Protocol - AX-Continuous Performance Test (AX-CPT)

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The AX-Continuous Performance Test (AX-CPT) is a computerized test, implemented in Eprime by the Cognitive Neuroscience Test Reliability and Clinical applications for Schizophrenia (CNTRACS) consortium, which evaluates goal maintenance in working memory. During AX-CPT, the subject views a series of cues and probe sequences (one at a time) and performs a button press indicating if the stimulus is the target or non-target. The four types of cue-probe combinations offered are AX, AY, BX, and BY, with AX being the only target (correct option). A total of 144 cue-probes are presented in four blocks of 36 with limited response windows. The majority of the cue-probes presented are AX, thus creating an expectancy for the subject to prepare a target response following a cue that is an A and to make a target response when a probe is an X.

Specific Instructions

The alternate (language-independent) task that uses a non-letter stimuli is the Dot Pattern Expectancy Task (DPX), also available at Cognitive Neuroscience Test Reliability and Clinical applications for Schizophrenia (CNTRACS).

There are a total of four neurocognitive assessments: Computerized Neurocognitive Battery (CNB) measures Global Cognitive Functioning, AX-Continuous Performance Test (AX-CPT) measures Context Processing, Relational and Item-Specific Encoding task (RiSE) measures Relational Encoding and Retrieval, and Auditory Continuous Performance Test (ACPT) battery measures Auditory Vigilance.

AX-CPT & RiSE can be run together and can be downloaded together.

AX-CPT can be combined with Task functional magnetic resonance imaging (fMRI) to assist in identifying specific neural circuits.


Limited Availability


Tasks can be downloaded for free from the Cognitive Neuroscience Test Reliability and Clinical applications for Schizophrenia (CNTRACS) website; once a Request form has been completed and submitted. Link to the Request form can be found here:


Copies of the tasks, written in Eprime, can be downloaded off of the CNTRACS website at the link below:


Personnel and Training Required

The interviewer must be trained to conduct personal interviews with individuals from the general population. The interviewer must be trained and found to be competent (i.e., tested by an expert) at the completion of personal interviews. The interviewer should be trained to prompt respondents further if a "don’t know" response is provided. Training by an experienced group in administering and analyzing the results is recommended.

Equipment Needs

The PhenX Working Group acknowledges these questions are administered in a computerized format and will require a laptop computer/handheld computer to administer this protocol. Eprime computer software is necessary to conduct this protocol.

Requirement CategoryRequired
Major equipment No
Specialized training No
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Performance-based task


Adolescent, Adult, Senior


Individuals 12 and older

Selection Rationale

Cognitive Neuroscience Test Reliability and Clinical applications for Schizophrenia (CNTRACS) tasks have been used for many years. The tasks have been well studied in CNTRACS and have good test/re-test reliability. The tasks are very easy to use and have standardized instructions and a high level of subject acceptability. CNTRACS contains psychology resources that can be used by individuals who are not psychologists.



Human Phenotype Ontology Memory impairment HP:0002354 HPO
Derived Variables


Process and Review

Not applicable.

Protocol Name from Source

Modified AX-Continuous Performance Test (AX-CPT)


MacDonald, A. W., III, Pogue-Geile, M. F., Johnson, M. K., &Carter, C. S. (2003). A specific deficit in context processing in the unaffected siblings of patients with schizophrenia. Archives of General Psychiatry, 60(1), 57-65. http://cntracs.ucdavis.edu/

General References

Gold, J. M., Barch, D. M., Carter, C. S., Dakin, S., Luck, S. J., MacDonald, A. W., III, Ragland, J. D., Ranganath, C., Kovacs, I., Silverstein, S. M., & Strauss, M. (2012). Clinical, functional, and intertask correlations of measures developed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia Consortium. Schizophrenia Bulletin, 38(1), 144-152. doi:10.1093/schbul/sbr142

Henderson, D., Poppe, A. B., Barch, D. M., Carter, C. S., Gold, J. M., Ragland, J. D., Silverstein, S. M., Strauss, M. E., & MacDonald, A. W., III. (2012). Optimization of a goal maintenance task for use in clinical applications. Schizophrenia Bulletin, 38(1), 104-113. doi:10.1093/schbul/sbr172

Sheffield, J. M., Gold, J. M., Strauss, M. E., Carter, C. S., MacDonald, A. W., III, Ragland, J. D., Silverstein, S. M., & Barch, D. M. (2014). Common and specific cognitive deficits in schizophrenia: relationships to function. Cognitive, Affective & Behavioral Neuroscience, 14(1), 161-174. doi:10.3758/s13415-013-0211-5

Strauss, M. E., McLouth, C. J., Barch, D. M., Carter, C. S., Gold, J. M., Luck, S. J., MacDonald, A. W., III, Ragland, J. D., Ranganath, C., Keane, B. P., & Silverstein, S. M. (2014). Temporal stability and moderating effects of age and sex on CNTRaCS task performance. Schizophrenia Bulletin, 40(4), 835-844. doi:10.1093/schbul/sbt089

Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX660201000000 Protocol 660201 - proprietary. Check DCW for more
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Early Psychosis Translational Research
Measure Name

Context Processing

Release Date

January 17, 2017


Computer-administered task that measures cognitive functions.


This measure assesses deficits in cognition-specifically, working memory and long-term memory.


Auditory Working Memory, AWM, Auditory Continuous Performance Test, ACPT, Continuous performance task, CPT, working memory, WM, AX-Continuous Performance Test, AX-CPT, Dot Pattern Expectancy Task, DPX, Schizophrenia, interference control, Cognitive Neuroscience Test Reliability and Clinical applications for Schizophrenia, CNTRACS, goal maintenance, early psychosis, psychometrics

Measure Protocols
Protocol ID Protocol Name
660201 AX-Continuous Performance Test (AX-CPT)

There are no publications listed for this protocol.