ADHD Testing for Attention, Executive Function, and Memory

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that can cause impairments in key areas, including executive function, attention, and memory. As a result, comprehensive testing is necessary to help understand each individual’s strengths, weaknesses, and overall capacities. Gaining a deeper understanding of one’s abilities not only enables the creation of more effective treatment plans but also fosters realistic expectations. This, in turn, provides individuals with ADHD the necessary support to successfully navigate school, work, and other areas of their lives.

What is Executive Function?

Executive function refers to higher-level cognitive processes that are used to help guide and regulate attention, behavior, and actions to help someone attain their goals and tackle everyday life more readily. Some of the key executive functions include: ^[1][2]

• Organizing and prioritizing tasks
• Focusing, sustaining, and shifting attention
• Managing and modulating emotions
• Using working memory and recall
• Self-regulating and monitoring actions

This is important because individuals with ADHD often have deficits in executive function, such as their working memory, attention span, response inhibition, emotional regulation, and planning. These deficits in executive function may be responsible for the primary symptoms of ADHD such as inattentiveness, impulsivity, and hyperactivity, while also having a significant influence on poor academic performance, behavior problems, and other common issues seen in associated with the disorder. ^[2][3]

Types of Executive Function Tests

There are a variety of tests to assess executive function in individuals with ADHD. Some of the more common executive function tests include: ^[4]

• Wisconsin Card Sorting Test
• Tower of London
• Stroop Color-Word Test
• Trail Making Test
• Verbal Fluency Test

Wisconsin Card Sorting Test

The Wisconsin Card Sorting Test (WCST) is a commonly used test of an individual’s executive function, measuring key aspects, such as cognitive shifting, impulse control, and general reasoning. In the WCST, individuals are given four cards that vary in classification e.g. color, shape, or number.

The task involves sorting the cards according to different rules, but the sorting rule changes without warning during the test. Participants must figure out the new rule based on feedback, without being explicitly told when the change occurs.

Performance is evaluated based on the number of correct sorts, errors made, and how easily the participant adapted to the changing rules.

Tower of London

The Tower of London Test is another common executive functioning test, particularly testing a person’s planning ability and higher-order problem-solving. In this test, individuals are presented with three discs with different colors stacked vertically on a peg. They then are given a “goal design” that they have to build with the given discs, with the objective being to complete it using the fewest possible moves.

Stroop Color-Word Test

The Stroop Color-Word Test (or simply Stroop Test) is a test that measures a person’s ability to handle cognitive interference alongside their general mental processing abilities. In this test, subjects go through a congruent and incongruent condition.

In the congruent condition, they have to read color words (e.g. blue, green, yellow) written in black ink, and then name the colors of different color patches.

In the incongruent condition, color words are presented in an ink color that doesn’t match the word, and subjects have to say the ink color of the word.

Trail Making Test

The Trail Making Test measures multiple areas of executive functioning, including visual processing and working memory. This test is divided into two parts. In part one, a sheet is filled with the numbers 1 through 25 in random locations, and subjects must draw a line connecting the numbers in consecutive order without lifting the pencil from the paper.

In part two, both numbers and their corresponding letters of the alphabet are scattered throughout a page. Subjects have to draw a line connecting the numbers and letters in alternate fashion (e.g. 1, a, 2, b, 3, c, etc), again without lifting the pencil. The goal is to complete the test as fast as possible.

Verbal Fluency Test

The Verbal Fluency Test is an executive functioning test focussing primarily on language ability and attention. This test is typically divided into two parts; the category/semantic test and the phonetic test.

In the category/semantic test, individuals must name as many things as they can from a particular category (e.g. animals, vegetables) in 60 seconds. In the phonetic test, individuals are given a letter of the alphabet and must say as many words as they can that start with that letter in 60 seconds.

What Attention Assessments are Used in ADHD?

In addition to measuring executive function, tests that measure attention directly are useful when diagnosing and testing ADHD. There are a variety of attention assessments, including performance assessments and rating scales.

Some of the most common ones are: ^[5]

• Conners Continuous Performance Test-2
• Rapid Visual Information Processing Task
• Test of Variables of Attention (TOVA)
• Test of Everyday Attention for Children
• ADHD Rating Scale-IV

Conners Continuous Performance Test-2

The Conners Continuous Performance Test-2 measures sustained attention ability. In this test, subjects are shown a series of letters spaced apart by 1, 2, or 4 seconds. Subjects are instructed to press the spacebar or the corresponding key for the letters that appear, all except for the letter, “x”.

There are a total of 360 letters presented, divided into 18 separate runs of 20 letters each. The total time for the test is around 14 minutes.

Rapid Visual Information Processing Task

The Rapid Visual Information Processing (RVP) Task is a 4-minute long task designed to measure sustained attention.

During the test, any of the numbers 2 through 9 can appear on the screen, and subjects are asked to identify when there are sequential patterns, such as 1-2-3, 2-4-6 or 3-5-7, or 4-6-8. Subjects are measured on the number of correct and incorrect responses.

Test of Variables of Attention

The Test of Variables of Attention (TOVA) is another common attention assessment. During this test, individuals are presented with a square in either the upper or lower half of the screen. If it’s in the upper half, they should respond, whereas if it’s in the lower half, they should ignore it.

In the first part, most of the presentations are in the upper half, whereas in the second part, the majority of presentations are in the lower half. When combined, this helps to measure impulse control and attentional swiftness.

