The main goal of this study is to improve dysexecutive symptoms (e.g., sustained attention, processing speed) in patients exhibiting post-acute sequelae of COVID-19 (PASC) through home-based transcranial direct current stimulation (tDCS), a noninvasive method that uses low intensity electric currents delivered to the brain through stimulation electrodes on the scalp.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
31
2 mA of anodal stimulation will be applied to the left prefrontal cortex over the F3 electrode based on the International 10-10 EEG system.
Sham stimulation will be applied to the left prefrontal cortex over the F3 electrode.
Massachusetts General Hospital
Charlestown, Massachusetts, United States
Inhibitory Control
Performance during the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention). The performance is quantified as the ratio of correct responses to all responses. For example, a score of 0.70 indicates that the participant responded to 70% of the trials correctly.
Time frame: Baseline
Inhibitory Control
Performance during the incongruent trials of the Eriksen Flanker Task were assessed approximately approximately 4-weeks after baseline. The performance is quantified as the ratio of correct responses to all responses. For example, a score of 0.70 indicates that the participant responded to 70% of the trials correctly.
Time frame: Posttreatment (1 month follow-up)
Processing Speed
Reaction time during the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention)
Time frame: Baseline
Processing Speed
Reaction time during the incongruent trials of the Eriksen Flanker Task were assessed approximately 4-weeks after baseline.
Time frame: Posttreatment (1 month follow-up)
EEG P300 Event-related Potential
EEG P300 amplitudes time-locked to the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention). EEG event-related potential amplitudes (measured in microvolts, µV) were normalized across EEG channels using a scaling procedure, in which each channel was rescaled to reduce variability in signal magnitude among electrodes while preserving temporal and spectral characteristics. While larger P300 amplitudes are typically associated with better cognitive outcomes, this can vary among study populations.
Time frame: Baseline
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EEG P300 Event-related Potential
EEG P300 amplitudes time-locked to the incongruent trials of the Eriksen Flanker Task were assessed approximately 4-weeks after baseline. EEG event-related potential amplitudes (measured in microvolts, µV) were normalized across EEG channels using a scaling procedure, in which each channel was rescaled to reduce variability in signal magnitude among electrodes while preserving temporal and spectral characteristics. While larger P300 amplitudes are typically associated with better cognitive outcomes, this can vary among study populations.
Time frame: Posttreatment (1 month follow-up)
Cognitive Flexibility
Performance on the NIH Toolbox Dimensional Change Card Sort Test, a computerized measure of executive function assessing cognitive flexibility, attention, and set-shifting. Participants match target stimuli based on changing rules (e.g., color or shape). Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better cognitive flexibility and executive control.
Time frame: Baseline
Cognitive Flexibility
Performance on the NIH Toolbox Dimensional Change Card Sort Test, a computerized measure of executive function assessing cognitive flexibility, attention, and set-shifting. Participants match target stimuli based on changing rules (e.g., color or shape). Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better cognitive flexibility and executive control.
Time frame: Posttreatment (1 month follow-up)
Working Memory
Performance on the NIH Toolbox List Sorting Working Memory Test, which assesses working memory capacity through sequencing and recall of visually and verbally presented stimuli in size order. The task requires temporary storage and manipulation of information across increasing list lengths. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better working memory performance.
Time frame: Baseline
Working Memory
Performance on the NIH Toolbox List Sorting Working Memory Test, which assesses working memory capacity through sequencing and recall of visually and verbally presented stimuli in size order. The task requires temporary storage and manipulation of information across increasing list lengths. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better working memory performance.
Time frame: Posttreatment (1 month follow-up)
Episodic Memory
Performance on the NIH Toolbox Picture Sequence Memory Test, a measure of episodic memory in which participants reproduce the order of a sequence of visually presented pictures. The task assesses the ability to encode, store, and retrieve sequential information. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better episodic memory function.
Time frame: Baseline
Episodic Memory
Performance on the NIH Toolbox Picture Sequence Memory Test, a measure of episodic memory in which participants reproduce the order of a sequence of visually presented pictures. The task assesses the ability to encode, store, and retrieve sequential information. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better episodic memory function.
Time frame: Posttreatment (1 month follow-up)