Causes and consequences of autonomic dysfunction in Chronic Fatigue Syndrome (PhD thesis)

[Dolphin]

Disappointing overall result.

From: Dr. Marc-Alexander Fluks


Source: Newcastle University
Date: January 2016
URL: https://theses.ncl.ac.uk/dspace/handle/10443/3185
https://theses.ncl.ac.uk/dspace/bitstream/10443/3185/1/Maclachlan, L. (MD) 2016.pdf


Causes and consequences of autonomic dysfunction in Chronic Fatigue
Syndrome
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Laura Maclachlan
- Institute of Cellular Medicine, Faculty of Medical Sciences,
Newcastle University


Abstract

Introduction
Chronic Fatigue Syndrome (CFS) is an incapacitating condition characterised by extreme fatigue. In the absence of an objective diagnostic test CFS remains a clinical diagnosis based on a broad spectrum of symptoms, including autonomic dysfunction and cognitive impairment. This has given rise to significant challenges, not least the development of multiple sets of diagnostic criteria that may represent different disease phenotypes. This thesis examines autonomic and cognitive features between subgroups that meet different diagnostic criteria to better understand this possibility. It also examines the overlap between symptoms of CFS and depression, a potential confounder.

Methods
A subset of data from a larger Medical Research Council funded observational study Understanding the pathogenesis of autonomic dysfunction in CFS and its relationship with cognitive impairment was examined. Patients were screened using the SCID-I assessment tool to exclude major depression prior to the main study. Depressive symptoms were compared to CFS Fukuda criteria. The DePaul Symptom Questionnaire (DSQ) was used to differentiate between diagnostic criteria. COMPASS and COGFAIL questionnaires were administered for self-reported autonomic and cognitive features respectively. The Task Force(r) Monitor was used for autonomic assessment and a battery of neuropsychological tests administered for objective cognitive assessment.

Results
Subjective autonomic and cognitive symptoms were significantly greater in CFS subjects compared to controls. There were no statistically significant differences in objective autonomic measures between CFS and controls. There were clinically significant differences between DSQ subgroups on objective autonomic testing. Psychomotor speed was significantly slower in CFS compared to controls. Visuospatial memory, verbal memory and psychomotor speed were significantly different between DSQ subgroups.

Conclusion
The findings indicate phenotypic differences between DSQ subsets and suggest that elucidating the symptoms seen in CFS, or its disease spectrum, will support research into its underlying pathophysiology and enable more tailored treatment. The absence of significant differences in objective autonomic function between CFS and controls in this cohort contrasts to findings of some other studies and may reflect study exclusion for depression. Together with the overlap between CFS and depressive symptoms, this reinforces the need to better understand the underpinning causality to allow appropriate identification and management.

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(c) 2016 Newcastle University

 

[A.B.]

The absence of significant differences in objective autonomic function between CFS and controls in this cohort contrasts to findings of some other studies and may reflect study exclusion for depression.

That might have something to do with the test

autonomic assessment with the Task Force® Monitor for continuous beat - to - beat blood pressure and heart rate measurement comprising of a ten minute rest, two minute active stand and Valsalva manoeuvre;

 

[duncan]

I think Dr. Baraniuk's (Georgetown University) ANS testing in CFS patients is yielding significantly different results.

 

[taniaaust1]

Yes it looks like this researcher had no idea how to properly test for autonomic malfunctions , unfortunately most people will only look at the study results and not why issues werent found.

 

[Esther12]

Null results can be useful for letting us know what isn't there.

I've been wondering how much of the positive autonomic results we've seen are secondary to people being exhausted. I don't really know what I'm talking about, but I've read a few non-CFS autonomic papers that have made me think that it's an area where there's less understanding and certainty than I'd assumed in the past. (I've probably become more sceptical of all medical research post-PACE!)

 

[duncan]

Baraniuk's ANS efforts with CFS patients appear to point repeatedly to POTS and brain stem involvement, if I am not mistaken, and seem to suggest ample differences between HC's and CFS patients in terms of objective metrics, e.g HR and BP etc, before and AFTER exertion in many CFS patients.