Effect of acupuncture sensation on body sway during one legged stance / 全日本鍼灸学会雑誌

[Objectives]The purpose of this study is to clarify the effect of acupuncture sensation on the body sway during a one-legged stance.[Methods] The study participants were 16 healthy adults (mean age 21.8±1.6 years). The study design was a crossover method, wherein the same individuals participated in the acupuncture stimulation condition and the control condition at intervals of more than one week. Evaluation was performed before and after each intervention by holding a one-legged stance for 40 seconds on a force plate. A total of six items of body sway were measured, including: circumferential area, rectangular area, effective value area, total trajectory length, unit trajectory length, and unit area trajectory length. In addition, Visual analog scale (VAS) was used to evaluate the ease with which the lower leg was subjected to force during measurement. In the acupuncture stimulation condition, single acupuncture was performed on the lower limb muscle group of the measuring leg, and the VAS of the acupuncture sensation was evaluated at the time of stimulation and at the end of measurement. Stainless steel disposable acupuncture needles (length: 50 mm, diameter: 0.20 mm.) were used for stimulation. The stimulation sites were the ST32, ST37, BL37, BL57, and GB37 of the test leg, and acupuncture needles were inserted to the desired depth and removed when sensation was felt. The control condition was the supine position for five minutes. Comparisons were made between the pre- and post-acupuncture stimulation conditions and the pre- and post-control conditions(body sway, lower leg VAS, acupuncture sensation VAS). [Results] There was no significant difference between the two conditions in terms of body sway. However, the VAS of lower limb effort was significantly lower, from 78.0±14.9 mm to 63.1±17.0 mm before and after the intervention (p<0.05). On the other hand, in the control condition, there was no significant difference from 79.5±12.3 mm to 75.2±12.7 mm before and after rest. The VAS of acupuncture sensation was 50.4±14.3 mm during stimulation and 9.8±9.0 mm at the end of measurement, which was significantly lower (p<0.05). [Conclusion] Acupuncture sensation did not affect the body sway before and after acupuncture stimulation. However, the subjective sensation of weakness appeared, suggesting that acupuncture stimulation may cause a transient sensation of weakness.

Change in balance ability in day time and the factors in healthy young people using a stabilometer / 体力科学

Maintaining posture and movement stabilities, that is, balance, is particularly important for safety in daily life along with performing exercises. The purpose of this study was to clarify the changes in static and dynamic balance abilities from 8:00 to 18:00 and investigate the factors of change in balance ability among healthy young people. The subjects were nine relatively active healthy university students. The static and dynamic balance abilities were measured by a body sway test while static standing and the Cross Test, in which the center of gravity was voluntarily moved to the maximum in the front, back, left, and right directions, respectively. No change with time was observed in the static balance index. However, the maximum amplitude in the anteroposterior direction, an index of dynamic balance, significantly increased with time (8:00 vs 18:00, p<0.05). Sleepiness score significantly decreased with time (8:00 vs 18:00, p<0.05). As a result of simple correlation analysis, there were significant relationships between static balance indices (environmental area and rectangle area) and autonomic activity index (heart rate variability) at many times (p<0.05). Thus, it was concluded that the static balance ability was not affected by time. Furthermore, the ability to move the center of gravity in the anteroposterior direction of dynamic balance was low during morning and increased with time in relatively active healthy young people. Additionally, it was suggested that autonomic nervous activity was associated with static balance and the sleepiness was associated with dynamic balance.

