Immediate and Delayed Memory Test (IMTDMT)

Background

The Immediate and Delayed Memory Task (IMT/DMT) is a specialized, computerized continuous performance test that was developed by Donald M. Dougherty and colleagues in 1998 to support the systematic study of sustained attention, working memory, and rapid-response (motor) impulsivity in higher functioning clinical populations as well as control populations. It provides an alternative to the Continuous Performance Test (CPT).

During the test, participants watch a computer monitor display a rapid sequence of multi-digit numbers (typically 2 to 7 digits) and the basic task is to watch out for repeat numbers. The test is run under two different conditions that place different demands on working memory:
• Immediate Memory Task (IM): Whenever a number repeats the previous one exactly, press the response button.
• Delayed Memory Task (DMT): Each test number is followed by three identical distractor numbers (the same throughout the test, e.g. '12345'). Whenever a test number repeats a previous test number exactly (ignoring the distractors), press the response button. Note that the specific number used for the distractor numbers will never be used as a test number.

The Millisecond IMT/DMT task divides the task into a practice and test script that can be run sequentially via a batch script or independently from each other.

Task Procedure

The Practice IMT/DMT task explains the task and its various conditions (IMT vs. DMT) to the participants and provides two practice runs with 19 trials for each of the conditions (starting with the IMT trials). During the practice runs, all numbers are presented for 2000ms, followed by an interstimulus interval of 2000ms. Participants have the entire 4000ms to respond. Error feedback is provided for 100ms. During practice, participants encounter targets (repeated numbers) with p=60% probability and fillers (different numbers with at least two different digits) with p=40% probability.

The Test IMT/DMT task does not run any instructions. It immediately starts with a test block. By default settings, the test runs two rounds of IMT-DMT testing. Each of the four blocks runs 300 trials. Presentation durations are much faster than during the practice session: all numbers are presented for 500ms, followed by an interstimulus interval of 500ms. Participants have 1000ms to respond, measured from onset of the test number. No trial error feedback is provided during the test session. Test blocks run target numbers with p=33% probability and fillers (different numbers with at least two different digits) with p=34% probability. In addition, test block also run 'catch' numbers that differ from the targets by only 1 digit with p=33% probability. Each block concludes with a block performance screen and 30 seconds of rest.

What it Measures

The Immediate and Delayed Memory Task (IMT/DMT) measures sustained attention and memory.

Psychological Domains

• Working Memory: Ability to actively keep and update test numbers in working memory, despite possible distractors
• Sustained Attention: Ability to maintain focus on a continuous repetitive task over a long time.
• Inhibitory Control: Ability to withhold a response to non-target stimuli

Main Performance Metrics

• Omission Errors: Rate of missed targets (inattention) in DMT and IMT blocks
• Commission Errors: Rate of false alarms, or responses to non-targets (response inhibition) in DMT and IMT blocks
• Reaction Time: Speed of responses (processing speed, alertness) in DMT and IMT blocks

Psychiatric Conditions

Researchers frequently use the IMT/DMT to study psychiatric conditions, neurodevelopmental disorders, substance use vulnerabilities, and the behavioral impacts of pharmacological manipulations (such as medications or drugs of abuse) in conditions such as

• Alcohol Use Disorder (AUD)
• Stimulant and Opioid Users
• Attention-Deficit/Hyperactivity Disorder (ADHD)
• Conduct Disorder or Oppositional Defiant Disorder (ODD)
• Bipolar Disorder
• Borderline Personality Disorder (BPD)
• Schizophrenia
• Multiple Sclerosis (MS)

Test Variations

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Immediate and Delayed Memory Test (IMTDMT).

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Dougherty D M (1999). IMT/DMT Immediate Memory Task & Delayed Memory Task: A Research Tool for Studying Attention and Memory Processes (Version 1.3) (computer software manual). Neurobehavioral Research Laboratory and Clinic, University of Texas Health Science Center at Houston, Houston, TX.

Dougherty, D.M., Marsh, D.M., and Mathias, C.W. (2002). Immediate and Delayed Memory Tasks: A computerized measure of memory, attention, and impulsivity. Behavior Research Methods, Instruments, and Computers, 34, 391-398.

Dougherty, Donald M. ; Bjork, James M. ; Harper, R. Andrew ; Mathias, Charles W. ; Moeller, F. Gerard ; Marsh, Dawn M. (2003). Validation of the immediate and delayed memory tasks in hospitalized adolescents with disruptive behavior disorders. The Psychological Record, Fall, 2003, Vol.53(4), p.509(24).

Dougherty, Donald M. ; Mathias, Charles W. ; Tester, Melissa L. ; Marsh, Dawn M. (2004). Age at First Drink Relates to Behavioral Measures of Impulsivity: The Immediate and Delayed Memory Tasks. Alcoholism: Clinical and Experimental Research, 2004, Vol.28(3), pp.408-414.

Moeller, Frederick G ; Hasan, Khader M ; Steinberg, Joel L ; Kramer, Larry A ; Dougherty, Donald M ; Santos, Rafael M ; Valdes, Ignacio ; Swann, Alan C ; Barratt, Ernest S ; Narayana, Ponnada A (2005). Reduced anterior corpus callosum white matter integrity is related to increased impulsivity and reduced discriminability in cocaine-dependent subjects: diffusion tensor imaging. Neuropsychopharmacology, 30(3), 610-7.

Dougherty, Donald M. ; Marsh-Richard, Dawn M. ; Hatzis, Erin S. ; Nouvion, Sylvain O. ; Mathias, Charles W. (2008). A test of alcohol dose effects on multiple behavioral measures of impulsivity. Drug and Alcohol Dependence, 2008, Vol.96(1), pp.111-120.

Broos, Nienke ; Schmaal, Lianne ; Wiskerke, Joost ; Kostelijk, Lennard ; Lam, Thomas ; Stoop, Nicky ; Weierink, Lonneke ; Ham, Jannemieke ; de Geus, Eco J. C ; Schoffelmeer, Anton N. M ; van den Brink, Wim ; Veltman, Dick J ; de Vries, Taco J ; Pattij, Tommy ; Goudriaan, Anna E. (2012). The Relationship between Impulsive Choice and Impulsive Action: A Cross-Species Translational Study (Differentiating Aspects of Impulsivity). PLoS ONE, 7(5), p.e36781