Copyright ©ERS Journals Ltd 2004 A short daytime test using correlation dimension for respiratory movement in OSAHS1 Division of Medical Oncology and Molecular Respirology, and 2 Division of Otolaryngology, Faculty of Medicine, Tottori University, Yonago, Japan CORRESPONDENCE: N. Burioka, Third Dept of Internal Medicine, Faculty of Medicine, Tottori University, 361 Nishimachi, Yonago 683-8504, Japan. Fax: 81 859348098, E-mail: burioka@grape.med.tottori-u.ac.jp Keywords: Breath-to-breath variations, correlation dimension, nonlinear analysis, obstructive sleep apnoea/hypopnea syndrome
Received: April 20, 2003
In order to examine the pathology in patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS), the nonlinear properties of respiratory movement and breath-to-breath variations during resting wakefulness with eyes closed was investigated.
Recording of the respiratory movement using inductive plethysmography was performed on 14 patients with OSAHS and 13 control subjects for 2 h in the supine position during daytime. To calculate the correlation dimension (D2) for respiratory movement, an algorithm proposed by Grassberger and Procaccia was applied. The indices of breath-to-breath variations were estimated. To calculate D2 and breath-to-breath variations, two different segments were selected (200 s each).
The value of D2 for respiratory movement in patients with OSAHS was significantly greater than that in control subjects. In the case of
In conclusion, the measurements of correlation dimensions for respiratory movement with a brief period during wakefulness may be a useful index for identifying patients with obstructive sleep apnoea/hypopnoea syndrome.
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