Doctor of Philosophy
Health and Rehabilitation Sciences
Dr. Joy MacDermid
Concussions are one of the most complex conditions to manage in sport medicine due to the individualized clinical presentation caused by the complex neurometabolic cascade that occurs. The identification, assessment and management of concussion requires clinicians to employ a multifaceted approach including the subjective disclosure of symptoms by patents. In order to aid in this, symptom checklists are commonly used as they provide a standardized method for collecting the severity of concussion symptoms. One of the most common symptom checklists is the 5th Sport Concussion Assessment Tool (SCAT5) symptom evaluation which is available in an adult and pediatric version. In order to better understand the psychometric and measurement properties of both versions of the SCAT5 multiple studies were conducted. Both versions of the SCAT5 were analyzed using Rasch analysis to determine the reliability and construct validity of the tools, the items that comprise the adult SCAT5 were examined using a qualitative survey to investigate how individuals interpret the underlying meaning of the symptoms and using a clinical-anchor approach the responsiveness and minimal clinically important difference (MCID) for all of the items, total number of symptoms endorsed and total symptom score for both versions were estimated. Both the adult and child SCAT5 were found to be reliable but a poor fit to the Rasch model due to the multidimensionality and redundancy within the items and the presence of response dependency between multiple pairs of items. Through an examination of the themes identified form the qualitative survey, 6 items that comprise the SCAT5 were being interpreted in a manor inconsistent with the original wording of the item. Finally, MCID estimates and measures of responsiveness were calculated and all of the MCID estimates for the adult SCAT5 were found to be significant however the child SCAT5 only had 12 of the items from the child section and 15 items from the adult section that were significant. Overall, both tools were found to have serious psychometric issues and require further refinement using a systematic test development methodology in order to guarantee the validity, reliably and clinical utility of the tools.
Summary for Lay Audience
The identification, assessment and management of concussions are a complicated task requiring health care professions to use traditional clinical techniques combined with checklists of concussion specific symptoms that help patients disclose the presence and severity of symptoms. The most commonly used symptom checklists is the 5th Sport Concussion Assessment Tool (SCAT5) symptom evaluation which is available in an adult and child version. In order to guarantee that the tool is providing reliable results and is actually measuring concussions symptoms the measurement properties of the tool needs to be evaluated. In order to evaluate how reliable and accurate the two versions of the SCAT5 symptom evaluation are a technique called Rasch analysis is used which compares various properties of the tool against a statistical model called the Rasch model. Additionally, it is important to understand how patients interpret the meanings of symptoms to ensure consistency and this can be accomplished by asking individuals to describe how they interpret each item using their own words. As clinicians rely on the results of SCAT5 symptom evaluation to track how patients are recovering it is important to understand how changes in the symptom scores reflect changes in the health status and the minimal clinically important difference is one method that can be used to understand this between. The results of the Rasch analysis revealed that both versions of the SCAT5 are reliable tools but were poor fits to the Rasch model because they were not measuring just concussion symptoms and multiple items were found to be overlapping and measuring the same trait. It was also discovered that 6 of the items on the adult SCAT5 were being interpreted differently then how the items are presented resulting in inconsistent interpretations. Finally, estimates of what is considered a clinically important change in responses for all of the items from both versions of the SCAT5 were calculated providing valuable information for health care providers to use when interpreting the results of the symptom checklists. Overall, both versions of the SCAT5 had serious measurement issues which require them to be redeveloped in order to guarantee accuracy and reliability.
Robinson, Michael, "Evaluation of the Psychometric and Measurement Properties of the SCAT5 and Child SCAT5" (2019). Electronic Thesis and Dissertation Repository. 6687.
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