Search Results (287)

Background: Orthostatic intolerance (OI) is an important factor affecting daily functional capacity in patients with long COVID. Traditionally, most OI symptoms have been attributed to exaggerated sympathetic nervous system activation associated with postural orthostatic tachycardia syndrome (POTS). Disequilibrium, also referred to as postural instability, may contribute to the development of OI in patients with long COVID. Methods: This study evaluated 32 patients with long COVID using neurological examinations and the active 10-min standing test. Disequilibrium was assessed using the Romberg and tandem gait tests. OI was defined as the inability to complete the active 10-min standing test. Results: Seven patients (22%) were diagnosed with OI. None of them had POTS, whereas six (86%) demonstrated disequilibrium, as detected by the Romberg and/or tandem gait test. POTS was observed in eight patients (25%), none of whom had OI. Disequilibrium was observed in nine patients (28%), six of whom (67%) had OI. Multiple regression analysis revealed that disequilibrium was positively associated with OI (r = 0.64, p < 0.001), whereas POTS was inversely associated (r = −0.38, p < 0.05). After 6 weeks of oral minocycline treatment in six patients and 2 weeks of repetitive transcranial magnetic stimulation therapy following minocycline in the other one patient, symptom amelioration was reported in six patients with OI. OI concomitant with disequilibrium recovered in five of the six patients treated and tested, although one patient who experienced symptom recovery failed to undergo the repeated standing test. Conclusions: Disequilibrium, rather than POTS, was the primary determinant of OI in patients with long COVID. Full article

Total hip arthroplasty (THA) reliably restores function, yet instability remains a clinically relevant complication. Increasing evidence indicates that postoperative stability is strongly influenced by the dynamic spine–pelvis–hip interaction, which modulates functional acetabular orientation across postures. This narrative review summarizes current evidence on postoperative spinopelvic alignment changes after THA with emphasis on temporal patterns, underlying mechanisms, and predictive factors. Early after THA, restoration of hip motion can partially normalize hip-driven compensatory patterns, however substantial interindividual variability persists. Mid- to long-term follow-up shows that pelvic orientation continues to evolve, particularly progressive posterior pelvic tilt in standing, largely driven by aging and spinal degeneration, with acceleration in older patients and those with spinal pathology. Prediction of postoperative pelvic behavior requires integrated assessment of pelvic orientation, spinal alignment and mobility, contralateral hip status, and whether imbalance is hip-driven versus spine-driven. Although classification- and model-based approaches can estimate postoperative pelvic tilt, clinically meaningful prediction uncertainty remains, supporting a strategy focused on risk stratification and adaptive preoperative planning. Full article

Background: Balance impairment and falls are a major health concern in older adults. Beyond vestibular and visual factors, growing evidence indicates that age-related hearing loss contributes to postural instability through altered multisensory integration. However, interventions addressing the interaction between auditory input and postural control remain limited. This study examined whether integrating Taopatch^® nanotechnology, based on localized photobiomodulation, into conventional hearing aids could influence postural control in individuals with hearing loss. Methods: Forty experienced hearing aid users (mean age 77.3 ± 15.6 years) completed five postural assessments using a SensorMedica^® baropodometric platform. Four sessions employed a placebo patch identical in appearance to the active device, and the fifth used Taopatch^®. Static and stabilometric parameters were analyzed under open- and closed-eye conditions. Results: Significant improvements were observed with the Taopatch^®-integrated device. Sway path length (−8%, p = 0.002), mean velocity (−8%, p = 0.002), and low-frequency sway (−30%, p = 0.04) decreased, indicating smoother and more efficient postural control. A lateral redistribution of plantar load and an increase in contact surface area (up to +15%) were also found. These effects were less evident without visual input. Conclusions: Preliminary findings suggest that localized photobiomodulation integrated into hearing aids may positively influence postural stability in older adults with hearing impairment, possibly by supporting sensory integration processes. Further controlled studies are needed to confirm these effects and clarify the underlying mechanisms. Full article

