BACKGROUND: Gait impairment is closely related to quality of life in patients with Parkinson's disease (PD). This study aimed to explore alterations in brain microstructure in PD patients and healthy controls (HCs) and to identify the correlation of gait impairment in the ON and OFF states of patients with PD, respectively. METHODS: We enrolled 24 PD patients and 29 HCs from the Movement Disorders Program at Beijing Friendship Hospital Capital Medical University between 2019 and 2020. We acquired magnetic resonance imaging (MRI) scans and processed the diffusion kurtosis imaging (DKI) images. Preprocessing of diffusion-weighted data was performed with Mrtrix3 software, using a directional distribution function to track participants' main white matter fiber bundles. Demographic and clinical characteristics were recorded. Quantitative gait and clinical scales were used to assess the status of medication ON and OFF in PD patients. RESULTS: The axial kurtosis (AK), mean kurtosis (MK), and radial kurtosis (RK) of five specific white matter fiber tracts, the bilateral corticospinal tract, left superior longitudinal fasciculus, left anterior thalamic radiation, forceps minor, and forceps major were significantly higher in PD patients compared to HCs. Additionally, the MK values were negatively correlated with Timed Up and Go Test (TUG) scores in both the ON and OFF in PD patients. Within the PD group, higher AK, MK, and RK values, whether the patients were ON or OFF, were associated with better gait performance (i.e., higher velocity and stride length). CONCLUSIONS PD exhibits characteristic regional patterns of white matter microstructural degradation. Correlations between objective gait parameters and DKI values suggest that dopamine-responsive gait function depends on preserved white matter microstructure. DKI-based Tract-Based Spatial Statistics (TBSS) analysis may serve as a tool for evaluating PD-related motor impairments (e.g., gait impairment) and could yield potential neuroimaging biomarkers.
Humans ; Parkinson Disease/diagnostic imaging* ; White Matter/physiopathology* ; Male ; Female ; Middle Aged ; Aged ; Gait/physiology* ; Diffusion Magnetic Resonance Imaging/methods* ; Diffusion Tensor Imaging/methods*

In order to investigate the mechanical response of lumbar vertebrae during gait cycle in adolescents with idiopathic scoliosis (AIS), the present study was based on computed tomography (CT) data of AIS patients to construct model of the left support phase (ML) and model of the right support phase (MR), respectively. Firstly, material properties, boundary conditions and load loading were set to simulate the lumbar vertebra-pelvis model. Then, the difference of stress and displacement in the lumbar spine between ML and MR was compared based on the stress and displacement cloud map. The results showed that in ML, the lumbar stress was mostly distributed on the convex side, while in MR, it was mostly distributed on the concave side. The stress of the two types of stress mainly gathered near the vertebral arch plate, and the stress of the vertebral arch plate was transmitted to the vertebral body through the pedicle with the progress of gait. The average stress of the intervertebral tissue in MR was greater than that in ML, and the difference of stress on the convex and convex side was greater. The displacement of lumbar vertebrae in ML decreased gradually from L1 to L5. The opposite is true in MR. In conclusion, this study can accurately quantify the stress on the lumbar spine during gait, and may provide guidance for brace design and clinical decision making.
Humans ; Lumbar Vertebrae/diagnostic imaging* ; Scoliosis/diagnostic imaging* ; Adolescent ; Gait/physiology* ; Biomechanical Phenomena ; Tomography, X-Ray Computed ; Stress, Mechanical ; Female ; Male

