RQA {RHRV}

Recurrence Quantification Analysis (RQA)

Description

The Recurrence Quantification Analysis (RQA) is an advanced technique for the nonlinear analysis that allows to quantify the number and duration of the recurrences in the phase space. This function computes the RQA of the RR time series.

Usage

RQA(HRVData, indexNonLinearAnalysis = length(HRVData$NonLinearAnalysis),
  numberPoints = NULL, embeddingDim = NULL, timeLag = NULL, radius = 1,
  lmin = 2, vmin = 2, distanceToBorder = 2, doPlot = FALSE)

Arguments

HRVData

Data structure that stores the beats register and information related to it

indexNonLinearAnalysis

Reference to the data structure that will contain the nonlinear analysis

numberPoints

Number of points from the RR time series to be used in the RQA computation. If the number of points is not specified, the whole RR time series is used.

embeddingDim

Integer denoting the dimension in which we shall embed the RR time series.

timeLag

Integer denoting the number of time steps that will be use to construct the Takens' vectors.

radius

Maximum distance between two phase-space points to be considered a recurrence.

lmin

Minimal length of a diagonal line to be considered in the RQA. Default lmin = 2.

vmin

Minimal length of a vertical line to be considered in the RQA. Default vmin = 2.

distanceToBorder

In order to avoid border effects, the distanceToBorder points near the border of the recurrence matrix are ignored when computing the RQA parameters. Default, distanceToBorder = 2.

doPlot

Logical. If TRUE, the recurrence plot is shown. However, plotting the recurrence matrix is computationally expensive. Use with caution.

Value

A HRVData structure that stores an rqa field under the NonLinearAnalysis list. The rqa field consist of a list with the most important RQA parameters:

• REC: Recurrence. Percentage of recurrence points in a Recurrence Plot.

• DET: Determinism. Percentage of recurrence points that form diagonal lines.

• LAM: Percentage of recurrent points that form vertical lines.

• RATIO: Ratio between DET and RR.

• Lmax: Length of the longest diagonal line.

• Lmean: Mean length of the diagonal lines. The main diagonal is not taken into account.

• DIV: Inverse of Lmax.

• Vmax: Longest vertical line.

• Vmean: Average length of the vertical lines. This parameter is also referred to as the Trapping time.

• ENTR: Shannon entropy of the diagonal line lengths distribution

• TREND: Trend of the number of recurrent points depending on the distance to the main diagonal

• diagonalHistogram: Histogram of the length of the diagonals.

• recurrenceRate: Number of recurrent points depending on the distance to the main diagonal.

Note

This function is based on the rqa function from the nonlinearTseries package.

References

Zbilut, J. P. and C. L. Webber. Recurrence quantification analysis. Wiley Encyclopedia of Biomedical Engineering (2006).

See Also

rqa, RecurrencePlot