Objective:To establish normal reference value ranges for dynamic balance function parameters in healthy Chinese adults aged 20-69 years. Methods:A total of 100 healthy subjects were selected and evenly divided into five age groups: 20-29, 30-39, 40-49, 50-59, and 60-69 years, with equal gender distribution in each group. Balance function was assessed using the EquiTest system （NeuroCom）, with following tests performed Sensory Organization Test （SOT）, Motor Control Test （MCT）, Adaptation Test （ADT）, and Limits of Stability （LOS） test. All parameters were statistically analyzed and expressed as ±S. Results:The normal reference ranges for SOT, MCT, ADT, and LOS parameters were established for each age group. Multiple balance function parameters demonstrated a gradual decline with advancing age, with more pronounced deterioration observed after the age of 60. Specific findings included decreased vestibular ratio and reduced visual preference in SOT, as well as prolonged reaction time, impaired directional control, and reduced maximum excursion in the backward direction during LOS testing. Conclusion:This study is the first to establish age-specific reference ranges for dynamic balance function parameters in a healthy Chinese population aged 20-69 years, providing localized and objective criteria for the assessment of balance function and supporting clinical diagnosis of balance-related disorders in China.
Humans ; Middle Aged ; Adult ; Postural Balance/physiology* ; Reference Values ; Aged ; Male ; Female ; Young Adult ; Healthy Volunteers

Neuromuscular electrical stimulation (NMES) has been proven to promote human balance, but research on its impact on motor ability mainly focuses on external physical analysis, with little analysis on the intrinsic neural regulatory mechanisms. This study, for the first time, investigated the effects of NMES on cortical activity and cortico-muscular functional coupling (CMFC) during standing balance. Twelve healthy subjects were recruited in bilateral NMES training, with each session consisting of 60 electrically induced isometric contractions. Electroencephalogram (EEG) signals, electromyogram (EMG) signals, and center of pressure (COP) signals of the foot sole were collected before stimulation, two weeks after stimulation, and four weeks after stimulation while the subjects maintained standing balance. The results showed that NMES training improved subjects' postural stability during standing balance. Additionally, based on the EMG power spectral density (PSD), the κ frequency band was defined, and EEG-EMG time-frequency maximal information coefficients (TFMIC) were calculated. It was found that NMES enhanced functional connectivity between the cortex and lower limb muscles, with varying degrees of increase in β-κ and γ-κ frequency band CMFC after stimulation. Furthermore, sample entropy (SE) of EEG signals also increased after training. The results of this study confirm that NMES training can enhance CMFC and brain activation during standing balance. This study, from the perspective of physiological electrical signals, validates the effectiveness of NMES for balance training and provides objective assessment metrics for the training effects of NMES.
Humans ; Postural Balance/physiology* ; Electromyography ; Electroencephalography ; Muscle, Skeletal/physiology* ; Electric Stimulation ; Motor Cortex/physiology* ; Male ; Standing Position ; Adult ; Female

BACKGROUND: Cervical vestibular evoked myogenic potential (cVEMP) testing is a strong tool that enables objective determination of balance functions in humans. However, it remains unknown whether cVEMP correctly expresses vestibular disorder in mice. OBJECTIVE: In this study, correlations of cVEMP with scores for balance-related behavior tests including rotarod, beam, and air-righting reflex tests were determined in ICR mice with vestibular disorder induced by 3,3'-iminodipropiontrile (IDPN) as a mouse model of vestibular disorder. METHODS: Male ICR mice at 4 weeks of age were orally administered IDPN in saline (28 mmol/kg body weight) once. Rotarod, beam crossing, and air-righting reflex tests were performed before and 3-4 days after oral exposure one time to IDPN to determine balance functions. The saccule and utricles were labeled with fluorescein phalloidin. cVEMP measurements were performed for mice in the control and IDPN groups. Finally, the correlations between the scores of behavior tests and the amplitude or latency of cVEMP were determined with Spearman's rank correlation coefficient. Two-tailed Student's t test and Welch's t test were used to determine a significant difference between the two groups. A difference with p < 0.05 was considered to indicate statistical significance. RESULTS: After oral administration of IDPN at 28 mmol/kg, scores of the rotarod, beam, and air-righting reflex tests in the IDPN group were significantly lower than those in the control group. The numbers of hair cells in the saccule, utricle, and cupula were decreased in the IDPN group. cVEMP in the IDPN group was significantly decreased in amplitude and increased in latency compared to those in the control group. cVEMP amplitude had significant correlations with the numbers of hair cells as well as scores for all of the behavior tests in mice. CONCLUSIONS This study demonstrated impaired cVEMP and correlations of cVEMP with imbalance determined by behavior tests in a mouse model of vestibular disorder.
Animals ; Behavior, Animal ; drug effects ; physiology ; Disease Models, Animal ; Hair Cells, Vestibular ; pathology ; Male ; Mice ; Mice, Inbred ICR ; Nitriles ; adverse effects ; Postural Balance ; drug effects ; physiology ; Saccule and Utricle ; pathology ; Sensation Disorders ; chemically induced ; physiopathology ; Vestibular Diseases ; chemically induced ; diagnosis ; pathology ; physiopathology ; Vestibular Evoked Myogenic Potentials ; drug effects ; physiology ; Vestibular Function Tests