OBJECTIVE: To investigate the load distribution on the more painful and less painful limbs in patients with mild-to-moderate and severe bilateral knee osteoarthritis (KOA) and explore the compensatory mechanisms in both limbs among bilateral KOA patients with different severity levels. METHODS: A total of 113 participants were enrolled between July 2022 and September 2023. This cohort comprised 43 patients with mild-to-moderate bilateral KOA (Kellgren-Lawrence grade 2-3), 43 patients with severe bilateral KOA (Kellgren-Lawrence grade 4), and 27 healthy volunteers (healthy control group). The visual analogue scale (VAS) score for pain, the Hospital for Special Surgery (HSS) score, passive knee range of motion (ROM), and hip-knee-ankle angle (HKA) were used to assess walking pain intensity, joint function, and lower limb alignment in KOA patients, respectively. Motion trajectories of reflective markers and ground reaction force data during walking were captured using a gait analysis system. Musculoskeletal modeling was then employed to calculate biomechanical parameters, including the peak knee adduction moment (KAM), KAM impulse, peak joint contact force (JCF), and peak medial/lateral contact forces (MCF/LCF). Statistical analyses were performed to compare differences in clinical and gait parameters between bilateral limbs. Additionally, one-dimensional statistical parametric mapping was utilized to analyze temporal gait data. RESULTS: Mild-to-moderate KOA patients showed the significantly higher HSS score (67.7±7.9) than severe KOA patients (51.9±8.9; t=8.747, P<0.001). The more painful limb in all KOA patients exhibited significantly greater HKA and higher VAS scores compared to the less painful limb ( P<0.05). While bilateral knee ROM did not differ significantly in mild-to-moderate KOA patients ( P>0.05), the severe KOA patients had significantly reduced ROM in the more painful limb versus the less painful limb ( P<0.05). Healthy controls showed no significant bilateral difference in any biomechanical parameters ( P>0.05). All KOA patients demonstrated longer stance time on the less painful limb ( P<0.05). Critically, severe KOA patients exhibited significantly higher peak KAM, KAM impulse, and peak MCF in the more painful limb ( P<0.05), while mild-to-moderate KOA patients showed the opposite pattern with lower peak KAM and KAM impulse in the more painful limb ( P<0.05) and a similar trend for peak MCF. CONCLUSION Patients with mild-to-moderate KOA effectively reduce load on the more painful limb through compensatory mechanisms in the less painful limb. Conversely, severe bilateral varus deformities in advanced KOA patients nullify compensatory capacity in the less painful limb, paradoxically increasing load on the more painful limb. This dichotomy necessitates personalized management strategies tailored to disease severity.
Humans ; Osteoarthritis, Knee/physiopathology* ; Range of Motion, Articular ; Male ; Female ; Middle Aged ; Biomechanical Phenomena ; Knee Joint/physiopathology* ; Pain Measurement ; Severity of Illness Index ; Aged ; Gait/physiology* ; Walking/physiology* ; Case-Control Studies ; Adult ; Weight-Bearing

An in-depth understanding of the mechanism of lower extremity muscle coordination during walking is the key to improving the efficacy of gait rehabilitation in patients with neuromuscular dysfunction. This paper investigates the effect of changes in walking speed on lower extremity muscle synergy patterns and muscle functional networks. Eight healthy subjects were recruited to perform walking tasks on a treadmill at three different speeds, and the surface electromyographic signals (sEMG) of eight muscles of the right lower limb were collected synchronously. The non-negative matrix factorization (NNMF) method was used to extract muscle synergy patterns, the mutual information (MI) method was used to construct the alpha frequency band (8-13 Hz), beta frequency band (14-30 Hz) and gamma frequency band (31-60 Hz) muscle functional network, and complex network analysis methods were introduced to quantify the differences between different networks. Muscle synergy analysis extracted 5 muscle synergy patterns, and changes in walking speed did not change the number of muscle synergy, but resulted in changes in muscle weights. Muscle network analysis found that at the same speed, high-frequency bands have lower global efficiency and clustering coefficients. As walking speed increased, the strength of connections between local muscles also increased. The results show that there are different muscle synergy patterns and muscle function networks in different walking speeds. This study provides a new perspective for exploring the mechanism of muscle coordination at different walking speeds, and is expected to provide theoretical support for the evaluation of gait function in patients with neuromuscular dysfunction.
Humans ; Walking Speed ; Muscle, Skeletal/physiology* ; Electromyography ; Gait/physiology* ; Walking/physiology*

OBJECTIVES: To investigate the effect of torso training on unstable surface on lower limb motor function in patients with incomplete spinal cord injury. METHODS: A total of 80 patients with incomplete spinal cord injury caused by thoracolumbar fracture admitted in Ningbo Yinzhou No.2 Hospital from April 2020 to December 2021 were randomly divided into control group and study group, with 40 cases in each group. In addition to routine training, the control group received torso training on stable surface and the study group received torso training on unstable surface. The gait, lower limb muscle strength, balance function, lower limb function, mobility and nerve function of the two groups were compared. RESULTS: After treatment, the stride length, stride frequency and comfortable walking speed improved in the two groups (all P<0.05), and the improvements in study group were more significant (all P<0.05). The muscle strength of quadriceps femoris, gluteus maximus, hamstring, anterior tibialis and gastrocnemius were improved in the two groups (all P<0.05), and the improvements in study group were more significant (all P<0.05); the total trajectories of static eye opening and static eye closing gravity center movement in the two groups were significantly shorter (all P<0.05), and the improvements in the study group were more significant (all P<0.05). The dynamic stability limit range and the American Spinal Injury Association (ASIA) lower extremity motor score, Berg balance scale, modified Barthel index scale in the two groups were significantly higher (all P<0.05), and these scores in study group were significantly higher than those in the control group (all P<0.05). Both groups showed a significant improvement in ASIA grade (all P<0.05), and the improvement in the study group was significantly better (P<0.05). CONCLUSIONS Torso training on unstable surface can effectively improve the gait and lower limb muscle strength of patients with incomplete spinal cord injury and improve the lower limb motor function.
Humans ; Walking/physiology* ; Spinal Cord Injuries ; Gait/physiology* ; Lower Extremity ; Torso

