Continuous performance tests may be used to help diagnose ADHD — but how do they work?
A diagnosis of attention deficit hyperactivity disorder (ADHD) relies primarily on subjective measures, such as observing a person’s symptoms and behaviors.
However, an objective computer test may also be used to support this diagnosis.
Computerized continuous performance tests (CPTs) can help measure selective attention, sustained attention, and impulsivity.
A computerized test typically involves the rapid presentation of a series of visual or auditory stimuli over a certain period of time. This may include numbers, letters, number and letter sequences, and geometric shapes.
The test is performed continuously without interruption. It’s typically administered by a licensed mental health professional or a physician.
Test takers are told to respond to a “target” stimulus and to avoid responding to “non-target” stimuli. The test administrator will tell you what each is before the test begins.
The number of times you respond to a non-target stimulus is called a commission error. The number of times you don’t respond to a target stimulus is an omission error.
Your responses may help in diagnosing the type of ADHD you have.
Commission errors may be considered a sign of impulsivity. If you respond too infrequently — so you get omission errors — it could show inattention symptoms.
If both types of errors are shown during the test, you might be showing signs of combined-type ADHD.
The clinician will look at the number of correct responses, response time, and the variability of response time.
There are a variety of computerized tests that may be used to help diagnose ADHD.
Test of Variables of Attention (TOVA)
The TOVA is an FDA-cleared computerized test.
It’s been shown to be reliable and can detect each subtype of ADHD: hyperactive-impulsive, inattentive, or combined.
The TOVA was designed to be free of anything that could skew the results, such as language-processing difficulties or short-term memory problems. It uses simple geometric shapes as both target and non-target stimuli.
During the visual test, you may be directed to click a button or switch when you see a target shape, and not click when you see a non-target shape.
The auditory test follows the same process, using a sound instead of a geometric shape.
Both the visual and auditory tests measure the same factors. For children ages 4–5, the TOVA test lasts about 10.9 minutes. For those ages 6 and up, the test is about 21.6 minutes.
In a small
The MOXO CPT consists of 8 levels and lasts about 15.2 minutes.
The test has a built-in distractor that provides visual and auditory distractions that the test taker has to ignore, just as they would in real life. This is the only computerized test that contains real-life distractions.
Each stimulus is followed by a void period of the same duration. The void is designed to distinguish accurate responses performed in “good timing” from accurate but slow responses (correct responses made during the void period).
A study in 2017 on the MOXO CPT was conducted in 339 children with ADHD (ages 7–12) and a control group of 459 age-matched children without ADHD. The test looked at 4 measures: attention, timing, impulsivity, and hyperactivity.
They found that children with ADHD scored lower in the attention and timing measures and higher in hyperactivity and impulsivity. The sensitivity rate was 85% or higher in all age categories.
Conners’ CPT 3rd Edition
The Conners’ CPT 3rd Edition is a 14-minute test for ages 8 and up. This test assesses the respondent’s performance in areas of inattention, impulsivity, sustained attention, and vigilance to help detect ADHD and other neurological conditions related to attention.
There’s currently not much information about whether this test is reliable for diagnosing ADHD.
But a 2019 study suggests the test might be helpful for measuring sustained attention — attention over a long period of time — and impulsivity.
IVA: Integrated Visual and Auditory CPT
The IVA CPT is a 13-minute test designed to differentiate individuals with ADHD from those with conduct disorder. It can also be used to monitor the effectiveness of neurofeedback training or medication.
Not much research has been done recently to evaluate whether IVA CPT is a helpful test for ADHD.
However, an older study in 2002 found that people with ADHD received lower scores on measures of reaction time, inattention, impulsivity, and variability of reaction time.
The QbTest is FDA-approved and combines attention and impulsivity measures with motion tracking analysis, which allows the clinician to evaluate fidgetiness and hyperactivity.
The test setup includes a computer screen and an infrared camera. You’ll wear a headband with an infrared marker attached to it and hold a responder button.
The QbTest is designed to assess and diagnose ADHD, as well as evaluate the effects of stimulant medication. Test results are collected into a report and compared with data from peopel without ADHD of the same sex and age.
The findings show relatively high accuracy among both adults and children: 79% (adults) and 78% (children) when using only objective measures. However, using both subjective and objective measures was found to be more accurate.
Computerized tests are only one possible part of the evaluation process for ADHD.
A thorough ADHD evaluation may include:
- an intake of your developmental and health history
- interviews with parents, teachers, caregivers, co-workers, and you
- a direct observation of your behaviors
- broad-based rating scales that consider all possibilities, or alternative explanations, for behaviors
- narrow rating scales of ADHD-specific behaviors
- a measure of intelligence
- tests of attention, memory, persistence, or executive functioning (may or may not be computerized)
- tests of reading, writing, and math if a learning disorder is suspected
There’s some debate over how effective computerized tests are in detecting or diagnosing ADHD.
One concern is whether these tests can truly evaluate for inattention among real-world distractions.
Another concern has been whether the score should be based on response time. Some experts say doing so doesn’t allow for differentiation between motor speed problems and inattention.
Another potential problem may be that people with other neurodevelopmental diagnoses — such as dyslexia and certain brain injuries — may have similar difficulties with executive functions and reaction time variability.
Another study found the tests to be fairly ineffective at diagnosing ADHD types in adults. The classification error was 80.3% for the inattentive type and 22.5% for the hyperactive type when using it to identify ADHD presentations.
If you think you or your child might have ADHD and you want to take a computerized test, contact your family physician or a mental health professional who has experience working with people with ADHD.
Clinicians might vary in their diagnosis process, so it’s helpful to ask if they offer computerized tests as an option and if they might be covered by insurance.