CPT & ADHD

Unlike many health conditions where bloodwork or a simple screening device can produce an immediate diagnosis, Attention Deficit Hyperactivity Disorder (ADHD) can be more difficult to pinpoint. ADHD is known for its primary symptoms of inattentiveness, impulsivity, hyperactivity, and limitations on executive functioning and organization. However, reaching a definitive diagnosis can take time and effort. One test used by professionals, the Conners' Continuous Performance Test (CPT), has achieved some success in identifying individuals with ADHD.

Overview of ADHD Diagnosis

• The CPT is a computer-based test for ADHD.

  Many doctors diagnose ADHD with the use of subjective tools, such as questionnaires filled out by family members, teachers or employers, and caretakers describing their observations of the patient's behavior and symptoms. The doctors use the responses and compare them to diagnostic criteria for ADHD.

  Clinicians and researchers seeking a less subjective method for diagnosing ADHD developed objective measures, including the CPT. The CPT requires the patient to sit at a computer terminal and press keys on the keyboard in response to visual images or stimuli that appear on the screen. The test lasts approximately 15 to 20 minutes. Scorers calculate the rate of missed cues and erroneous responses. Individuals with ADHD tend to make more errors on the test than people who do not have the condition.

Research Results

• Some studies provide encouraging results affirming the effectiveness of CPT.

  In research published in the October 1995 issue of "Child Neuropsychology," the CPT was found to have a 72 percent accuracy rate for identifying patients with ADHD in comparisons with normal controls, and a 66 percent accuracy rate in comparisons with non-ADHD control subjects. However, the researchers noted that "average" performance did not ensure that the patient did not have ADHD.

  Another study, published by a team of Duke University researchers in the "Journal of Abnormal Child Psychology," found that patients who had already been identified as having ADHD through subjective measures consistently performed poorly on the CPT.

  These studies suggest the test may be useful as a diagnostic tool.

Another Research Perspective

• Other studies find that subjective analysis is more effective in diagnosing ADHD.

  An article featured in the November 2005 issue of "Psychiatry MMC" concluded that ADHD requires a clinical diagnosis, despite the results of studies evaluating the use of CPT and other objective tests for the condition. The authors of the study, from North Carolina Neuropsychiatry Clinics, pointed out that computerized tests are quicker and cheaper than observation and analysis conducted over an extended period, but that time is needed to make an accurate and complete assessment.

Practice Guidelines Do Not Recommend CPT

• The American Academy of Pediatrics places little emphasis on CPT in its ADHD guidelines.

  The American Academy of Pediatric's Clinical Practice Guidelines for ADHD do not include CPT or other computerized tests in its recommended protocol. In fact, they state that CPT and other tests "are not routinely indicated" for ADHD diagnosis.

Conclusion

• Overall, using a variety of methods may provide the most accurate diagnosis.

  Although CPT has shown some usefulness as an objective standard for identifying ADHD, the medical establishment relies more heavily on subjective observations from individuals who are familiar with the patient's behavior in a variety of settings and other criteria in diagnosing ADHD.