Schillings, M L, Kalkman, J S, van der Werf, S P et al. · Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology · 2004 · DOI
This study compared how the brains and muscles of ME/CFS patients and healthy people control muscle strength during a sustained squeeze test. Researchers found that ME/CFS patients had weaker voluntary control from their brain to their muscles at the start of the task, even though their muscles themselves were less fatigued afterward. This suggests that in ME/CFS, the problem may originate from reduced brain-to-muscle signaling rather than muscle weakness itself.
This study provides objective neurophysiological evidence that reduced brain-to-muscle signaling contributes to exercise limitation in ME/CFS, moving beyond subjective symptom reporting. Understanding this central mechanism could help validate ME/CFS as a physiological condition and guide development of targeted interventions based on the underlying cause rather than symptoms alone.
This study does not prove that central activation failure is the only cause of exercise intolerance in ME/CFS, nor does it establish the specific neurological or biochemical mechanisms responsible for the impaired signaling. The cross-sectional design cannot determine whether reduced central activation is a primary disease feature or a secondary adaptation, and results are limited to a single muscle group in female participants only.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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