Utilização da informação visual no controle postural de crianças com paralisia cerebral / Use of visual information on the postural control of children with cerebral palsy

INTRODUÇÃO: As limitações impostas pela paralisia cerebral (PC) levam à persistência de distúrbios dos movimentos e da postura. Sendo assim, o controle postural tem um papel importante, pois a capacidade de manter a orientação postural é fundamental para realização das atividades de vida diária. OBJETIVOS: Investigar a utilização da informação visual no controle postural de crianças com PC e de crianças neurologicamente normais (NN). MATERIAIS E MÉTODOS: Foram avaliadas nove crianças com PC diplégica e nove crianças NN de ambos os sexos, entre 6 e 12 anos de idade. Todas as crianças permaneceram em pé e paradas dentro de uma sala móvel nas seguintes condições experimentais: sem movimento da sala com olhos abertos e com olhos fechados e com movimento da sala nas frequências de 0,2 e 0,5 Hz. O registro dos movimentos da sala e das crianças foi realizado por marcadores ativos afixados entre as escápulas das crianças e na parede da sala, respectivamente, e do sistema OPTOTRAK. RESULTADOS: As crianças com PC oscilaram mais em relação às crianças NN, e o movimento da sala influenciou a oscilação corporal de todas as crianças de maneira similar, sendo que todas elas foram influenciadas pela frequência em que a sala foi movimentada. CONCLUSÃO: Crianças com PC e NN são influenciadas pela manipulação da informação visual durante a manutenção da postura ereta e quieta e pela frequência em que o estímulo visual é apresentado.

INTRODUCTION: The limitations imposed by cerebral palsy lead to persistence of disorders of movement and posture, therefore postural control plays an important role, since the ability to maintain postural orientation is fundamental to perform activities of daily living. OBJECTIVES: To investigate the use of visual information in postural control of children with cerebral palsy (CP) and neurologically normal children (NN). MATERIALS AND METHODS: We evaluated eight children with diplegic CP and eight NN children of both genders, aged 6 to 12 years old, as they remained standing still inside of a moving room in the following experimental conditions: no movement of the room with eyes open and eyes closed during movement of the 30s and 60s in the room for frequencies 0.2 and 0.5 Hz. Registration of movements of the room and children was performed by active markers fixed on the front wall of the room, and on the trunk between the scapulae of children, through the OPTOTRAK system. RESULTS: Children with CP swayed more than NN children in the two movement conditions of the room, and all children swayed more with no vision than with vision on the condition that the room was moved. Moreover, the movement of the moving room influenced children with PC and NN and similarly all children were influenced by the frequency at which the room has been moved. CONCLUSION: Children with CP and NN are influenced by the manipulation of visual information during maintenance of upright stance and by the frequency at which the visual stimulus is presented.

Investigating the center of pressure velocity Romberg's quotient for assessing the visual role on the body sway / Avaliando a importância da visão nas oscilações posturais utilizando o quociente de Romberg da velocidade do centro de pressão

The classical Romberg's test based on stabilometric tests in eyes open (EO) and closed (EC) conditions was used for investigating the influence of visual feedback in the body sway control in healthy adult subjects. Stabilograms from 144 subjects (aged 18-40) resting over a force platform were recorded for 30 s in EO and 30 s in EC conditions. The mean velocity was obtained for EO (VmEO) and EC (VmEC) in both anterior-posterior (y) and medial-lateral (x) directions and in the (x,y) plane, and thus used for computing the respective Romberg's quotient (RQ V). All Vm and RQ V parameter histograms presented unimodal asymmetric shapes, which were adequately fitted to lognormal distributions (Kolmogorov-Smirnov test, p > 0.05). These findings suggest a single homogeneous group in terms of visual strategy. Taking the threshold scores (95% confidence interval) of the Vm and RQ V distributions, only four subjects (2.7%) presented values below the lower limit, as expected by the confidence level (two tailed, 5%). A strong dependence was also found between each RQ V and the respective VmEC (Spear correlation > 0.86, R² > 74.0%), with VmEO presenting almost negligible coefficients of determination (R² < 2.9%). One can conclude that RQ V derived from a single stabilometric trial could be not sufficient for the diagnosis of body sway control impairment by vision. Nevertheless, the RQ V could be useful to indicate subjects to carry out additional tests to investigate a possible deficit in the integration of the visual information in the postural control system.

