Executive Function Training in Chronic Traumatic Brain Injury Patients: Study Protocol
Authors: Krawczyk Daniel , Han Kihwan , Martinez David , Rakic Jelena , Kmiecik Matthew , Chang Zhengsi , Nguyen Linda , Lundie Michael , Cole Richard , Nagele Marielle , Didehbani Nyaz 
Published: February 2019

Abstract
Background: Some individuals who sustain traumatic brain injuries (TBIs) continue to experience significant cognitive impairments chronically (months-to-years post-injury). Many tests of executive function are insensitive to these executive function impairments, as such impairments may only appear during complex daily life conditions. Daily life often requires us to divide our attention and focus on abstract goals. In the current study, we compare the effects of two one-month electronic cognitive rehabilitation programs for individuals with chronic TBI. The active program (Expedition: Strategic Advantage) focuses on improving goal-directed executive functions including working memory, planning, long-term memory, and inhibitory control by challenging participants to accomplish life-like cognitive simulations. The challenge level of the simulations increase in accordance with participant achievement. The control intervention (Expedition: Informational Advantage) is identical to the active; however, the cognitive demand level is capped preventing participants from advancing beyond a set level. We will evaluate these interventions with a military veteran TBI population.
Methods: One hundred individuals will be enrolled in this double-blinded clinical trial (all participants and testers are blinded to condition). Each individual will be randomly assigned to one of two interventions. The primary anticipated outcomes are improvement of daily life cognitive function skills and daily life functions. These are measured by a daily life performance task, which tests cognitive skills, and a survey that evaluates daily life functions. Secondary outcomes are also predicted to include improvements in working memory, attention, planning, and inhibitory control as measured by a neuropsychological test battery. Lastly, neuroimaging measures will be used to evaluate changes in brain networks supporting cognition pre-intervention and post-intervention.
Discussion: We will test whether electronically delivered cognitive rehabilitation aimed at improving daily life functional skills will provide cognitive and daily life functional improvements for individuals in the chronic phase of TBI recovery (greater than three months post-injury). We aim to better understand the cognitive processes involved in recovery and the characteristics of individuals most likely to benefit. This study will also address the potential to observe generalizability, or transfer, from a software-based cognitive training tool toward daily life improvement.
Trial Registration: ClinicalTrials.gov Identifier: NCT03704116 (retrospectively registered) https://clinicaltrials.gov/ct2/show/NCT03704116?term=tbi+krawczyk&rank=1
Keywords: Cognitive rehabilitation, traumatic brain injury, executive functions, daily life functions, memory, attention, planning.
Support: Joint Warfighter Program; U. S. Dept. of Defense W81XWH-16-1-0053