Hemophilia is an X-linked inherited bleeding disorder characterized by joint hemorrhages and progressive arthropathy. While mutation type is known to influence disease severity, its impact on postural balance strategies has remained unclear. This cross-sectional study investigated the relationship between gene mutation type and postural control in hemophilia A patient using center of pressure (CoP) analysis and radiographic joint assessment with the Pettersson score. Thirty-five participants were divided into an INV group (intron 22 or intron 1 inversion of the F8 gene) and a NonINV group (other mutations). While the Pettersson scores and traditional time-domain CoP parameters (sway area, velocity) were comparable between groups, frequency domain analysis revealed a significant difference. INV group exhibited significantly higher energy content above 2 Hz in the anteroposterior direction compared to NonINV group. This genotype-specific spectral signature emerged despite comparable radiographic arthropathy and conventional CoP metrics, suggesting that frequency-domain CoP analysis can uncover subclinical postural adaptations in hemophilia A. These findings highlight the need for targeted proprioceptive training in this specific subpopulation to prevent subclinical instability and potential falls. Full article

A safe physical human–robot interaction (pHRI) in rehabilitation requires reliable perception and low-latency decision making under heterogeneous and unreliable sensor inputs. This paper presents a multimodal sensor-fusion-based safety framework that integrates physical state estimation, semantic information fusion, and an edge-deployed large language model (LLM) for real-time pHRI safety control. A dynamics-based virtual sensing method is introduced to estimate internal joint torques from external force–torque measurements, achieving a normalized mean absolute error of $18.5\%$ in real-world experiments. An asynchronous semantic state pool with a time-to-live mechanism is designed to fuse visual, force, posture, and human semantic cues while maintaining robustness to sensor delays and dropouts. Based on structured multimodal tokens, an instruction-tuned edge LLM outputs discrete safety decisions that are further mapped to continuous compliant control parameters. The framework is trained using a hybrid dataset consisting of limited real-world samples and LLM-augmented synthetic data, and evaluated on unseen real and mixed-condition scenarios. Experimental results show reliable detection of safety-critical events with a low emergency misdetection rate, while maintaining an end-to-end decision latency of approximately 223 ms on edge hardware. Real-world experiments on a rehabilitation robot demonstrate effective responses to impacts, user instability, and visual occlusions, indicating the practical applicability of the proposed approach for real-time pHRI safety monitoring. Full article

Low back pain (LBP) remains a leading cause of disability worldwide, imposing substantial socioeconomic burdens. Among its many causes, facetogenic pain accounts for a significant proportion of cases and is generally attributed to irritation of the richly innervated facet joint capsule, mediated by the medial branches of the dorsal rami. This narrative, hypothesis-driven review synthesises the current anatomical, biomechanical, neurophysiological, and clinical literature and advances a conceptual framework proposing a novel anatomical mechanism that may contribute to LBP. We hypothesise that ossification of the mamillo-accessory ligament (MAL) may be a plausible but under-recognised anatomical variant that may influence lumbar biomechanics and neural interfaces. The MAL connects the mammillary and accessory processes of lumbar vertebrae, serving as a stabilising anchor for deep paraspinal muscles and forming a conduit for the medial branch of the dorsal ramus (MBDR). Ossification of the MAL, resulting in a mamillo-accessory foramen, may theoretically impair spinal biomechanics via three principal mechanistic domains: (1) disruption of muscle attachment and segmental stabilisation, (2) potential compression of the MBDR causing denervation and muscle atrophy, and (3) chronic nerve entrapment leading to asymmetrical postural adaptations and persistent pain. Collectively, these pathways may contribute to spinal instability, facet degeneration, and variable response to standard interventional treatments such as radiofrequency ablation. Recognition of MAL ossification may have potential implications for clinical assessment, targeted imaging strategies, and treatment stratification in patients with chronic, non-specific LBP. Full article

This case report describes the successful management of a 7-month-old Pomeranian with congenital vertebral malformation (CVM) causing kyphosis and progressive myelopathy, characterized by non-ambulatory paraparesis, decreased postural reactions, and increased spinal reflexes in the hind limbs. Initial management involved a dorsal approach for decompression and stabilization; however, the patient failed to regain hindlimb function. Following two failed surgical attempts due to implant failure and progressive instability, a salvage stabilization was performed using a transthoracic approach. Stabilization was achieved using titanium screws and polymethyl methacrylate (PMMA) applied to the vertebral bodies. The patient exhibited marked postoperative improvement, regaining weight-bearing ability within one week and achieving a normal gait by four weeks. At the 19-month follow-up, the dog maintained normal ambulatory function with no recurrence of neurological deficits. While the transthoracic approach is well-documented in brachycephalic breeds, this is the first report describing its successful application in a toy breed. This case highlights the transthoracic approach as a highly effective salvage technique, offering a novel solution when conventional dorsal elements are irreversibly compromised due to the extremely diminutive and fragile nature of toy breed vertebrae. Full article

