The test is conducted in two parts, each with its specific aims and purposes. The goal of the TMT is to complete the tests as quickly and accurately as possible to reveal any potential signs of cognitive impairment.

This article outlines the history of the Trail Making Test and explains how it is administered and scored. It also looks at how accurate the TMT is in diagnosing cognitive impairment and the benefits and limitations of its use.

History of the TMT

The Trail Making Test (TMT) was created in 1944 by Ralph Reiten, an American neuropsychologist who is to be considered to be one of the fathers of clinical neuropsychology.

The test was initially developed for the Army to evaluate the general intelligence of soldiers based on their ability to maintain visual attention and demonstrate “task switching” (the ability to unconsciously shift focus from one task to the next).

In 1946, clinical psychologist Stewart G. Armitage proposed that the test be used to evaluate brain damage sustained by soldiers during the Second World War.

Since then, the TMT has been incorporated into the Halstead-Reitan Neuropsychological Test Battery (HRNB), a comprehensive panel of tests used to assess the condition and functioning of the brain.

An Overview of the Parts of the Test

The TMT can be used in people 15 to 89 who are suspected of having cognitive impairment. It can provide insights into a person’s cognitive function based on how fast they can search, scan, and process visual information without losing track of what they are doing.

The test also provides information about a person’s mental flexibility (meaning how quickly they can shift from one thought process to another).

All of these abilities are a part of what is known as executive functioning. A marked loss or decline of these abilities may be an indication of cognitive impairment.

The TMT is timed and performed in two parts using only a pen and a piece of paper.

Part A

TMT Part A consists of 25 circles on a piece of paper with the numbers 1 to 25 written randomly in each.

For Part A, the person is tasked with drawing a line from one circle to the next in ascending numerical order, from 1 to 25, as quickly as possible. The lines between the circles are referred to as the “trail.”

Part B

TMT Part B also consists of 25 circles on a piece of paper, But, rather than all of the circles containing numbers, they contain numbers (1 to 12) and letters (A through L).

For Part B, the person is tasked with connecting the circles in ascending order, alternating back and forth from numbers to letters. In other words, the “trail” would be connected like this:

1-A-2-B-3-C-4-D-5-E-6-F-7-G-8-H-9-I-10-J-11-K-12-L-13

Test Administration

The TMT is highly sensitive to certain types of cognitive impairment. It does not require specialist training to administer but is conducted in a specific way to ensure accuracy.

The TMT is administered in the following steps:

Give the person the TMT Part A worksheet with the circles and numbers already drawn on them. Explain the directions, then demonstrate how Part A is done on a sample page. Start timing the test as soon as the person begins. If the person makes a mistake, let them know and allow them to correct the mistake and continue. Record the time when the person is finished. Repeat with TMT Part B.

If the person is unable to complete Parts A and B after five minutes, you can discontinue the test.

Scoring

The Trail Making Test is scored based on how long it takes to complete the test. There are no penalties for mistakes other than they extend the final recorded time.

The scores are the number of seconds it takes to complete a test. Each part of the test is scored individually. Higher scores indicate a higher degree of cognitive impairment.

Acceptable Scores

Based on the scores, the TMT can provide useful information about two things:

Cognitive function is described in relation to the “average” score for each test. Higher scores indicate cognitive decline. Lower scores suggest a person’s cognitive abilities are intact. Cognitive impairment is described by scores that exceed a certain time. After that time, a person’s score is said to be “deficient. "

For TMT Part A and Part B, the “average” and “deficient” scores are categorized as follows:

TMT Part A is a good measure of working memory.

Part B is generally good at evaluating executive functioning since the test requires multiple abilities. It may also be useful in determining whether someone with dementia can safely drive since the test involves both visual processing and mental flexibility.

With that said, the accuracy of the TMT can vary based on what condition is being investigated. The accuracy is determined by the test’s sensitivity (the percentage of times it correctly identifies a person with a disease) and specificity (the percentage of times it correctly identifies a person without a disease).

The Oral Trail Making Test

The Trail Making Test can also be administered verbally. The oral test can be used when a person is physically unable to perform the written test or in a situation where illness and fatigue might affect the written results.

For Part A, rather than giving the person a piece of paper and pen, you can simply ask the person to count from 1 to 25.

For Part B, the person is asked to verbally recite numbers and letters, alternating between numbers and letters (like 1-A-2-B-3-C, etc.)

Pros and Cons of the Trail Making Test

There are pros and cons to the Trail Making Test. Depending on the aims of testing, it may not be the right choice for everyone or every situation.

Summary

The Trail Making Test is a quick and simple test that can help detect cognitive problems like dementia. It is conducted in two parts using only a pen and a piece of paper.

Part A of the test requires you to connect 25 randomly placed circles in ascending numerical order. Part B also requires you to connect 24 randomly placed circles in ascending order, alternating between numbers and letters.

The test is scored based on how many seconds it takes you to complete each part. Higher scores indicate a higher degree of cognitive impairment. The test, while very useful, may be less accurate in older adults and have varying degrees of accuracy based on the condition being investigated.

A Word From Verywell

As useful as the Trail Making Test is, it is not meant to be used in isolation or to self-test yourself for dementia or any other cognitive problem. The TMT is most beneficial when used as part of a comprehensive panel of screening tests by a qualified healthcare provider.

If you think you or someone you love may have dementia, ask your primary care provider for a referral to a specialist for further evaluation. This may include a neurologist who treats disorders of the brain and nervous system or a geriatrician who specializes in the healthcare of older adults.

Correction - October 31, 2022: This article was updated to correct the number of circles included in the Trail Making Test Part B.

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