The hands' default location guides tactile spatial selectivity.

Our skin is a two-dimensional sheet that can be folded into a multitude of configurations due to the mobility of our body parts. Parts of the human tactile system might account for this flexibility by being tuned to locations in the world rather than on the skin. Using adaptation, we scrutinized the spatial selectivity of two tactile perceptual mechanisms for which the visual equivalents have been reported to be selective in world coordinates: tactile motion and the duration of tactile events. Participants' hand position-uncrossed or crossed-as well as the stimulated hand varied independently across adaptation and test phases. This design distinguished among somatotopic selectivity for locations on the skin and spatiotopic selectivity for locations in the environment, but also tested spatial selectivity that fits neither of these classical reference frames and is based on the default position of the hands. For both features, adaptation consistently affected subsequent tactile perception at the adapted hand, reflecting skin-bound spatial selectivity. Yet, tactile motion and temporal adaptation also transferred across hands but only if the hands were crossed during the adaptation phase, that is, when one hand was placed at the other hand's typical location. Thus, selectivity for locations in the world was based on default rather than online sensory information about the location of the hands. These results challenge the prevalent dichotomy of somatotopic and spatiotopic selectivity and suggest that prior information about the hands' default position -right hand at the right side-is embedded deep in the tactile sensory system.

Math on cortex-enhanced delta phase synchrony in math experts during long and complex math demonstrations.

Neural oscillations are important for working memory and reasoning and they are modulated during cognitively challenging tasks, like mathematics. Previous work has examined local cortical synchrony on theta (4-8 Hz) and alpha (8-13 Hz) bands over frontal and parietal electrodes during short mathematical tasks when sitting. However, it is unknown whether processing of long and complex math stimuli evokes inter-regional functional connectivity. We recorded cortical activity with EEG while math experts and novices watched long (13-68 seconds) and complex (bachelor-level) math demonstrations when sitting and standing. Fronto-parietal connectivity over the left hemisphere was stronger in math experts than novices reflected by enhanced delta (0.5-4 Hz) phase synchrony in experts. Processing of complex math tasks when standing extended the difference to right hemisphere, suggesting that other cognitive processes, such as maintenance of body balance when standing, may interfere with novice's internal concentration required during complex math tasks more than in experts. There were no groups differences in phase synchrony over theta or alpha frequencies. These results suggest that low-frequency oscillations modulate inter-regional connectivity during long and complex mathematical cognition and demonstrate one way in which the brain functions of math experts differ from those of novices: through enhanced fronto-parietal functional connectivity.

Cortical activations associated with spatial remapping of finger touch using EEG.

The spatial coding of tactile information is functionally essential for touch-based shape perception and motor control. However, the spatiotemporal dynamics of how tactile information is remapped from the somatotopic reference frame in the primary somatosensory cortex to the spatiotopic reference frame remains unclear. This study investigated how hand position in space or posture influences cortical somatosensory processing. Twenty-two healthy subjects received electrical stimulation to the right thumb (D1) or little finger (D5) in three position conditions: palm down on right side of the body (baseline), hand crossing the body midline (effect of position), and palm up (effect of posture). Somatosensory-evoked potentials (SEPs) were recorded using electroencephalography. One early-, two mid-, and two late-latency neurophysiological components were identified for both fingers: P50, P1, N125, P200, and N250. D1 and D5 showed different cortical activation patterns: compared with baseline, the crossing condition showed significant clustering at P1 for D1, and at P50 and N125 for D5; the change in posture showed a significant cluster at N125 for D5. Clusters predominated at centro-parietal electrodes. These results suggest that tactile remapping of fingers after electrical stimulation occurs around 100-125 ms in the parietal cortex.

Tilt in Place Microscopy: a Simple, Low-Cost Solution to Image Neural Responses to Body Rotations.

