• Welcome to Phoenix Rising!

    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of and finding treatments for complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia (FM), long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

    To become a member, simply click the Register button at the top right.

Chalder Fatigue Questionnaire is a valid & reliable measure of perceived fatigue severity in MS

Dolphin

Senior Member
Messages
17,567
Minority interest

Because of its use in quite a lot of ME/CFS research (including a lot of CBT and GET studies) I thought there might be somebody who was interested in this. I have read it myself as of yet.

Free full text: https://kclpure.kcl.ac.uk/portal/fi...gue_CFA_final_submitted_MS_JUNE_2015_v4_.docx


ACCEPTED VERSION-Proof copy

The Chalder Fatigue Questionnaire is a valid and reliable measure of perceived fatigue severity in multiple sclerosis


Joseph Chilcot1, Sam Norton1, Maedhbh Etain Kelly2, Rona Moss-Morris1


1Health Psychology Section, Psychology Department, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, UK

2 Department of Psychosis Studies, PO63, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK

Correspondence: Rona Moss-Morris (rona.moss-morris@kcl.ac.uk)

Health Psychology Section, Institute of Psychiatry, Psychology and Neuroscience King’s College London, 5th floor Bermondsey Wing, Guy’s Hospital Campus, London Bridge, London, SE1 9RT

Key words: Chalder fatigue questionnaire; Chalder fatigue scale; fatigue; multiple sclerosis; MS; psychometrics; measurement; confirmatory factor analysis


Conflict of interest: None declared

Abstract

Background: Fatigue is one of the most distressing symptoms of Multiple Sclerosis (MS). Measuring MS fatigue poses a number of challenges. Many measures confound definitions of severity and impact of fatigue and/or lack psychometric validation in MS.

Objective: To evaluate the psychometric properties of an 11 item fatigue severity measure, the Chalder Fatigue Questionnaire (CFQ) in MS including validity of the factor structure, internal reliability, discriminant validity, and sensitivity to change.

Methods: Data was pooled from four previous studies investigating MS-fatigue using the CFQ (n=444). Data analysis included confirmatory factor analysis to determine the factor structure and model fit, correlations to assess discriminant validity, and effects sizes to determine sensitivity to change.

Results: A bi-factor model with one general fatigue factor, incorporating 2 smaller group factors (mental and physical fatigue) had good model fit and appeared the most appropriate factor structure underlying the CFQ scale. The CFQ had high internal consistency, showed small to moderate correlations with impact of fatigue and mood, and was sensitive to change across low and high intensity behavioural interventions.

Conclusions: The CFQ measuring a composite of physical and mental fatigue severity (i.e. a total score) is a psychometrically sound measure of fatigue severity in MS.
 
Messages
13,774
So how come those with MS who've had CBT report having less fatigue than healthy controls? Seems like that might be a bit dodgy, eh?

I don't see how these sorts of studies can claims to be assessing 'validity' and 'reliability' unless they totally twist those words to mean something worthless (which does just seem to be acceptable in research of this sort).
 
Last edited:

daisybell

Senior Member
Messages
1,613
Location
New Zealand
Where do these researchers come from..... King's College London of course. No conflict of interest but a good dose of cronyism.
 

Snow Leopard

Hibernating
Messages
5,902
Location
South Australia
Factor analysis of questionnaires alone? Sigh.

Sensitivity to change from behavioural interventions is not proof of its validity at all. In fact, if percieved ratings improved, but objective function did not improve, then sensitivity to change from behavioural interventions in the absence of objective changes in functioning proves that it is invalid to use it in this context...
 
Last edited:

Sean

Senior Member
Messages
7,378
In fact, if percieved ratings improved, but objective function did not improve, then sensitivity to change from behavioural interventions in the absence of objective changes in functioning proves that it is invalid to use it in this context...
Worth repeating.
 

user9876

Senior Member
Messages
4,556
The questionaire
So how come those with MS who've had CBT report having less fatigue than healthy controls? Seems like that might be a bit dodgy, eh?

I don't see how these sorts of studies can claims to be assessing 'validity' and 'reliability' unless they totally twist those words to mean something worthless (which does just seem to be acceptable in research of this sort).


I've aways found the wording of this questionnaire confusing in that I've never been sure if it is trying to measure change in fatigue or fatigue levels in general. There answer catagories are in the form of 'less than normal'; 'no more than usual'; 'more than usual'; 'much more than usual'

So I believe that a healthy person would normally score 'no more than usual' on most questions. That is in the time period being asked about then its much the same as other (not well defined time periods).

