Treatment of Verbal Retrieval Deficits in Mild Traumatic Brain Injury with High Definition Transcranial Direct Current Stimulation
Abstract
A debilitating and common cognitive symptom in those with combat related traumatic brain injury (TBI) is the inability to retrieve words when needed. This inability to retrieve words affects one’s conversations, ability to fluidly exchange information verbally, and retrieving information from memory. Our group has studied the ability to retrieve words using functional neuroimaging (e.g., fMRI) and electroencephalography (EEG), and we have discovered patterns of brain activity that are important for verbal retrieval. We have also found abnormal patterns of brain activity in patients who have problems retrieving words as a consequence of multiple conditions, including TBI. We have used our observations of patterns of brain activity to design a noninvasive, non-pharmacological treatment for those with word retrieval deficits that uses High-Definition transcranial Direct Current Stimulation (HD tDCS). We use HD tDCS to deliver low levels of painless and safe electrical stimulation to specific regions of the head to stimulate the brain regions underlying that electrode location. This stimulation is delivered from electrodes in a cap that is placed on the subject’s head, which safely and painlessly delivers the stimulation. In this study, we plan to study combat veterans who have suffered TBI and who have word retrieval deficits to determine whether delivery of HD tDCS over specific brain regions will improve performance in verbal retrieval-related tasks. We will administer pre-treatment tests of verbal retrieval measures (assessing finding words, naming of objects, memory of the names of items in a list), as well as recording brain electrical activity from the scalp using EEG. This EEG will record both resting brain electrical activity and activity associated with performing a task related to selecting target objects. We will then administer 15 sessions of HD tDCS in approximately 40 Veterans. To evaluate placebo and retest effects, we will have 40 Veterans go through the same procedures, except while they will have the cap placed on their head, the stimulation will not be turned on (called the sham condition). As there is nothing a person feels when the current is on, these subjects will not know that they are receiving the current or not. We will then compare performance between the “active” group receiving the HD tDCS and the sham group by performing the same tests of verbal retrieval that we performed prior to the treatment several times up to 3 months after the last treatment session was given. This will allow for assessing whether the HD tDCS treatment had a significant effect on performing verbal retrieval tasks and to determine whether there are changes in patterns of brain electrical activity to account for how this treatment worked. In addition, we will take the subjects pretreatment performance on the verbal retrieval tests and their concussion history and compare those measures to a subject’s responses 3 months after completion of treatment to see whether we can predict who will have the best response to HD tDCS treatment and what may be the optimal number of treatment sessions for an individual subject to get an effective improvement in verbal retrieval. At the conclusion of this study, the effectiveness of HD tDCS for improving verbal retrieval deficits will be established, and we will determine whether this is a useful treatment modality that significantly and functionally changes not only the performance on neuropsychological tests, but also affects a person’s day-to-day functions. We predict that the treatment will improve a patient’s ability to produce their words fluently in a conversation and remember the words that they want to say, leading to improved skills in both social and work situations. This treatment has the added advantage of having few if any known side effects such as an individual might experience when taking medicine. The system used to deliver these electrical pulses is
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010846
Entities
People
- John Hart
Organizations
- United States Army
- University of Texas at Dallas