O Teste de Romberg clássico, baseado em testes estabilométricos nas condições de olhos abertos (EO) e fechados (EC), tem sido utilizado para investigar a influência da realimentação visual no controle das oscilações posturais em sujeitos adultos saudáveis. Estabilogramas de 144 sujeitos (18 a 40 anos) em posição ortostática sobre uma plataforma de força foram coletados durante 30 s na condição EO e 30 s em EC. As velocidades médias para EO (VmEO) e EC (VmEC), obtidas nas direções anteroposterior (y), mediolateral (x) e no plano (x,y), foram utilizadas no cálculo dos respectivos quocientes de Romberg (RQV). Os histogramas dos parâmetros Vm e RQV apresentaram morfologia unimodal assimétrica, aos quais foram ajustadas distribuições lognormais (Teste de Kolmogorov-Smirnov, p > 0,05). Tais distribuições sugerem haver um único grupo homogêneo no que concerne à estratégia visual. Considerando o intervalo de confiança de 95%, somente quatro sujeitos (2,7%) apresentaram valores de Vm e QRV abaixo do limite inferior, percentual este compatível com o teste bicaudal. A Correlação de Spear entre o RQV e seu respectivo VmEC foi sempre superior a 0,86, sendo o coeficiente de determinação R2 > 74,0%, enquanto que com VmEO R2 < 2,9%. Tais achados sugerem que o RQV obtido a partir de um único teste estabilométrico não seria adequado ao diagnóstico de problemas de controle das oscilações posturais ocasionados pela visão. No entanto, o RQV pode ser útil para indicar a realização de testes adicionais com vistas a investigar possível déficit na integração da informação visual no sistema de controle postural.

A DYNAMIC MODEL OF BODY SWAY CONTROL DURING UPRIGHT STANCE IN HUMAN / 体力科学

The aim of this study is to establish a new dynamic model for balance keeping control in upright standing; and to deduce the underlying possible control mechanism of central neuronal system with a special concern on the roles of pelvis and its muscles. The dynamic model including five joints, i. e. two ankles, two hips and one lumbosacral making up a multi-link system being driven by two pairs of muscles, the psoas major (PM) and glutaeus medius (GM). In coronal section, experimental data shows the ankle and lumbosacral sway in almost the same amplitude, whereas their phase difference is approximately equal to π. The results indicate that the trunk is keeping perpendicularly to horizon during the standing process. By defining the model's physical parameters, assuming that the corrective torque needed for balance keeping process is regulated by PID (stands for proportional, integral and derivative) control, the body sway can be simulated. The simulation result is quite consistent with the experimental data suggests that the pelvis is one of the most important structure in balance keeping, moreover, the dynamics of the present proposed balance keeping model is a quite useful model for analyzing the posture sway.

BODY SWAY CONTROL AND VISUAL INFLUENCE DURING QUIET UPRIGHT STANDING / 体力科学

Keeping upright stance is important to other complex motions like locomotion and running for human beings. The mechanism of balance-keeping control in upright standing is still unknown. This study was conducted to analyze the body sway by using a simple PID (proportional, integral, derivative) control model and to investigate the influence of vision on its gains. Ten healthy subjects took part in the study. The upright body was modeled as one-link inversed pendulum model. While determining the model parameters according to subject's physical statue, the gain of PID parameters, (<i>K_P</i>, <i>K_D</i>, <i>K_I</i> are gains of proportion, derivative, and integral respectively.) could be estimated. Four kinds of visual patterns, (three for central visual field stimulation, one is eyes closed) were designed for visual stimulation. The results showed that the gain of <i>K_D</i> was decreased significantly in eyes closed (131.5±37.6 Nms/rad in eyes open and 90.4±26.0 Nms/rad in eyes closed, p<0.001), and, <i>K_P</i>, <i>K_I</i> were not changed. The results suggested that the PID control model was a promising means for individual balance ability analysis and that the visual effect on balance-keeping control in upright standing was analogized to a damper in the mechanical system.