A Functional Capacity Evaluation (FCE) is a comprehensive, performance-based assessment of an individual’s physical or cognitive ability to participate safely in work and other major life activities.

However, a traditional Physical Functional Capacity Evaluation and a Cognitive Functional Capacity Evaluation are not the same service.

A Physical FCE is primarily designed to determine whether an individual can meet the physical demands of work. A Cognitive Functional Capacity Evaluation, sometimes called a Cognitive FCE or Cog-FCE, expands the evaluation to examine whether the individual can meet the cognitive, behavioural, and communicative demands of a specific job.

This distinction becomes particularly important when an individual reports mental fatigue, reduced concentration, memory problems, difficulty multitasking, or “brain fog.” The evaluator is not simply trying to determine whether cognitive symptoms exist. The more useful question is whether those symptoms affect the individual’s ability to perform and sustain the cognitive demands of work.

How Is a Cognitive FCE Different From a Physical FCE?

A traditional Physical FCE may assess abilities such as:

• lifting and carrying
• pushing and pulling
• standing and walking
• sitting and positional tolerance
• reaching, crouching, kneeling, and climbing
• cardiovascular and physical endurance

A Cognitive FCE adds an assessment of work-related cognitive and behavioural abilities. Depending on the referral question and the person’s job, these may include:

• attention to detail
• memory
• performance of multiple tasks
• tolerance to distracting stimuli
• communication
• computer use
• self-supervision
• problem-solving
• organization
• tolerance to deadline pressure

Cognitive functional testing requires specialized training beyond the preparation required to conduct a standard physical FCE. It also requires additional assessment tools, work simulations, interpretation, and reporting.

Because standardized cognitive assessments are added to the physical evaluation, a Cognitive FCE generally requires more testing time. It is therefore a more comprehensive and more costly evaluation than a standard Physical FCE.

Begin With the Cognitive Demands of the Job

Workplace cognition should not be treated as a single, undefined ability.

The evaluator should first identify the cognitive demands that are actually required by the person’s job. This is similar to identifying lifting, carrying, standing, or reaching requirements before designing a job-specific Physical FCE.

A cognitive Job Demands Analysis can separate workplace cognition into individual functional demands. A corresponding Functional Abilities Evaluation can then define what the worker must demonstrate during testing.

This creates a direct comparison between:

• what the job requires
• what the individual reports being able to do
• what the individual demonstrates during testing

For example, the relevant cognitive demands of a secretary or administrative professional may include:

• attention to detail
• working memory
• performance of multiple tasks
• tolerance to distracting stimuli
• communication
• computer use
• organization
• tolerance to deadline pressure

The referral question is not simply:

Does this person have brain fog?

A more functionally useful question is:

Can this individual perform and sustain the specific cognitive demands of their job?

What Is Cognitive Endurance?

Cognitive endurance is the ability to maintain effective cognitive performance over time while completing tasks that require attention, memory, information processing, organization, decision-making, or other mental activity.

A person may perform adequately during a brief cognitive assessment but experience increasing mental fatigue as the duration or complexity of the activity increases.

This is particularly relevant when assessing individuals who report fatigue associated with conditions such as fibromyalgia. An individual may experience a strong subjective sense of mental fatigue even when brief cognitive test results appear relatively preserved.

That does not mean the reported fatigue should be dismissed. It means the evaluator must distinguish between several possible findings:

• reduced cognitive ability at baseline
• preserved baseline ability with reduced endurance
• increasing subjective fatigue without measurable performance change
• increasing fatigue accompanied by slower or less accurate performance

This distinction cannot be made from a single short test or symptom report.

Use the Same Testing Philosophy Applied in a Physical FCE

Physical FCEs do not rely exclusively on what an individual says they can do.

The evaluator establishes a baseline, introduces progressively greater or sustained demands, monitors the person’s responses, and determines whether performance changes over time.

The same general philosophy can be applied to cognitive endurance.

The evaluator can:

1. establish the individual’s subjective baseline
2. measure objective cognitive performance
3. expose the individual to sustained physical and cognitive demands
4. repeat the subjective and objective measures
5. compare the findings

This approach integrates the individual’s reported experience with observed performance rather than treating either source of information as sufficient on its own.

A Four-Step Framework for Assessing Cognitive Endurance

Step 1: Establish the Subjective Baseline

Begin by documenting the individual’s perception of their current mental fatigue.

A standardized fatigue questionnaire or rating scale may be used. Possible options include:

• Multidimensional Fatigue Inventory
• Modified Fatigue Impact Scale
• a Visual Analogue Scale for mental fatigue

The purpose of this step is not to prove cognitive impairment. It is to establish a measurable subjective baseline before cognitive and physical loading begins.

