Trail Making Test: Assess Visual Attention & Task Switching

Assess your visual attention, processing speed, and cognitive flexibility.

What is the Trail Making Test?

The Trail Making Test (TMT) is a widely used neuropsychological assessment that measures visual attention, processing speed, and cognitive flexibility. First developed by the U.S. Army in 1944 for personnel screening, it has become one of the most commonly administered tests in clinical neuropsychology.

The test is deceptively simple: connect numbered or lettered circles in order as quickly as possible. Yet this straightforward task reveals crucial information about brain function.

How the Trail Making Test Works

Part A: Number Sequencing

Task: Connect circles numbered 1-25 in order as quickly as possible.

What it measures:

Visual scanning (finding the next number)
Processing speed (how fast you can execute)
Graphomotor speed (physical movement efficiency)
Attention to sequence (not skipping numbers)

Typical completion time: 29-78 seconds for healthy adults

Part B: Number-Letter Alternation

Task: Connect circles alternating between numbers and letters: 1-A-2-B-3-C... and so on.

What it measures:

All Part A skills plus:
Set-shifting (switching between rules)
Cognitive flexibility (adapting mental set)
Working memory (holding two sequences)
Executive function (managing complex task)

Typical completion time: 75-273 seconds for healthy adults

The Key Difference

Part B is significantly more demanding because it requires:

Maintaining two simultaneous sequences
Switching between number and letter sets
Inhibiting automatic continuation of either sequence
Detecting and correcting errors quickly

The Science Behind TMT

Neuropsychological Foundation

The TMT engages multiple brain regions:

Part A primarily involves:

Occipital cortex (visual processing)
Parietal cortex (spatial attention)
Motor cortex (movement execution)

Part B additionally requires:

Dorsolateral prefrontal cortex (executive control)
Anterior cingulate cortex (error monitoring)
Increased coordination between regions

What Research Shows

TMT performance correlates with:

General cognitive ability
Academic achievement
Driving safety in older adults
Functional independence
Quality of life in clinical populations

Clinical Sensitivity

TMT is particularly sensitive to:

Frontal lobe dysfunction
Diffuse brain damage
Processing speed decline
Executive function impairment
Early cognitive change

Understanding Your Results

Scoring

Primary scores:

Time to complete Part A: Lower is better
Time to complete Part B: Lower is better
B-A difference: Isolates set-shifting component
B/A ratio: Another way to assess relative difficulty

Normative Comparisons

Performance is compared to age- and education-matched norms. Typical interpretations:

Part A Time:

<29 seconds: Superior
29-35 seconds: Above average
36-78 seconds: Average
78 seconds: Below average

Part B Time:

<75 seconds: Superior
75-100 seconds: Above average
101-273 seconds: Average
273 seconds: Below average

B-A Difference:

Small difference: Good cognitive flexibility
Large difference: May indicate set-shifting difficulty

Error Analysis

Beyond time, errors matter:

Sequence errors: Missing numbers/letters
Switching errors: Failing to alternate
Self-corrections: Recognizing and fixing errors

Errors that are quickly self-corrected are less concerning than those that go unnoticed.

Practical Applications

Clinical Uses

TMT helps identify:

Traumatic brain injury: Often shows slowed Part B
ADHD: May show impulsive errors
Depression: Can show processing speed reduction
Dementia: Progressive decline on both parts
Stroke: Pattern depends on lesion location

Everyday Relevance

TMT-related abilities matter for:

Driving: Scanning, divided attention, quick responses
Work tasks: Multitasking, switching between activities
Daily activities: Following complex instructions
Safety: Noticing hazards while performing tasks

Tracking Change

Serial TMT testing can:

Monitor recovery from brain injury
Track cognitive aging
Assess treatment effects
Identify early decline

Factors Affecting Performance

Age

TMT performance:

Improves through adolescence
Peaks in young adulthood
Gradually declines with age
Part B shows larger age effects than Part A

Education

Higher education generally correlates with:

Faster completion times
Fewer errors
Better maintenance of performance with age

Practice

Modest practice effects occur:

Greater improvement on Part A than B
Most improvement on first few administrations
Alternate forms can reduce practice effects

State Factors

Performance is impaired by:

Fatigue
Sleep deprivation
Medication effects
Anxiety (though moderate arousal may help)
Pain or discomfort

How to Optimize Performance

Before the Test

Prepare by:

Getting adequate sleep
Being well-rested
Minimizing stress
Avoiding alcohol or sedating medications

During the Test

Strategies:

Scan ahead to locate the next target
Don't lift the pen (wastes time)
Keep moving; don't second-guess
For Part B, verbalize the alternating pattern
Self-correct quickly if you make errors

General Cognitive Health

Long-term strategies:

Regular physical exercise
Cognitive engagement (varied mental activities)
Social connection
Managing cardiovascular risk factors
Adequate sleep

TMT in Context

Part of Comprehensive Assessment

TMT is typically used alongside other tests:

Memory tests: TMT doesn't measure memory
Language tests: TMT is largely non-verbal
Executive function batteries: TMT covers some aspects
IQ tests: TMT contributes to processing speed

What TMT Doesn't Measure

Long-term memory
Verbal abilities
Crystallized intelligence
Emotional functioning
Motor strength (as distinct from speed)

Supplementary Assessments

For comprehensive cognitive understanding, consider:

Stroop Test: Cognitive inhibition
Wisconsin Card Sorting: Rule learning and flexibility
Digit Span: Working memory capacity

Variations of the Trail Making Test

Oral Trail Making

For individuals with motor impairments:

Examiner points to circles
Subject names the sequence verbally
Removes motor speed component

Color Trails Test

Designed for greater cross-cultural fairness:

Uses colored circles instead of letters
Reduces language and education bias
Similar cognitive demands

Comprehensive Trail Making Test

Extended version with additional conditions:

More circles (increases difficulty)
More alternation rules
Greater sensitivity to subtle impairment

Common Misconceptions

"Slow Part A Means Brain Damage"

Slow performance can reflect:

Normal variation
Motor difficulties
Vision problems
Lack of familiarity with tests
Anxiety

Single test results should be interpreted cautiously.

"I Can Practice to Get Better"

While some practice effect exists:

It doesn't indicate improved underlying ability
Clinical interpretation accounts for practice
The skills TMT measures have limited trainability

"Part B is Just Harder Math"

Part B difficulty is about:

Set-shifting between categories
Not mathematical complexity
The letters aren't harder than numbers
The alternation rule creates the demand

Explore other cognitive assessments:

Stroop Test: Also measures cognitive control and processing
Wisconsin Card Sorting: Deeper assessment of cognitive flexibility
Digit Span: Working memory that supports TMT performance