RESUMEN
After stroke, ankle-hip coordination during stance is characterized by changes in the postural system dynamics, specifically the disappearance of the in-phase pattern and the reduced stability of the anti-phase pattern. This study was conducted to assess the success of a coordination visual biofeedback for the (re)learning of the two preferred patterns, and to explore the effect of this treatment on postural and functional abilities. Twenty four patients were randomly assigned to one of two experimental groups or to a control group. During one month, patients from experimental groups followed a training protocol on the two preferred postural patterns using the biofeedback device. These two groups improved their in-phase coordination after the (re)learning compared with control group, and showed a related improvement of the functional independence measure. Results suggest that (re)learning the in-phase pattern is possible and seems to improve independence in poststroke patients.
Asunto(s)
Ataxia/rehabilitación , Biorretroalimentación Psicológica/métodos , Hemiplejía/rehabilitación , Equilibrio Postural/fisiología , Postura/fisiología , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular/fisiopatología , Actividades Cotidianas/clasificación , Anciano , Ataxia/fisiopatología , Biorretroalimentación Psicológica/instrumentación , Encéfalo/fisiopatología , Femenino , Hemiplejía/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Examen Neurológico , Reconocimiento Visual de Modelos/fisiología , Desempeño Psicomotor/fisiología , Procesamiento de Señales Asistido por Computador/instrumentaciónRESUMEN
We investigate human postural sway velocity time series by computing two dynamical statistics quantifying the smoothness (the central tendency measure or CTM) and the regularity (the sample entropy or SampEn) of their underlying dynamics. The purpose of the study is to investigate the effect of aging and vision on the selected measures and to explore the nature of postural dynamics by performing surrogate data tests. A group of 14 young subjects was compared to a group of 11 older healthy subjects in two visual conditions: with eyes open (EO) and with eyes closed (EC). The results suggest that vision and age do not influence the two statistics of the velocity data in the same way. More specifically, the smoothness statistic is able to detect the aging effect. The regularity measure is sensitive to the visual feedback removal. In contrast with some findings in the literature, the results of the surrogate data tests indicate that the center of pressure velocity dynamics are stochastic and are not produced by a purely deterministic behavior. Finally, we discuss some potential implications of our results in terms of postural control mechanisms.