Gait & posture最新文献

Background: Postural control is maintained through sensory information from visual, audio-vestibular and somatosensory inputs. When one of these senses are challenged, individuals shift their reliance more heavily onto other inputs to maintain postural control. Manipulation of vision to progress and regress lower limb rehabilitation has been researched extensively however, there is limited research on the effects of audio stimuli on postural control. In order to assess how audio stimuli can be manipulated for postural control and rehabilitation purposes, a reliable method must be identified.

Research question: When testing postural control under alternative auditory conditions, is there an acceptable level of reliability for lower limb center of pressure measures?

Methods: Thirteen healthy participants completed three 30 s single leg balance (SLB) trials in five auditory conditions (no sound, white noise, audio book, ear to ear and non-ear to ear) on a force plate in random order. Intraclass correlation (ICC) and coefficient of variation (CV) with 95 % confidence intervals were used to assess the reliability of the center of pressure (COP) anterior-posterior (AP), medial-lateral (ML) and total sway path (TSP) outcome measures.

Results: The CV for each COP sway path measure remained under 10 %, ranging from 3.44 % to 7.28 %. Based on the ICC, reliability was excellent for all sway path COP outcome measures (ICC= 0.705-0.950), except no sound and white noise conditions in the AP direction which show low reliability scores (ICC= 0.39 0.42).

Significance: Three 30 s SLB trials were sufficient to ensure excellent within session reliability of COP TSP, in ML and some AP directions during alternative auditory conditions.

Background: Falls are a leading cause of morbidity and mortality in older adults, requiring better longitudinal assessment tools. While established clinical methods such as the One-Legged Stand Test (OLST) are effective, they rely on supervised, contact- or video-based systems and are typically performed only annually, missing changes in fall risk between visits.

Objective: We evaluated a privacy-preserving Frequency-Modulated Continuous Wave (FMCW) radar system's ability to autonomously proctor the OLST and assess postural instability during the test, compared with simultaneously collected gold-standard measurements of force plates and motion capture (MOCAP).

Methods: In a cross-sectional study of 32 healthy adults (15 young ≤32 y, 17 older ≥64 y), synchronized radar, force plate, and motion capture data were collected during short (4 s) and long (20 s) OLST trials. A convolutional neural network-long short-term memory-attention (CNN-LSTM-Attention) model was trained on radar-derived range-Doppler maps to classify OLST phases, with performance evaluated against force plate and MOCAP ground truth. All de-identified data and visualization code are publicly available on PhysioNet.

Results: The model detected Foot-Up (FU) and Foot-Down (FD) events with 94.0% and 90.7% accuracy, respectively, improving to 96.9% and 94.5% after logical post-processing. In long trials, radar-derived Doppler wobble metrics during the stability phase strongly correlated with OLST duration (R²=0.58, p<0.001), and aligned with similar trends in force plate (COP ellipse area, R²=0.72, p<0.001) and MOCAP (trunk pitch-period IQR, R²=0.65, p<0.001) metrics. In short trials, radar-derived features separated the three study-defined cohorts, with significant pairwise differences (p<0.05) and large effect sizes (d=1.13-2.72).

Conclusion: FMCW radar accurately detects OLST transitions and captures wobble signatures linked to neuromuscular control and fall risk. These findings establish proof-of-concept for non-contact radar assessment of balance in older adults and support further clinical validation for at-home monitoring.

Background: Chronic pain is a debilitating condition in older adults that can lead to mobility impairments, disability, and premature death. While older adults with chronic pain demonstrate gait impairments compared to healthy older adults, how gait patterns change following cognitive or psychological tasks remain unclear.

Research question: How do gait patterns change from usual walking to dual-task walking, following an acute rumination task, and following an acute mindfulness task in older adults with chronic pain? Secondarily, what is the relationship between pain, number of pain medications, and gait?

Methods: In this ancillary study, 21 participants walked over a four-meter instrumented walkway at their usual speed, while performing a cognitive task, following an acute mindfulness task, and following an acute rumination task. Participants also reported their pain interference and number of pain medications. Paired t-tests were used to determine differences in spatiotemporal gait measures from usual walking to dual-task, mindfulness, and rumination. Spearman's correlations determined the relationship between pain interference, medications, and gait measures.

Results: Compared to usual walking, older adults walked slower, with shorter steps, and greater variability during dual-task walking. Following acute mindfulness, older adults walked with moderately longer steps, and following acute rumination, there were no changes in gait. Increased pain intensity was associated with greater gait variability and longer step time, and more pain medications were associated with slower gait speed.

Significance: Nonpharmacological interventions, such as dual-task training or longer, repeated bouts of mindfulness training, should be explored as interventions to improve gait and mobility in older adults with chronic pain.

Background: Human-in-the-loop optimization provides a standardized approach to enhance the effectiveness of assistive technology for gait by tuning devices to the needs of the individual user. Metabolic cost is frequently used as optimization objective. However, the assessment of metabolic cost requires relatively long-lasting physiological steady-state conditions. Subjective user preference could be an interesting alternative optimization objective that could shorten trial duration. We aim to explore whether the measured metabolic cost of walking correlates with the perceived comfort of the user during human-in-the-loop optimization process.

Methods: Ten transtibial amputees underwent an optimization protocol while walking on a treadmill with an experimental prosthetic foot with tuneable stiffness and alignment. We used human-in-the-loop optimization to minimize the metabolic cost of walking by optimizing the stiffness and alignment of the prosthetic foot, using an evolutionary optimization algorithm. The participant's perceived comfort of every optimization trial was determined via the visual analogue comfort scale. To determine the association between metabolic cost and perceived comfort during the optimization period, we performed a repeated measures correlation and a separate Pearson correlation for every individual.

Results: Results showed a moderate negative correlation between metabolic cost and perceived comfort. On an individual level a significant correlation was found in six out of ten cases.

Significance: Perceived comfort allows people to prioritize different optimization objectives simultaneously, and apparently, metabolic cost is prioritized to varying extents.

Introduction: Downhill walking increases fall risk in older adults due to greater balance control demands and postural instability. Steeper inclines amplify gravitational shear forces, requiring precise lower limb coordination to maintain stability. This study investigated the effects of age and slope angle on COM-COP inclination angles (IAs) and rates of change of inclination angles (RCIAs) to better understand age-related adaptations in balance control.

Materials and methods: Fifteen young and fifteen older adults walked at self-selected speeds on level ground and three downhill slopes (5°, 10°, and 15°). Motion capture and force plates recorded gait parameters, from which IAs and RCIAs were calculated. Analysis of covariance (ANCOVA) was used to control for walking speed variations and assess age and slope effects.

Results: As ramp-down angles increased, both groups exhibited reduced walking speed, step length, and single-limb support duration, while double-limb support duration increased. After adjusting for walking speed, significant slope effects were observed for sagittal IA and RCIA at toe-off, as well as for sagittal and frontal RCIA at contralateral heel-strike. Older adults exhibited significantly higher frontal IA and RCIA at contralateral heel-strike, suggesting increased lateral postural demand. These changes may reflect a compensatory effort to maintain stability.

Conclusion: Older adults rely on conservative gait strategies but experience greater lateral instability at contralateral heel-strike, increasing fall risk. These findings highlight the need for targeted balance training and infrastructure modifications to improve safety on sloped surfaces.