title: Wavelet coherence analysis of spontaneous oscillations in cerebral tissue oxyhemoglobin concentrations and arterial blood pressure in elderly subjects.
abstract: This study aims to assess the relationship between spontaneous oscillations in changes in cerebral tissue oxyhemoglobin concentrations (Delta [HbO2]) and arterial blood pressure (ABP) signals in healthy elderly subjects during the resting state using wavelet coherence analysis. Continuous recordings of near-infrared spectroscopy (NIRS) and ABP signals were obtained from simultaneous measurements in 33 healthy elderly subjects (age: 70.7±7.9 years) and 27 young subjects (age: 25.2±3.7 years) during the resting state. The coherence between Delta [HbO2] and ABP oscillations in six frequency intervals (I, 0.4-2 Hz; II, 0.15-0.4 Hz; III, 0.05-0.15 Hz; IV, 0.02-0.05 Hz, V, 0.005-0.0095 Hz and VI, 0.005-0.0095 Hz) was analyzed using wavelet coherence analysis. In elderly subjects, the Delta [HbO2] and ABP oscillations were significantly wavelet coherent in interval I, and wavelet phase coherent in intervals I, II and IV. The wavelet coherence in interval I was significantly higher (p=0.040), in elderly subjects than in young subjects whereas that in interval V significantly lower (p=0.015). In addition, the wavelet phase coherence in interval IV was significantly higher in elderly subjects than in young subjects (p=0.028). The difference in the wavelet coherence of the elderly subjects and the young subjects indicates an altered cerebral autoregulation caused by aging. This study provides new insight into the dynamics of Delta [HbO2] and ABP oscillations and may be useful in identifying the risk for dynamic cerebral autoregulation processes.
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China.
authors.forename: Ruofei
authors.initials: R
authors.lastname: Cui
authors.affiliation: Interdisciplinary Division of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region P.R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China. Electronic address: zyongli@sdu.edu.cn.
authors.forename: Zengyong
authors.initials: Z
authors.lastname: Li
authors.affiliation: Hospital of Shandong University, Jinan 250061, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Xin
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China.
authors.forename: Liqian
authors.initials: L
authors.lastname: Lu
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China.
authors.forename: Weiei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Han
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, 250061, PR China.
authors.forename: Yuanjin
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D062186:Arterial Pressure; D001795:Blood Pressure Determination; D002560:Cerebrovascular Circulation; D005260:Female; D064368:Healthy Volunteers; D006706:Homeostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D010108:Oxyhemoglobins / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D058067:Wavelet Analysis; D055815:Young Adult
chemical_list: D010108:Oxyhemoglobins