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Time-varying electrodermal sympathetic index (TVSymp)

Source: R/eda-sympathetic.R
edaTVSymp.Rd

A time-resolved sympathetic-tone index built by complex demodulation of the dominant components of the electrodermal signal in the sympathetic band (Posada-Quintero et al. 2016). The two strongest spectral components in the band are demodulated to their instantaneous amplitudes, combined, and normalised to a reproducible trajectory that rises when sympathetic oscillations appear.

Usage

edaTVSymp(
  x,
  band = c(0.08, 0.24),
  assay_name = NULL,
  resample_hz = 2,
  n_components = 2,
  lp_hz = NULL
)

Arguments

x

A PhysioExperiment object with an electrodermal assay.

band

Numeric c(low, high) sympathetic band in Hz (default c(0.08, 0.24)).

assay_name

Input assay (default: defaultAssay(x)).

resample_hz

Rate (Hz) the signal is downsampled to (default 2; NULL keeps the native rate).

n_components

Number of dominant band components to demodulate (default 2).

lp_hz

Low-pass cutoff (Hz) of the demodulation envelope (default 0.5 of the band width).

Value

A data frame with one row per time sample per channel: channel, time_sec, tvsymp (combined instantaneous amplitude) and tvsymp_norm (unit-variance normalised). The dominant component frequencies are attached as the "components" attribute.

References

Posada-Quintero, H.F. et al. (2016). Time-varying analysis of electrodermal activity during exercise. PLoS ONE 11(8):e0161553.

See also

edaSympatheticIndex()

Examples

pe <- edaSimulate(n_time = 1200, sr = 4, scr_count = 6, seed = 1)
tv <- edaTVSymp(pe)
head(tv)
#>   channel time_sec    tvsymp tvsymp_norm
#> 1       1      0.0 0.1596698   1.2560419
#> 2       1      0.5 0.1565969   1.2318688
#> 3       1      1.0 0.1480711   1.1648007
#> 4       1      1.5 0.1362271   1.0716296
#> 5       1      2.0 0.1244556   0.9790289
#> 6       1      2.5 0.1166002   0.9172346