Animals use information about gravity and other destabilizing forces to balance and navigate through their environment. Measuring how brains respond to these forces requires considerable technical knowledge and/or financial resources. We present a simple alternative-Tilt In Place Microscopy (TIPM), a low-cost and noninvasive way to measure neural activity following rapid changes in body orientation. Here, we used TIPM to study vestibulospinal neurons in larval zebrafish during and immediately after roll tilts. Vestibulospinal neurons responded with reliable increases in activity that varied as a function of ipsilateral tilt amplitude. TIPM differentiated tonic (i.e., sustained tilt) from phasic responses, revealing coarse topography of stimulus sensitivity in the lateral vestibular nucleus. Neuronal variability across repeated sessions was minor relative to trial-to-trial variability, allowing us to use TIPM for longitudinal studies of the same neurons across two developmental time points. There, we observed global increases in response strength and systematic changes in the neural representation of stimulus direction. Our data extend classical characterization of the body tilt representation by vestibulospinal neurons and establish the utility of TIPM to study the neural basis of balance, especially in developing animals.SIGNIFICANCE STATEMENT Vestibular sensation influences everything from navigation to interoception. Here, we detail a straightforward, validated, and nearly universal approach to image how the nervous system senses and responds to body tilts. We use our new method to replicate and expand on past findings of tilt sensing by a conserved population of spinal-projecting vestibular neurons. The simplicity and broad compatibility of our approach will democratize the study of the response of the brain to destabilization, particularly across development.

Effect of a False Inertial Cue in the Velocity-Storage Circuit on Head Posture and Inertia Perception.

The velocity-storage circuit participates in the vestibulopostural reflex, but its role in the postural reflex requires further elucidation. The velocity-storage circuit differentiates gravitoinertial information into gravitational and inertial cues using rotational cues. This implies that a false rotational cue can cause an erroneous estimation of gravity and inertial cues. We hypothesized the velocity-storage circuit is a common gateway for all vestibular reflex pathways and tested that hypothesis by measuring the postural and perceptual responses from a false inertial cue estimated in the velocity-storage circuit. Twenty healthy human participants (40.5 ± 8.2 years old, 6 men) underwent two different sessions of earth-vertical axis rotations at 120°/s for 60 s. During each session, the participants were rotated clockwise and then counterclockwise with two different starting head positions (head-down and head-up). During the first (control) session, the participants kept a steady head position at the end of rotation. During the second (test) session, the participants changed their head position at the end of rotation, from head-down to head-up or vice versa. The head position and inertial motion perception at the end of rotation were aligned with the inertia direction anticipated by the velocity-storage model. The participants showed a significant correlation between postural and perceptual responses. The velocity-storage circuit appears to be a shared neural integrator for the vestibulopostural reflex and vestibular perception. Because the postural responses depended on the inertial direction, the postural instability in vestibular disorders may be the consequence of the vestibulopostural reflex responding to centrally estimated false vestibular cues.SIGNIFICANCE STATEMENT The velocity-storage circuit appears to participate in the vestibulopostural reflex, which stabilizes the head and body position in space. However, it is still unclear whether the velocity-storage circuit for the postural reflex is in common with that involved in eye movement and perception. We evaluated the postural and perceptual responses to a false inertial cue estimated by the velocity-storage circuit. The postural and perceptual responses were consistent with the inertia direction predicted in the velocity-storage model and were correlated closely with each other. These results show that the velocity-storage circuit is a shared neural integrator for vestibular-driven responses and suggest that the vestibulopostural response to a false vestibular cue is the pathomechanism of postural instability clinically observed in vestibular disorders.

Coordination of Locomotion by Serotonergic Neurons in the Predatory Gastropod Pleurobranchaea californica.

