Sensory Conditions Research Articles

Case Report: Modulation of Effective Connectivity in Brain Networks after Prosthodontic Tooth Loss Repair

INTRODUCTION. Recent neuroimaging studies suggest that dental loss replacements induce changes in neuroplasticity as well as in correlated connectivity between brain networks. However, as the typical temporal delay in detecting brain activity by neuroimaging cannot account for the influence one neural system exerts over another in a context of real activation (“effective” connectivity), it seems of interest to approach this dynamic aspect of brain networking in the time frame of milliseconds by exploiting electroencephalographic (EEG) data. MATERIAL AND METHODS. The present study describes one subject who received a new prosthodontic provisional implant in substitution for previous dental repairs. Two EEG sessions led with a portable device were recorded before and after positioning the new dental implant. By following MATLAB-EEGLAB processing supported by the plugins FIELDTRIP and SIFT, the independent component analysis (ICA) derived from EEG raw signals was rendered as current density fields and interpolated with the dipoles generated by each electrode for a dynamic study of the effective connectivity. One more recording session was undertaken six months after the placement of the final implant. RESULTS. Compared to the baseline, the new prosthodontic implant induced a novel modulation of the neuroplasticity in sensory-motor areas which was maintained following the definitive implant after six months, as revealed by changes in the effective connectivity from the basal strong enslavement of a single brain area over the others, to an equilibrate inter-related connectivity evenly distributed along the frontotemporal regions of both hemispheres. CONCLUSIONS. The rapid shift of the effective connectivity after positioning the new prosthodontic implant and its substantial stability after six months suggest the possibility that synaptic modifications, induced by novel sensory motor conditions, modulate the neuroplasticity and reshape the final dynamic frame of the interarea connectivity. Moreover, given the viability of the EEG practice, this approach could be of some interest in assessing the association between oral pathophysiology and neuronal networking.

Game-like interactive exercise versus visual feedback in patients with chemotherapy induced peripheral neuropathy post mastectomy: A randomized comparative study

Background Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most frequent side effects of antineoplastic agents, with a prevalence of 19 to 85%. In terms of clinical manifestations, CIPN is primarily a sensory neuropathy with motor and autonomic alterations of varying intensity and duration. CIPN consider as major problem for both cancer patients and survivors, as well as for their healthcare providers, possibly increasing the risk of falling. Objective: To evaluate the efficacy of game-like interactive exercise versus visual feedback training on the risk of falling and sensory integration in patients with chemotherapy-induced peripheral neuropathy after mastectomy. Methods: In this randomized comparative study, 30 female patients diagnosed with chemotherapy-induced peripheral neuropathy after mastectomy were randomly allocated into two equal groups; group (A) underwent game-like interactive exercise using the Biodex Balance System (BBS), while group (B) underwent a visual feedback training program using BBS. The treatment was applied for three sessions per week for four consecutive weeks. All subjects in both groups were assessed using the fall risk index and sensory integration test (sway index) in four sensory conditions at baseline and at the end of the study for both groups.

Joint entropy analysis of anterior-posterior and medial-lateral body sway.

We studied the Shannon entropy of center of pressure (COP) trajectories under different sensory feedback conditions and analyzed the interrelations between medial-lateral (ML), anterior-posterior (AP) and joint (ML and AP) sway entropy. Static balance was assessed on a force platform under different visual and proprioceptive feedback conditions: Standing on firm support with eyes open (condition 1) or closed (condition 2) and standing on foam with eyes closed (condition 3). Postural sway was analyzed by means of linear and nonlinear, information theoretic metrics (entropy of ML and AP sway, joint ML and AP entropy). ML entropy, AP entropy and joint ML and AP entropy remained stable from condition 1 through condition 3. The values of ML and AP entropies were practically at their theoretical maximum in all conditions. On the other hand, joint ML and AP entropies were clearly submaximal. Decreasing the reliability of visual and proprioceptive input does not alter the Shannon entropy of body sway, although it does increase the magnitude of conventional linear sway metrics. Importantly, individual ML and AP sway entropies tend towards absolute randomness, whereas the joint, ML and AP, sway entropy exhibits a higher degree of regularity, suggesting its role as the actual controlled variable.

