Test of Variables of Attention
(TOVA)
A Computerized Assessment for ADHD

One of the evaluation procedures used for diagnosing ADHD is the Test of Variables of Attention (TOVA), a computerized Continual Performance Test (CPT) used to help identify factors related to problems with attention and impulsivity. In some ways it is like a "stress test for the brain." The TOVA helps the clinician see how a person does in a boring task that requires vigilance.

The TOVA can be used as young as age 4, although beginning at age 6 is more practical. It is also normed for adults through age 70. 

The TOVA uses only two symbols. No reading skill is needed. The person being tested is to push the button on the microswitch when the see the target, and "pass" when they see the non-target. The images flash on the screen for just a moment, about 2 seconds apart.

         Target                    Non-target

The TOVA is a 22 minute test that helps determine how well one can focus on a simple task that requires constant attention. The test is done in both a visual version as well as an auditory version. The TOVA addresses several factors:

•  Variability- the evenness of a person's response

•  Response Time- how fast the person responds

•  Errors of Commission-a measure of impulsivity

•  Errors of Omission -a measure of inattentiveness

•  Anticipatory Errors (pushing the button before you see the target) measure problems  with holding back as required, versus "jumping the gun."

•  Post commission response time (do you slow down or speed up after errors)

•  Response data by quarters so can tell how well one does over time

•  Low brain stimulation task for first half of the test, and a high brain stimulation task for second half of the test

•  Compares the person to others by age and sex.

•  Uses micro-switch accurate to 1/1000 of a second to measure response time

• Provides the counselor an opportunity to observe vigilance on a boring task

• Has an ADHD score in the visual mode that compares to those who have been diagnosed with ADHD

No one test, checklist or brief interview is adequate to evaluate for ADHD or any other disorder for that matter. The total pattern of problems, as well as the disabling quality of the problems is important in order to get an accurate diagnosis. It also assists in identifying areas to observe for improvement when medication is administered. The TOVA can be administered after giving medication to monitor medication improvements.

The TOVA alone does not determine ADHD.  But it can help confirm the diagnosis, and help more clearly see the type of problems that a person with ADHD has.

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