which interferes with activity of both prime movers and postural muscles. This effect of fatigue has been reported both for single segment movements and for locomotion. However, little is known regarding the effects of fatigue on anticipatory postural adjustments (APAs) during gait initiation, a task in which the control of focal movement should be strictly coupled to a feedforward control of posture.MethodsWe studied APAs during gait initiation in 16 healthy well-trained adult males, searching for muscle activities that precede the backward shift of the Center of Pressure (CoP). Participants stood on a force plate for about 10 s and then started walking at their natural speed. APAs were evaluated before and after a 1 min exhausting sequence of countermovement jumps. An optoelectronic system captured the heel-off events while a force plate measured the CoP position and vertical ground reaction force. Wireless probes recorded the electromyogram of trunk and leg muscles from both sides.ResultsIt was observed that muscle fatigue delayed excitatory and inhibitory APAs, of about 40 and 80 ms, respectively, and a parallel delay was induced on prime movers; moreover, velocity and amplitude of backward CoP shift were reduced. Regarding APAs sign and occurrence, most of the participants showed bilateral inhibition in dorsal muscles and excitation in the ventral ones, displaying a forward “diving” strategy that was almost unaffected by fatigue. However, after fatigue, three of the “diving” participants switched to a “turning” strategy, i.e., they displayed a reciprocal activation/inhibition pattern in the dorsal muscles, compatible with a trunk rotation.DiscussionThe “turning” strategy has been previously described in untrained individuals and in a toes-amputee mountain climber, who showed a “diving” approach to gait initiation when wearing his prosthetic shoes and switched to the “turning” approach when barefoot. Altogether, these results support the idea that one and the same person may develop a repertoire of postural strategies among which the central nervous system will choose, according to the personal fitness and the constraints in which the action is performed.

Standing on Elevated Platform Changes Postural Reactive Responses during Arm Movement.

Background/Objectives: This study investigated the behavior of postural adjustments throughout the entire action: from the preparatory phase (anticipatory postural adjustment, APA), the focal movement phase (online postural adjustments, OPA), to the compensatory phase (compensatory postural adjustment, CPA) while raising the arms in a standing position, both with eyes opened and closed. The goal was to analyze the effects of reduced sensorial information and different heights on postural muscle activity during these three phases. Methods: Eight young women performed rapid shoulder flexion while standing on the ground and on a 1-m elevated platform. The EMG activity of the trunk and lower limb muscles was recorded during all three phases. Results: Although average muscle activity was similar on the ground and the elevated platform, the pattern of postural muscle activation varied across the motor action. During OPA, all postural muscle activity was the highest, while it was the lowest during APA. On the elevated platform postural muscles have increased their activation during APA. In the most stable condition (standing on the ground with eyes opened), muscle activity showed a negative correlation between APA and OPA, but there was no correlation between OPA and CPA. Conclusions: Our results suggest postural control adapts to sensory, motor, and cognitive conditions. Therefore, the increased demand for postural control due to the height of the support base demands greater flexibility in postural synergies and alters muscle activity.

High-Intensity focused ultrasound linear array and system for dermatology treatment

Dermatological lesions are typically located just a few millimeters below the surface of the skin, which constrains the efficacy of optical-based therapeutic methods such as photothermal and photodynamic therapy due to limited therapeutic depth caused by optical scattering. As an alternative, high-intensity focused ultrasound (HIFU) has been explored for its potential to treat a variety of dermatological conditions because it offers greater flexibility in terms of treatment depth. Since dermatological lesions have a small thickness ranging from 1.5 to 2.0 mm, high-frequency ultrasound (3–10 MHz or higher) is preferred as the focal area is proportional to the operating frequency. However, due to the difficulty in fabricating HIFU array transducers at this frequency range, the majority of HIFU treatments for dermatology rely on single element transducers. Despite the advantages of HIFU, single-element-based HIFU systems are limited in prevalent use for dermatology treatment due to their fixed focal length and mechanical movement for treatment, which can be time-consuming and unsuitable for treating multiple lesions. To address this, we present a newly developed HIFU linear array and 128-channel driving electronics specifically designed for dermatology treatment. This array consists of 128 elements, has a center frequency of 3.7 MHz, an elevation focal length of 28 mm, and an F-number of 1.27 in the elevation direction. The array has a footprint of 71.6 mm by 22 mm. Experiments using a tissue-mimicking phantom have demonstrated that the HIFU linear array and system are capable of transmitting sufficient ultrasound energy to create coagulation inside the phantom.