The evaluator may also ask:

• What cognitive activities cause fatigue?
• How long can the person concentrate before performance becomes difficult?
• Does fatigue affect accuracy, speed, memory, or communication?
• What strategies or breaks are required?
• How does performance change over a normal workday?

Step 2: Establish the Objective Cognitive Baseline

Next, select a task that reflects one or more important cognitive demands of the individual’s job.

For a secretary, administrative assistant, or office worker, testing might examine:

• attention to detail
• working memory
• divided attention
• multitasking
• computer-based work
• executive functioning
• accuracy under time pressure

The task may be a standardized cognitive assessment, a performance-based cognitive measure, or a structured work simulation.

Examples of standardized or performance-based assessments that may be considered by appropriately trained clinicians include:

• Test of Everyday Attention
• Executive Function Performance Test
• Behavioural Assessment of the Dysexecutive Syndrome
• other validated measures selected for the referral question and occupational demands

Test selection should be guided by the demands of the job rather than by a desire to administer a broad battery of unrelated cognitive tests.

The evaluator should record relevant performance measures such as:

• accuracy
• number and type of errors
• completion time
• processing speed
• need for repetition or cueing
• ability to recognize and correct errors
• ability to maintain attention

Step 3: Use the Physical FCE as a Period of Cognitive Loading

The physical FCE does not eliminate cognitive demands.

Throughout the evaluation, the individual must:

• listen to instructions
• learn unfamiliar procedures
• remember testing requirements
• shift attention between activities
• organize movements
• solve problems
• respond to questions
• monitor symptoms
• maintain concentration despite increasing fatigue

The physical evaluation can therefore serve as a prolonged period of cognitive loading.

This does not mean that every Physical FCE automatically becomes a valid Cognitive FCE. Formal cognitive conclusions require appropriately selected cognitive measures, specialized training, and a clear connection to the referral question.

However, performance during the physical evaluation may provide valuable observational data about instruction retention, attention, communication, task organization, problem-solving, and the need for cueing.

Step 4: Reassess Cognitive Fatigue and Performance

After an appropriate period of testing, repeat:

• the subjective mental-fatigue rating
• the same objective cognitive task or a suitable equivalent form

The evaluator can then compare baseline and post-loading performance.

Questions to consider include:

• Did perceived mental fatigue increase?
• Did objective performance remain stable?
• Did attention to detail decline?
• Were more errors made?
• Did processing or completion speed change?
• Was more cueing required?
• Did the individual lose track of instructions?
• Did accuracy improve because of familiarity with the task?
• Did performance remain unchanged despite a substantial increase in reported fatigue?

The repeated assessment provides more useful evidence about cognitive endurance than either the baseline test or the individual’s fatigue report could provide independently.

Interpret Subjective and Objective Findings Together

The purpose of cognitive endurance testing is not to decide whether the individual’s symptoms are “real” based on whether an objective score changes.

Subjective fatigue and objective performance measure different aspects of the person’s response.

For example, an individual may report a substantial increase in mental fatigue while maintaining accuracy and processing speed. That finding may indicate that performance was sustained during the evaluation, although potentially with increased perceived effort or a need for recovery afterward.

Another individual may demonstrate:

• increasing errors
• slower performance
• reduced attention to detail
• difficulty retaining instructions
• greater need for cueing
• difficulty shifting between tasks

Those findings may support a measurable reduction in cognitive endurance under the conditions tested.

Neither pattern should be interpreted from one isolated score. The evaluator should consider:

• the referral question
• the cognitive demands of the job
• medical and occupational history
• subjective fatigue ratings
• baseline cognitive performance
• performance after sustained loading
• behavioural observations
• consistency across tasks
• physical fatigue and symptom response

This reflects the broader FCE principle of integrating multiple sources of evidence before reaching a functional conclusion.

Do Not Confuse Cognitive Symptoms With a Diagnosis

A Cognitive Functional Capacity Evaluation is not intended to diagnose fibromyalgia, a learning disability, a psychiatric condition, a neurological disorder, or another cause of cognitive impairment.

The evaluator’s role is to assess function.

Depending on the referral question and the evaluator’s professional scope, further neuropsychological, psychological, medical, speech-language, or occupational therapy assessment may be required to investigate diagnosis or impairment in greater detail.

The Cog-FCE should remain focused on the relationship between demonstrated cognitive abilities and the cognitive demands of work.

Apply the “No More Than Necessary” Principle

A Cognitive FCE should not become a collection of every cognitive test available.

Testing should be progressed only as needed to allow possible functional limitations to emerge and to answer the referral source’s questions.

For example, an evaluator does not need to administer an extensive memory battery when the job does not place meaningful demands on independent recall. Similarly, a generic attention test may provide limited occupational information if the primary job demand involves multitasking in a distracting office environment.

The evaluator should select the smallest defensible group of measures capable of answering the functional question.

