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Limb-ataxia composite from reaching sub-metrics

Source: R/ataxia.R
limbAtaxiaIndex.Rd

Aggregates the standard limb-ataxia sub-metrics, each oriented so that a higher value means more ataxic movement. Supply them from the existing primitives: dysmetria from endpointError() (absolute_error or the magnitude of constant_error), decomposition from movementUnits() (the submovement count), smoothness as a jerk/roughness score where higher is worse (e.g. -sparc from sparc(), since SPARC is more negative for less smooth movement, or ldlj magnitude), and irregularity from pathStraightness() (index_of_curvature).

Usage

limbAtaxiaIndex(
  dysmetria = NA_real_,
  decomposition = NA_real_,
  smoothness = NA_real_,
  irregularity = NA_real_,
  reference = NULL,
  weights = NULL
)

Arguments

dysmetria, decomposition, smoothness, irregularity

Numeric sub-metrics (higher = more ataxic); any may be NA to omit it.

reference

Optional data.frame of the same-named columns measured in a healthy reference sample; when given, each sub-metric is z-standardised against it and averaged into composite. Without a reference the composite is NA and only the sub-metrics are returned.

weights

Optional named weights for the composite (default equal).

Value

An S3 limb_ataxia list: metrics, per-metric z, and composite.

See also

pathStraightness(), reachingKinematics(), gaitAtaxiaIndex()

Examples

limbAtaxiaIndex(dysmetria = 3.2, decomposition = 4, smoothness = 5.1,
                irregularity = 1.4)
#> Limb-ataxia sub-metrics (higher = more ataxic):
#>   dysmetria      3.2
#>   decomposition  4
#>   smoothness     5.1
#>   irregularity   1.4
#>   composite z    : NA (no reference supplied)