The effect of limited sensory information on exoskeleton performance in people with complete spinal cord injury.

Despite the absence of somatosensory information from the lower extremities, people with complete spinal cord injury (SCI) can maintain postural stability in an exoskeleton. This is partly because humans are able to reweigh the relative dependence on each of the senses. However, when the sensory environment is changed, people with complete SCI are limited in their ability to reweigh their sensory organization towards more dependence on somatosensory information. The aim of this study was to investigate the effect of limited visual and/or auditory information on exoskeleton performance in people with complete SCI. Three experienced exoskeleton users performed twelve walking trials in the ReWalk exoskeleton. In each trial, the presence or absence of visual and/or auditory information was varied. Exoskeleton performance was operationalized as the walking distance covered and the amount of crutch loading. In one participant, the distance covered decreased when visual information was limited. The other two participants did not show substantial differences in distance covered between sensory conditions. Two participants decreased crutch loading when visual information was restricted, and one participant decreased crutch loading when auditory information was limited. The current study suggests a limited influence of the presence or absence of visual and auditory information on the distance covered in people with complete SCI walking in an exoskeleton. Interestingly, crutch loading seemed to decrease rather than increase when visual or auditory information was limited.

Neuroanatomical shifts mirror patterns of ecological divergence in three diverse clades of mimetic butterflies.

Microhabitat partitioning in heterogenous environments can support more diverse communities but may expose partitioned species to distinct perceptual challenges. Divergence across microhabitats could therefore lead to local adaptation to contrasting sensory conditions across small spatial scales, but this aspect of community structuring is rarely explored. Diverse communities of ithomiine butterflies provide an example where closely related species partition tropical forests, where shifts in mimetic coloration are tightly associated with shifts in habitat preference. We test the hypothesis that these mimetic and ecological shifts are associated with distinct patterns of sensory neural investment by comparing brain structure across 164 individuals of 16 species from three ithomiine clades. We find distinct brain morphologies between Oleriina and Hypothyris, which are mimetically homogenous and occupy a single microhabitat. Oleriina, which occurs in low‐light microhabitats, invests less in visual brain regions than Hypothyris, with one notable exception, Hyposcada anchiala, the only Oleriina sampled to have converged on mimicry rings found in Hypothyris. We also find that Napeogenes, which has diversified into a range of mimicry rings, shows intermediate patterns of sensory investment. We identify flight height as a critical factor shaping neuroanatomical diversity, with species that fly higher in the canopy investing more in visual structures. Our work suggests that the sensory ecology of species may be impacted by, and interact with, the ways in which communities of closely related organisms are adaptively assembled.

Classification of Tonic Pain Experience based on Phase Connectivity in the Alpha Frequency Band of the Electroencephalogram using Convolutional Neural Networks.

The complexity of brain activity involved in the generation of the experience of pain makes it hard to identify neural markers able to predict pain states. The within and between subjects variability of pain hinders the predictive potential of machine learning models trained across participants. This challenge can be tackled by implementing deep learning classifiers based on convolutional neural networks (CNNs). We targeted phase-based connectivity in the alpha band recorded with electroencephalography (EEG) during resting states and sensory conditions (eyes open [O] and closed [C] as resting states, and warm [W] and hot [H] water as sensory conditions). Connectivity features were extracted and re-organized as square matrices, because CNNs are effective in detecting the patterns from 2D data. To assess the classifier performance we implemented two complementary approaches: we 1) trained and tested the classifier with data from all participants, and 2) using a leave-one-out approach, that is excluding one participant at a time during training while using their data as a test set. The accuracy of binary classification between pain condition (H) and eyes open resting state (O) was 94.16% with the first approach, and 61.01 % with the leave-one-out approach. Clinical relevance-Further validation of the CNN classifier may help caregivers track the rehabilitation of chronic pain patients and dynamically modify the therapy. Further refinement of the model may allow its application in critical care setting with unresponsive patients to identify pain-like states otherwise incommunicable to medical personnel.

Multisensory information about changing object properties can be used to quickly correct predictive force scaling for object lifting.

