TDCS Combined With CT In Opioid Use Disorder (OpiStim)

Iowa Gambling Task net score is the total score of the task (between -100 and 100) that generally assesses the decision making under ambiguity, but also assesses the decision making under risk at the later stages. Higher scores in the task represents better decision making and healthy people generally have scores above 8-10 in the task.

The Balloon Analogue Risk Task is the commonly used computerized measure of decision making under risk. Main outcome variable of the task is the Adjusted Number of Pumps which includes the mean number of pumps in the trials that not resulted with an explosion. Lower values mean lower impulsivity.

The stroop effect (Interference Time) consists of both the semantic and the response conflict. Response conflict (time in milliseconds) is obtained by subtracting the semantic conflict (time in milliseconds obtained in the second step of the protocol) from the stroop effect (time in milliseconds obtained in the first step of the protocol). Minimum time difference is 0 and maximum time difference is 100 milliseconds. Lower time differences indicate better performance and higher time differences indicate worse performance.

The Stop-Signal Task (SST) is a task requiring inhibition of a prepotent motor response. The SST requires participants to respond to a target stimulus as quickly and accurately as possible by pressing a button, but also to withhold their response when they hear an auditory signal. Thus, this task involves a competition between activating and inhibiting processes. The primary outcome variable is change in the stop signal reaction time (SSRT) for the task administered seconds to minutes before and seconds to minutes after stimulation. The theoretical minimum is zero seconds and there is no theoretical maximum. Higher SSRT scores reflect greater impulsivity.

Verbal fluency is a test that measure multiple domains of cognition such as executive functions and language functions. Phonemic Fluency assesses the number of words beginning with certain letters that participants can generate within 60 seconds, the semantic Fluency assesses the number of words within particular categories participants can generate within 60 seconds. Alternating fluency assesses the number of fruit-name pairs reported in a minute duration. Theoretical minimum is zero and there is no theoretical maximum . Lower scores indicate worse performance and higher scores indicate better performance.

The Digit Span test is a measure of verbal short-term/working memory. Subjects must recall all digits either in forward (digit span forward) or backward (digit span backward) order. Digit span forward total score: 0-10; higher score indicate better performance, digit span backwards total score: 0-10; higher score indicate better performance

Trail Making A Test is a widely used as a quick and easy to administer measure of attention. Lower reaction times indicate better performance and higher reaction times indicate worse performance. Minimum time is 10 milliseconds and maximum time is 150 milliseconds.

Trail Making B Test is a widely used as a quick and easy to administer measure of executive functions. Lower reaction times indicate better performance and higher reaction times indicate worse performance. Minimum time is 10 milliseconds and maximum time is 150 milliseconds.

Letter number is a test of working memory which involves ordering a series of up to 8 letters and numbers in which the numbers are repeated back first in order starting with the lowest number, then followed by the letters in alphabetical order. LNS consists of 10 items and each item has 3 trials rated as Incorrect (0) or Correct (1). The LNS total raw score (range 0 to 30) is auto-calculated by summing the 10 individual item scores (range 0 to 3 for each item). Higher number of correct items correlated to better performance and a negative change from baseline indicates worsening.