Association between sleep disturbances and challenging behavior in children and adolescents with Angelman syndrome

Angelman Syndrome (AS) is a neurodevelopmental disorder with severe symptoms and associated comorbidities. It is caused by the inactivity or lack of the UBE3a gene. Symptoms of the syndrome include intellectual disability and developmental delay.The current study investigated sleep disturbances (SD) in children and adolescents with AS, associations between SD and possible predictors of SD. Variables examined included age, gender, newborn and infancy history, challenging behavior, type of therapy received, genetic type of AS, and seizures. The sample included data from 109 participants with a mean age of 8.21, accessed via the Global Angelman Syndrome Registry. Chi-square tests were carried out to assess the associations between the variables and a logistical regression was carried out to assess the possible predictors of SD. Associations were found between SD and certain repetitive behaviors: slapping walls, focal hand movements, and agitation at new situations. From these associations, a regression formed a predictive model for sleep disturbances. The findings of this research demonstrated the importance of investigating the relationship between sleep disturbances and challenging behavior in children and adolescents with AS and the need for further research in this area.

Noncontact Haptic Rendering of Static Contact With Convex Surface Using Circular Movement of Ultrasound Focus on a Finger Pad.

A noncontact tactile stimulus can be presented by focusing airborne ultrasound on the human skin. Focused ultrasound has recently been reported to produce not only vibration but also static pressure sensation on the palm by modulating the sound pressure distribution at a low frequency. This finding expands the potential for tactile rendering in ultrasound haptics as static pressure sensation is perceived with a high spatial resolution. In this study, we verified that focused ultrasound can render a static pressure sensation associated with contact with a small convex surface on a finger pad. This static contact rendering enables noncontact tactile reproduction of a fine uneven surface using ultrasound. In the experiments, four ultrasound foci were simultaneously and circularly rotated on a finger pad at 5 Hz. When the orbit radius was 3 mm, vibration and focal movements were barely perceptible, and the stimulus was perceived as static pressure. Moreover, under the condition, the pressure sensation rendered a contact with a small convex surface with a radius of 2 mm. The perceived intensity of the static contact sensation was equivalent to a physical contact force of 0.24 N on average, 10.9 times the radiation force physically applied to the skin.

Lingual dystonia secondary to medication use: a review of case reports (P12-11.004)

<h3>Objective:</h3> The aim of our study was to determine which drugs cause secondary lingual dystonia. <h3>Background:</h3> Lingual dystonia is a type of focal movement disorder characterized by tongue muscles involuntary contractions or abnormal postures maintenance. It can be primary or secondary to a number of conditions, including trauma, autoimmune diseases, viral infections, and medication use. Even though there are many case reports about lingual dystonia secondary to drugs, there is no review, to our knowledge, about the most common drugs causing it. <h3>Design/Methods:</h3> A search was performed by the authors in the PubMed/Medline database. The descriptor used was “lingual dystonia”, and no filters were applied. All of the articles found had their abstract read. Exclusion criteria were articles that did not specify the clinical features of lingual dystonia, that did not expose data clearly separating tongue dystonia from other types, and studies that did not analyze lingual dystonia secondary to medication use. <h3>Results:</h3> Forty-two subjects from 39 case-reports matched our inclusion criteria. The mean age was 39.42 years old (± 20.36; ranging from 6 to 80), and the female to male ratio found was 25:17. Haloperidol (7) and metoclopramide (7) were the two medication most correlated with lingual dystonia, followed by multiple antipsychotics associations (5), risperidone (3), ziprasidone (3), chloroquine (2), lithium (1), levodopa (1), perphenazine (1), cisapride (1), primozide (1), betahistine (1), nitric oxide (1), propofol (1), meperidine (1), compazine (1), methotrimeprazine (1), cyclizine (1), aripiprazole (1) general anesthetics (1) and antidepressants (1). <h3>Conclusions:</h3> The findings of this review suggest antipsychotics and anti-emetic medication are the leading causes of lingual dystonia secondary to medication. Age and sex appear not to be a predisponent factor. Further studies may be helpful to evaluate influence of dosage in symptoms occurrence. <b>Disclosure:</b> Miss Duarte has nothing to disclose. Dr. Teive has nothing to disclose.

