Changes in Detrended Fluctuation Indices with Aging in Healthy and Congestive Heart Failure Subjects
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2009-06-15T09:01:00Z
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Detrended Fluctuation Analysis (DFA) aims to quantify
the fractal correlation properties in nonstationary time series,
and it has successfully been applied in the assessment
of the Heart Rate Variability (HRV) for cardiac risk
stratification purposes. However the physiological meaning
of DFA indices and its relation with aging have not
yet been completely established. Given that a loss of complexity
in the physiological regulation of elderly subjects
has been reported in the literature, we hypothesized that
DFA indices could be modified by aging. In this work
we computed the Hurst exponent (estimated using DFA
method) and DFA indices alfa1 and alfa2 to assess the HRV
in healthy and Congestive Heart Failure (CHF) subjects,
and we studied the dependence of these indices on aging
for both healthy and CHF subjects. We found that only
alfa2 and Hurst exponent, and only in the case of healthy
subjects, have significant discrimination capability to distinguish
between young and elderly groups, and also that
these indices have a steady increase with aging. Therefore,
we can conclude that the loss of complexity due to aging
can be quantified by changes in the values of alfa2 and Hurst
exponent.