Renato Claudino

Compensatory but not anticipatory adjustments are altered in older adults during lateral postural perturbations

OBJECTIVE This study investigated anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) and their relationship in older adults during lateral postural perturbations. METHODS Unpredictable and predictable postural disturbances were induced by a swinging pendulum that impacted at the shoulder level of two groups of older adults, non-fallers (20) and fallers (20), and in a group of young control subjects (20). The electromyographic (EMG) activity of the postural muscles and the center of pressure (COP) displacement were recorded and quantified within the time intervals typical for APAs and CPAs. RESULTS Both groups of older adults (non-fallers and fallers) showed higher magnitude of EMG activity in the lateral muscles and increased COP displacement, particularly, during the CPAs time interval when compared to the young group. Older adults, however, were able to change the electrical activity of the muscles during the predictable task by generating APAs with similar magnitudes of those found in young subjects. CONCLUSIONS Compensatory but not anticipatory adjustments are altered in older adults during predictable lateral postural perturbations. SIGNIFICANCE These findings provide new data on the role of APAs and CPAs in their relationship in older adults during external lateral perturbations and may advance current rehabilitative management strategies to improve balance control in older individuals.

Using an accelerometer for analyzing a reach-to-grasp movement after stroke

O objetivo deste estudo foi usar um acelerometro para avaliar a cinematica do movimento de alcance e preensao de individuos com hemiparesia. Participaram deste estudo oito individuos (59,4 ± 6,9 anos) com hemiparesia cronica (50,9 ± 25,8 meses pos-AVE). A avaliacao cinematica foi realizada atraves de acelerometro triaxial (EMG Systems do Brasil) fixado no antebraco. Os individuos realizaram 10 movimentos de alcancar uma garrafa de 500 ml pelo membro superior (MS) paretico e nao paretico. As seguintes variaveis espaco-temporais foram calculadas e utilizadas para comparar o MS paretico e nao paretico: tempo de movimento (TM), tempo para alcancar o pico de velocidade, absoluto e relativo (TPV e TPV%TM), duracao relativa da desaceleracao(DEC%TM), tempo para alcancar o pico de aceleracao (TPA) e pico de aceleracao da mao (PA). Os movimentos foram mais lentos no MS paretico com maiores TM, TPA e DEC. A utilizacao do acelerometro permitiu identificar alteracoes no movimento de alcance em individuos com hemiparesia. Quando sistemas mais compexos nao sao disponiveis, acelerometros podem ser uma alternativa para medir o movimento do MS.

Anticipatory and Compensatory Postural Adjustments in Response to External Lateral Shoulder Perturbations in Subjects with Parkinson’s Disease

The purpose of this study was to investigate the anticipatory (APA) and compensatory (CPA) postural adjustments in individuals with Parkinson’s disease (PD) during lateral instability of posture. Twenty-six subjects (13 individuals with PD and 13 healthy matched controls) were exposed to predictable lateral postural perturbations. The electromyographic (EMG) activity of the lateral muscles and the displacement of the center of pressure (COP) were recorded during four time intervals that are typical for postural adjustments, i.e., immediately before (APA1, APA2) and after (CPA1 and CPA2) the postural disturbances. The magnitude of the activity of the lateral muscles in the group with PD was lower only during the CPA time intervals and not during the anticipatory adjustments (APAs). Despite this finding, subjects with PD exhibit smaller COP excursions before and after the disturbance, probably due to lack of flexibility and proprioceptive impairments. The results of this study suggest that postural instability in subjects with PD can be partially explained by decreased postural sway, before and after perturbations, and reduced muscular activity after body disturbances. Our findings can motivate new studies to investigate therapeutic interventions that optimize the use of postural adjustment strategies in subjects with PD.

