Peripheral Neuropathy Does Not Alter the Fractal Dynamics of Stride Intervals of

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J Appl Physiol. 2006 Nov 16

Peripheral Neuropathy Does Not Alter the Fractal Dynamics of Stride

Intervals of Gait.

Gates DH, Dingwell JB.

Biomedical Engineering, University of Texas at Austin, Austin,

Texas, United States.

The purpose of this study was to determine the effect (if any) of

significant sensory loss on the long-range correlations normally

observed in the stride intervals of human gait. Fourteen patients

with severe peripheral neuropathy, and 12 gender-, age-, height-,

and weight-matched non-diabetic controls participated. Subjects

walked around an approximately 200m open level walkway for 10

minutes at their comfortable pace.

Continuous knee joint kinematics were recorded and used to calculate

a stride interval time series for each subject. Power spectral

density and detrended fluctuation analyses were used to determine if

these stride intervals exhibited long-range correlations. If the

loss of long-range correlations indicates deterioration of the

central control of gait, then changes in peripheral sensation should

have no effect. If instead, the loss of long-range correlations is a

consequence of a general inability to regulate gait cycle timing,

then a similar loss should occur in patients with peripheral

locomotor disorders.

Both power spectral density analyses and detrended fluctuation

analyses showed that temporal correlations in the stride times of

neuropathic and control subjects were statistically identical (p =

0.954 and p = 0.974, respectively), despite slower gait speeds (p =

0.008) and increased stride time variability (p = 0.036) among the

neuropathy patients. All subjects in both groups exhibited long-

range correlations. These findings demonstrate that the normal long-

range correlation structure of stride intervals is unaltered by

significant peripheral sensory loss. This further supports the

hypothesis that the central nervous system is involved in the

regulation of long-range correlations.