Sensory information about object properties, such as size or material, can be used to make an estimate of object weight and to generate an accurate motor plan to lift the object. When object properties change, the motor plan needs to be corrected based on the new information. The current study investigated whether such corrections could be made quickly, after the movement was initiated. Participants had to grasp and lift objects of different weights that could be indicated with different cues. During the reaching phase, the cue could change to indicate a different weight and participants had to quickly adjust their planned forces in order to lift the object skilfully. The object weight was cued with different object sizes (Experiment 1) or materials (Experiment 2) and the cue was presented in different sensory modality conditions: visually, haptically or both (visuohaptic). Results showed that participants could adjust their planned forces based on both size and material. Furthermore, corrections could be made in the visual, haptic and visuohaptic conditions, although the multisensory condition did not outperform the conditions with one sensory modality. These results suggest that motor plans can be quickly corrected based on sensory information about object properties from different sensory modalities. These findings provide insights into the information that can be shared between brain areas for the online control of hand-object interactions.

Difference in postural stability between STarT Back Tool subgroups of patients with low back pain under conditions of sensory deprivation and cognitive load.

ObjectiveWe explored differences in postural stability between subgroups of patients with low back pain (LBP) and varying risk levels for developing chronicity measured using the Subgroups for Targeted Treatment (STarT) Back Tool.MethodsThis was a cross-sectional, single-session, double-blind experimental study among 65 participants who had LBP for more than 14 days. Postural stability was assessed by measuring the center of pressure (COP) range, displacement area, and velocity in anterior–posterior and mediolateral directions under four sensory and cognitive conditions: (i) eyes open and counting forward, (ii) eyes closed and counting forward, (iii) eyes closed and counting forward in multiples of seven, and (iv) eyes closed and counting backward in multiples of seven. The participants were stratified into low-/medium- (n = 53) and high-risk (n = 9) subgroups.ResultsThere were no significant between-group differences among patients with LBP stratified as having a low/medium or high risk of chronicity in postural stability and sensory and cognitive conditions.ConclusionsImpaired postural stability is important to consider when treating patients with LBP. However, we found that these impairments were not strongly aggravated in groups with a higher risk of chronicity, as measured using the STarT Back Tool.

The trunk-tail junctional region in Ciona larvae autonomously expresses tail-beating bursts at ∼20second intervals.

Swimming locomotion in aquatic vertebrates, such as fish and tadpoles, is expressed through neuron networks in the spinal cord. These networks are arranged in parallel, ubiquitously distributed and mutually coupled along the spinal cord to express undulation patterns accommodated to various inputs into the networks. While these systems have been widely studied in vertebrate swimmers, their evolutionary origin along the chordate phylogeny remains unclear. Ascidians, representing a sister group of vertebrates, give rise to tadpole larvae that swim freely in seawater. In the present study, we examined the locomotor ability of the anterior and posterior body fragments of larvae of the ascidian Ciona that had been cut at an arbitrary position. Examination of more than 200 fragments revealed a necessary and sufficient body region that spanned only ∼10% of the body length and included the trunk-tail junction. 'Mid-piece' body fragments, which included the trunk-tail junctional region, but excluded most of the anterior trunk and posterior tail, autonomously expressed periodic tail-beating bursts at ∼20s intervals. We compared the durations and intervals of tail-beating bursts expressed by mid-piece fragments, and also by whole larvae under different sensory conditions. The results suggest that body parts outside the mid-piece effect shortening of swimming intervals, particularly in the dark, and vary the burst duration. We propose that Ciona larvae express swimming behaviors by modifying autonomous and periodic locomotor drives that operate locally in the trunk-tail junctional region.

Dietary Flavonoid Intake and Chronic Sensory Conditions: A Scoping Review.

Dietary flavonoids have antioxidant, anti-inflammatory, and vascular health benefits, which align with the proposed pathophysiology of age-related eye conditions and hearing problems (hearing loss and tinnitus). This scoping review is based on Arksey and O’Malley’s six-stage framework and aims to summarise current evidence on the association between the dietary flavonoid intake and chronic sensory conditions in adults, and to identify the research gaps in this area. Eligible studies were identified by searching MEDLINE, EMBASE PsycINFO via the OVID platform, and Google Scholar, as well as manually searching the reference lists of the eligible articles. The inclusion criteria included: articles with full-text access, written in the English language, and focused on chronic sensory conditions and dietary flavonoid intake in an adult population. Studies focused on flavonoid supplements were excluded. Ten studies were included in this review. The evidence suggests that the flavonoid subclass, flavonols, are protective against eye conditions, including age-related macular degeneration, cataract, and glaucoma. There is insufficient evidence to support an association with hearing loss or tinnitus. Overall, dietary flavonol intake appears to be protective against some chronic eye conditions. However, for most eye and hearing-related conditions, only one study was identified. Thus, there is a need for more recent high-quality research to be conducted to confirm any significant associations.

