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Baroreflex_Analysis

Baroreflex analysis using multi channel non stationnary signal analysis method

Calling Sequence

results = Baroreflex_Analysis(RR,SBP,freq_sampling,frequency_band ,options)
results = Baroreflex_Analysis(RR,SBP,freq_sampling,frequency_band ,BPfrequencybounds, BPfilterlength ,options)

Parameters

RR

a real vector of length N: The vector of re-sampled (see ResampleRR) interbeat intervals of the R waves in the electrocardiogram (ms).

SBP

a real vector of length N: The vector of systolic blood pressure.

freq_sampling

a real positive scalar, the sampling frequency (in Hz) of the RR and SBPsignals.

frequency_band

a two column array with Nr rows,[fmin fmax] each row specifies a frequency range (in Hz) to be studied. See the Caution section for details.

BPfrequency_bounds

a real row vector of length 2: the band pass filter frequency bounds (in Hz) or an empty matrix. In the latter case BPfrequency_bounds is set to [0.9*min(fmin) max(fmax)*1.1].

BPfrequency_bounds is used to perform a wide range band pass filtering of the given RR and SBP signals.

BPfilterlength
a real scalar with integer value: the order of the FIR Hamming band_pass filter. The default value is 355. If BPfilterlength is set to 0 no wide range band pass filtering is done. See the Caution section for details.
options

a struct with fields:

  • sectionlength: an integer, the signal section length to be used for power and cross spectrum computation. The default value is 256.

  • sectionstep: an integer, the step to be applied for one signal section to the next one. sectionstep must be less or equal to sectionlength. Overlap is sectionlength-sectionstep. The default value is 128.

  • smoothwindowlength: an integer, the length of the smoothing window (hanning). the default value is 5.

  • minimalcoherence: a positive number in ]0 1]. Used to check if RR can be approximated as a linear filtering of SBP. The default value is 0.5.

result
a "RRB typed list with following fields:
  • datatime: a real row vector of length M, the time discretization of the given RR and SBPsignals.
  • RR: a real row vector, the given RR signal.
  • SBP: a real row vector, the given SBP signal.
  • RR_energy: a real M by Nr matrix. Each row contains the smoothed windowed energy of the RR signal in the corresponding frequency range.
  • SBP_energy: a real M by Nr matrix. Each row contains the smoothed windowed energy of the SBP signal in the corresponding frequency range.
  • resulttime: a real row vector of length M, the time discretization of the comptuded signals.
  • RR_fmin: a real M by Nr matrix. Each row contains the frequency around which the dispersion of the RR signal is minimal in the corresponding frequency range.
  • SBP_fmin: a real M by Nr matrix. Each column contains the frequency around which the dispersion of the SBP signal is minimal in the corresponding frequency range.
  • RR_SPSDmin: a real M by Nr matrix. Each column contains the value of the Smoothed Power Spectral Density (SPSD) at the frequency of minimal dispersion for the RR signal in the corresponding frequency range.
  • SBP_SPSDmin: a real M by Nr matrix. Each column contains the value of the Smoothed Power Spectral Density (SPSD) at the frequency of minimal dispersion for the SBP signal in the corresponding frequency range.
  • RR_dispmin: a real M by Nr matrix. Each column contains the value of the minimal dispersion for the RR signal in the corresponding frequency range. Dispersion value is zero when the signal is merely a sinusoide, only one components, whereas is 1 if the spectra is completely spread, so there isn't a principal component.
  • SBP_dispmin: a real M by Nr matrix. Each column contains the value of the minimal dispersion for the SBP signal in the corresponding frequency range. Dispersion value is zero when the signal is merely a sinusoide, only one components, whereas is 1 if the spectra is completely spread, so there isn't a principal component.
  • SBP_RR_gain: a real M by Nr matrix. Each column contains the SBP to RR transfer function gain in the corresponding frequency range.
  • SBP_RR_coherence: a real M by Nr matrix. Each column contains the coherence between SBP and RR signals in the corresponding frequency range.

Description

Baroreflex analysis using multi channel non stationnary signal analysis method

Caution

Examples

Signals acquisition and filtering

d=read(cardiovascularpath()+"demos/DATA/tilt_divers",-1,5)';//[RR SBP DBP Vt time] 
freq_sampling=2;
shift=600;
RR= d(1,shift:$);
SBP=d(2,shift:$);

Analysis

clear options
options.sectionlength=64;
fbands=[0.04 0.15; //LF
        0.2 0.3];  //HF
result=Baroreflex_Analysis(RR,SBP,freq_sampling,fbands,options)

Drawing

PlotBaroreflexAnalysis(result,"Tilt")

Authors

Bibliography

Rapport de recherche INRIA RR-4427:"Short term control of the cardivascular system: modelling and signal analysis" Alessandro Monti, Claire Médigue, Michel Sorine,2002 pp 50-

Used Functions

np_mc_nss_analysis

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