Effects of postural instability on the coordination between posture and arm reaching

Reaching from standing requires adjustments of hand movement and posture, which are assured by redundant kinematic degrees of freedom. However, the increased demand for postural adjustments may interfere with the stability of reaching. The objective of this study was to investigate the effect of postural instability on the use of kinematic redundancy to stabilize the finger and center-of-mass trajectories during reaching from standing in healthy adults. Sixteen healthy young adults performed reaching movements from standing with and without postural instability induced by small base-of-support. The three-dimensional positions of 48 markers were recorded at 100 Hz. The uncontrolled manifold (UCM) analysis was performed separately with the finger and center-of-mass positions being the performance variables, and joint angles being the elemental variables. ΔV, the normalized difference between the variance in joint angle that does not affect task performance (VUCM) and the variance that does affect task performance (VORT), was calculated separately for finger (ΔVEP) and center-of-mass (ΔVCOM) positions, and was compared between stable and unstable base-of-support conditions. ΔVEP decreased after movement onset and reached its minimum value at around 30–50% of the normalized movement time, and increased until movement offset, while ΔVCOM remained stable. At 60%–100% normalized movement time, ΔVEP was significantly reduced in the unstable base-of-support, compared to the stable base-of-support condition. ΔVCOM remained similar between the two conditions. At movement offset, ΔVEP was significantly reduced in the unstable base-of-support, compared to the stable base-of-support condition, and was associated with a substantial increase in VORT. Postural instability might reduce the ability to use kinematic redundancy to stabilize the reaching movement. The central nervous system may prioritize the maintenance of postural stability over focal movement when postural stability is challenged.

Encephalitis: diagnosis, management and recent advances in the field of encephalitides.

Encephalitis describes inflammation of the brain parenchyma, typically caused by either an infectious agent or through an autoimmune process which may be postinfectious, paraneoplastic or idiopathic. Patients can present with a combination of fever, alterations in behaviour, personality, cognition and consciousness. They may also exhibit focal neurological deficits, seizures, movement disorders and/or autonomic instability. However, it can sometimes present non-specifically, and this combined with its many causes make it a difficult to manage neurological syndrome. Despite improved treatments in some forms of encephalitides, encephalitis remains a global concern due to its high mortality and morbidity. Prompt diagnosis and administration of specific and supportive management options can lead to better outcomes. Over the last decade, research in encephalitis has led to marked developments in the understanding, diagnosis and management of encephalitis. In parallel, the number of autoimmune encephalitis syndromes has rapidly expanded and clinically characteristic syndromes in association with pathogenic autoantibodies have been defined. By focusing on findings presented at the Encephalitis Society's conference in December 2021, this article reviews the causes, clinical manifestations and management of encephalitis and integrate recent advances and challenges of research into encephalitis.

Mechanical Cues for Triggering and Regulating Cellular Movement Selectively at the Single-Cell Level.