Background: Previous studies have demonstrated the benefits of virtual reality (VR) as an intervention tool guided by specialists. However, little is known about whether VR may pose risks in uncontrolled environments. Considering its implications for clinics and practice, this study aimed to assess the potential risks of a 3D VR simulation on postural control in young adults. Methods: Seventy-nine community-dwelling young adults completed a VR program using a head-mounted display that simulated a 3D roller-coaster ride while standing. Postural control was assessed using a force platform measuring frontal and lateral sway, center-of-pressure sway area, and frontal and lateral imbalance speed. The assessments were conducted with and without VR. Statistical analyses were performed using paired comparisons. Significance was set at 5%. Effect sizes (ESs) are reported. Results: Engaging in a VR roller-coaster simulation increased the participants’ imbalance in terms of frontal sway (p = 0.001; ES = 0.919), center-of-pressure sway area (p = 0.001; ES = 0.849), frontal imbalance speed (p = 0.001; ES = 0.910), and lateral imbalance speed (p = 0.001; ES = 0.663). No significant difference was observed in the lateral sway (p = 0.383). During VR exposure, 25% of the participants showed a clinically significant increase in postural instability. Despite having normal baseline parameters, participants with higher postural instability showed greater deterioration in postural control during VR exposure than those with lower postural instability. Conclusions: A 3D VR simulation affected several measures of postural control in community-dwelling young adults. Precautions should be taken when engaging in VR without appropriate specialist supervision. Full article

Background/Objectives: Degenerative cervical myelopathy (DCM) may result from posture-dependent spinal cord compromise not detectable on neutral imaging. Dynamic MRI can uncover clinically relevant mechanisms underlying otherwise unexplained myelopathy and guide management. This report illustrates a dynamic cervical myelopathy phenotype revealed by flexion–extension imaging and its impact on surgical decision-making. Methods: A 49-year-old man presented with progressive bilateral upper-limb paresthesias, intrinsic hand atrophy, and distal weakness. Neutral cervical MRI, standard radiographs, and flexion–extension MRI were performed to investigate a suspected dynamic etiology, including differentiation from Hirayama disease. Surgical treatment consisted of anterior cervical discectomy and fusion (ACDF), with clinical and radiological follow-up. Results: Neutral MRI showed intramedullary T2 hyperintensity from C4 to C6 without static canal stenosis or frank compression, while radiographs demonstrated segmental kyphosis without instability. Flexion MRI revealed reproducible spinal cord contact with a small cranially located osteophyte at C5–C6, concordant with the myelopathic signal. ACDF at C4–C6 led to clinical improvement. One year later, recurrent symptoms from adjacent-segment pathology (C3–C4 myelopathic signal and C6–C7 foraminal disc herniation) required a second ACDF, resulting in durable neurological stability. Conclusions: This case demonstrates flexion-dependent cord–osteophyte conflict causing cervical myelomalacia in the absence of static stenosis. Dynamic MRI resolved a clinical–radiological mismatch and directly informed surgical planning. Recognition of dynamic myelopathy phenotypes and vigilance for adjacent-segment disease after fusion are essential for optimizing outcomes. Full article

Background: Motor as well as attentional skills are deficient in children with attention deficit hyperactivity disorder (ADHD). The aim of the present study was to explore whether a short immersive rehabilitation therapy could improve motor and visuo-attentional capabilities in children with ADHD. Methods: Forty children with ADHD participated in this study; IQ-, sex- and age-matched children were splitted in two groups (G1 and G2) of twenty. An unpredictable random sequence was used to allocate a child to group G1 (trained group) or G2 (control group). Oculomotor and postural performance for both groups of children were objectively assessed twice (before and after 16 min) by using an eye tracker and platform. Group G1 only underwent 16 min of immersive rehabilitation therapy, while the control group (G2) had 16 min of resting. The immersive therapy consisted of performing physical movement while training visual discrimination, attention and spatial orientation skills. Results: After 16 min, significant improvements in the fixation area (p = 0.008) and in the number of catch-up saccades during pursuit eye movements (p < 0.001), as well as a smaller postural instability index (PII) (p < 0.001), were observed for the trained group (G1) only. Conclusions: These findings suggest that children with ADHD could benefit from a short immersive therapy to improve both visual–attention and motor performances. This new immersive therapy is a useful tool allowing a better integration of both visual and motor sensory inputs via the cortico/cerebellar network. Follow-up studies on a larger number of children with ADHD will be necessary to explore the eventual possible persistence of such a training effect and imaging works will help to understand where such adaptive mechanisms take place. Full article

