Traumatic Brain Injury (TBI) often results in a wide array of cognitive impairments, which can significantly diminish quality of life for affected individuals. While traditional rehabilitation methods typically adopt a standardized approach, it's crucial to acknowledge the significant heterogeneity within the TBI patient population. Neglecting these variations reduces the likelihood of otherwise effective treatments being considered for widespread adoption. Emerging evidence highlights the potential of transcranial direct current stimulation (tDCS) as a promising adjunctive therapy. tDCS, a noninvasive and safe neuro-rehabilitative procedure, has shown efficacy when integrated with cognitive training across various neurological disorders, such as depression, post-stroke aphasia, and neurodegenerative conditions. This study aims to investigate the effectiveness of tDCS paired with behavioral therapy, particularly cognitive training, in improving cognition and executive function in chronic TBI patients. Additionally, tDCs targets in the current study will be tailored to each individual patient, recognizing the patient's unique needs and circumstances
Objective: This pilot study (targeting a sample of 10 TBI patients) aims to investigate whether combining cognitive training with anodal tDCS can enhance cognitive function more effectively compared to cognitive training alone in individuals with chronic TBI. The target for tDCS application will be the left dorsolateral prefrontal cortex (DLPFC), thought to be the area associated with executive impairment in TBI patients. Study Design: Each participant will undergo an initial neuropsychological evaluation and Functional magnetic resonance imaging (fMRI). Following the preliminary evaluation, participants will undergo either tDCS or sham stimulation for 3 weeks, with follow-up assessments immediately after and 2 months later, to measure cognitive training progress. After the 2-month follow-up, participants will undergo another 3 weeks of cognitive training with either sham or tDCS, based on the participant's condition in phase 1. Post-training, there will be additional follow-ups immediately after and 2 months later.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
20
Combination Product: Active tDCS and cognitive training intervention. Participants will receive cognitive training paired with active tDCS for 3 weeks, followed by follow-up sessions immediately after and 2 months later, during which the patient's performance on the cognitive training exercises and executive functions will be assessed. Cognitive training exercises have been drawn from a computer-aided cognitive training program (BrainHQ). For the active tDCS, stimulation will be delivered by a battery-driven constant current stimulator. The electrical current will be administered to the left DLPFC at an intensity of 2 milliamperes (mA) (estimated current density 0.04 mA/cm2; estimated total charge 0.048 Coulombs/cm2) in a ramp-like fashion for a maximum of 20 minutes.
Combination Product: Sham tDCS and cognitive training intervention Participants will receive cognitive training paired with sham tDCS for 3 weeks, followed follow-up sessions immediately after and 2 months later, during which the patient's performance on the cognitive training exercises and executive functions will be assessed. Cognitive training exercises have been drawn from a computer-aided cognitive training program (BrainHQ). For the sham tDCS, electrodes will be placed in the same area as in the active tDCS condition, but current will be administered in a ramp-like fashion but after the ramping the intensity will drop to 0 mA. Current under the Sham condition will last for a maximum of 30 seconds.
Change in Selective attention and cognitive flexibility as assessed by the Attention Network Task (ANT)
This will be measured using the Attention Network Task (ANT). An efficiency score for executive attention is derived by comparing scores on trials with congruent flankers to trials with incongruent flankers. Subjects will tend to be slower and less accurate for incongruent trials, the size of the difference indicates the extent to which an individual can supress conflicting response tendencies. A larger difference between congruent and incongruent trials score indicates a lower executive efficiency (score range: 0-96)..
Time frame: Before intervention, immediately after intervention
Change in attention and task switching as assessed by the N-Back score
The N-back task is a well-established task that assesses working memory and working memory capacity. Participants are presented with words in sequence and instructed to reply whether the current word matches the one presented 2 words ago (2-back). Scoring will be based on the total number of correct responses (hit rate) minus the number of incorrect responses (false alarm rate), where a greater score is better (score range: 0-80).
Time frame: Before intervention, immediately after intervention
Change in Self-Ordered Pointing Task (SOPT)
The SOPT is a test used to assess executive functioning. In this task, participants are shown a series of pages, each displaying the same set of abstract images arranged in a random order. On each page, the participant must point to one image, ensuring not to select the same image more than once across the entire series. A correct response involves selecting a previously un-chosen image, while an error is recorded when a participant selects an image already chosen on a previous page. Performance will be measured by total number of errors measured out of the total number of possible responses, with a higher error count indicating greater impairment.
Time frame: Before intervention, immediately after intervention
Change in attention and task switching as assessed by the Trail Making Task
This will be measured using Trail Making Task and N-Back scores. The Trail Making Test is scored by time. Participants are allowed 0 - 300 seconds to complete the task. Less time needed to complete the task is indicative of better task-switching.
Time frame: Before intervention, immediately after intervention
Change in Digit Span Forward
Digit span forward involves the recall of a series of single digits (sets of 1-8 digits) in the same order the digits were presented. Scoring is based on the number of digits or blocks shown in a trial (i.e. 1,7 is 2 digits). There are two trials for each span, if both trials are correct the score is a whole number (i.e. 2). If one trial is incorrect in a span, subtract 0.5 from that tier (i.e. 1.5). A higher number is considered better. (Score range for forward tasks: 0-9)
Time frame: Before intervention, immediately after intervention
Change in Digit Span Backward
This will be measured using Digit Span Backward for verbal working memory and spatial span Backward for spatial working memory. The digit span backward is a well-established task that assesses rote immediate verbal memory and working memory. Participants are presented with a series of digits and are instructed to repeat the digits in the reverse order. Scoring is based on the number of digits shown in a trial (i.e. 1,7 is 2 digits). There are two trials for each span, if both trials are correct the score is a whole number (i.e. 2). If one trial is incorrect in a span, subtract 0.5 from that tier (i.e. 1.5). A higher number is considered better. (Score range for backwards tasks: 0-8)
Time frame: Before intervention, immediately after intervention
Change in attention and inhibition as assessed by the Simon Task
This will be measured using Simon test scores. The Simon task assesses an individual's ability to flexibly shift the perceptual focus in response to changing demands, particularly the participant's capacity to inhibit a habitual response in favor of an unconventional one. Performance on the Simon task is typically scored based on measures such as reaction time and accuracy. Increased reaction times and higher error rates on incongruent trials are indicative of greater difficulty in inhibiting the interference caused by the word's meaning, reflecting decreased cognitive flexibility and inhibition abilities (accuracy score range: 0-120).
Time frame: Before intervention, immediately after intervention
Change in Spatial Span Forward
Spatial span forward involves the recall of a series of of positions on a board (sets of 1-9) in the same order the digits were presented. Scoring is based on the number of blocks shown in a trial (i.e. 1,7 is 2 blocks). There are two trials for each span, if both trials are correct the score is a whole number (i.e. 2). If one trial is incorrect in a span, subtract 0.5 from that tier (i.e. 1.5). A higher number is considered better. (Score range for forward tasks: 0-9)
Time frame: Before intervention, immediately after intervention
Change in Spatial Span Backward
This will be measured using Spatial Span Backward. Participants are presented with a series of block positions and are instructed to repeat the positions in the reverse order. Scoring is based on the number of blocks shown in a trial (i.e. 1,7 is 2 blocks). There are two trials for each span, if both trials are correct the score is a whole number (i.e. 2). If one trial is incorrect in a span, subtract 0.5 from that tier (i.e. 1.5). A higher number is considered better. (Score range for backwards tasks: 0-8)
Time frame: Before intervention, immediately after intervention
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