This improves:

• content validity
• clinical relevance
• testing efficiency
• interpretability
• utility for the referral source

The Final Question Is About Sustained Work Performance

The goal of a Cognitive FCE is not simply to confirm that an individual experiences mental fatigue.

The evaluation should help answer a more clinically and occupationally useful question:

Can this individual sustain the cognitive demands of their specific job throughout the required work period?

Answering that question requires more than a symptom checklist or a brief cognitive screening test.

It requires:

• a clear understanding of the job’s cognitive demands
• appropriately selected performance-based tests
• measurement of subjective and objective baseline findings
• exposure to sustained cognitive demands
• reassessment after loading
• integration of findings across the complete evaluation

That is what turns the assessment from a general discussion of “brain fog” into a functional evaluation of cognitive work capacity.

Frequently Asked Questions

What is a Cognitive Functional Capacity Evaluation?

A Cognitive Functional Capacity Evaluation is a performance-based assessment of an individual’s ability to meet the cognitive, behavioural, communicative, and organizational demands of work. It may be completed alongside a Physical FCE when both physical and cognitive work abilities must be evaluated.

Is a Cognitive FCE the same as a Physical FCE?

No. A Physical FCE primarily assesses physical work abilities such as lifting, carrying, mobility, positional tolerance, and physical endurance. A Cognitive FCE adds specialized testing of work-related cognitive and behavioural abilities.

Why does a Cognitive FCE cost more?

A Cognitive FCE generally requires additional standardized assessments, work simulations, testing time, interpretation, and reporting beyond the components of a standard Physical FCE.

What is cognitive endurance?

Cognitive endurance is the ability to sustain effective mental performance over time while completing tasks that require attention, memory, information processing, decision-making, organization, or other cognitive activity.

Can someone report mental fatigue but perform normally on cognitive testing?

Yes. An individual may report increasing mental fatigue while maintaining measurable performance during a brief test. This is why subjective fatigue and objective performance should be measured separately and interpreted together.

Can a brief cognitive test measure cognitive endurance?

A brief test may establish baseline performance, but it does not necessarily show whether that performance can be sustained. Cognitive endurance assessment generally requires cognitive loading and reassessment over time.

Can the physical FCE be used to assess cognition?

The physical FCE creates ongoing cognitive demands and may provide useful observations about attention, memory for instructions, communication, organization, and cueing. However, it does not become a Cognitive FCE unless appropriate cognitive measures are deliberately selected, administered, and interpreted by a qualified evaluator.

Does a Cognitive FCE diagnose the cause of brain fog?

No. A Cognitive FCE evaluates functional performance in relation to occupational demands. Diagnosis may require assessment by other appropriately qualified medical, psychological, neuropsychological, occupational therapy, or speech-language professionals.

Which cognitive tests should be included?

Test selection depends on the referral question and the cognitive demands of the job. The evaluator should select content-valid measures rather than administer the same cognitive battery to every individual.

How should cognitive endurance findings be reported?

The report should describe the individual’s baseline performance, subjective fatigue, testing conditions, cognitive loading, repeated performance, errors, speed, cueing, behavioural observations, and the relationship between demonstrated abilities and job demands.

Related Functional Capacity Evaluation Articles

• Unpacking Functional Capacity Evaluations
• How to Progress During an FCE
• The Intake Interview in a Functional Capacity Evaluation
• Why Do We Measure More Than Once in a Functional Capacity Evaluation?
• Understanding Coefficient of Variation in Functional Capacity Evaluations
• Job Demands Analysis
• Occupational Rehabilitation

Learn More About Functional Capacity Evaluation Training

Metriks Functional Capacity Evaluation Certification teaches rehabilitation professionals how to design, perform, interpret, and report Functional Capacity Evaluations using a structured, evidence-informed approach.

The course addresses referral analysis, job demands, test selection, physical functional testing, clinical interpretation, performance consistency, and defensible report writing.

Learn more about Metriks Functional Capacity Evaluation Certification.

References

• Allison S, Galper J, Hoyle D, Mecham J. Current Concepts in Functional Capacity Evaluation: A Best Practices Guideline. 2018.
• MacMasters W, Allison S, Wickstrom R, McMenamin P. Functional Capacity Evaluation and Disability Determination. Academy of Orthopaedic Physical Therapy, APTA; 2022.
• Hartman-Maeir A, Katz N, Baum CM. Cognitive Functional Evaluation process for individuals with suspected cognitive disabilities. Occupational Therapy in Health Care. 2009;23(1):1–23.
• Baum CM, Connor LT, Morrison T, Hahn M, Dromerick AW, Edwards DF. Reliability, validity, and clinical utility of the Executive Function Performance Test. American Journal of Occupational Therapy. 2008;62(4):446–455.