Does “MS fatigue” capture the symptom experience?

  • Fatigue related to MS is poorly understood, and as a result, difficult to treat and manage for many people living with MS.
  • Fatigue is widely acknowledged as a major cause of inability to work and a cause of reduced quality of life for people living with MS.
  • Capturing the full experience and meaning of MS fatigue, and how it can be managed to improve quality of life for people with MS, remains an unmet need across international MS research.

Recent guidance from the International Progressive MS Alliance addressing MS symptoms highlights that very little progress has been made in treating and understanding one of the most debilitating MS-related symptoms: “MS fatigue”.

It has often been suggested that the term “MS fatigue” is confusing and challenging to understand, and is a poor descriptor of the condition, as it fails to capture the full spectrum of the experience for people with MS. Research suggests that the type of activity (or inactivity) undertaken by a person with MS, does not necessarily reflect the type of fatigue impairment they experience. That is, on some days, it is not caused by “overdoing it” or working too hard, but rather, extreme fatigue can occur regardless of the amount of activity undertaken. Whilst major advances in diagnosis, modifiable risk factors and treatments have dominated MS research in the last two decades, there has been a stalemate in understanding and treating the group of (often) “daily onset symptoms” that comprise of “MS fatigue”. MS fatigue can be described as tiredness, lassitude, and bone-deep exhaustion. In an article in the internationally recognised, Multiple Sclerosis Journal, researchers propose that the words “MS fatigue” cannot fully capture the symptom experience for people who feel this fatigue. To drive effective research and treatment into fatigue, the article authors are recommending that the MS community needs to work harder towards renaming this clinical diagnostic term.

The origins of MS fatigue

MS was first identified as a disease over 200 years ago. There has been steady progress made in understanding the course of MS, but very little leeway in understanding and treating MS-related fatigue. Back in 1890, fatiguability of mental functions (cognitive, or mind fatigue) was one of the first symptoms of MS described and attributed to the condition. Early in the twentieth century, myelin damage and inflammation in the central nervous system (brain, optic nerves and spine) was identified as a diagnostic of MS, together with an “inexplicable transitory daily tiredness”, which remained unnamed. By the mid-twentieth century, fatigue emerged as the clinical term to describe the tiredness observed in, and described by, people with MS. By the late twentieth century, the first fatigue measurement scales were developed, primarily as research tools to follow the progress of fatigue symptoms in clinical studies and trials. These tools however only heavily relied on the subjective responses of the person with MS. Currently, there is still no objective measure to assess fatigue in MS, which makes it difficult to assess and understand, and therefore difficult to treat and manage.

What are the authors proposing to change?

The proposal is to introduce new classifications and a framework to define and assess MS fatigue in a better way. Presently, there is difficulty in defining and assessing different types of fatigue, such as motor fatigue (from exercise and activity), tiredness, cognitive fatigue (feeling mentally tired), central fatigue (caused by damage in the central nervous system) and performance fatigue (tiredness from performing set tasks), as well as differences in the way a healthcare professional and patient report and communicate about fatigue. It has been suggested that renaming this diagnostic term to reflect the cause and breadth of the fatigue experience, might be helpful and assist to drive more effective research and management into the condition. The authors are recommending an international MS initiative is set up to progress this further and present the renaming criteria to the World Health Organisation for consideration. Potential early suggestions to rename MS fatigue include:

  • Central neurophysiological dysnervation/denervation (denervation means to cut a nerve supply)
  • Transitory multifocal central nervous system denervation
  • Cyclic lesion inflammation

The process to rename a recognised symptom is a rigorous and challenging process and will require multidisciplinary engagement, using expertise from all specialities of MS healthcare.

How can this process help people with MS?

Although many things about living with MS have improved in recent times, the prognosis of living with the daily onset of MS fatigue has not. It has been suggested that maintaining this inappropriate label hinders clinical research primarily because if it is hard to measure and describe, it is difficult to then assess whether treatments and interventions have made a difference. If we can break the cycle and offer changes which reflect a better understanding of the whole fatigue condition, this could potentially lead to research which provides a deeper understanding of the neuroprocesses involved in fatigue. This, in turn, would support changes to how we treat and manage MS fatigue.

MS Australia has funded previous fatigue research (see the project details here and here), and together with the International Progressive MS Alliance, supports the call to action to advance fatigue research in MS. Addressing the needs of people living with MS struggling with fatigue, could lead to an improved quality of life, improved communication of symptoms with healthcare professionals, enhanced relationships with family, friends and employers and less social isolation. Importantly, we would be addressing a major gap in understanding MS that has remained for over 200 years.

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Does “MS fatigue” capture the symptom experience?