Ajustes posturais antecipatórios e compensatórios ao pegar uma bola em condição de estabilidade e instabilidade postural

Young individuals preselect their postural adjustment strategies before an external perturbation, based on the characteristics of the task. However, it is not well documented how the central nervous system deals with anticipatory and compensatory postural adjustments during some balance training programs, which are commonly used in Physical Therapy settings. Thirteen young individuals were submitted to 20 external postural perturbations of catching a ball thrown by an experimenter in conditions of postural stability and instability (standing on a foam). The electromyographic activities of triceps brachii (focal muscle), rectus abdominis, and lumbar paraspinal muscles were investigated in the time windows typical for anticipatory and compensatory postural adjustments, as well as the center of body pressure peak displacement after the perturbation. The magnitude of the triceps brachii integral electromyographic activity was significantly smaller in conditions of postural instability, there was no statistical difference between the stable and unstable conditions for the integral electromyographic activity of the rectus abdominis, and lumbar paraspinal muscles. The peak of the center of body pressure anterior posterior displacement was similar between the two conditions. Balance training associated with external perturbation standing on a foam might not be more effective or efficient than when standing on a stable surface, when it seeks to modify the activity of the postural trunk muscles. In addition, this balance training may contribute to decrease the electromyographic activity (anticipatory postural adjustments) of the focal muscle.

El uso de un acelerómetro para analizar un movimiento de alcance i e preensão después del accidente cerebrovascular

O objetivo deste estudo foi usar um acelerometro para avaliar a cinematica do movimento de alcance e preensao de individuos com hemiparesia. Participaram deste estudo oito individuos (59,4 ± 6,9 anos) com hemiparesia cronica (50,9 ± 25,8 meses pos-AVE). A avaliacao cinematica foi realizada atraves de acelerometro triaxial (EMG Systems do Brasil) fixado no antebraco. Os individuos realizaram 10 movimentos de alcancar uma garrafa de 500 ml pelo membro superior (MS) paretico e nao paretico. As seguintes variaveis espaco-temporais foram calculadas e utilizadas para comparar o MS paretico e nao paretico: tempo de movimento (TM), tempo para alcancar o pico de velocidade, absoluto e relativo (TPV e TPV%TM), duracao relativa da desaceleracao(DEC%TM), tempo para alcancar o pico de aceleracao (TPA) e pico de aceleracao da mao (PA). Os movimentos foram mais lentos no MS paretico com maiores TM, TPA e DEC. A utilizacao do acelerometro permitiu identificar alteracoes no movimento de alcance em individuos com hemiparesia. Quando sistemas mais compexos nao sao disponiveis, acelerometros podem ser uma alternativa para medir o movimento do MS.

Usando um acelerômetro para analisar o movimento de alcance e e preensão após o AVE

O objetivo deste estudo foi usar um acelerometro para avaliar a cinematica do movimento de alcance e preensao de individuos com hemiparesia. Participaram deste estudo oito individuos (59,4 ± 6,9 anos) com hemiparesia cronica (50,9 ± 25,8 meses pos-AVE). A avaliacao cinematica foi realizada atraves de acelerometro triaxial (EMG Systems do Brasil) fixado no antebraco. Os individuos realizaram 10 movimentos de alcancar uma garrafa de 500 ml pelo membro superior (MS) paretico e nao paretico. As seguintes variaveis espaco-temporais foram calculadas e utilizadas para comparar o MS paretico e nao paretico: tempo de movimento (TM), tempo para alcancar o pico de velocidade, absoluto e relativo (TPV e TPV%TM), duracao relativa da desaceleracao(DEC%TM), tempo para alcancar o pico de aceleracao (TPA) e pico de aceleracao da mao (PA). Os movimentos foram mais lentos no MS paretico com maiores TM, TPA e DEC. A utilizacao do acelerometro permitiu identificar alteracoes no movimento de alcance em individuos com hemiparesia. Quando sistemas mais compexos nao sao disponiveis, acelerometros podem ser uma alternativa para medir o movimento do MS.

Estratégias de ajustes posturais em indivíduos idosos diante do distúrbio de pegar uma bola

Resumen pt: Introducao: Alteracoes relacionadas com o envelhecimento podem levar a importantes limitacoes na estabilidade postural em idosos, como deficits nas estra...