Postural Balance in Young Tennis Players of Varied Competition Levels.

The aim of this study was to investigate the effect of young tennis players' expertise on their postural balance (PB) under sensorial conditions with eyes open (EO) and with eyes closed (EC). Our participants were 75 healthy adolescents aged 15-18 years, divided into three groups based on their skill levels: (a) national tennis players (NAT; n = 25), regional tennis players (REG; n =25), and a control group of non-sport practitioners (CG; n = 25). We recorded center of pressure area and mean velocity on a force platform while participants stood in bipedal and unipedal stances in EO and EC conditions for all three groups. Statistical analyses showed that NAT participants swayed less than CG participants in all conditions and less than REG participants in the bipedal stance with EC and in the unipedal stance, both with EO and EC. Thus, tennis practice/experience may have improved PB in this sample, as high-level tennis players had better PB compared to novices, especially in challenging conditions.

Identification and quantification of nociceptive Schwann cells in mice with and without Streptozotocin-induced diabetes

Specialized cutaneous Schwann cells (SCs), termed nociceptive SCs, were recently discovered. Their function is not fully understood, but they are believed not only to support peripheral axons in mouse skin by forming a mesh-like neural-glio networking structure in subepidermal area, but also contributing to transduction of mechanical sensation and neuropathic pain. Diabetic neuropathy (DPN) is one of the most common complication of diabetes, however, the mechanisms behind painful and painless DPN remain unclear. Using a mouse model of DPN, we want to investigate if there are quantitative differences in nociceptive SC density between the condition of hyperglycemia-induced sensory abnormalities and control condition and at which stage in the disease the damage occurs. Here, we developed a set of counting rules for nociceptive SCs based on immunofluorescent staining, and applied the method to quantify the density of nociceptive SCs in control mice (n = 10), mice with nociceptive hypersensitivity at early diabetic stage (n = 5), and mice with sensory hyposensitivity at late diabetic stage (n = 5) in the Streptozotocin (STZ) model of type 1 diabetes. Nociceptive SCs were identified as S100+/Sox10+/DAPI+ cells abutting to peripheral nerves, with the somas located within 25 µm depth in the subepidermal area and outside glands and large fiber bundles. Hypersensitive diabetic mice had decreased nociceptive SC density, despite having normal epidermal nerve fiber density, compared with age-matched control mice (P = 0.023). In contrast, there was a reduction in intraepidermal nerve fiber density but no difference in nociceptive SC density between hyposensitive diabetic mice and the age-matched control mice. This study provides a detailed description of how to identify and quantify nociceptive SC and demonstrates that nociceptive SC density declines before nerve fiber deterioration, which supports previous observations that nociceptive SCs are critical for maintenance of cutaneous sensory nerves.

Facilitators and Barriers to Care for Patients with Disabilities in Primary Pediatrics.

Nearly 20% of children in the United States have special health care needs, and they often experience disparities in health outcomes. This article reviews barriers to and facilitators of primary pediatric care for children within four defined categories of disability: (1) physical disabilities, both temporary and permanent; (2) chronic conditions requiring accommodations, including mental health conditions; (3) sensory disabilities and conditions; and (4) cognitive, educational, neurodevelopmental, and social disabilities. Primary care facilitators include interventions for both providers and patients that focus on time as a valued resource, provide psychosocial support, coordinate interdisciplinary teams of care, and provide training for providers. Barriers include exclusion of patients with disabilities from research trials and gaps in educational reform regarding ableism and hidden disabilities. Identified facilitators should be implemented on a larger scale, and barriers need to be addressed further so we may better support children with disabilities. [Pediatr Ann. 2022;51(6):e243-e253.].