Similar design characterizes neuronal networks for goal-directed motor control across the complex, segmented vertebrates, insects, and polychaete annelids with jointed appendages. Evidence is lacking for whether this design evolved independently in those lineages, evolved in parallel with segmentation and appendages, or could have been present in a soft-bodied common ancestor. We examined coordination of locomotion in an unsegmented, ciliolocomoting gastropod, the sea slug Pleurobranchaea californica, which may better resemble the urbilaterian ancestor. Previously, bilateral A-cluster neurons in cerebral ganglion lobes were found to compose a multifunctional premotor network controlling the escape swim and feeding suppression, and mediating action selection for approach or avoidance turns. Serotonergic As interneurons of this cluster were critical elements for swimming, turning, and behavioral arousal. Here, known functions were extended to show that the As2/3 cells of the As group drove crawling locomotion via descending signals to pedal ganglia effector networks for ciliolocomotion and were inhibited during fictive feeding and withdrawal. Crawling was suppressed in aversive turns, defensive withdrawal, and active feeding, but not during stimulus-approach turns or prebite proboscis extension. Ciliary beating was not inhibited during escape swimming. These results show how locomotion is adaptively coordinated in tracking, handling, and consuming resources, and in defense. Taken with previous results, they also show that the A-cluster network acts similarly to the vertebrate reticular formation with its serotonergic raphe nuclei in facilitating locomotion, postural movements, and motor arousal. Thus, the general scheme controlling locomotion and posture might well have preceded the evolution of segmented bodies and articulated appendages.SIGNIFICANCE STATEMENT Similar design in the neuronal networks for goal-directed motor control is seen across the complex, segmented vertebrates, insects, and polychaete annelids with jointed appendages. Whether that design evolved independently or in parallel with complexity in body and behavior has been unanswered. Here it is shown that a simple sea slug, with primitive ciliary locomotion and lacking segmentation and appendages, has similar modular design in network coordination as vertebrates for posture in directional turns and withdrawal, locomotion, and general arousal. This suggests that a general neuroanatomical framework for the control of locomotion and posture could have arisen early during the evolution of bilaterians.

Relationship of device measured physical activity type and posture with cardiometabolic health markers: pooled dose-response associations from the Prospective Physical Activity, Sitting and Sleep Consortium.

AIMS/HYPOTHESIS: The aim of this study was to examine the dose-response associations of device-measured physical activity types and postures (sitting and standing time) with cardiometabolic health. METHODS: We conducted an individual participant harmonised meta-analysis of 12,095 adults (mean ± SD age 54.5±9.6 years; female participants 54.8%) from six cohorts with thigh-worn accelerometry data from the Prospective Physical Activity, Sitting and Sleep (ProPASS) Consortium. Associations of daily walking, stair climbing, running, standing and sitting time with a composite cardiometabolic health score (based on standardised z scores) and individual cardiometabolic markers (BMI, waist circumference, triglycerides, HDL-cholesterol, HbA1c and total cholesterol) were examined cross-sectionally using generalised linear modelling and cubic splines. RESULTS: We observed more favourable composite cardiometabolic health (i.e. z score <0) with approximately 64 min/day walking (z score [95% CI] -0.14 [-0.25, -0.02]) and 5 min/day stair climbing (-0.14 [-0.24, -0.03]). We observed an equivalent magnitude of association at 2.6 h/day standing. Any amount of running was associated with better composite cardiometabolic health. We did not observe an upper limit to the magnitude of the dose-response associations for any activity type or standing. There was an inverse dose-response association between sitting time and composite cardiometabolic health that became markedly less favourable when daily durations exceeded 12.1 h/day. Associations for sitting time were no longer significant after excluding participants with prevalent CVD or medication use. The dose-response pattern was generally consistent between activity and posture types and individual cardiometabolic health markers. CONCLUSIONS/INTERPRETATION: In this first activity type-specific analysis of device-based physical activity, ~64 min/day of walking and ~5.0 min/day of stair climbing were associated with a favourable cardiometabolic risk profile. The deleterious associations of sitting time were fully attenuated after exclusion of participants with prevalent CVD and medication use. Our findings on cardiometabolic health and durations of different activities of daily living and posture may guide future interventions involving lifestyle modification.

Developing a novel dual-injection FDG-PET imaging methodology to study the functional neuroanatomy of gait.

