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​Latest research: Onset patterns and more

February 15, 2019

Supporting you to stay informed about M.E. research, we aim to publish regular round-ups of papers published in peer-reviewed journals.

Please note this is not an exhaustive list – we have selected to highlight the studies, all published this year, which we think are most likely to resonate with the daily lives of those affected by the condition. In each case, we have used the same name for the illness as the researchers publishing the paper. We will also report separately on further studies of significance, as and when they are published.

You can search online directory PubMed for most studies about M.E. published in peer-reviewed journals.

Onset patterns and course of M.E./CFS, Lily Chu and Jose Montoya

This epidemiology study gives a broad overview of potential causes and symptom patterns in M.E./CFS, in a sample of 150 subjects. All patients were at least 14 years old and fit the Fukuda criteria for M.E./CFS.

Participants completed a detailed survey concerning the initial and subsequent stages of their illness. Fifteen factors were available for associated onset; however, 61% of participants only selected one or two factors.

This study indicates that a gradual onset of symptoms preceded by an infectious event is the most common pattern in the development of M.E./CFS (64% of participants).

For 22% of participants it took one – six months for initial symptoms to turn in to consistent illness. 38% said it took over six months for the development of a full set of M.E./CFS symptoms.

Whilst stress/major life event was the second highest factor (39%) it was rarely chosen as the only precipitant – appearing mostly in conjunction with infection. This suggests that stress is not a causing factor but supports previous theories that suggest that stress, “decreases the immune system’s ability to fight off and contain infections.”

The Importance of accurate diagnosis of M.E./CFS in children and adolescents, Keith James Geraghty and Charles Adeniji

By using a collection of studies published between 1997 and the present, this research offers a detailed commentary on the history of diagnosis, research and treatment of M.E./CFS in young people. It argues that there is “considerable misdiagnosis of paediatric cases and over- inflation of estimates of paediatric M.E./CFS.”

The paper identifies the difficulties faced by medical professionals in diagnosing M.E./CFS in children and teenagers when fatigue is a common complaint amongst the age group. Here considering how broad diagnosis criteria for M.E./CFS, paired with a need for more robust screening methods for illnesses where fatigue is a symptom, inflate case estimates and create unreliability.

Previous studies suggest that mental health, depression and substance abuse are the leading causes of unexplained fatigue in young people, but that these can be misdiagnosed as M.E./CFS.

Some criteria’s failure to require screenings to include cardinal symptoms (such as post-exertional malaise) create room for misdiagnosis of M.E./CFS, which then allows unreliable recruitment of participant samples in research. He says: “Many teenagers with general chronic fatigue issues may meet UK Oxford/NICE criteria for M.E./CFS” and therefore evidence for therapies such as CBT and GET are “contaminated by the inclusion of significant numbers of false-positive cases.”

The authors conclude that new sampling strategies need to be agreed by researchers when investigating M.E./CFS, while medical professionals need to “use a comprehensive triangulation approach” in the diagnosis of M.E./CFS in young people.

Impairments in cognitive performance in CFS, Julia Newton et al.

This laboratory study investigated cognitive difficulties in CFS and depression, using a number of neuropsychological assessments that tested cognitive memory, speed and function (such as Verbal Working Memory and Intellectual Function tests).

All participants in this study met the Fukuda diagnostic criteria and there were two participant cohorts and a control group:

  • Cohort one - exploring cognitive performance in an unselected cohort of CFS patients. Patients were assessed by a clinician using a depression subscale of the Hospital Anxiety and Depression Scale. Anxiety and depression was found in 25 out of the 48 patients in this group.
  • The control group was also recruited through an advertisement in a local hospital and posters that were distributed in a local M.E. patient support group.
  • Cohort two - patients in this cohort were recruited using the same method as cohort one. However, patients in this cohort were excluded if they screened positive for a major depressive episode.

This study found cognitive impairments in all cohorts – even those where the variable of depression had been rigorously tested for and excluded. This suggests that whilst depression does impair cognitive functioning it is not the cause of the symptom in CFS patients.

Cohort one showed reductions in cognitive performance in three of the memory tests, whereas cohort two had significantly weaker performance in just one memory measure. This suggests that “memory deficits in CFS are less consistent and may perhaps depend on the exact nature of the tasks used to assess memory function.”

Cohort one and two’s results in psychomotor speed tests showed that patients with CFS had a reduced processing speed. This finding suggests that CFS patients experience a “general slowing of either basic perceptual-cognitive processes, basic motor responses or both.” Additionally, this result shows that cognitive slowing cannot be explained through depressive conditions, although this has shown to exacerbate symptoms.

The authors conclude that, while people with CFS do experience cognitive difficulties, these are only found in certain areas, such as slowing in basic processing speed. While depressive symptoms do exacerbate cognitive impairments in CFS, they are not responsible for the symptom itself.