ImPact Test-Retest Reliability: Reliably Unreliable?

This study is an observational study of the reliability of follow up tests. In my personal opinion, ANY patient who is SYMPTOMATIC but has a normal test AND any ASYMPTOMATIC patient with an abnormal test should have an expert evaluation .

Do experts review all these baseline tests and provide an interpretation?

Do parents get results and an option to evaluate their child?
Are schools  putting students with abnormal tests in the game?

hmmm...

 JR

ImPact Test-Retest Reliability: Reliably Unreliable?

Jacob Resch , PhD, ATC*; Aoife Driscoll , BSc†; Noel McCaffrey , MD†; Cathleen Brown , PhD, ATC‡; Michael S. Ferrara , PhD, ATC, FNATA‡; Stephen Macciocchi , PhD, ABPP§; Ted Baumgartner , PhD‡; Kimberly Walpert , MD‖

*University of Texas at Arlington;

†Dublin City University, Ireland;

‡University of Georgia, Athens;

§Shepherd Center, Atlanta, GA;

‖Georgia Neurological Surgery, Athens

Context: Computerized neuropsychological testing is commonly used in the assessment and management of sport-related concussion. Even though computerized testing is widespread, psychometric evidence for test-retest reliability is somewhat limited. Additional evidence for test-retest reliability is needed to optimize clinical decision making after concussion.

Objective: To document test-retest reliability for a commercially available computerized neuropsychological test battery (ImPACT) using 2 different clinically relevant time intervals.

Design: Cross-sectional study.

Setting: Two research laboratories.

Patients or Other Participants: Group 1 (n = 46) consisted of 25 men and 21 women (age = 22.4 ± 1.89 years). Group 2 (n = 45) consisted of 17 men and 28 women (age = 20.9 ± 1.72 years).

Intervention(s): Both groups completed ImPACT forms 1, 2, and 3, which were delivered sequentially either at 1-week intervals (group 1) or at baseline, day 45, and day 50 (group 2). Group 2 also completed the Green Word Memory Test (WMT) as a measure of effort.

Main Outcome Measures: Intraclass correlation coefficients (ICCs) were calculated for the composite scores of ImPACT between time points. Repeated-measures analysis of variance was used to evaluate changes in ImPACT and WMT results over time.

Results: The ICC values for group 1 ranged from 0.26 to 0.88 for the 4 ImPACT composite scores. The ICC values for group 2 ranged from 0.37 to 0.76. In group 1, ImPACT classified 37.0% and 46.0% of healthy participants as impaired at time points 2 and 3, respectively. In group 2, ImPACT classified 22.2% and 28.9% of healthy participants as impaired at time points 2 and 3, respectively.

Conclusions: We found variable test-retest reliability for ImPACT metrics. Visual motor speed and reaction time demonstrated greater reliability than verbal and visual memory. Our current data support a multifaceted approach to concussion assessment using clinical examinations, symptom reports, cognitive testing, and balance assessment.

Key Words:  intraclass correlation, concussions, mild traumatic brain injuries, neuropsychological 
testing, athletes

FULL study here

Address correspondence to Jacob Resch, PhD, ATC, University of Texas at Arlington, Box 19259, 113 Maverick Activities Center, Arlington, TX 76102. Address e-mail to resch@uta.edu.