Postoperative inferior alveolar nerve paresthesia and impacted third molar distance to the mandibular canal

The goals of this study were to assess the incidence of inferior alveolar nerve (IAN) paresthesia after impacted lower third molars extraction and to observe the distance between them and the mandibular canal (MC) cortical using cone beam computed tomography (CBCT). For this study, 29 patients with both impacted lower third molars (totaling 58 teeth) were selected. They initially underwent clinical examination and evaluation of preoperative sensory condition according to standard protocol for nerve injury. Subsequently, they underwent CBCT and third molar extraction at the Oral and Maxillofacial Surgery Residency Program from the Western Paraná State University. On the seventh postoperative day, they were submitted again to the sensory analysis protocol to check for IAN paresthesia. In CBCT, the distance between the MC cortical bone and the tooth was determined by the arithmetic mean of the closest measurement of these two structures in each of the tomography three sections (axial, coronal and sagittal). There was one paresthesia case (1.72%) and regarding the CBCT, 57 third molars were in close contact with the MC. It was concluded that CBCT played an important role in surgical planning and it is believed that its use contributed to the considerably low IAN paresthesia rate.

Do Our Hands See What Our Eyes See: Investigating the Relationships Between Spatial and Haptic Abilities

IntroductionSpatial abilities (SA) are the cognitive ability to manipulate mental images of objects to problem solve and are linked to comprehension of three‐dimensional (3D) spatial knowledge in gross anatomy and in learning clinical procedures. Similarly, haptic abilities (HA) refer to translating tactile information from the immediate environment into mental images and are involved in handling anatomical specimens and technical skill acquisition common to clinicians. Both abilities independently play an important role in learning anatomy, yet the relationships between SA and HA are unknown. The objective of this study is to explore SA‐HA interactions.MethodsThe Mental Rotations Test (MRT) and the newly developed haptic abilities test (HAT) respectively quantified SA and HA in undergraduate students. The HAT, modelled after the MRT, consisted of untimed, matching questions utilizing MRT‐styled 3D handheld wooden objects (~10cm3) under three sensory conditions using sight (S), haptics (H) and the combination of both sight and haptics (SH). While HAT condition scores and response times determined accuracy, video recorded subject gaze and haptic behaviours on a question‐by‐question basis. Scores for MRT are presented as mean ± SD and HAT scores as median (Q1‐Q3).ResultsSubjects (n=16, 10F, 20‐28yrs) completed the MRT and HAT and were categorized into high (n=9, 4F, MRT: 14.8±3) and low (n=7, 6F, MRT: 6.3±3) (H/LSA) groups (p<0.0001). Scores obtained in the H condition [14 (13‐15) vs14 (14‐14), p=0.0031] were significantly lower than in the S [15 (15‐15) vs14 (14‐15)] and SH conditions [15 (15‐15) vs14 (14‐15)] in H/LSA groups respectively. Spearman’s correlation coefficient illustrated MRT scores were moderately related in the S condition (r=0.506, p=0.038), but unrelated in the SH and H conditions (SH: r=0.325, p=0.203; H: r=0.162, p=0.534). The number of pupillary fixations per question was similar (S:6.0±3.0 vs5.9±1.4, p=0.910; SH: 4.5±2.0 vs6.7±2.0, p=0.099) for H/LSA groups respectively. Initial descriptive analyses of hand behaviours (n=4) suggest H/LSA objects differently.DiscussionDespite significant difference in SA, when individuals are presented identical environmental 3D objects to view, view and touch, or touch alone, it is difficult to differentiate SA. These data suggest that the addition of haptic sensory information may aid LSA individuals completing spatial tasks. Although visual attention and timing of haptic behaviours may be similar between H/LSA subjects, further kinematic analysis of haptic strategies may be more meaningful to isolate how somatosensory inputs aid problem solving behaviours in LSA persons. This is some of the first data to simultaneously measure hand and gaze behaviour during spatially challenging tasks in individuals with divergent SA. Given recent migrations to online anatomy teaching and learning environments due to COVID‐19, understanding learner behaviour when sensory inputs, like haptics, are removed is valuable evidence that can inform future anatomy curriculum and resource development.