PURPOSE: This study investigated the correlation between isometric muscle strength, gross motor function, and gait parameters in patients with spastic cerebral palsy and to find which muscle groups play an important role for gait pattern in a flexed knee gait. MATERIALS AND METHODS: Twenty-four ambulatory patients (mean age, 10.0 years) with spastic cerebral palsy who were scheduled for single event multilevel surgery, including distal hamstring lengthening, were included. Preoperatively, peak isometric muscle strength was measured for the hip flexor, hip extensor, knee flexor, and knee extensor muscle groups using a handheld dynamometer, and three-dimensional (3D) gait analysis and gross motor function measure (GMFM) scoring were also performed. Correlations between peak isometric strength and GMFM, gait kinematics, and gait kinetics were analyzed. RESULTS: Peak isometric muscle strength of all muscle groups was not related to the GMFM score and the gross motor function classification system level. Peak isometric strength of the hip extensor and knee extensor was significantly correlated with the mean pelvic tilt (r=-0.588, p=0.003 and r=-0.436, p=0.033) and maximum pelvic obliquity (r=-0.450, p=0.031 and r=-0.419, p=0.041). There were significant correlations between peak isometric strength of the knee extensor and peak knee extensor moment in early stance (r=0.467, p=0.021) and in terminal stance (r=0.416, p=0.043). CONCLUSION: There is no correlation between muscle strength and gross motor function. However, this study showed that muscle strength, especially of the extensor muscle group of the hip and knee joints, might play a critical role in gait by stabilizing pelvic motion and decreasing energy consumption in a flexed knee gait.
Biomechanical Phenomena ; Cerebral Palsy/*physiopathology/surgery ; Female ; Gait/*physiology ; Humans ; Isometric Contraction/physiology ; Knee/physiopathology ; Knee Joint/surgery ; Male ; Muscle Spasticity/etiology/physiopathology ; Muscle Strength/*physiology ; Muscle Strength Dynamometer ; Muscle, Skeletal/*physiopathology ; Pelvis ; Postural Balance/physiology ; Tenotomy

Nowadays, for gait instability phenomenon, many researches have been carried out at home and abroad. However, the relationship between plantar pressure and gait parameters in the process of balance adjustment is still unclear. This study describes the human body adaptive balance reaction during slip events on slippery level walk by plantar pressure and gait analysis. Ten healthy male subjects walked on a level path wearing shoes with two contrastive contaminants (dry, oil). The study collected and analyzed the change rule of spatiotemporal parameters, plantar pressure parameters, vertical ground reaction force (VGRF), etc. The results showed that the human body adaptive balance reaction during slip events on slippery level walk mainly included lighter touch at the heel strikes, tighter grip at the toe offs, a lower velocity, a shorter stride length and longer support time. These changes are used to maintain or recover body balance. These results would be able to explore new ideas and provide reference value for slip injury prevention, walking rehabilitation training design, research and development of walking assistive equipments, etc.
Adaptation, Physiological ; Foot ; Gait ; Humans ; Male ; Postural Balance ; physiology ; Pressure ; Reference Values ; Walking

In order to evaluate the ability of human standing balance scientifically, we in this study proposed a new evaluation method based on the chaos nonlinear analysis theory. In this method, a sinusoidal acceleration stimulus in forward/backward direction was forced under the subjects' feet, which was supplied by a motion platform. In addition, three acceleration sensors, which were fixed to the shoulder, hip and knee of each subject, were applied to capture the balance adjustment dynamic data. Through reconstructing the system phase space, we calculated the largest Lyapunov exponent (LLE) of the dynamic data of subjects' different segments, then used the sum of the squares of the difference between each LLE (SSDLLE) as the balance capabilities evaluation index. Finally, 20 subjects' indexes were calculated, and compared with evaluation results of existing methods. The results showed that the SSDLLE were more in line with the subjects' performance during the experiment, and it could measure the body's balance ability to some extent. Moreover, the results also illustrated that balance level was determined by the coordinate ability of various joints, and there might be more balance control strategy in the process of maintaining balance.
Acceleration ; Biomechanical Phenomena ; Humans ; Models, Biological ; Motion ; Nonlinear Dynamics ; Postural Balance ; physiology