Gait is an excellent indicator of physical, emotional, and mental health. Previous studies have shown that gait impairments in ageing are common, but the neural basis of these impairments are unclear. Existing methodologies are suboptimal and novel paradigms capable of capturing neural activation related to real walking are needed. In this study, we used a hybrid PET/MR system and measured glucose metabolism related to both walking and standing with a dual-injection paradigm in a single study session. For this study, 15 healthy older adults (10 females, age range: 60.5-70.7 years) with normal cognition were recruited from the community. Each participant received an intravenous injection of [18F]-2-fluoro-2-deoxyglucose (FDG) before engaging in two distinct tasks, a static postural control task (standing) and a walking task. After each task, participants were imaged. To discern independent neural functions related to walking compared to standing, we applied a bespoke dose correction to remove the residual 18F signal of the first scan (PETSTAND) from the second scan (PETWALK) and proportional scaling to the global mean, cerebellum, or white matter (WM). Whole-brain differences in walking-elicited neural activity measured with FDG-PET were assessed using a one-sample t-test. In this study, we show that a dual-injection paradigm in healthy older adults is feasible with biologically valid findings. Our results with a dose correction and scaling to the global mean showed that walking, compared to standing, increased glucose consumption in the cuneus (Z = 7.03), the temporal gyrus (Z = 6.91) and the orbital frontal cortex (Z = 6.71). Subcortically, we observed increased glucose metabolism in the supraspinal locomotor network including the thalamus (Z = 6.55), cerebellar vermis and the brainstem (pedunculopontine/mesencephalic locomotor region). Exploratory analyses using proportional scaling to the cerebellum and WM returned similar findings. Here, we have established the feasibility and tolerability of a novel method capable of capturing neural activations related to actual walking and extended previous knowledge including the recruitment of brain regions involved in sensory processing. Our paradigm could be used to explore pathological alterations in various gait disorders.

Effect of size on expression of bistability in mouse spinal motoneurons.

Bistability in spinal motoneurons supports tonic spike activity in the absence of excitatory drive. Earlier work in adult preparations suggested that smaller motoneurons innervating slow antigravity muscle fibers are more likely to generate bistability for postural maintenance. However, whether large motoneurons innervating fast-fatigable muscle fibers display bistability is still controversial. To address this, we examined the relationship between soma size and bistability in lumbar (L4-L5) ventrolateral α-motoneurons of choline acetyltransferase (ChAT)-green fluorescent protein (GFP) and Hb9-GFP mice during the first 4 wk of life. We found that as neuron size increases, the prevalence of bistability rises. Smaller α-motoneurons lack bistability, whereas larger fast α-motoneurons [matrix metalloproteinase-9 (MMP-9)+/Hb9+] with a soma area ≥ 400 µm2 exhibit significantly higher bistability. Ionic currents associated with bistability, including the persistent Nav1.6 current, the thermosensitive Trpm5 Ca2+-activated Na+ current, and the slowly inactivating Kv1.2 current, also scale with cell size. Serotonin evokes full bistability in large motoneurons with partial bistable properties but not in small motoneurons. Our study provides important insights into the neural mechanisms underlying bistability and how motoneuron size correlates with bistability in mice.NEW & NOTEWORTHY Bistability is not a common feature of all mouse spinal motoneurons. It is absent in small, slow motoneurons but present in most large, fast motoneurons. This difference results from differential expression of ionic currents that enable bistability, which are highly expressed in large motoneurons but small or absent in small motoneurons. These results support a possible role for fast motoneurons in maintenance of tonic posture in addition to their known roles in fast movements.

Predictive posture stabilization before contact with moving objects: equivalence of smooth pursuit tracking and peripheral vision.

Postural stabilization is essential to effectively interact with our environment. Humans preemptively adjust their posture to counteract impending disturbances, such as those encountered during interactions with moving objects, a phenomenon known as anticipatory postural adjustments (APAs). APAs are thought to be influenced by predictive models that incorporate object motion via retinal motion and extra-retinal signals. Building on our previous work that examined APAs in relation to the perceived momentum of moving objects, here we explored the impact of object motion within different visual field sectors on the human capacity to anticipate motion and prepare APAs for contact between virtual moving objects and the limb. Participants interacted with objects moving towards them under different gaze conditions. In one condition, participants fixated on either a central point (central fixation) or left-right of the moving object (peripheral fixation), while in another, they followed the moving object with smooth pursuit eye movements (SPEM). We found that APAs had the smallest magnitude in the central fixation condition and that no notable differences in APAs were apparent between the SPEM and peripheral fixation conditions. This suggests that the visual system can accurately perceive motion of objects in peripheral vision for posture stabilization. Using Bayesian Model Averaging, we also evaluated the contribution of different gaze variables, such as eye velocity and gain (ratio of eye and object velocity) and showed that both eye velocity and gain signals were significant predictors of APAs. Taken together, our study underscores the roles of oculomotor signals in modulation of APAs.

Associations between static foot posture, dynamic in-shoe plantar foot forces and knee pain in people with medial knee osteoarthritis: A cross-sectional exploratory study.

