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Age Suppresses the Association Between Traumatic Brain Injury Severity and Functional Outcomes: A Study Using the
Laraine Winter1, Helene Moriarty, Keith M Robinson
1Author Affiliations: M. Louise Fitzpatrick College of Nursing (Drs Winter and Whitehouse), Villanova University, Villanova, Pennsylvania; Research Service (Dr Winter, Dr Moriarty, and Ms Schmidt), Nursing Service (Dr Moriarty), Physical Medicine and Rehabilitation/Rehabilitation Medicine Service (Dr Robinson and Dr Swanson), Center for Neurotrauma, Neurodegeneration and Restoration (Dr Swanson), Corporal Michael J. Crescenz Veterans Affairs Medical Center, Department of Physical Medicine and Rehabilitation (Dr Robinson and Dr Swanson), Perelman School of Medicine, University of Pennsylvania, and Division of Biostatistics, Department of Pharmacology, Physiology, and Cancer Biology (Dr Leiby), Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania.
Age at injury significantly impacts traumatic brain injury (TBI) recovery predictions. This study reveals age acts as a suppressor variable, masking the true relationship between TBI severity and long-term functional outcomes.
Area of Science:
- Neuroscience
- Rehabilitation Medicine
- Biostatistics
Background:
- Predicting recovery from traumatic brain injury (TBI) is challenging.
- TBI severity often shows weak predictive validity for functional outcomes.
- Suppression effect, where a third variable masks a true association, is a potential explanation.
Purpose of the Study:
- To investigate age at injury as a suppressor variable.
- To examine the predictive chain between TBI severity and functional disability up to 10 years post-TBI.
Main Methods:
- Utilized data from the 2020 NDILRR Model Systems National Dataset.
- Employed successive cross-sectional multiple regression analyses.
- Operationalized TBI severity by post-traumatic amnesia duration and functioning via the Glasgow Outcomes Scale-Extended (GOS-E).
Main Results:
- Inclusion of age at injury in regression models significantly strengthened the association between TBI severity and functioning.
- This effect was observed up to 10 years post-TBI.
Conclusions:
- Age at injury functions as a suppressor variable.
- It masks the true impact of injury severity on long-term functional outcomes.
- Further research should identify mediators of this suppression for TBI rehabilitation.