Background and Objectives: Postural instability is a key feature of Parkinson’s disease (PD), contributing to disability and increased risk of falls. Pharmacological treatments are important, but it is necessary to integrate them with rehabilitation programs that provide benefits for gait and balance. Focal muscle vibration (fMV) has been proposed as a proprioceptive-oriented intervention to enhance postural control, but evidence in PD remains heterogeneous. This observational, retrospective, and controlled pilot study aimed to evaluate whether the integration of fMV into a standardized rehabilitation program provides additional benefits for balance, gait, and fall risk compared to standardized exercise alone in patients with PD. Materials and Methods: Medical records of 35 outpatients with Parkinson’s disease (Hoehn & Yahr stage II–III) were reviewed. All practiced a standardized rehabilitation exercise group program. Of these, 18 patients agreed to undergo fMV before the exercise sessions (fMV group); 17 patients did not accept fMV due to personal organizational reasons (EG) and were considered a retrospective control group. In detail, (i) the fMV group receivdc focal muscle vibration during the first three weeks in addition to a standardized group rehabilitation exercise program, and (ii) the EG underwent a standardized rehabilitation program only. Both groups then completed an identical 16-week standardized rehabilitation program. Functional outcomes were assessed at baseline (T0) and after one month (T1). Results: Groups were homogeneous at baseline. The fMV group showed significant improvements in SPPB (from 8.16 ± 1.6 to 10.2 ± 1.6 p < 0.001) in the Tinetti total (from 18.38 ± 3.2 to 21.5 ± 2.9 p < 0.05). Stabilometric analysis revealed a significant improvement in the Romberg Quotient in the fMV group (p < 0.005). Conclusions: A short time-limited fMV intervention may act as a sensory primer, enhancing the effects of a subsequent standardized rehabilitation program in PD. Full article

Functional ankle instability (FAI) is a common consequence of lateral ankle sprains, characterized by impaired sensorimotor control. While orthoses and localized vibration have shown individual benefits for FAI, their combined application in a wearable device has not been previously investigated. This pilot randomized trial compared the effects of a vibrotactile foot orthosis (VFO) and a vibrotactile ankle orthosis (VAO) on joint position sense (JPS) and postural control in individuals with FAI. Sixteen participants were randomized to receive either a VFO or a VAO, both delivering 30–50 Hz pulsed vibration in 20 min sessions, three times a week, for two weeks. Outcome measures included joint position sense (JPS) error (°), center of pressure (COP) velocity (mm/s), the Star Excursion Balance Test (SEBT), and the Six-Meter Hop Test (SMHT), which were assessed pre-intervention, immediately post-intervention, and after two weeks of use. The analysis showed a statistically significant interaction between time and intervention group for JPS error (p = 0.02, η² = 0.42). Specifically, the VFO group improved JPS significantly more than VAO at two weeks follow-up (MD = −1.75°, p = 0.005, d = −1.68). Both groups significantly reduced in anteroposterior COP velocity after two weeks (VFO: MD = 1, p = 0.003, d = 1.47; VAO: MD = 1.39, p ˂ 0.001, d = 2.05) with no between-group differences. No changes were observed in the SEBT or SMHT. Plantar-based vibrotactile stimulation was more effective than ankle-based stimulation in enhancing proprioceptive acuity in individuals with FAI. Both interventions improved static postural stability, supporting the potential of integrated vibrotactile orthoses in FAI rehabilitation. No major practical issues were reported during the intervention. Two participants experienced minor discomfort related to the electronic housing bulk in the first week, which was resolved by week two. No further complaints regarding device weight or usability were observed. Full article