OBJECTIVE: To investigate relationships between static foot posture, dynamic plantar foot forces and knee pain in people with medial knee osteoarthritis (OA). DESIGN: Data from 164 participants with symptomatic, moderate to severe radiographic medial knee OA were analysed. Knee pain was self-reported using a numerical rating scale (NRS; scores 0-10; higher scores worse) and the Knee Injury and Osteoarthritis Outcome Score pain subscale (KOOS; scores 0-100; lower scores worse). Static foot posture was assessed using clinical tests (foot posture index, foot mobility magnitude, navicular drop). Dynamic plantar foot forces (lateral, medial, whole foot, medial-lateral ratio, arch index) were measured using an in-shoe plantar pressure system while walking. Relationships between foot posture and plantar forces (independent variables) and pain (dependent variables) were evaluated using linear regression models, unadjusted and adjusted for sex, walking speed, Kellgren & Lawrence grade, shoe category, and body mass (for dynamic plantar foot forces). RESULTS: No measure of static foot posture was associated with any knee pain measure. Higher medial-lateral foot force ratio at midstance, and a higher arch index during overall stance, were weakly associated with higher knee pain on the NRS (regression coefficient = 0.69, 95% confidence interval (CI) 0.09 to 1.28) and KOOS (coefficient=3.03, 95% CI 0.71 to 5.35) pain scales, respectively. CONCLUSION: Dynamic plantar foot forces, but not static foot posture, were associated with knee pain in people with medial knee OA. However, the amount of pain explained by increases in plantar foot force was small; thus, these associations are unlikely to be clinically meaningful.

Effect of Clinician Posture on Patient Perceptions of Communication in the Inpatient Setting: A Systematic Review.

BACKGROUND: Nonverbal communication plays a pivotal role in the provision of effective patient care and has been associated with important patient health outcomes. Clinician posture, a nonverbal form of communication, may influence the patient experience and satisfaction. The relationship between clinician posture (i.e., standing or at the patient's eye level) and patient perceptions of clinician communication in the hospital-a setting with heightened power dynamics between patient and clinician-is currently unknown. METHODS: We conducted searches of Ovid MEDLINE, EBSCO CINAHL Complete, EBSCO PsycInfo, Elsevier Embase/Embase Classic, Elsevier Scopus, and Web of Science Core Collection up to May 2023. English language studies were included if they compared clinician posture (eye-level or standing) during adult inpatient (including emergency department) interactions. Two authors independently abstracted data from included studies and assessed risk of bias or quality of evidence. A third author arbitrated any disagreements. Studies reported adherence to the posture intervention and/or patient perception outcomes. The latter included encounter duration, preferences for posture type, perceptions of interaction quality and clinician communication and compassion, and standardized assessments of patient satisfaction. RESULTS: Fourteen studies (six randomized controlled trials, four quasi-experimental studies, four observational studies) assessed clinician posture at the bedside. Ten noted at least one favorable outcome for clinicians who communicated at the patient's eye level, three revealed no differences in patient perceptions between standing and sitting, and one noted higher patient ratings for standing clinicians. Findings were limited by variation in interventions and outcomes, generally high risk of bias, and relatively low adherence to assigned posture groups. DISCUSSION: Compared to standing, eye-level communication by clinicians appears beneficial. The magnitude and types of benefits clinicians and patients may gain from this behavior remain unclear given heterogeneity and generally high risk of bias in available studies. With its relatively easy implementation and potential for benefit, clinicians should consider communicating with their hospitalized patients at eye level. REGISTRATION: PROSPERO, CRD42020199817.

Position- and posture-dependent vascular imaging-a scoping review.

