Classify Muscles as Responders, Non-Responders, or Deteriorated

Compares first and last timepoint to determine if each muscle shows clinically meaningful change beyond the MDC threshold.

Usage

mskDetectResponderStatus(
  tracker,
  mdc_result = NULL,
  threshold_type = c("mdc", "effect_size"),
  instrument = NULL,
  population = NULL,
  direction = c("increase", "decrease")
)

Arguments

tracker

An MSKLongitudinalTracker object.

mdc_result

An MSKMinimalDetectableChange object (or NULL to use effect size threshold).

threshold_type

Character, "mdc" (default) or "effect_size" (Cohen's d > 0.8).

instrument

Optional validated instrument id (e.g. "fma_ue") to delegate dual MDC-vs-MCID classification to PhysioClinical.

population

Optional population stratum for the instrument's clinimetric lookup (used only with instrument).

direction

"increase" (default) or "decrease" — the direction of clinical benefit, passed to the clinimetric classifier.

Value

An S3 object of class "MSKResponderStatus" with:

classification

data.frame (muscle, status, change, threshold, effect_size_d; plus clinical_class when delegated)

summary

counts of responders/non-responders/deteriorated

overall_status

"responder" if majority of muscles improve

method

"clinimetric" (delegated) or "threshold"

Details

When a validated instrument and population are supplied and the PhysioClinical package is available, classification is delegated to PhysioClinical::classifyResponder(), which applies the published dual MDC-vs-MCID rule (adding a clinical_class column). Otherwise the single-threshold path (MDC or effect size) is used.

Examples

C <- matrix(c(1,1,0,0,0, 0,1,1,0,0, 0,0,1,1,0, 0,0,0,1,1, 1,0,0,0,1, 0,1,0,1,0),
            nrow = 6, byrow = TRUE,
            dimnames = list(paste0("bone", 1:6),
              c("Biceps Brachii", "Deltoid", "Trapezius",
                "Triceps Brachii", "Brachialis")))
hg <- MSKHypergraph(C)
mk <- function(s) { set.seed(s); m <- matrix(abs(rnorm(300 * 4)), 300, 4)
  colnames(m) <- c("Biceps Brachii", "Deltoid", "Trapezius", "Triceps Brachii"); m }
tracker <- mskLongitudinalTracker(list(T0 = mk(1), T1 = mk(2), T2 = mk(3)), hg = hg)
status <- mskDetectResponderStatus(tracker)
status
#> MSK Responder Status
#> ====================
#> Overall: non_responder 
#> 
#> Summary:
#>   Responders: 0 
#>   Non-responders: 2 
#>   Deteriorated: 2 
#> 
#> Per-muscle classification:
#>           muscle        status  change threshold effect_size_d
#>   Biceps Brachii non_responder  0.0302    0.0433        0.5572
#>          Deltoid  deteriorated -0.0205    0.0190       -0.8596
#>        Trapezius  deteriorated -0.1226    0.0519       -1.8908
#>  Triceps Brachii non_responder  0.0133    0.0267        0.3971