Identification Test (IDT)

Background

The Identification Task (IDT), part of the Cogstate Brief Battery (CBB), is a computerized simple choice reaction time test to measure visual attention and decision-making speed ('choice reaction time'). The task is described in the 2009 article published by Paul Maruff and colleagues in which they studied the validity of the CBB. In addition to the IDT, the Millisecond library also provides implementations of the CBB's 'Detection Task', 'The One-Card Learning Task' and the 'NBack Task - Touchscreen' (aka the 'One-Back Task' of the CBB). All Millisecond implementations are based on the publicly available information provided (e.g. Maruff et al, 2009). All tasks of the CBB use a similar card-game user interface and are designed to run on touchscreens. Nevertheless, Millisecond's implementations will adapt to mouse-use on non-touchscreens.

Task Procedure

Participants learn about the task in a brief tutorial that includes a short practice. In addition, the entire tutorial can be repeated as often as necessary before starting the test phase.

The interface of the IDT consists of a 'deck' of red and black joker cards presented in the center of the screen, a 'YES' and a 'NO' response button as well as a circle-shaped home button on which the response finger rests until a joker card is turned over. The home button is implemented to ensure that response fingers are roughly equally distanced from the response buttons for each trial. Once a joker card is turned over, participants are asked to press the 'YES' response button for red jokers or the 'NO' response button for black jokers as fast as possible. After the response is made, a card-animation is started that 'returns' the card back to the stack.

By default, the task runs 1 test block with 30 trials, using the same joker card for every trial. Should researchers run the script with more than one block, the script provides a brief, self-paced rest trial in between test blocks. During each trial, a joker card is turned over randomly with a 500-5000ms delay after the home button is pressed. A reminder to press the home button is presented after 2 seconds. Pressing the home button starts the random delay period. If the home button is released during this period for more than 250ms (this period is implemented to account for possible, short tremors), the trial is terminated, participants are asked to return to the home button, and a new random delay is selected for the interrupted trial. After one of the response buttons has been successfully pressed, the response finger can return to the home button immediately. In this case, the next trial starts immediately after the 1-second card animation has concluded.

What it Measures

The Identification Task (IDT) is a measure visual attention and decision-making speed

Psychological domains

• Processing Speed: Speed with which stimuli get processed and responded to
• Decision Making: Choosing the correct response from multiple alternatives.
• Selective Attention: Ability to discriminate between different stimuli and select the correct one
• Sustained Attention: Maintaining consistent focus on a monotonous task over an extended period of time

Main Performance Metrics

• Response Times: mean (raw and log10 transformed) and median correct response times (in ms) to stimulus presentation; main measure of decision-making speed
• Response Times Variability: response time variability of correct responses across the task (raw standard deviation and log10 transformed standard deviation)
• LISAS: measure of error-corrected processing speed

Psychiatric Conditions

The following patient groups are routinely assessed with the IDT

• Mild Cognitive Impairment (MCI)
• Alzheimer’s Disease (AD)
• Parkinson’s Disease (PD)
• Huntington’s Disease (HD)
• Multiple Sclerosis (MS)
• Stroke Patients
• Traumatic Brain Injury (TBI)
• Schizophrenia
• Attention Deficit Hyperactivity Disorder (ADHD)

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Identification Test (IDT).

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Maruff P, Thomas E, Cysique L, Brew B, Collie A, Snyder P, Pietrzak RH. Validity of the CogState brief battery: relationship to standardized tests and sensitivity to cognitive impairment in mild traumatic brain injury, schizophrenia, and AIDS dementia complex. Arch Clin Neuropsychol. 2009 Mar;24(2):165-78