OBJECTIVES: Position- and posture-dependent deformation of the vascular system is a relatively unexplored field. The goal of this scoping review was to create an overview of existing vascular imaging modalities in different body positions and postures and address the subsequent changes in vascular anatomy. METHODS: Scopus, Medline, and Cochrane were searched for literature published between January 1, 2000, and June 30, 2022, incorporating the following categories: image modality, anatomy, orientation, and outcomes. RESULTS: Out of 2446 screened articles, we included 108. The majority of papers used ultrasound (US, n = 74) in different body positions and postures with diameter and cross-sectional area (CSA) as outcome measures. Magnetic resonance imaging (n = 22) and computed tomography (n = 8) were less frequently used but allowed for investigation of other geometrical measures such as vessel curvature and length. The venous system proved more sensitive to postural changes than the arterial system, which was seen as increasing diameters of veins below the level of the heart when going from supine to prone to standing positions, and vice versa. CONCLUSIONS: The influence of body positions and postures on vasculature was predominantly explored with US for vessel diameter and CSA. Posture-induced deformation and additional geometrical features that may be of interest for the (endovascular) treatment of vascular pathologies have been limitedly reported, such as length and curvature of an atherosclerotic popliteal artery during bending of the knee after stent placement. The most important clinical implications of positional changes are found in diagnosis, surgical planning, and follow-up after stent placement. CLINICAL RELEVANCE STATEMENT: This scoping review presents the current state and opportunities of position- and posture-dependent imaging of vascular structures using various imaging modalities that are relevant in the fields of clinical diagnosis, surgical planning, and follow-up after stent placement. KEY POINTS: • The influence of body positions and postures on the vasculature was predominantly investigated with US for vessel diameter and cross-sectional area. • Research into geometrical deformation, such as vessel length and curvature adaptation, that may be of interest for the (endovascular) treatment of vascular pathologies is limited in different positions and postures. • The most important clinical implications of postural changes are found in diagnosis, surgical planning, and follow-up after stent placement.

Boosting arousal and cognitive performance through alternating posture: Insights from a multi-method laboratory study.

This study investigated the role of arousal and effort costs in the cognitive benefits of alternating between sitting and standing postures using a sit-stand desk, while measuring executive functions, self-reports, physiology, and neural activity in a 2-h laboratory session aimed to induce mental fatigue. Two sessions were conducted with a one-week gap, during which participants alternated between sitting and standing postures each 20-min block in one session and remained seated in the other. In each block, inhibition, switching, and updating were assessed. We examined effects of time-on-task, acute (local) effects of standing versus sitting posture, and cumulative (global) effects of a standing posture that generalize to the subsequent block in which participants sit. Results (N = 43) confirmed that time-on-task increased mental fatigue and decreased arousal. Standing (versus sitting) led to acute increases in arousal levels, including self-reports, alpha oscillations, and cardiac responses. Standing also decreased physiological and perceived effort costs. Standing enhanced processing speed in the flanker task, attributable to shortened nondecision time and speeded evidence accumulation processes. No significant effects were observed on higher-level executive functions. Alternating postures also increased heart rate variability cumulatively over time. Exploratory mediation analyses indicated that the positive impact of acute posture on enhanced drift rate was mediated by self-reported arousal, whereas decreased nondecision time was mediated by reductions in alpha power. In conclusion, alternating between sitting and standing postures can enhance arousal, decrease effort costs, and improve specific cognitive and physiological outcomes.

Questioning the Impact of Vestibular Rehabilitation in Mal de Debarquement Syndrome.

INTRODUCTION: Mal de debarquement syndrome (MdDS) is a rare and poorly understood clinical entity defined as a persistent sensation of rocking and swaying that can severely affect the quality of life. To date, the treatment options are very limited. Even though vestibular rehabilitation (VR) efficacy following peripheral vestibular lesion is well-documented, little is known about its influence on MdDS. The objective of the study was to explore the influence of traditional VR program on postural control in a patient diagnosed with MdDS. METHODS: We assessed 3 different participants: 1 healthy control; 1 participant with identified peripheral vestibular impairment (VI); 1 participant diagnosed with MdDS. Postural control was assessed using a force plate (AMTI, Accusway). Participants were assessed following the modified Clinical Test Sensory Integration Balance protocol (mCTSIB, eyes open on firm surface/eyes closed on firm surface/eyes open on foam/eyes closed on foam). The raw data were exported and analyzed in a custom-made Matlab script (Matlab R2020a). We retrieved the center of pressure velocity in both anterior-posterior and mediolateral directions and performed an analysis of the frequency content using Daubechies wavelet of order 4 with 6 levels of decomposition. Protocol VI and MdDS patients performed a 4-week VR program. Postural control, using a force plate, and Dizziness Handicap Inventory (DHI) were assessed before and after the VR program. Healthy control was assessed twice separated by 1 week without any specific intervention. RESULTS: VI participant showed clear improvement on DHI and sway velocity on condition eyes closed with foam. Accordingly, a reduction of energy content within frequency bands (0.39-0.78 Hz and 0.78-1.56 Hz) was observed post-rehabilitation for VI participant in both conditions with foam. Interestingly, MdDS participant demonstrated a reduction in sway velocity in most of the conditions but the frequency content was not modified by VR and was comparable to healthy control. Accordingly, the DHI of the MdDS participant failed to demonstrate any difference following VR. CONCLUSION: The results of the present study question the use of VR as an efficient treatment option for MdDS. Future studies must recruit a larger sample size and focus on the relationship between illusion of movement and postural characteristics such as sway velocity.