Mobile robots conducting inspection tasks in coal-mine roadways and operating in complex underground environments are often subjected to demanding conditions such as low adhesion, uneven friction distribution, and localized slippery surfaces. These challenges are significant, predisposing the robots to trajectory deviation and posture instability, thereby presenting substantial obstacles to high-precision tracking control. The primary innovation of this study lies in proposing a hierarchical model predictive control (HMPC) strategy, which addresses the challenges through synergistic, kinematic and dynamic optimization. The core contribution is the construction of dual-layer optimization architecture. The upper-layer kinematic MPC generates the desired linear and angular velocities as reference commands. The lower-layer MPC is designed based on a dynamic model that incorporates ground adhesion characteristics, enabling the online computation of optimal driving forces (F_L, F_R) for the left and right tracks that simultaneously satisfy tracking performance requirements and practical actuation constraints. Simulation results demonstrate that the proposed hierarchical framework significantly outperforms conventional kinematic MPC in terms of steady-state accuracy, response speed, and trajectory smoothness. Experimental validation further confirms that, in environments with low adhesion and localized slippery conditions representative of actual roadways, the proposed method effectively coordinates geometric accuracy with dynamic feasibility. It not only markedly reduces longitudinal and lateral tracking errors but also ensures excellent dynamic stability and reasonable driving force distribution, providing key technical support for reliable operation in complex underground environments. Full article

Background: The Identification of Functional Ankle Instability (IdFAI) questionnaire is widely used to screen for functional ankle instability (FAI), but its link to objective landing kinetics in multidirectional sports like netball is not well-understood. This study aimed to (i) compare landing kinetics between idFAI stratified netball players, and (ii) examine associations between IdFAI scores with dynamic postural stability (DPS) indices and peak vertical ground reaction forces (PvGRF) during vertical drop landings. Methods: A cross-sectional exploratory study using a repeated-measures landing protocol was conducted on female university netball players (n = 24), stratified into FAI (n = 12) and non-FAI (n = 12) groups using the IdFAI (≥11 indicating possible FAI). Participants completed 18 unilateral drop jump landings in forward (FW), diagonal (DI), and lateral (LA) directions. Ground reaction forces (GRFs) were recorded to obtain DPS and PvGRF metrics (1000 Hz). Mann–Whitney U tests compared FAI groups, and Spearman correlations assessed associations (p < 0.05). Results: Players with FAI showed greater anteroposterior instability during LA landings (U = 33.5, p = 0.020, ES = 0.65). IdFAI scores correlated moderately with lateral anteroposterior deficits (rs = 0.473, p = 0.020, CI = 0.062–0.746). Conclusions: These findings suggest that players with greater FAI display increased anteroposterior instability during LA landings, with higher IdFAI scores moderately associated with these deficits. Despite the small exploratory, hypothesis-generating sample, the results emphasize the practical relevance of direction-targeted landing-stability training to improve DPS in vertical landings. This may provide insight into ankle-injury risk among FAI netball players, given that LA landings represent a documented ankle sprain mechanism. Full article

Intelligent lower-limb exoskeleton rehabilitation robots are increasingly superseding traditional rehabilitation equipment, making them a focus of research in this field. However, existing systems remain challenged by dynamic instability resulting from various disturbances during actual walking. To address this limitation, this study proposes a novel dynamic stability criterion. Through an analysis of the principles and limitations of the traditional zero-moment point (ZMP) stability criterion, particularly during the late single-leg support phase, a new stability criterion is introduced, which is founded on the swing projection polygon during single-leg support. This approach elucidates the variation patterns of the stability polygon during a single-step motion and facilitates a qualitative analysis of the stability characteristics of the human–robot system in multiple postures. To further enhance the stability and smoothness of gait trajectories in lower-limb exoskeleton rehabilitation robots, the shortcomings of conventional gait planning approaches, namely their non-intuitive nature and discontinuity, are addressed. A recurrent gait planning method leveraging Long Short-Term Memory (LSTM) neural networks is proposed. The integration of the periodic motion characteristics of human gait serves to validate the feasibility and correctness of the proposed method. Finally, based on the recurrent gait planning method, the dynamic stability of walking postures is verified through theoretical analysis and experimental comparisons, accompanied by an in-depth analysis of key factors influencing dynamic stability. Full article