正常幼童從平躺轉為60度上揚時其LF/HF會升高但具有癲癇症者則失去此功能
Power spectrum analysis of
heart rate variability in children with epilepsy
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摘要 Object: Children with epilepsy have been found to be at increased risk of death
during childhood. Sudden unexpected death (SUDEP) has accounted for at least
12% of deaths of children with epilepsy. The exact mechanisms of SUDEP are
unknown; however, theories suggested have, to date, focused on autonomic
instability. The purpose of this study was to investigate autonomic function
in children with chronic epilepsy by means of power spectrum analysis of
heart rate variability. Methods: Thirty patients with epilepsy and 30 control subjects, all between the
ages of 4 and 10 years, were enrolled in this study. Power spectrum analysis
of heart rate variability (HRV) was performed under standardized conditions
after the patients had rested for 15 min. Each patient was tested in a supine
position first and then again in a head-up tilted position, with 15 min
between the two tests. Results: There was no significant difference between the low-frequency component
(LF) and the high-frequency component (HF) of heart rate variability, or the
LF/HF ratio, between the study and control groups, whether the test subjects
were in the supine or the head-up tilt position. In the control group,
however, the subjects showed a significantly greater LF component and a
smaller HF component of heart rate variability, and a greater LF/HF ratio in
the head-up position than in the supine position. This implies a normal sympathovagal balance. This phenomenon was not observed
in the study group. This implies that the modulating effects on autonomic
function deriving from the hemisphere were probably disturbed, owing to the
brain lesions that each of the study group patients had already sustained. Conclusions: A
disturbed balance of activity between the sympathetic and parasympathetic
nervous system might result from the loss of hemispheric influence in
patients with epilepsy. Nevertheless, further investigation is clearly
necessary to ascertain the possible association of this disturbed balance
with SUDEP. Further investigation is also needed to establish the exact
location of the region in the brain that gives rise to this modulating
influence. |
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