Clinical Autonomic Research

, Volume 10, Issue 4, pp 169–175

Is fatigue in patients with multiple sclerosis related to autonomic dysfunction?

  • Laurence Keselbrener
  • Solange Akselrod
  • Anat Ahiron
  • Michael Eldar
  • Yoram Barak
  • Zeev Rotstein
Research Paper

DOI: 10.1007/BF02291352

Cite this article as:
Keselbrener, L., Akselrod, S., Ahiron, A. et al. Clinical Autonomic Research (2000) 10: 169. doi:10.1007/BF02291352

Abstract

Time-dependent frequency decomposition of fluctuations in cardiovascular signals (heart rate [HR], blood pressure, and blood flow) provides noninvasive and quantitative evaluation of autonomic activity during transient and steady-state conditions. This method was applied during a change of position from supine to standing in patients with multiple sclerosis (MS) who experienced unexplained fatigue and in age-matched control subjects.

No difference in response to standing, as reflected in the time domain parameters (mean HR, mean blood pressure, and mean blood flow), was observed between patients with MS and control subjects. Moreover, no difference was observed in very-low-frequency and low-frequency (related to sympathetic activity) content of HR, blood pressure, blood flow, or high-frequency content of HR (related to parasympathetic activity). The only spectral estimates that showed a significant diffenence between groups were the ratio of low-frequency to high-frequency content of HR and low-frequency content of HR normalized to total power. Both these parameters provide an estimate of the sympathovagal balance. A significant increase in these two estimates on standing was observed in control subjects only, indicating possible impairment of the sympathovagal balance response to standing in patients with MS who experienced fatigue. The authors observed a significant age dependence between close age subgroups, which occurred in the MS group only and was observed in some of the investigated spectral estimates that reflect vagal activity. Therefore, the authors assumed that age-related reduction in vagal activity occurred earlier in patients with MS who experienced fatigue. This reduction could also explain the lack of increase in the sympathovagal balance on standing. To validate this enhanced age dependence, further investigation should be performed in a larger group of subjects with a wider age range.

Key words

multiple sclerosis fatigue heart rate variability time-frequency analysis 

Copyright information

© Lippincott Williams & Wilkins 2000

Authors and Affiliations

  • Laurence Keselbrener
    • 1
  • Solange Akselrod
    • 1
  • Anat Ahiron
    • 2
  • Michael Eldar
    • 3
  • Yoram Barak
    • 2
  • Zeev Rotstein
    • 3
  1. 1.Abramson Center of Medical PhysicsTel Aviv UniversityIsrael
  2. 2.Multiple Sclerosis CenterSheba Medical CenterTel HashomerIsrael
  3. 3.Sheba Medical CenterHeart InstituteTel HashomerIsrael
  4. 4.School of PhysicsTel Aviv UniversityTel AvivIsrael

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