Package {PPCSexRx}

Type:	Package
Title:	Prescribe Sub-Symptom Exercise for Adolescent Concussion
Version:	0.1.0
Description:	A clinical decision support system for sub-symptom threshold aerobic exercise (SSTAE) prescription in adolescents with persistent post-concussion symptoms (PPCS). Implements an evidence-based protocol derived from a systematic review of seven studies (Li, 2026; <doi:10.17605/osf.io/kvuf6>), encoding safety screening, Buffalo Concussion Treadmill Test (BCTT)-guided heart rate prescription, session-level progress tracking, and evidence disclosure using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework into an open-source tool for athletic trainers and clinicians. Designed to support implementation in resource-limited settings where BCTT equipment may be unavailable. GRADE certainty of evidence: LOW. For clinician use only; not a substitute for clinical judgement.
License:	MIT + file LICENSE
Encoding:	UTF-8
RoxygenNote:	8.0.0
Imports:	graphics, utils
Suggests:	knitr, rmarkdown, testthat (≥ 3.0.0)
VignetteBuilder:	knitr
URL:	https://github.com/guangl10/PPCSexRx
BugReports:	https://github.com/guangl10/PPCSexRx/issues
NeedsCompilation:	no
Packaged:	2026-05-27 21:09:57 UTC; liguang
Author:	Guang Li [aut, cre]
Maintainer:	Guang Li <guangli@isu.edu>
Repository:	CRAN
Date/Publication:	2026-06-01 08:30:15 UTC

Plot rehabilitation progress for a ppcs_track object

Description

Generates a dual-panel plot showing PCSS symptom trajectory and achieved HR over time. Requires base R graphics only (no dependencies).

Usage

## S3 method for class 'ppcs_track'
plot(x, ...)

Arguments

Value

Invisibly returns x, called for its side effect of drawing a two-panel base-graphics figure: the upper panel shows Post-Concussion Symptom Scale (PCSS) scores across sessions; the lower panel shows achieved and target heart rate (bpm) across sessions. Returns a message (via message) and invisible(x) without plotting if fewer than two sessions are recorded.

Prescribe Sub-symptom Aerobic Exercise for Adolescent PPCS

Description

Implements the evidence-based protocol from Li (2026). GRADE: LOW certainty, Conditional recommendation FOR. Run screen_ppcs first to confirm eligibility.

Usage

prescribe_ppcs(
  age,
  days_post_injury,
  hrst = NULL,
  vestibular_symptoms = FALSE,
  cervical_symptoms = FALSE,
  sessions_completed = 0,
  last_session_worse = FALSE
)

Arguments

Value

An object of class ppcs_prescription with prescription details.

References

Li G. (2026). Sub-symptom Threshold Aerobic Exercise for Adolescents With PPCS: A Critically Appraised Topic. Winner, NATA Foundation Student Writing Contest.

Examples

# Case 1: Rural clinic, no BCTT available
prescribe_ppcs(age = 16, days_post_injury = 35)

# Case 2: University clinic with BCTT data
prescribe_ppcs(age = 17, days_post_injury = 40, hrst = 160)

# Case 3: Safety stop - vestibular symptoms present
try(prescribe_ppcs(age = 15, days_post_injury = 30,
                   vestibular_symptoms = TRUE))

Print method for ppcs_prescription objects

Description

Displays a formatted clinical prescription sheet.

Usage

## S3 method for class 'ppcs_prescription'
print(x, ...)

Arguments

Value

Invisibly returns x (a ppcs_prescription list), called primarily for its side effect of printing the formatted prescription to the console.

Print method for ppcs_screen objects

Description

Print method for ppcs_screen objects

Usage

## S3 method for class 'ppcs_screen'
print(x, ...)

Arguments

Value

Invisibly returns x (a ppcs_screen list), called primarily for its side effect of printing the eligibility screen result to the console.

Print method for ppcs_track objects

Description

Print method for ppcs_track objects

Usage

## S3 method for class 'ppcs_track'
print(x, ...)

Arguments

Value

Invisibly returns x (a ppcs_track list), called primarily for its side effect of printing the session progress summary to the console.

Screen Adolescent for SSTAE Eligibility

Description

Implements the PICO-based eligibility criteria from Li (2026). Run this before prescribe_ppcs to confirm the patient is appropriate for sub-symptom threshold aerobic exercise.

Usage

screen_ppcs(
  age,
  days_post_injury,
  vestibular_symptoms = FALSE,
  cervical_symptoms = FALSE,
  vision_symptoms = FALSE,
  verbose = TRUE
)

Arguments

Value

A list of class ppcs_screen with fields:

status

"eligible", "contraindicated", or "needs_referral"

reason

Character. Clinical rationale for status.

referral

Character or NA. Recommended referral if applicable.

next_step

Character. Recommended action.

References

Li G. (2026). Sub-symptom Threshold Aerobic Exercise for Adolescents With PPCS: A Critically Appraised Topic. Winner, NATA Foundation Student Writing Contest.

Vernau BT, Haider MN, Fleming A, et al. Exercise-Induced Vision Dysfunction Early After Sport-Related Concussion Is Associated With Persistent Postconcussive Symptoms. Clin J Sport Med. 2023;33(4):388-394.

Examples

# Eligible athlete
screen_ppcs(age = 16, days_post_injury = 35)

# Contraindicated: too early
screen_ppcs(age = 16, days_post_injury = 20)

# Needs referral: vestibular symptoms present
screen_ppcs(age = 16, days_post_injury = 35, vestibular_symptoms = TRUE)

# Patient/caregiver output
screen_ppcs(age = 16, days_post_injury = 35, verbose = FALSE)

Track SSTAE Rehabilitation Progress Over Time

Description

Records and evaluates session-level data over the course of a sub-symptom threshold aerobic exercise programme. Compares observed progress against the progression and stop rules described in Li (2026), p.14, and generates a recommendation for the next session.

Usage

track_progress(
  log,
  current_pcss,
  current_hr,
  current_duration,
  prescription,
  verbose = TRUE
)

Arguments

Value

A list of class ppcs_track with fields:

updated_log

Data frame. The log with today's session appended.

phase

Character. Current rehabilitation phase.

recommendation

Character. Action for the next session.

adjust_hr

Numeric. Suggested HR target for next session (bpm).

sessions_total

Integer. Total sessions recorded.

pcss_change

Numeric. PCSS change from first to today.

verbose

Logical. Passed through for print method.

References

Li G. (2026). Sub-symptom Threshold Aerobic Exercise for Adolescents With PPCS: A Critically Appraised Topic. Winner, NATA Foundation Student Writing Contest. p.14.

Kurowski BG, et al. Aerobic Exercise for Adolescents With Prolonged Symptoms After Mild Traumatic Brain Injury. J Head Trauma Rehabil. 2017;32(2):79-89.

Examples

# Step 1: get a prescription
rx <- prescribe_ppcs(age = 16, days_post_injury = 35, hrst = 160)

# Step 2: first session - no prior log
t1 <- track_progress(
  log               = NULL,
  current_pcss      = 28,
  current_hr        = 120,
  current_duration  = 18,
  prescription      = rx
)
t1

# Step 3: second session - pass updated log forward
t2 <- track_progress(
  log               = t1$updated_log,
  current_pcss      = 24,
  current_hr        = 122,
  current_duration  = 20,
  prescription      = rx
)
t2