Towards an explanation for 'unexplained' dizziness in older people.

BACKGROUND: Subjective unsteadiness or dizziness, usually without increase in body sway, is common in older people. The absence of mechanistic understanding of such symptoms renders clinical management difficult. Here, we explore the mechanisms behind such idiopathic dizziness (ID), focusing on postural control abnormalities. METHODS: Thirty patients with ID and 30 age-matched controls stood on a moving platform. Platform oscillations were randomly delivered at different velocities (from 0 to 0.2 m/s). Markers of postural control, including objective sway (trunk sway path, recorded via a sensor attached to vertebrae C7), stepping responses, subjective instability and anxiety ratings were obtained. MRI scans were available for correlations with levels of cerebral small vessel disease in 28 patients and 24 controls. RESULTS: We observed a significant relationship between objective and subjective instability in all groups. The slope of this fit was significantly steeper for patients than controls, indicating greater perceived instability for the same body sway. Stepwise linear regression showed that the slopes of this objective-subjective instability relationship were best explained by concerns about falling (Falls Efficacy Scale-International), clinical physical functioning (Short Physical Performance Battery) and, to some degree, by neuroimaging markers of cerebral small vessel disease. In addition, patients had a reduced stepping threshold, suggesting an overly cautious postural response. CONCLUSION: The distorted perception of instability and subtle impairments in balance control, including abnormal and overly cautious stepping responses, underlies the emergence of ID. It appears to relate to changes in postural performance, psychological functioning and disruption of postural brain networks associated with cerebral small vessel disease.

Using wearable technology for Posture Regulation to Improve Surgical Ergonomics in the paediatric operating room: the UPRISE trial: a pilot study.

BACKGROUND: The rising prevalence of work-related musculoskeletal disorders has numerous physical, financial, and mental repercussions for surgeons. This study aims to establish whether the use of a wearable posture device can improve the operating time spent in suboptimal, high-risk postures. METHODS: Surgeons were recruited in Phase 1 of this prospective randomised study and baseline postural data was obtained. In Phase 2, participants were randomised to receive either a traditional educational workshop or intraoperative vibrations from the device to correct postural lapses. During minor elective day cases, intraoperative postural data was collected and stratified by forward flexion angle, into five risk categories (negligible to very high). Participants' experience with the sensor was also assessed. RESULTS: A total of 100 surgical procedures (Phase 1: n = 50; Phase 2: n = 50) were performed by eight surgeons of varying seniority. Exposure to the educational intervention increased time spent in suboptimal posture (Phase 1 vs. Phase 2); 47.5% vs. 67.8%, p = 0.05. However, the vibrational intervention significantly reduced this time; 50.0% vs. 20.7%, p = 0.005. Procedure type didn't influence posture although, laparoscopic interventions spent most time in negligible-risk postures; 47.7% vs. 49.3%, compared to open procedures. Surgical consultants spent less time in suboptimal posture compared to fellow/registrars; 30.3% vs. 72.6% (Phase 1) and 33.8% vs. 65.3% (Phase 2). CONCLUSION: Vibrational intervention from the device significantly decreased the time spent in suboptimal, high-risk postures. As procedure type wasn't correlated with postural changes, surgeon-specific factors in regulating posture are paramount. Finally, surgeon experience was positively correlated with improved surgical ergonomics.

Effects of multi-gravitational suspension-based therapy on posture, physical fitness, quality of life, depression, and sleep quality in women without regular exercise habits.

