Continuous performance task

Continuous Performance Task (CPT) is a neuropsychological assessment tool used to measure an individual's sustained and selective attention and impulsivity. It is a task-oriented computerized assessment of attentional functions, particularly useful in diagnosing Attention Deficit Hyperactivity Disorder (ADHD), as well as other neurological and psychiatric conditions that affect attention span.

Overview

The Continuous Performance Task requires participants to respond or not respond to stimuli presented on a computer screen over a set period. The stimuli are usually letters or numbers, and the participant is instructed to press a button or key when a specific target stimulus appears, which requires continuous monitoring and quick reactions to the changing information.

Types of CPT

There are several variations of the CPT that focus on different aspects of attention and impulsivity, including:

• X-CPT: Where the participant must respond to a specific letter, such as "X," after a non-target letter.
• AX-CPT: Requires a response to the letter "X" only if it is preceded by the letter "A."
• Identical Pairs CPT: Participants respond to any number or letter that is identical to the one immediately preceding it.

Applications

CPT is widely used in clinical settings and research to evaluate attentional capacities in individuals, helping to diagnose conditions like ADHD, schizophrenia, and brain injuries. It is also used to monitor the effectiveness of treatment interventions for these conditions.

Administration

The task is typically administered on a computer, with the duration and complexity of the task varying depending on the specific version of the CPT being used. The administrator can adjust the task's parameters, such as the length of time, the inter-stimulus intervals, and the ratio of target to non-target stimuli, to suit the assessment's goals.

Scoring

Scoring of the CPT involves several metrics, including:

• Hit Rate: The percentage of correctly identified targets.
• False Alarms: The number of times a participant incorrectly identifies a non-target as a target.
• Reaction Time: The average time it takes for the participant to respond to targets.
• Variability: The consistency of the participant's reaction times over the course of the task.

Limitations

While the CPT is a valuable tool for assessing attentional functions, it is not without limitations. Factors such as the participant's motivation, understanding of the task, and physical condition can influence performance. Additionally, the CPT cannot definitively diagnose any condition on its own but should be used as part of a comprehensive assessment.

See Also

• Attention Deficit Hyperactivity Disorder
• Neuropsychological Test
• Psychological Assessment