Sensory environment affects Icelandic threespine stickleback's anti-predator escape behaviour.

Human-induced changes in climate and habitats push populations to adapt to novel environments, including new sensory conditions, such as reduced visibility. We studied how colonizing newly formed glacial lakes with turbidity-induced low-visibility affects anti-predator behaviour in Icelandic threespine sticklebacks. We tested nearly 400 fish from 15 populations and four habitat types varying in visibility and colonization history in their reaction to two predator cues (mechano-visual versus olfactory) in high versus low-visibility light treatments. Fish reacted differently to the cues and were affected by lighting environment, confirming that cue modality and light levels are important for predator detection and evasion. Fish from spring-fed lakes, especially from the highlands (likely more diverged from marine fish than lowland fish), reacted fastest to mechano-visual cues and were generally most active. Highland glacial fish showed strong responses to olfactory cues and, counter to predictions from the flexible stem hypothesis, the greatest plasticity in response to light levels. This study, leveraging natural, repeated invasions of novel sensory habitats, (i) illustrates rapid changes in anti-predator behaviour that follow due to adaptation, early life experience, or both, and (ii) suggests an additional role for behavioural plasticity enabling population persistence in the face of frequent changes in environmental conditions.

IDF21-0192 Preliminary findings of plantar stimulation combined with balance training on postural stability in diabetic neuropathy

Background: Diabetic peripheral neuropathy (DPN) is most common complication seen in the patients with type 2 diabetes mellitus. It is usually reduced sensation of plantar surface of foot. There are evidences demonstrate that patients with type 2 diabetes mellitus with DPN are associated with decline in postural stability in standing and increase risk of falls. Previous studies found that plantar electrical stimulation can improve plantar sensation. Recently, exercise is possibly an alternative intervention to improve balance in the adults. However, balance exercise is inappropriate for patients with type 2 diabetes mellitus with DPN who are impaired plantar sensation and concern about the potential risk of falls. However, no studies have explored whether plantar electrical stimulation combined with standing balance training has positive effects in patients with type 2 diabetes mellitus with DPN. Aim: The purpose of this pilot study was to determine the immediate and long-term effects of 4-week of plantar electrical stimulation combined with standing balance training on postural stability and walking ability in patients with type 2 diabetes mellitus with DP. Method: Four patients with type 2 diabetes mellitus with DPN were participated in this study. Each patient was completed plantar electrical stimulation combined with standing balance training 3 days per week for 4 weeks. Electrical stimulation (biphasic pulse current with a pulse duration of 0.1 ms, 100 Hz) was delivered via two self-adhesive surface electrodes for plantar of feet. The proximal electrode was placed over plantar forefoot area and the distal electrode was placed over plantar heel area. The current intensity was adjusted to produce tingling sensation without any discomfort. During plantar electrical therapy, each patient was performed simultaneously with standing balance training with both feet apart, feet together, tandem standing under eyes open and eyes closed conditions. Postural sway was assessed by total sway area using Lord’s sway meter during standing on 4 sensory conditions (eyes open and closed on a firm surface, eyes open and closed on a foam rubber mat) for 30 seconds of each condition. The walking ability was assessed by 10-meter walk test (10MWT) at preferred speed and maximum speed. All outcome measures were assessed before training, after 4-week training and 2-week follow-up. Results: Four weeks after training, all patients showed decreased total sway area during standing on 4 sensory conditions and increased walking speed on preferred and maximum conditions. Moreover, the results showed a trend toward decreased total sway area during standing on 4 sensory conditions and increased walking speed at 2-week follow-up period. Discussion: The findings from this pilot study showed that the immediate and long-term effects of 4-week of plantar electrical stimulation combined with standing balance training could help to improve postural stability and walking speed in patients with type 2 diabetes mellitus with DPN. This present method might be use as method for improving postural stability and reducing risk of falls in patients with type 2 diabetes mellitus with DPN. However, large sample sizes are still needed to confirm the finding in further study.