Lower limb ankle exoskeletons have been used to improve walking efficiency and assist the elderly and patients with motor dysfunction in daily activities or rehabilitation training, while the assistance patterns may influence the wearer's lower limb muscle activities and coordination patterns. In this paper, we aim to evaluate the effects of different ankle exoskeleton assistance patterns on wearer's lower limb muscle activities and coordination patterns. A tethered ankle exoskeleton with nine assistance patterns that combined with differenet actuation timing values and torque magnitude levels was used to assist human walking. Lower limb muscle surface electromyography signals were collected from 7 participants walking on a treadmill at a speed of 1.25 m/s. Results showed that the soleus muscle activities were significantly reduced during assisted walking. In one assistance pattern with peak time in 49% of stride and peak torque at 0.7 N·m/kg, the soleus muscle activity was decreased by (38.5 ± 10.8)%. Compared with actuation timing, the assistance torque magnitude had a more significant influence on soleus muscle activity. In all assistance patterns, the eight lower limb muscle activities could be decomposed to five basic muscle synergies. The muscle synergies changed little under assistance with appropriate actuation timing and torque magnitude. Besides, co-contraction indexs of soleus and tibialis anterior, rectus femoris and semitendinosus under exoskeleton assistance were higher than normal walking. Our results are expected to help to understand how healthy wearers adjust their neuromuscular control mechanisms to adapt to different exoskeleton assistance patterns, and provide reference to select appropriate assistance to improve walking efficiency.
Aged ; Ankle/physiology* ; Ankle Joint/physiology* ; Biomechanical Phenomena/physiology* ; Electromyography ; Exoskeleton Device ; Gait/physiology* ; Humans ; Muscle Contraction ; Muscle, Skeletal/physiology* ; Walking/physiology*

Neurocognitive impairment is a group of clinical syndromes characterized by impaired cognitive function and decreased motor ability. Non-pharmacological interventions such as physical exercise have advantages in the treatment of patients with neurocognitive impairment. Multicomponent exercise is a combination of various physical exercises, including strength training, endurance training, balance training and flexibility training, that can improve gait, balance and cardiopulmonary function by increasing muscle mass, strength and endurance in people with neurocognitive impairment, while also reducing the risk of falls in elders. This article reviews the benefits of multicomponent exercise for patients with neurocognitive impairment and its evaluation methods; also describes 4 intervention programs and their clinical application, to provide evidence for clinical practice and promote the application of multicomponent exercise in patients with neurocognitive impairment.
Accidental Falls ; Aged ; Cognition ; Exercise/physiology* ; Gait ; Humans ; Resistance Training

The purpose of this paper was to investigate the effects of wearable lower limb exoskeletons on the kinematics and kinetic parameters of the lower extremity joints and muscles during normal walking, aiming to provide scientific basis for optimizing its structural design and improving its system performance. We collected the walking data of subjects without lower limb exoskeleton and selected the joint angles in sagittal plane of human lower limbs as driving data for lower limb exoskeleton simulation analysis. Anybody (the human biomechanical analysis software) was used to establish the human body model (the human body model without lower limb exoskeleton) and the man-machine system model (the lower limb exoskeleton model). The kinematics parameters (joint force and joint moment) and muscle parameters (muscle strength, muscle activation, muscle contraction velocity and muscle length) under two situations were compared. The experimental result shows that walking gait after wearing the lower limb exoskeleton meets the normal gait, but there would be an occasional and sudden increase in muscle strength. The max activation level of main lower limb muscles were all not exceeding 1, in another word the muscles did not appear fatigue and injury. The highest increase activation level occurred in rectus femoris (0.456), and the lowest increase activation level occurred in semitendinosus (0.013), which means the lower limb exoskeletons could lead to the fatigue and injury of semitendinosus. The results of this study illustrate that to avoid the phenomenon of sudden increase of individual muscle force, the consistency between the length of body segment and the length of exoskeleton rod should be considered in the design of lower limb exoskeleton extremity.
Biomechanical Phenomena ; Exoskeleton Device ; Gait ; Humans ; Lower Extremity ; physiology

OBJECTIVETo investigate acrylamide (ACR)-induced subacute neurotoxic effects on the central nervous system (CNS) at the synapse level in rats.