Cell motility plays important roles in many biophysical and physiological processes ranging from in vitro biomechanics, wound healing, to cancer metastasis. This work introduces a new means to trigger and regulate motility individually using transient mechanical stimulus applied to designated cells. Using BV2 microglial cells, our investigations indicate that motility can be reproducibly and reliably initiated using mechanical compression of the cells. The location and magnitude of the applied force impact the movement of the cell. Based on observations from this investigation and current knowledge of BV2 cellular motility, new physical insights are revealed into the underlying mechanism of force-induced single cellular movement. The process involves high degrees of myosin activation to repair actin cortex breakages induced by the initial mechanical compression, which leads to focal adhesion degradation, lamellipodium detachment, and finally, cell polarization and movement. Modern technology enables accurate control over force magnitude and location of force delivery, thus bringing us closer to programming cellular movement at the single-cell level. This approach is of generic importance to other cell types beyond BV2 cells and has the intrinsic advantages of being transient, non-toxic, and non-destructive, thus exhibiting high translational potentials including mechano-based therapy.

Effectiveness of structured teaching programme on knowledge regarding lamaze technique among antenatal mothers in selected maternity hospitals Bangalore

Objectives of the study1)To assess the existing knowledge regarding Lamaze technique among antenatal mothers in selected maternity hospitals at Bangalore. 2)To evaluate the effectiveness of structured teaching program on knowledge regarding Lamaze technique among antenatal mothers in selected maternity hospitals at Bangalore. 3)To find an association between post-test knowledge scores regarding Lamaze technique and selected socio-demographic variables among antenatal mothers in selected hospitals at Bangalore. Method: Evaluative approach is adopted for this study as its aim is to test the hypothesis that establishes a relationship between Lamaze technique and reduction in labour pain. A pilot study was conducted with six samples in the selected hospital to refine the methodology and to find the feasibility of the study. The setting of the study is selected tertiary care hospital, Bangalore. The main study samples were about 60 in number. Non probability convenient sampling technique was used to select the samples. Research design adopted for this study was pre-experimental, one group pre-test post-test design. Lamaze technique which includes Lamaze breathing techniques, partner massage, imagery and visualization, pushing techniques, focal point imagery, movements and relaxation techniques was given to the antenatal mothers. An opinionative on Lamaze technique was administered after the delivery process among antenatal mothers.Result: The overall mean percentage knowledge score in the pre-test and post-test were 27.5% and 87.60%, respectively. Enhancements in mean percentage score were found to be 60.1%. The statistical paired‘t’ test indicates that enhancement in the mean percentage knowledge score was found to be significant at 0.05 level for all the aspects under study. The association found to be partly significant between post-test knowledge scores and selected socio-demographic variables at 0.05 level (p<0.05).Intrepretation and Conclusion: The data was analyzed by applying Descriptive and Inferential statistics. The study findings suggested that structured teaching programme is an effective instructional method in improving the knowledge regarding Lamaze technique among antenatal mothers.HypothesesH1: The mean post-test-knowledge score among antenatal mothers regarding importance of Lamaze technique will be significantly higher than their pre-test knowledge score.H2: There will be significant association between post-test knowledge score and selected socio-demographic variables among antenatal mothers regarding importance of Lamaze technique.

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia.

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients' ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations.

Eye movement patterns in complex tasks: Characteristics of ambient and focal processing

