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

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

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

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

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*

PURPOSE: The purposes of this study was to develop a comprehensive community-based fall prevention program and to test the effects of the program on the muscle strength, postural balance and fall efficacy for elderly people. METHODS: The design of this study was a nonequivalent control group pretest-posttest design. There were 28 participants in the experimental group and 29 in the control group. The program consisted of balance exercises, elastic resistance exercises and prevention education. The program was provided five times a week for 8 weeks and each session lasted 90 minutes. Data were analyzed using chi2-test, independent t-test and paired t-test using the SPSS program. RESULTS: Muscle strength of the lower extremities, postural balance and fall efficacy scores significantly improved in the experimental group compared to the control group. CONCLUSION: These results suggest that this program can improve lower extremity muscle strength, postural balance and fall efficacy in elders. Therefore, this program is recommended for use in fall prevention programs for elders living in the community.
Accidental Falls/*prevention & control ; Aged ; Aged, 80 and over ; Ankle/physiology ; Exercise ; Female ; Health Knowledge, Attitudes, Practice ; Hip/physiology ; Humans ; Knee/physiology ; Male ; *Muscle Strength ; *Postural Balance ; *Program Evaluation

BACKGROUNDAttention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed psychiatric disorder in childhood. ADHD children with overlapping symptoms and signs of motor problems have more serious prognosis than that of children with ADHD only. However, the motor and sensory processing problems in children with ADHD have not been studied well. Few people adopt the technique of computerized dynamic posturography (CDP) in the study of ADHD, which is applied widely in clinical and laboratory research to objectively evaluate human's balance performance. This study aimed to assess the characteristics of postural control and sensory information processing of boys with two subtypes of ADHD by using CDP, so as to provide the proof for non-drug therapy of ADHD.

METHODFrom June 2003 to September 2004, a total of 73 boys (7-15 years of age) with ADHD and 73 normal developing boys matched by age and intelligence quotient from Peking University Institute of Mental Health were recruited in the study. The Sensory Organization Test was adopted to test the static balance performance under six sensory input conditions by SMART EquiTest 8.0 (NeuroCom) instrument. The sensory information from three sensory systems were available under condition 1, the visual inputs were removed or distorted under condition 2 or 3, the somatosensory inputs were in conflict with or without the visual inputs removed under condition 4 or 5, and both the visual and somatosensory inputs were in conflict under condition 6. The indexes of equilibrium score, somatosensory, vestibular, and visual ratios, and strategy scores were analyzed to indicate the subjects' postural control ability.

RESULTSADHD boys had significantly lower composite equilibrium score (CES) than the normal group (P < 0.05). Under condition 1 and conditions 3-6, the equilibrium scores (ES) of the ADHD group were significantly lower (all P < 0.05) than those of the control. Significantly lower visual and vestibular ratios and strategy scores under conditions 4-6 were found in boys with ADHD compared with the control group (P < 0.05). Boys of ADHD-predominantly inattentive (ADHD-I) type had a significantly lower CES and ES under conditions 4-6 than the controls (all P < 0.05) while the ESs of ADHD-combined type (ADHD-C) boys under each condition were similar with that of boys with ADHD-I and no significant difference was found between boys with ADHD-C and the control group (all P > 0.05). Compared with the control group, the ADHD-I boys showed significantly lower visual and vestibular ratios and strategy scores under conditions 4-6 whereas the ADHD-C boys showed a trend of lower visual ratio (all P < 0.05).

CONCLUSIONSADHD boys had a poorer static postural control ability and impaired function of processing visual and vestibular information compared with the normal control. Boys with ADHD-I showed particularly severe defect of static postural control and vestibular function integrating conflict information than normal boys. These deficits may be an important contributor to the clinical presentation of ADHD children and their cognitive deficits. Assessment and training of postural control function would be suggested during the diagnosis and treatment of ADHD children.

Adolescent ; Attention Deficit Disorder with Hyperactivity ; physiopathology ; Case-Control Studies ; Child ; Humans ; Male ; Postural Balance ; physiology

OBJECTIVETo compare balance ability between elderly individuals who practiced Tai-Chi-Chuan (TCC) for average 9.64 years and elderly individuals who did not practice TCC and its relationship with lower extremity muscle strength and ankle proprioception.

METHODSTwenty-five elderly volunteers were divided into two groups according to their TCC practcing experience. Sixteen were TCC group and the other nine were control population. Subjects completed a static balance test and ankle proprioception test using a custom-designed evaluation system, and concentric and eccentric knee extensor and flexor muscle strength tests. Subjects stood on the plate form to measure the proprioception in functional standing position which was differed from the previous studies. Multiple linear regressions were also used to predict the important factor affecting balance.

RESULTSTCC group performed better than the control group in balance, proprioception, and muscle strength of lower extremity. The proprioception was the most important factor related to balance ability and it can be accounted for explaining 44% of variance in medial-lateral sway direction, and 53% of variance in antero-posterior sway direction. The proprioception may be a more important factor which affecting the balance ability.

CONCLUSIONTCC training is recommended to the elders; as it can improve balance ability through better proprioception.

Aged ; Ankle Joint ; physiology ; Female ; Humans ; Kinesthesis ; Linear Models ; Male ; Middle Aged ; Muscle Strength ; physiology ; Postural Balance ; physiology ; Posture ; physiology ; Proprioception ; physiology ; Tai Ji