title: Assessment of cerebral oxygenation oscillations in subjects with hypertension.
abstract: OBJECTIVE
  The objective of this study was to assess the spontaneous oscillations in subjects with hypertension based on the wavelet transform of cerebral oxygenation signal measured with near-infrared spectroscopy (NIRS).
  
  
  METHODS
  Continuous recordings of NIRS and arterial blood pressure (ABP) signals were obtained from simultaneous measurements in 20 healthy subjects (age: 70.8±5.2 years) and 22 subjects with hypertension (age: 72.5±6.8 years).
  
  
  RESULTS
  Using spectral analysis based on wavelet transform, five frequency intervals were identified (I, 0.4-2 Hz; II, 0.15-0.4 Hz; III, 0.06-0.15 Hz; IV, 0.02-0.06 Hz and V, 0.005-0.02 Hz). The amplitudes of Δ[Hb] and Δ[HbO2] in intervals I, II and III were significantly higher in hypertensive patients, who have increased mean flow velocity in middle cerebral artery (MCA), compared to that in the healthy subjects (p<0.01). The amplitudes of the ABP in frequency intervals III and V were significantly higher in hypertensive patients than in the healthy subjects (p<0.01).
  
  
  CONCLUSIONS
  The present findings revealed that hypertension and increased mean flow velocity in MCA have significant effect on the cerebral oscillations. The higher cerebral oscillations might be related to the intracerebral atherosclerosis in response to systemic hypertension. In addition, the higher spontaneous oscillations in intervals III and V in ABP indicate a metabolic regulation and myogenic response to hypertension.
authors.affiliation: School of Mechanical Engineering, Shandong University, Jinan, 250061 PR China. zyongli@sdu.edu.cn
authors.forename: Zengyong
authors.initials: Z
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Qing
authors.initials: Q
authors.lastname: Xin
authors.forename: Site
authors.initials: S
authors.lastname: Luo
authors.forename: Weiei
authors.initials: W
authors.lastname: Zhou
authors.forename: Ruofei
authors.initials: R
authors.lastname: Cui
authors.forename: Liqian
authors.initials: L
authors.lastname: Lu
mesh_terms: D000368:Aged; D001794:Blood Pressure; D001921:Brain / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005583:Fourier Analysis; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D009991:Oscillometry / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D013997:Time Factors; D018608:Ultrasonography, Doppler / Q000379:methods; D058067:Wavelet Analysis
chemical_list: D010100:Oxygen