Analyzing the time course of eye movements during scene viewing often indicates that people progress through two distinct modes of visual processing: an ambient mode, which is associated with overall spatial orientation in a scene, followed by a focal mode, which requires central vision of an object. However, the shifts between ambient and focal processing modes have mainly been identified relative to changes in the environment, such as relative to the onset of various visual stimuli but also following scene cuts or subjective event boundaries in dynamic stimuli. The results so far do not allow conclusions about the nature of the two processing mechanisms beyond the influence of externally triggered events. It remains unclear whether people shift back and forth from ambient to focal processing also based on internal triggers, such as switching between different tasks while no external event is given. The present study therefore investigated ambient to focal processing shifts in an active task solving paradigm. The Rubik's Cube task introduced here is a multi-step task, which can be broken down into smaller sub-tasks that are performed serially. The time course of eye movements was analyzed at multiple levels of this Rubik's Cube task, including when there were no external changes to the stimuli but when internal representations of the task were hypothesized to change (i.e., switching between different sub-tasks). Results suggest that initial ambient exploration is followed by a switch to more focal viewing across various levels of task processing with and without external changes to the stimuli. More importantly, the present findings suggest that ambient and focal eye movement characteristics might serve as a probe for the attentional state in task processing, which does not seem to be influenced by changes in task performance.

What does ‘occupancy’ mean in passive acoustic surveys?

Occupancy modelling is an increasingly common framework for analysing acoustic data to study the variation in populations through space and time, but different survey designs endow survey locations with varying degrees of biological meaning. Recording units may be preferentially deployed in areas known to be important to a species, which implies an ‘area of occupancy’ conception of a species range, or recording units may be randomly deployed without knowledge of focal species space‐use (e.g. a survey grid), which implies an ‘extent of occurrence’ conception of a species range. Preferential sampling requires substantial pre‐survey information (e.g. the location of focal species territories) but leads to intuitive parameter interpretation and greater precision; vastly greater survey coverage is attainable with random sampling, but the resulting data merit careful post‐processing to achieve precise, ecologically meaningful results. Importantly, occupancy, detection, extinction and colonization estimates are incomparable between study designs. However, an understanding of focal species movement and vocal behaviour can inform the development of creative definitions of acoustic detections – and thus site occupancy – which may help bring the ecological realism of preferential sampling to the data yielded by the more scalable random sampling approach. Understanding the implications of study design choices on parameter interpretation is a fundamental aspect of basic ecological inference and endangered species monitoring.

262 Limb-shaking linked to haemodynamic cerebrovascular disease

Limb-shaking transient ischaemic attacks (TIAs) are under-recognised in neurology and typically consists of involuntary movements resembling focal seizure-like activity. This form of TIA suggests severe carotid occlusive disease and is a warning for future strokes. Awareness can help avoid unnecessary medication, lifestyle measures and driving implications.We present a case of a 61-year-old patient who developed transient but persistent right upper limb shaking and syncope on turning to the left. He suffered a recent NSTEMI causing severe left ventricular dysfunction and associated anaemia. His ictal EEG was unremarkable. CT angiography and doppler ultrasound revealed severe left internal carotid artery stenosis. This suggested an underlying low-flow TIA and symptoms resolved with blood pressure optimisation and blood transfusions.Cerebrovascular events typically present with acute negative symptoms including loss of power, sensation, vision or speech. Alternatively, focal movement abnormalities would generally make the physician think of a non-cerebrovascular disorder. This stresses the need to raise awareness of limb-shaking TIAs to expedite diagnosis and instigate management strategies to lower future stroke risk.Along with secondary stroke prevention, attacks can be abolished by improving blood supply through optimisation of blood pressure, cardiac function and treating anaemia. Failing this, surgical revasculari- sation procedures should be considered.jkcleaver88@gmail.com

Focal clonic movements elicited by electrical cortical stimulation of primary motor cortex (P1-1.Virtual)

Focal clonic movements elicited by electrical cortical stimulation of primary motor cortex (P1-1.Virtual)

Effect of non-contact boxing training on the frequency and timing of anticipatory postural adjustments in healthy adults.

