Myalgic Encephalomyelitis and Functional Capacity: Why One Good Day Can Be Misleading

Myalgic encephalomyelitis, often written as ME/CFS, can create a difficult problem when someone’s ability to work or complete daily activities needs to be documented. A person may appear capable during a short appointment and still be unable to repeat the same level of activity across a normal workday or workweek.

That difference matters. Functional capacity is not only about whether a task can be completed once. It is also about whether the activity can be performed safely, consistently and often enough to meet real world demands.

What Makes ME/CFS Different From Ordinary Fatigue?

ME/CFS is a complex and potentially disabling illness. The Centers for Disease Control and Prevention identifies reduced ability to perform usual activities, post exertional malaise and unrefreshing sleep among its central features. Cognitive problems or orthostatic intolerance are also included in current diagnostic criteria.

Post exertional malaise is especially important because symptoms can become worse after physical, mental or emotional effort. The decline may not occur immediately. Someone can finish an activity and then experience a significant worsening later that day or during the following one or two days.

That delayed response can make a brief observation misleading if the evaluator looks only at what happened while the task was being performed.

Why Sustainable Function Matters

Many jobs require repetition. An employee may need to sit upright for hours, move between work areas, concentrate on detailed information, respond to customers or maintain a predictable pace throughout the day.

A person with ME/CFS might be able to perform one of those activities for a limited period. The more important question may be what happens afterward and whether the same performance can be repeated.

This is one reason descriptions such as “can lift,” “can sit” or “can concentrate” do not always tell the whole story. Duration, recovery, symptom changes, consistency and the ability to return the next day can all affect real world function.

Cognitive Limitations Can Be Part of the Picture

ME/CFS does not affect physical stamina alone. Many people experience problems involving concentration, memory and the ability to think clearly. Orthostatic symptoms can also worsen while sitting or standing upright.

Those limitations can become particularly important in jobs that look physically easy. Office work may still require prolonged sitting, sustained attention, decision making, communication and the ability to work accurately under time pressure.

A Cognitive Functional Capacity Evaluation can examine how cognitive and physical demands interact. MEASURAbilities specifically evaluates areas including attention, memory processing, activity tolerance, fatigue and executive functioning.

A Functional Capacity Evaluation Does Not Diagnose ME/CFS

Diagnosis belongs with the person’s treating medical professionals. A Functional Capacity Evaluation has a different purpose. It measures function.

For a complex condition such as ME/CFS, an appropriately planned evaluation may consider physical tolerance, postural tolerance, pace, concentration, fatigue, symptom behavior and consistency of performance. Medical information, job demands and observations during testing can help place the findings in context.

The practical questions are straightforward. What can the person do now? How long can the activity be sustained? Are restrictions required? Can the performance reasonably be repeated in an ordinary working environment?

Documenting Function in Complex Disability Cases

ME/CFS can be difficult to describe because symptoms may fluctuate and important limitations are not necessarily obvious to an outside observer. Clear functional documentation can help physicians, insurers, attorneys, employers and disability professionals understand how a medical condition translates into everyday activity.

MEASURAbilities has provided Functional Capacity Evaluation services since 1997 and also offers Cognitive Functional Capacity Evaluations for complex medical and disability cases. To discuss whether an FCE or COG FCE may be appropriate for your client or case, contact Sandy Goldstein, PT, CDMS, at 480.285.6212.