Testing for ADHD can be a challenge. There is no available test that 'proves' that a person has ADHD. Thorough testing requires multiple screening tool and assessment. The accurate diagnosis of attention disorders is difficult but essential as there are multiple adverse outcomes related to undiagnosed and untreated ADHD. Unfortunately, the traditional method of ADHD diagnosis, which relies on the completion of symptom surveys by parents and teachers, is considered by many people to be highly subjective.
Russell Barkley has reported that the degree of agreement between parents and teachers for any dimension of child behavior are modest, ranging in the 30% to 50% range. This lack of agreement between teacher and parent can be problematic as the DSM criteria for diagnosing ADHD requires that the ADHD symptoms of hyperactivity, impulsiveness, and inattentiveness be present in at least 2-3 environments.
Many parents are reluctant to medicate a child with ADHD unless there is an objective 'test' which positively identifies the presence of this disorder. Since there is no objective 'proof' for the diagnosis of ADHD, many parents struggle with accepting a treatment plan. A family's reluctance to treat ADHD can result in tremendous detriments for these children and families.
Last year a test known as the Quotient(TM) ADHD System became available. This system, formerly known as M-MAT, was developed by a Harvard Psychiatry professor and was similar to the continuous performance task test but added a motion analysis component. The company that promotes this test reports that this is the most accurate non-invasive testing method for ADHD. The test uses a computer program and motion detectors placed on the individual's forehead and shins to evaluate hyperactivity, inattention, and Impulsiveness.
There is very little information in the literature on using this test for the initial diagnosis of ADHD. The studies that I was able to find evaluating this took looked at the reliability of this tool for assessing the effectiveness of stimulant medication. The Quotient(TM) ADHD seems to work well in this regard but these studies do not answer the question of how useful this test is for identifying ADHD
There have been many studies done on the use of the continuous performance task test, known as CPT, as a diagnostic tool. The results of this test have all been positive for identifying a problem with attention and/or impulsiveness but there are problems with the interpretation of these results. The CPT can identify a problem with attention but it does determine that these problems are caused by ADHD. An abnormal CPT could be the result of another diagnosis such as anxiety, depression, learning disabilities, or low IQ.
It would be exciting to find a blood test or other marker that incontrovertibly determined the presence or absence of ADHD. Currently there is no such test. Other methods being studied to identify ADHD include EEGs, imaging studies, and DNA markers. These test are only now be evaluated as diagnostic tools but I am hopeful that, in the near future, some of these test may prove fruitful in the accurate diagnosing ADHD.