Test of Everyday Attention for Children

The Test of Everyday Attention for Children (TEA-Ch) is a multifaceted assessment that measures selective attention, sustained attention, and executive control. During this test, children must complete different tasks, such as counting tones they hear during an audiotape and looking for target symbols on a map full of distractors. Some of these tasks are also combined to measure multiple variables simultaneously.

ADHD Rating Scale-IV

The ADHD Rating Scale-IV is one of the most prevalent tools used to assess the symptoms of ADHD. It consists of 18 total items on a 4-point scale (from 0 or never, to 3 or always), with 9 items assessing inattentiveness and 9 items assessing hyperactivity-impulsivity.

This test for ADHD in children is completed by parents/caregivers and/or teachers, while adults complete the test themselves.

Memory Evaluation in ADHD Testing

Evaluating memory is also important during ADHD testing, especially since individuals with ADHD have been shown to exhibit deficits in working memory and other areas of memory. These deficits can significantly impact a person’s ability to perform well in school, at work, and in daily life. ^[6]

A wide variety of memory tests within the context of ADHD can be used, including:

• Digit Span Test
• Benton Visual Retention Test
• Brown-Peterson Consonant Trigram
• California Verbal Learning Test

Digit Span Test

The Digit Span Test is one of the most commonly used tests for short-term and working memory. In this test, subjects are presented with a sequence of verbally stated or written numbers and must recall them in the correct order.

There are two types of digit span test:

• The digit span forward test, in which one has to recall the numbers in the order they were given.
• The digit span backward test, in which one has to say the numbers in reverse order.

Benton Visual Retention Test

The Benton Visual Retention Test assesses visual memory and perception. In this test, individuals are shown a series of geometric figures (typically 10) and then have to reproduce as many of these as they can on a piece of paper.

Brown-Peterson Consonant Trigram

The Brown-Peterson Consonant Trigram is a test of short-term memory and recall. In this test, the experimenters present three consonants to the subject, before immediately distracting them with a separate task, such as having the participants count backward by 3s or 4s.

After the distraction, participants have to try to recall the three consonants presented.

California Verbal Learning Test

The California Verbal Learning Test is a common test used to measure verbal learning and memory. This test is composed of a series of steps. Firstly, subjects are presented with a list of 16 words grouped into four categories. After seeing them, they are asked to name as many as they can without any prompting, a step known as ‘free recall’. This same 16-word list is repeated four times, but after the fifth time, a distractor list of 16 words is given to test for the effects of interference.

After the distractor list, participants have to name the words from the original list using ‘cued recall’ (the experimenter cues them with the category names).

Participants must then observe a 20-minute waiting session, before undergoing another ‘cued recall’ session. Finally, there is a recognition period where a new list containing words from the original list and the distractor list is read out.. Subjects must then indicate which words from this final list were on the original list.

Interpreting ADHD Test Results

Mental health professionals interpret the results of these tests using objective markers, by which performance below a certain marker is indicative of ADHD. This is done by recognized ADHD diagnostic tools, including the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) diagnostic criteria, self-report questionnaires, and interviews.

This approach yields a more thorough diagnosis by incorporating both objective measures and subjective insights.

Limitations of ADHD Testing

While these objective tests for executive functions, attention, and memory are certainly useful, they have limitations.

One of the main limitations is the sensitivity of these tests. Sometimes these tests don’t accurately predict ADHD symptom severity. For example, one would expect a somewhat negative linear relationship, in which a decrease in performance on these tests would be associated with greater ADHD symptom severity, but this isn’t always the case. ^[7]

Another limitation is the lack of standardization in the type of assessments used. Unlike the diagnostic criteria in the DSM-5-TR, which clearly defines the parameters for an ADHD diagnosis, no one test is always used when it comes to assessing an individual’s executive functions.

As such, different tests can lead to different results, making it unclear which test is a more accurate indicator of ADHD. ^[7]

In addition, performance on these tests may vary depending on an individual’s stress, fatigue, or even the environment they’re in, casting doubt on the test’s veracity. ^[7]

Can Neuroimaging Be Used in ADHD Assessments?

Due to technological advancements, neuroimaging is also coming to the forefront as a potential additional tool to use during ADHD assessments.

Neuroimaging refers to the use of brain imaging techniques to analyze the structure and activity of the brain. Examples of these techniques include functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS). ^[8]

Enabling us to analyze the structure and function of the brain, neuroimaging can help give researchers a better understanding of potential differences in the brains of individuals with ADHD.

These images could then be analyzed within the context of the performance-based assessments of executive function to provide a more thorough ADHD assessment.

Interestingly, these neuroimaging techniques have already identified some key differences in individuals with ADHD compared to those without. For example, people with ADHD appear to have differences in activity and connectivity in the prefrontal cortex, which is involved in attention and executive functioning. In addition, researchers have found differences in the structure and function of key brain regions related to reward processing and motor control. ^[8]

What Happens After ADHD Testing?

After testing, mental health professionals will gather and analyze all of the information and make a diagnosis. This approach is based on all the assessments used, including the performance tests discussed in this article, questionnaires, interviews, and specific diagnostic criteria.

If you are given an ADHD diagnosis, your mental health professional will then explain treatment options, such as medication and/or therapy, with the possible addition of support groups, skills training, and behavior interventions.

Your mental health professional will likely schedule follow-up assessments to monitor progress and evaluate the effectiveness of treatments. While these assessments can vary depending on the individual, they generally include a mix of self-report questionnaires, neuropsychological tests, and performance-based measures, similar to those used in the initial assessment, though typically less exhaustive and time-consuming.