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Altered fractal dynamics of gait: reduced stride-interval correlations with aging and Huntington's diseaseFluctuations in the duration of the gait cycle (the stride interval) display fractal dynamics and long-range correlations in healthy young adults. We hypothesized that these stride-interval correlations would be altered by changes in neurological function associated with aging and certain disease states. To test this hypothesis, we compared the stride-interval time series of 1) healthy elderly subjects and young controls and of 2) subjects with Huntington's disease and healthy controls. Using detrended fluctuation analysis we computed alpha, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. The scaling exponent alpha was significantly lower in elderly subjects compared with young subjects (elderly: 0.68 +/- 0.14; young: 0.87 +/- 0.15; P < 0.003). The scaling exponent alpha was also smaller in the subjects with Huntington's disease compared with disease-free controls (Huntington's disease: 0.60 +/- 0.24; controls: 0.88 +/-0.17; P < 0.005). Moreover, alpha was linearly related to degree of functional impairment in subjects with Huntington's disease (r = 0.78, P < 0.0005). These findings demonstrate that strike-interval fluctuations are more random (i.e., less correlated) in elderly subjects and in subjects with Huntington's disease. Abnormal alterations in the fractal properties of gait dynamics are apparently associated with changes in central nervous system control.
Document ID
20040173069
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hausdorff, J. M.
(Beth Israel Hospital Boston 02115, United States)
Mitchell, S. L.
Firtion, R.
Peng, C. K.
Cudkowicz, M. E.
Wei, J. Y.
Goldberger, A. L.
Date Acquired
August 22, 2013
Publication Date
January 1, 1997
Publication Information
Publication: Journal of applied physiology (Bethesda, Md. : 1985)
Volume: 82
Issue: 1
ISSN: 8750-7587
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: AG-08812
CONTRACT_GRANT: AG-10829
CONTRACT_GRANT: AG-00294
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center

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