Regresses the catch angle against the peak stretch velocity across a series of passive stretches at varying velocities. A negative slope is the signature of velocity-dependent spasticity (the catch occurs earlier - at a smaller angle - as the stretch gets faster).
Arguments
- stretches
A list of
tardieuStretch()results (>= 2), one per stretch.
Value
An S3 reflex_threshold list: slope (deg per deg/s), intercept,
catch_angles, peak_velocities and the linear model.
Examples
fs <- 200
mk <- function(catch, rise, total = 0.8) {
t <- seq(0, total, by = 1 / fs)
ifelse(t <= rise, catch * t / rise, catch + 8 * (t - rise) / (total - rise))
}
st <- lapply(list(c(30, .5), c(20, .25), c(15, .13)),
function(p) tardieuStretch(mk(p[1], p[2]), sampling_rate = fs,
onset = "velocity"))
reflexThreshold(st)$slope
#> [1] -0.2571113