Application of a Digital Twin Virtual Engineering Tool for Ground Vehicle Maintenance Forecasting

<div class="section abstract"><div class="htmlview paragraph">The integration of sensors, actuators, and real-time control in transportation systems enables intelligent system operation to minimize energy consumption and maximize occupant safety and vehicle reliability. The operating cycle of military ground vehicles can be on- and off-road in harsh weather and adversarial environments, which demands continuous subsystem functionality to fulfill missions. Onboard diagnostic systems can alert the operator of a degraded operation once established fault thresholds are exceeded. An opportunity exists to estimate vehicle maintenance needs using model-based predicted trends and eventually compiled information from fleet operating databases. A digital twin, created to virtually describe the dynamic behavior of a physical system using computer-mathematical models, can estimate the system behavior based on current and future operating scenarios while accounting for past effects. In this manner, the collection of real-time data of the physical vehicle can be compared with the virtual counterpart to assess the likelihood of degraded operation and recommend maintenance. This paper creates a digital twin for an off-road tracked ground vehicle with an accompanying parameter database. A modular architecture enables different design reconfigurations to evaluate various chassis subsystems and vehicle-ground mobility interfaces. A preventive maintenance algorithm is applied to monitor the operating behavior of the vehicle. The prediction tool, operating in parallel with the digital twin, may use model-based and sensory signal condition indicators to monitor vehicle performance. A case study investigates two operating scenarios: a virtual wheeled suspension system is degraded; and a virtual tracked vehicle experiences missing trackpads, which subtly alter the performances. The numerical results will offer insight into the pathway to begin creating a digital twin-based maintenance forecasting strategy.</div></div>

Balance Adaptation While Standing on a Compliant Base Depends on the Current Sensory Condition in Healthy Young Adults.

BackgroundSeveral investigations have addressed the process of balance adaptation to external perturbations. The adaptation during unperturbed stance has received little attention. Further, whether the current sensory conditions affect the adaptation rate has not been established. We have addressed the role of vision and haptic feedback on adaptation while standing on foam.MethodsIn 22 young subjects, the analysis of geometric (path length and sway area) and spectral variables (median frequency and mean level of both total spectrum and selected frequency windows) of the oscillation of the centre of feet pressure (CoP) identified the effects of vision, light-touch (LT) or both in the anteroposterior (AP) and mediolateral (ML) direction over 8 consecutive 90 s standing trials.ResultsAdaptation was obvious without vision (eyes closed; EC) and tenuous with vision (eyes open; EO). With trial repetition, path length and median frequency diminished with EC (p < 0.001) while sway area and mean level of the spectrum increased (p < 0.001). The low- and high-frequency range of the spectrum increased and decreased in AP and ML directions, respectively. Touch compared to no-touch enhanced the rate of increase of the low-frequency power (p < 0.05). Spectral differences in distinct sensory conditions persisted after adaptation.ConclusionBalance adaptation occurs during standing on foam. Adaptation leads to a progressive increase in the amplitude of the lowest frequencies of the spectrum and a concurrent decrease in the high-frequency range. Within this common behaviour, touch adds to its stabilising action a modest effect on the adaptation rate. Stabilisation is improved by favouring slow oscillations at the expense of sway minimisation. These findings are preliminary to investigations of balance problems in persons with sensory deficits, ageing, and peripheral or central nervous lesion.

Sex differences in the association of postural control with indirect measures of body representations

Besides anthropometric variables, high-order body representations have been hypothesised to influence postural control. However, this has not been directly tested before. Moreover, some studies indicate that sex moderates the relationship of anthropometry and postural control. Therefore, as a proof of concept we investigated the association of body representations with postural control as well as the influence of participants’ sex/gender. Body image measures were assessed with a figural drawing task. Body schema was tested by a covert and an overt task. Body sway was measured during normal bipedal quiet standing with eyes closed (with/without neck extended). Statistical analysis consisted of hierarchical multiple linear regressions with the following regression steps: (1) sensory condition, (2) sex/gender, (3) age, (4) anthropometry, (5) body schema, (6) body image, (7) sex/gender-interactions. Across 36 subjects (19 females), body schema was significantly associated with body sway variability and open-loop control, in addition to commonly known influencing factors, such as sensory condition, gender, age and anthropometry. While in females, also body image dissatisfaction substantially was associated with postural control, this was not the case in males. Sex differences and possible causes why high-order body representations may influence concurrent sensorimotor control of body sway are discussed.