ME Research UK comments on research into muscle weakness, July 21 2015:
One of the key difficulties that ME/CFS patients face is standing (orthostasis), particularly standing still. For them, simply being upright can trigger a cluster of symptoms, such as dizziness, altered vision, nausea, fatigue, headache or sweating. This ‘orthostatic intolerance’ can have many causes (see our article, “Standing up for ME”), but a lack of endurance in the muscles of the trunk, which maintain the upright position, could be a contributing factor, as a new study shows.
For the investigation, researchers at Antwerp University Hospital recruited 72 women with ME/CFS, 30 women with osteoporosis (who also have standing problems) and 55 healthy women. All underwent a timed-loaded standing test which measures how long a person can hold a 1 kg dumbbell in each hand in front of her with straight arms.
This test assesses combined trunk and arm endurance, and is intended to simulate the performance of the torso during everyday activities. As expected, timed-loaded standing was significantly shorter in patients with osteoporosis (84.5 seconds on average) than in the healthy women (165 seconds).
In women with ME/CFS, however, timed-loaded standing was significantly lower (50 seconds) than in either of these groups. The authors note that problems with standing upright and physical activity are similar in ME/CFS and osteoporosis patients – both groups have problems keeping their spines vertical (read the report). This, and the specific biomechanical weakness identified in the women with ME/CFS, certainly needs further investigation.
This research group in Belgium had previously examined upper limb muscle recovery – a feature that had never been subjected to research in ME/CFS patients, despite the fact that these muscles are most frequently used for everyday activities, such as combing and washing hair, ironing and cooking (report).
After an exercise challenge consisting of 18 maximal contractions and a recovery phase of 45 minutes, muscle recovery was significantly slower in ME/CFS patients than healthy people (muscle strength was still recovering 30-45 minutes after the exercise).
Intriguingly, this was only true for patients who also fulfilled the 2010 criteria for fibromyalgia, i.e. who had a high degree of “widespread pain” as well as the symptoms shared with ME/CFS. As many ME/CFS patients fall into this category (see our funded study ‘Pain characteristics’), the test could be a simple way of objectively measuring muscle impairment in a substantial number of people. The fact that muscle recovery of the upper limb muscles was NOT delayed in an equivalent experiment in multiple sclerosis patients makes the findings even more intriguing (read more).
Both investigations show that relatively simple, easy-to-perform measurements – such as the endurance of the muscles in the trunk and arms, or the change in upper arm strength over a short period – can yield potentially important clinical information about biomechanical weakness in ME/CFS. Historically, muscle fatigability and weakness, often in response to minor degrees of exercise, was a characteristic feature of ME (read more), and muscle cramps, fasciculations (twitching) and extreme muscle tenderness were also common findings (read more). These aspects are rarely discussed in the modern literature and are largely ignored by healthcare professionals today. Just how many ME/CFS patients have had a proper clinical examination of their affected muscles? Probably very few, if any – and this needs to change.
Sources
Timed loaded standing in female chronic fatigue syndrome compared with other populations. Eyskens JB, et al. JRRD, 2015; 52 (1).21-30. Read more (full text).
Recovery of upper limb muscle function in chronic fatigue syndrome with and without fibromyalgia. Ickmans K, et al. Eur J Clin Invest, 2014 Feb; 44(2): 153–9. Read more (abstract).
The Specificity of the C D C-1994 criteria for chronic fatigue syndrome: comparison of health status in three groups of patients who fulfill the criteria. Kennedy G, et al. Annals of Epidemiology, 2004 Feb; 14(2): 95–100. Read more (essay).
Ramsay AM. Epidemic neuromyasthenia 1955-1978. Postgraduate Medical Journal 1978; 54: 718-721. Read more (full text).
