Transcranial Direct Current Stimulation (tDCS)

The perceived ease of use of tDCS will be assessed using a subscore of the Technology Acceptance Model (TAM) questionnaire.

Participants will rate the device on a 5-point Likert scale (1 = Extremely Difficult, 5 = Extremely Easy) across seven questions. The total score will range from 7 (extremely difficult) to 35 (extremely easy), with higher scores indicating greater ease of use. Questions will assess: (1) ease of use, (2) sponge preparation, (3) attaching sponges, (4) starting/stopping therapy, (5) charging, (6) mobility while wearing the device, and (7) task completion during use.

The TAM subscore will be calculated by summing individual scores, with median values reported as an overall measure of ease of use.

The perceived usefulness of tDCS was assessed using a subscore of the Technology Acceptance Model (TAM) questionnaire.

Participants rated the usefulness of the device on a 5-point scale: 1 = Decreased Significantly, 2 = Decreased, 3 = Neutral, 4 = Increased, 5 = Increased Significantly. Six questions were used to assess overall perceived usefulness, focusing on benefits related to mental activity, energy levels, memory, attention, concentration, and alertness. The total score ranged from 6 (not at all useful) to 30 (highly useful), with higher values indicating greater perceived usefulness.

The TAM subscore for perceived usefulness was calculated by summing the individual component scores and determining the median value across participants.

The attitude toward use of the tDCS device was assessed using a subscale of the Technology Acceptance Model (TAM) questionnaire.

Participants will rate their attitude toward use on a 5-point Likert scale (1 = Extremely Difficult, 5 = Extremely Easy) based on two questions: (1) I would continue this therapy after completing the study, and (2) I would recommend this therapy to friends/family. The total score ranges from 2 (extremely difficult) to 10 (extremely easy), with higher scores reflecting a more positive attitude toward the device.

The TAM subscore is calculated by summing individual component scores, with median values reported, providing an overall measure of perceived ease of use and intention to use.

A digit memory test assesses short-term and working memory by having participants recall sequences of numbers presented in either the same order (forward) or reverse order (backward). Scores are based on the longest sequence accurately recalled, with higher scores indicating better memory capacity. This test is commonly used in cognitive evaluations and research to monitor memory function and detect impairments. Percentage of changes in the total score were assessed at the 4-week mark compared to baseline. The range will be -100% to +100%. A score of zero indicates no change in memory performance, positive values reflect improvement, and negative values indicate a decline in memory performance.

The average scores for all analyzed participants were reported.

The Hopkins Verbal Learning Test-Revised (HVLT-R) is a brief neuropsychological tool assessing verbal learning and memory. Participants recall 12 words across three trials (max score: 36) and a delayed recall trial (max score: 12), yielding a total score of 48, with higher scores indicating better memory.

Percentage changes in cumulative scores from baseline to week 4 were evaluated, with averages reported across all participants who completed the study. Scores range from -100% to +100%, where positive values indicate improvement, zero denotes no change, and negative values reflect a decline.

The Trail Making Task (TMT) is a neuropsychological test used to assess attention, processing speed, and task-switching. It consists of two parts: Part A (connecting numbered circles sequentially) and Part B (alternating between numbers and letters). Performance is measured in seconds (completion time) and errors, with shorter times and fewer mistakes indicating better cognitive function. This study reported changes in TMT completion times at week 4 compared to baseline for both parts. Negative values indicate improvement (reduction in completion time compared to baseline) in cognitive function.

Cognitive status was assessed using the Montreal Cognitive Assessment (MoCA), which provides a score ranging from 0 to 30. Changes in scores from baseline to week 4 were reported, with positive values indicating improvement and negative values reflecting deterioration.