The experiment tested the effect of non-contact boxing training on the frequency and timing of anticipatory postural adjustments (APAs) resulting from self-induced postural perturbations in healthy adults. The 8-week non-contact boxing intervention study involved 33 healthy adults between 18 and 27 years of age who had no boxing experience (control group = 17 participants, boxing group = 16 participants). Pretests and post-tests utilized rapid bilateral arm raising as a focal movement to elicit APAs. EMG in the anterior deltoid, thoracic and lumbar erector spinae, semitendinosus, and soleus muscles was recorded. The boxing group completed twenty 90-min non-contact boxing training sessions over 8 weeks, whereas the control group kept physical activity consistent during the intervention period. Non-contact boxing training caused APAs to become more frequent during the focal movement, in comparison to the control group, in the soleus and in the semitendinosus after an outlier was removed. Non-contact boxing training caused earlier APA onset during the focal movement, in comparison to the control group, in the lumbar erector spinae after an outlier was removed. Non-contact boxing training had a modest positive effect on the frequency and timing of APAs resulting from self-induced postural perturbations in healthy adults.

Linear 2D Beam Steering With a Large Focusing Grating via Focal Point Movement and Wavelength

We demonstrate a 2D beam-steering device in SiN based on a large focusing grating, achieving a steering range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.2^\circ \times 46^\circ $ </tex-math></inline-formula> , with discrete steps in azimuth. Despite the curved geometry, it achieves linear raster scanning. It employs only a single SiN layer and a low-resolution full etch.

Varied phenotypic spectrum presenting of paroxysmal exercise-induced dyskinesia: a Turkish family with SLC2A1 mutation.

Paroxysmal exercise-induced dyskinesia (PED) is characterized by repeated episodes of involuntary movement disorders that are typically caused by prolonged walking or running and mostly caused by SLC2A1 gene mutations. Phenotypes vary from focal dystonia, ataxia, tremor, and complex non-kinesigenic movements to other movement disorders in patients with SLC2A1 mutation. Also, SLC2A1 mutations carriers may present with also other phenotypes such as epileptic seizure and migraine. We report five patients with various phenotypic spectrums of PED in a Turkish family. Whole exome sequencing revealed a likely pathogenic synonymous variant p.Ser324Ser (c.972G > A) in the SLC2A1 gene (ENST00000426263.3) and the variant segregated in all affected family members. Also, other than PED, the phenotypical spectrum of affected individuals in this family includes epilepsy, mental retardation, and weakness. We concluded that family members with the same SLC2A1 gene mutation may show very heterogenous phenotypes. Clinicians should be aware of wide variety of symptoms of the patients with PED. We also emphasized that even if a mutation in the coding sequence does not make an amino acid change, it may cause the disease.

Electroclinical features and outcome of ANKRD11-related KBG syndrome: A novel report and literature review

Electroclinical features and outcome of ANKRD11-related KBG syndrome: A novel report and literature review

Fatal cerebral edema in patients with decompensated cirrhosis: A case series.

Unlike patients with acute liver failure, patients with cirrhosis are not traditionally thought to be at risk for developing cerebral edema. In the largest case series to date, we document clinical characteristics of cirrhotic patients who develop cerebral edema. In this retrospective case series, seventeen adult patients with acute-on-chronic liver failure (ACLF) were identified using Morbidity & Mortality data. Neurological decompensation was defined by focal neurological deficits or abnormal movements. Elevated ICP was diagnosed clinically by pupillary reflex change improving with hyperosmolar therapy, or by herniation on CT. Pulsatility indices >1.2 on transcranial Dopplers (TCDs) and/or optic nerve sheath diameter (ONSD) >0.5cm were acceptable alternatives. Median MELD-Na was 36 (IQR 31.5,43) compared with 20 (IQR 19,23) prior to admission. Neurological decompensation was associated with abnormal pupil reactivity in 76% and abnormal movements in 65%. Cerebral edema was diagnosed by CT (n=14). For those too ill to transport, elevated ICP was confirmed with TCDs for three patients and ONSD for two. Mortality was 100% a median of 3days (IQR 1.5,5) from neurologic decompensation. ACLF patients with neurological decompensation exhibit distinct clinical changes. Noninvasive bedside techniques may serve as surrogate measures for ICP.