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Fatigue and fibromyalgia syndrome: Clinical and neurophysiologic pattern

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The concept of ‘fatigue’ is strictly related to parameters of the setting in which fatigue is measured. Therefore, it is mandatory to provide a definition of fatigue and the modalities of its use. This is of pivotal importance with regard to the fibromyalgia (FM) syndrome, where fatigue is the most invalidating symptom and where, paradoxically, no clear and widely accepted definition of fatigue is available in the literature as yet.

In the clinical setting, fatigue can be measured by different methods of various complexity. The simplest technique to assess fatigue involves the use of a visual analogue scale (VAS); however, a number of scales with differing levels of complexity are available for use. It is, often, difficult to detach the term ‘fatigue’ from tiredness and task failure, which correspond to two completely distinguished forms of fatigue: one with central origin (tiredness) and another which is localised within the muscle (peripheral muscle fatigue). The former is related to changes in motor-unit-recruitment strategies, whereas the latter is attributed to changes in membrane properties. To extensively assess fatigue and, partially, to avoid confusion among the types of fatigue described above, a number of laboratory tests have been developed; among these, there are multichannel surface electromyography (EMG) recordings. Using this type of an approach, it is possible the estimation of motor unit location within the muscle, the decomposition of the surface EMG (sEMG) interference signal into constituent trains of motor unit action potentials (MUAPs) and the analysis of single unit properties.

Section snippets

Fatigue in FM. a character in search of an author

Six Characters in Search of an Author is a play, written by the Nobel prize-winning Italian writer Luigi Pirandello, in which the director, who is about to begin the play, is unexpectedly interrupted by the arrival of six strange people who are characters in search of an author who can complete their story.

In certain ways, this is the situation with regard to fatigue in the fibromyalgia (FM) syndrome:Is fatigue a real character in the FM play or is it a character in search of its own, separate

Definition of fatigue

A definition of fatigue is essential for developing clinical and experimental measures that concur for diagnosis and treatment of the condition.

The definition of fatigue has been modified over time. Earlier, fatigue was defined as a transient phenomenon caused by physical activity and which lead to an inability to maintain the requisite or expected force [1]; here, fatigue is considered a reduction in the force-generating capacity of the neuromuscular system during an isometric maximal

Clinical features of fatigue in FM

It is surprising that it is quite impossible to identify, in the FM literature, a clear, acceptable and exhaustive definition of fatigue. Furthermore, the Merriam-Webster dictionary cannot be of assistance here because it defines fatigue as a weariness or exhaustion occurring from labour exertion or stress and, also, as the temporary loss of power to respond that is induced in a sensory receptor or motor-end organ by continued stimulation. With regard to the above definition of fatigue, from

Fatigue in the clinical setting

In the clinical setting, fatigue can be measured using different methods of various complexity [6]. The simplest method for assessing fatigue involves the use of the visual analogue scale (VAS). Studies using the VAS have reported that fatigue was identified in 88–98% of patients with rheumatic disease and was clinically relevant in more than 41% of patients with rheumatoid arthritis or osteoarthritis as well as in 76% of patients with FM [7].

In the healthy individual, fatigue is defined as the

Concluding remarks

Fatigue, as perceived and reported in the patient with FM, is the result of at least two different but interconnected mechanisms: a failure of central motor control and the remodelling of the muscle fibres related to an altered suprasegmental control [21]. These two aspects can be differently described in clinics with a range of clinical and neurophysiologic pictures extending from a disabling sensation of fatigue but with preservation of muscle-fibres composition (no or minimal prevalence of

References (24)

  • F. Wolfe et al.

    The prevalence and meaning of fatigue in rheumatic disease

    Journal of Rheumatology

    (1996)
  • N. Adams et al.

    Rehabilitation approaches in fibromyalgia

    Disability and Rehabilitation

    (2005)
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