EMG muscle-activation summary of an ADL task

Summarises how an agonist-antagonist muscle pair drives one ADL task from an EMG envelope: the co-contraction index (via emgCoContraction()), each muscle's peak and mean activation (as percent of a maximal reference when mvc_data is given, else raw envelope units), and the fraction of the task each muscle is active. Higher antagonist co-contraction means less efficient, more guarded movement.

Usage

emgADLActivation(
  x,
  agonist,
  antagonist,
  mvc_data = NULL,
  task = c("reaching", "drinking", "feeding", "dressing", "grooming"),
  cc_method = c("falconer_winter", "rudolph", "frost"),
  active_frac = 0.2,
  assay_name = NULL
)

Arguments

x

A PhysioExperiment of EMG envelope data (rectified / smoothed).

agonist, antagonist

Channel index or colData$label of the pair.

mvc_data

Optional PhysioExperiment of maximal-effort (MVC) data with the same channels; enables percent-MVC amplitudes.

task

ADL task realised: "reaching" (d445), "drinking" (d560), "feeding" (d550), "dressing" (d540) or "grooming" (d520).

cc_method

Co-contraction index method (see emgCoContraction()).

active_frac

Activation threshold as a fraction of a muscle's own peak (default 0.2) for the active-time summary.

assay_name

EMG assay to use (default: the first assay).

Value

an emg_adl_activation list: task, icf_code, cocontraction_index, unit ("%MVC" or "envelope"), per-muscle agonist_peak/agonist_mean/antagonist_peak/antagonist_mean and agonist_active_frac/antagonist_active_frac.

See also

emgCoContraction(), emgAmplitudeNormalize()

Examples

set.seed(1)
n <- 1000; t <- seq_len(n)
ag <- exp(-((t - 500) / 150)^2) + rnorm(n, 0, 0.02)     # agonist burst
an <- 0.2 * exp(-((t - 500) / 150)^2) + rnorm(n, 0, 0.02) # low antagonist
pe <- PhysioCore::PhysioExperiment(
  assays = S4Vectors::SimpleList(envelope = cbind(BIC = ag, TRI = an)),
  colData = S4Vectors::DataFrame(label = c("BIC", "TRI"), type = "EMG"),
  samplingRate = 1000)
emgADLActivation(pe, "BIC", "TRI", task = "drinking")$cocontraction_index
#> [1] 86.30546