METHODSThirty-six Sprague Dawley (SD) rats were randomized into three groups, (1) a 30 mg/kg ACR-treated group, (2) a 50 mg/kg ACR-treated group, and (3) a normal saline (NS)-treated control group. Body weight and neurological changes were recorded each day. At the end of the test, cerebral cortex and cerebellum tissues were harvested and viewed using light and electron microscopy. Additionally, the expression of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were investigated.

RESULTSThe 50 mg/kg ACR-treated rats showed a significant reduction in body weight compared with untreated individuals (P < 0.05). Rats exposed to ACR showed a significant increase in gait scores compared with the NS control group (P < 0.05). Histological examination indicated neuronal structural damage in the 50 mg/kg ACR treatment group. The active zone distance (AZD) and the nearest neighbor distance (NND) of synaptic vesicles in the cerebral cortex and cerebellum were increased in both the 30 mg/kg and 50 mg/kg ACR treatment groups. The ratio of the distribution of synaptic vesicles in the readily releasable pool (RRP) was decreased. Furthermore, the expression levels of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were decreased in both the 30 mg/kg and 50 mg/kg ACR treatment groups.

CONCLUSIONSubacute ACR exposure contributes to neuropathy in the rat CNS. Functional damage of synaptic proteins and vesicles may be a mechanism of ACR neurotoxicity.

Acrylamide ; toxicity ; Animals ; Cerebellum ; cytology ; drug effects ; Cerebral Cortex ; cytology ; drug effects ; Drug Administration Schedule ; Gait ; Gene Expression Regulation ; drug effects ; Male ; Neurons ; drug effects ; Neurotoxicity Syndromes ; pathology ; Rats ; Rats, Sprague-Dawley ; Synapses ; drug effects ; Synapsins ; genetics ; metabolism ; Synaptic Vesicles ; drug effects ; physiology ; Weight Loss ; drug effects

PURPOSE: To investigate the effect of intramuscular Botulinum toxin type A (BoNT-A) injection on gait and dynamic foot pressure distribution in children with spastic cerebral palsy (CP) with dynamic equinovarus foot. MATERIALS AND METHODS: Twenty-five legs of 25 children with CP were investigated in this study. BoNT-A was injected into the gastrocnemius (GCM) and tibialis posterior (TP) muscles under the guidance of ultrasonography. The effects of the toxin were clinically assessed using the modified Ashworth scale (MAS) and modified Tardieu scale (MTS), and a computerized gait analysis and dynamic foot pressure measurements using the F-scan system were also performed before injection and at 1 and 4 months after injection. RESULTS: Spasticity of the ankle plantar-flexor in both the MAS and MTS was significantly reduced at both 1 and 4 months after injection. On dynamic foot pressure measurements, the center of pressure index and coronal index, which represent the asymmetrical weight-bearing of the medial and lateral columns of the foot, significantly improved at both 1 and 4 months after injection. The dynamic foot pressure index, total contact area, contact length and hind foot contact width all increased at 1 month after injection, suggesting better heel contact. Ankle kinematic data were significantly improved at both 1 and 4 months after injection, and ankle power generation was significantly increased at 4 months after injection compared to baseline data. CONCLUSION: Using a computerized gait analysis and foot scan, this study revealed significant benefits of BoNT-A injection into the GCM and TP muscles for dynamic equinovarus foot in children with spastic CP.
Adolescent ; Ankle Joint ; Botulinum Toxins, Type A/administration & dosage/*pharmacology ; Cerebral Palsy/*complications/drug therapy ; Child ; Child, Preschool ; Clubfoot/*drug therapy/*etiology/physiopathology ; Female ; Foot ; Gait/*drug effects/physiology ; Humans ; Injections, Intramuscular ; Male ; Muscle Spasticity/drug therapy ; Muscle, Skeletal/diagnostic imaging ; Neuromuscular Agents/administration & dosage/*pharmacology ; Pressure ; Prospective Studies ; Treatment Outcome ; Weight-Bearing