ABSTRACT
The purpose of this study was to describe the characteristics of stroke patient gait using the acceleration signals which were obtained during walking. Sixty-three stroke hemiplegic patients and 21 age-matched healthy elderly individuals took part in this study. A wireless tri-axial accelerometer, fixed to a belt at the level of the L3 spinous process, was used to measure trunk acceleration. Subjects were instructed to walk at a self-selected, comfortable walking speed. The acceleration signal was sampled at the rate of 200 Hz. Gait parameters and functional recovery tests were also evaluated. We analyzed the correlation between the gait parameters, functional recovery and acceleration. Acceleration was utilized as the root mean square (RMS), normalized RMS by velocity and average step length, as a measure of gait smoothness, and autocorrelation (AC) as a measure of stride similarity and regularity. The raw RMS and AC values of the stroke were significantly lower than the matched healthy elderly (p<0.01) in all axes. In contrast, the stroke patients' normalized RMS values were higher than the controls (p<0.05) in all axes. These results suggest that accelerometry gait parameters can discriminate between the stroke patients and the control group. The values of normalized RMS correlated with the smoothness or dynamics of the walking pattern, which reflects motor recovery and gait abilities. This study suggests that normalized RMS of accelerometer recordings from the trunk is valid in objectively measuring walking movements as an index of treatment outcome for patients in rehabilitation.
Subject(s)
Gait Disorders, Neurologic/rehabilitation , Hemiplegia/rehabilitation , Postural Balance/physiology , Signal Processing, Computer-Assisted , Stroke/complications , Walking/physiology , Acceleration , Aged , Biomechanical Phenomena , Case-Control Studies , Female , Gait Disorders, Neurologic/etiology , Gait Disorders, Neurologic/physiopathology , Hemiplegia/etiology , Hemiplegia/physiopathology , Humans , Male , Middle Aged , Probability , Reference Values , Sensitivity and Specificity , Stroke/diagnosis , Stroke RehabilitationABSTRACT
BACKGROUND AND PURPOSE: Comparisons of spontaneous movements of premature infants with brain injuries and those without brain injuries can provide insights into normal and abnormal processes in the ontogeny of motor development. In this study, the characteristics of spontaneous upper-extremity movements of premature infants with brain injuries and those without brain injuries were examined with time series analysis. SUBJECTS: Participants were 7 premature infants with brain injuries and 7 matched, low-risk, premature infants at the age of 1 month after term. METHODS: A triaxial accelerometer was used to measure upper-extremity limb acceleration in 3-dimensional space. Acceleration signals were recorded from the right wrist when the infant was in an active, alert state and lying in the supine position. The recording time was 200 seconds. The acceleration signal was sampled at a rate of 200 Hz. The acceleration time series data were analyzed by nonlinear analysis as well as linear analysis. RESULTS: The nonlinear time series analysis indicated that spontaneous movements of premature infants have nonlinear, chaotic, dynamic characteristics. The movements of the infants with brain injuries were characterized by larger dimensionality, and they were more unstable and unpredictable than those of infants without brain injuries. DISCUSSION AND CONCLUSION: As determined by nonlinear analysis, the spontaneous movements of the premature infants with brain injuries had the characteristics of increased disorganization compared with those of the infants without brain injuries. Infants with brain injuries may manifest problems with self-organization as a function of the coordination of subsystems. Physical therapists should be able to support interactions among the subsystems and promote self-organization of motor learning through the individualized provision of various sensorimotor experiences for infants.
Subject(s)
Brain Injuries/physiopathology , Infant, Premature, Diseases/physiopathology , Movement/physiology , Upper Extremity/physiology , Acceleration , Case-Control Studies , Data Interpretation, Statistical , Female , Humans , Infant, Newborn , Infant, Premature , Male , Spectrum Analysis , Time FactorsABSTRACT
The authors evaluated the characteristics of infants' spontaneous movements by using dynamical systems analysis. Participants were 6 healthy 1-month-old full-term newborn infants (3 males, 3 females). They used a triaxial accelerometer to measure limb acceleration in 3-dimensional space. Acceleration signals were recorded during 200 s from the right wrist when the infant was in an active alert state and lying supine (sampling rate 200 Hz). and was stored in the system's memory. Digitized data were transferred to a PC for subsequent processing with analysis software. The acceleration time series data were analyzed linearly and nonlinearly. Nonlinear time series analysis suggested that the infants' spontaneous movements are characterized by a nonlinear chaotic dynamics with 5 or 6 embedding dimensions. The production of infants'spontaneous movements involves chaotic dynamic systems that are capable of generating voluntary skill movements.
