Using two treatment arms, the study will examine improvement of verbal retrieval and other cognitive deficits associated with remote traumatic brain injury by comparing (1) 1 milliamp transcranial direct current stimulation (tDCS) active treatment applied to presupplementary motor area for 20 minutes over 10 sessions to (2) sham tDCS following the same schedule. Additionally, after completing the initial active or sham treatment and 2-month follow-up testing sessions, participants will be invited back for newly assigned treatment conditions, 20 minutes over 10 sessions and will be re-evaluated at 2-months follow-up testing sessions.~Civilians with histories of traumatic brain injuries and observed cognitive deficits will be randomly assigned to one of the two treatment arms (and re-assigned for the second round of intervention, as described above). Primary outcome verbal retrieval measures, secondary neuropsychological and electroencephalography (EEG) measures, and prescreening assessments for study concussion history and contraindications for treatment will be collected prior to being assigned to a treatment arm (i.e., baseline). Magnetic resonance imaging of the brain will be obtained only at the baseline assessment.~Primary outcome verbal retrieval measures and secondary neuropsychological and electroencephalography (EEG) measures will be collected after treatment session 10 and one time following treatment competition (i.e., 2-months). For participants who complete the second round of intervention, primary outcome verbal memory measures and secondary neuropsychological and electroencephalography (EEG) measures will be collected again after treatment session 10 and one time following competition of the second treatment (i.e., 2-months).
The purpose of the study is to test whether low level electric stimulation, called transcranial Direct Current Stimulation (tDCS), on the part of the brain (i.e., pre-supplementary motor area) thought to aid in memory will improve verbal retrieval in civilian (non-military, non-veteran) participants with histories of traumatic brain injuries. The primary outcome measures are neuropsychological assessments of verbal retrieval, and the secondary measures are neuropsychological assessments of other cognitive abilities and electroencephalography (EEG) measures. Additionally, the study will examine the degree to which baseline assessments of cognition, concussion history, structural brain imaging, and EEG predict responses to treatment over time, both on assessments administered within the intervention period and at follow-up.