This study looked into the efficacy of a modified titration protocol of intratympanic gentamicin injection (ITG) in the patients with unilateral intractable Ménière's disease (MD). Modified titration protocol of ITG at a low dose (20 mg/mL) was administered to 10 patients with definite unilateral intractable MD. After initial first two fixed ITGs on weekly basis, the patients might or might not be given any more injections, depending on the appearance of unilateral vestibular loss (UVL). ITG was terminated if the patients satisfied the criteria of UVL. All patients were followed-up for at least two years. The effects of ITG on the vertigo attack, functional level scores and postural balance were evaluated. Of the 10 cases, 8 showed the sign of UVL after receiving initial two ITGs and were not given any more intratympanic injections, and the other 2 patients were administered three ITGs. A two-year follow-up revealed that complete and substantial vertigo control was achieved in 9 cases, and limited vertigo control in 1 patient. Hearing level was lowered in 2 patients. The posture stability and functional level scores were improved. Our study showed that the modified titration protocol of ITG at a low dose could effectively control vertigo in patients with unilateral intractable MD.
Adult ; Drug Administration Schedule ; Ear, Inner ; drug effects ; microbiology ; pathology ; Female ; Follow-Up Studies ; Gentamicins ; therapeutic use ; Hearing ; drug effects ; physiology ; Humans ; Injection, Intratympanic ; Male ; Meniere Disease ; drug therapy ; microbiology ; pathology ; Middle Aged ; Postural Balance ; drug effects ; physiology ; Protein Synthesis Inhibitors ; therapeutic use ; Vertigo ; drug therapy ; microbiology ; pathology

The present study was aimed at the optimal solution of the main muscular force distribution in the lower extremity during standing balance of human. The movement musculoskeletal system of lower extremity was simplified to a physical model with 3 joints and 9 muscles. Then on the basis of this model, an optimum mathematical model was built up to solve the problem of redundant muscle forces. Particle swarm optimization (PSO) algorithm is used to calculate the single objective and multi-objective problem respectively. The numerical results indicated that the multi-objective optimization could be more reasonable to obtain the distribution and variation of the 9 muscular forces. Finally, the coordination of each muscle group during maintaining standing balance under the passive movement was qualitatively analyzed using the simulation results obtained.
Algorithms ; Gait ; Humans ; Joints ; Models, Biological ; Models, Theoretical ; Movement ; Muscles ; physiology ; Postural Balance

OBJECTIVE: To analyze the balance function of injured lower limb by dynamic posturography. METHODS: Using the dynamic posturography instrument, the postural evoked responses of sixty-two normal people and two hundred and fifty-eight people with injured lower limb bones and joints were detected. The test was included sensory organization test (SOT) and adaption test (ADT). The results of two groups were compared by t test. RESULTS: Compared with the normal people, the impaired people had significant statistical differences in balance scores of SOT3-SOT6 and proportion score of dynamic proprioception (P < 0.05). There was no obvious decrease in ADT. CONCLUSION The balance function of injured lower limb significantly decreases.
Case-Control Studies ; Humans ; Lower Extremity/physiopathology* ; Postural Balance/physiology* ; Posture/physiology* ; Proprioception/physiology*

BACKGROUNDLow back pain (LBP) is a common clinical problem. Many researchers have demonstrated that LBP disorders have difference in sensory strategies for postural control. Optokinetic stimulation (OKS) of optic flow has been widely applied to study its effect on vision, but has not been applied to LBP. Here we used OKS on different surfaces to investigate the characteristics of chronic nonspecific LBP (CNLBP) posture control, so as to provide new theoretical and experimental data for further recognizing CNLBP and enriching its treatment.

METHODSFifteen individuals with CNLBP (age range 25-40 years) and 15 age and gender-matched control subjects were recruited. Each subject, while standing on a stable or soft surface, was exposed to random-dot patterns projected on a large screen, with the dots displaying expansion (+) and contraction (-) and velocities including 80°, 40°, and 20° per second. The visual stimulus used a "stimuli-interval" pattern. The peak velocity, different phases' standard deviation (SD) of the anterior-posterior centre of pressure (COP) displacements and the total length of the medial-lateral COP sway (LML) for stable surface and soft surface were recorded by force platform.

RESULTSThe main effect of surface on all parameters was significant, while the main effect of group and OKS showed no significance with the exception of peak velocity (F(3, 95) = 3.6, P = 0.01) and A2 (F(5, 140) = 9.34, P < 0.01) for which the effect of OKS was significant. The interactions of group by OKS of A2 (F(5, 140) = 3.65, P < 0.01) and group by surface by OKS (F(5,140) = 2.83, P = 0.02), and surface by OKS of A1 and A3 (P < 0.05) were significant. It was reported that significantly more SD in amplitude in the T2 phase was seen in persons with CNLBP when confronting the + 40 stimuli on the soft surface (P < 0.05) compared to healthy individuals.

CONCLUSIONSThere was no significance between persons with CNLBP and healthy people when using the stable surface. Subjects with LBP showed decreased efficiency of postural adjustment when exposed to more complicated tasks and environments, especially OKS in the expansion direction, and displayed a visual-dependent phenomenon. This result suggested that the treatment of abnormal motor patterns in people with LBP should take the properties of task and environment into account.

Adult ; Case-Control Studies ; Female ; Healthy Volunteers ; Humans ; Low Back Pain ; physiopathology ; Male ; Postural Balance ; physiology ; Posture ; physiology