BACKGROUND: Multi-gravitational suspension-based therapy (M-Gravity) is a comprehensive discipline based on the principles of non-gravity, which serves to increase the quality of life and holistic health of the individual with the rehabilitation content of non-pressure inversion therapy and suspension systems. AIMS: To examine the effects of M-Gravity exercise on posture, physical fitness, quality of life, depression, and sleep quality in women without regular exercise habits. METHODS: This study included 20 women without regular exercise habits, who participated in M-Gravity exercise and 20 women who did not participate in any exercise program. Posture was measured by the New York posture rating chart, flexibility of the hamstring and pectoral muscles were assessed with flexibility tests, and endurance of the core muscles was measured with plank test. Depression levels were measured by Beck Depression Inventory, sleep quality was measured by Pittsburgh Sleep Quality Index, and Nottingham Health Profile was used to measure the perceived health levels of the subjects. Measurement of the core stability was performed with the Stabilizer Pressure Biofeedback. Two evaluations were made at baseline and after 4 weeks of exercise program. RESULTS: Although statistically significant results were achieved for all parameters in the M-Gravity group, no differences were observed in the control group between baseline and post-test scores (p < 0.05). CONCLUSIONS: We came to the idea that eight sessions of M-Gravity program may have positive effects on posture, physical fitness and quality of life in women who do not have regular exercise habits.

The resting calcaneal stance position (RCSP): an old dog, with new tricks.

The objective of this study was to establish the accuracy of the resting calcaneal stance position (RCSP) for the assessment of flat foot (FF) in children, aligned to the validity of the foot posture index (FPI). The RCSP cut-off point was explored, in context of both FF prevalence and the relationship between FF and body weight. A total of 205 healthy children, aged 5 to 10 years, participated in a cross-sectional study. Correlation was performed between RCSP and FPI. ROC curve technique was calculated to assess differentiation between groups. A score equal to or greater than 7 on the FPI was used as the 'gold standard' for analysis. The correlation between FPI and RCSP was significant (r = 0.63; p < 0.01). The discrimination score on the ROC curve (6 points/degrees) shows that the model can be used to identify FF through RCSP, with a sensitivity of 67% and specificity of 85% returned.  Conclusion: The results of this study indicate the role of RCSP for simple, accessible and quick screening of paediatric FF. This is especially pertinent for non-podiatric healthcare professional without specialised paediatric foot knowledge. What is Known: • Most children develop a normal arch quickly, and flat feet usually resolve on their own between 2 and 6 years of age. • The measurement used to diagnose flat foot in children must be accurate, consistent, and valid to characterize the standard foot position. The Resting Calcaneal Stance Position (RCSP) is another widely used measure to evaluate the position of the flat foot in children. What is New: • The RCSP cut-off point 6 shows a sensitivity of 67% and a specificity of 85% thanks to the FPI as the Gold standard. • The RCSP is useful for health professionals who are not specialised in pediatric foot health. The RCSP is useful to detect flat foot in children.

Early-onset and late-onset Parkinson's disease exhibit a different profile of gait and posture features based on the Kinect.

INTRODUCTION: Gait and posture abnormalities are the common disabling motor symptoms in Parkinson's disease (PD). This study aims to investigate the differential characteristics of gait and posture in early-onset PD (EOPD) and late-onset PD (LOPD) using the Kinect depth camera. METHODS: Eighty-eight participants, including two subgroups of 22 PD patients and two subgroups of 22 healthy controls (HC) matched for age, sex, and height, were enrolled. Gait and posture features were quantitatively assessed using a Kinect-based system. A two-way analysis of variance was used to compare the difference between different subgroups. RESULTS: EOPD had a significantly higher Gait score than LOPD (p = 0.031). Specifically, decreased swing phase (p = 0.034) was observed in the EOPD group. Although the Posture score was similar between the two groups, LOPD was characterized by an increased forward flexion angle of the trunk at the thorax (p = 0.042) and a decreased forward flexion angle of the head relative to the trunk (p = 0.009). Additionally, age-independent features were observed in both PD subgroups, and post hoc tests revealed that EOPD generally performed worse gait features. In comparison, LOPD was characterized by worse performance in posture features. CONCLUSIONS: EOPD and LOPD exhibit different profiles of gait and posture features. The phenotype-specific characteristics likely reflect the distinct neurodegenerative processes between them.