For people who have been ill for a long time they say compare yourselves to when you were last well. But for people with chronic illness this can be difficult especially for people who have been ill for a long time. So some 'less than normals' could easily slip in especially given most questionaires are measuring state rather than change in state (e.g. the SF36 scale measures what activities you think you can do) so when given within a bank of questionnaires I think more linguistic confusion would occur.

So I don't find it surprising that people with MS could get better scores than healthy people because language of the questionnaire is so confused.
 

user9876

Senior Member
Messages
4,556
Wow, they don't even know how to validate a scale. Factor analysis lol

They also talk about it fitting a bi-factor model with mental and physical fatigue being different factors. What I don't understand is how you can expect to convert a two different factors into an interval scale which is assumed in the stats they are doing. Economists do this with something like the EQ5D scale by surveying a population and estimating a utility function that defines how different dimensions should be combined for a given population - but I think these are largely independant dimensions.

With the CFQ they have a a number of questions on physical fatigue, a different number of mental fatigue which are clearly correlated to a degree but not completely correlated. They then just sum these up and the bias in the number of questions weights physical fatigue as more important than mental fatigue.
 
Messages
15,786
It also sounds like a further foray into turning MS into a partially psychosomatic disease, and minimizing non-fatigue aspects:
Fatigue is reported as one of the most common and disabling symptoms of multiple sclerosis (MS)1, 2.
Somehow I doubt that many patients would agree, if any.
MS fatigue has been defined as “a subjective lack of physical and/or mental energy that is perceived by the individual or caregiver to interfere with usual and desired activities” 3, and remains a complex and debilitating phenomenon.
So they aren't really wiped out from being ill, they just think they are. Cue the psychobabblers!
Although attempts at objective measures of fatigability have been made, self-report questionnaires are the most common, and possibly the most effective way of evaluating fatigue in both research and clinical settings9, 10.
Unlike subjective symptoms, subjective questionnaire responses are obviously as real and meaningful as objective ones, if not more so :rolleyes: Well, they are if you're a quack whose turn-ons include baseless theories and research which is designed to support your preordained conclusions.

They're also using the Hospital Anxiety and Depression Scale on MS patients, which is a fairly good one for creating mood disorders out of thin air in chronic multi-system diseases with a lack of effective treatments. And, of course, concluding that fatigue and anxiety or depression are related based upon it. Though they aren't strongly pushing that angle (yet). My guess is that they'll follow up with another study focused on HADS and BDI responses, using this study to cite as support.
 
Last edited:

user9876

Senior Member
Messages
4,556
The questionaire



I've aways found the wording of this questionnaire confusing in that I've never been sure if it is trying to measure change in fatigue or fatigue levels in general. There answer catagories are in the form of 'less than normal'; 'no more than usual'; 'more than usual'; 'much more than usual'

So I believe that a healthy person would normally score 'no more than usual' on most questions. That is in the time period being asked about then its much the same as other (not well defined time periods).

For people who have been ill for a long time they say compare yourselves to when you were last well. But for people with chronic illness this can be difficult especially for people who have been ill for a long time. So some 'less than normals' could easily slip in especially given most questionaires are measuring state rather than change in state (e.g. the SF36 scale measures what activities you think you can do) so when given within a bank of questionnaires I think more linguistic confusion would occur.

So I don't find it surprising that people with MS could get better scores than healthy people because language of the questionnaire is so confused.

I was being slightly inaccurate here.

They use two different scoring systems in PACE. but in this paper they are looking at the binomial scoring where they group the better, same categories together and group the more than usual an much more than usual together. So a healthy person should generally score around 0 but the linguistics problems persist about what is more fatigue than normal (for a healthy person it could be they are tired due to a deadlines at work, a particularly busy social life etc...)

What is interesting about their scoring methods if you were to take 100 people who were distributed over the scale using their 'validated' binomial scoring then distribute them using the continuous scoring the order fatiguedness of the people would change. But in this paper they only cover the binomial but with PACE they had to change this so they could get better results.
 

user9876

Senior Member
Messages
4,556
I
They're also using the Hospital Anxiety and Depression Scale on MS patients, which is a fairly good one for creating mood disorders out of thin air in chronic multi-system diseases with a lack of effective treatments. And, of course, concluding that fatigue and anxiety or depression are related based upon it. Though they aren't strongly pushing that angle (yet). My guess is that they'll follow up with another study focused on HADS and BDI responses, using this study to cite as support.

Its interesting to validate a one scale by looking it against another with issues

http://www.jpsychores.com/article/S0022-3999(12)00093-1/fulltext
 

user9876

Senior Member
Messages
4,556
They also talk about it fitting a bi-factor model with mental and physical fatigue being different factors. What I don't understand is how you can expect to convert a two different factors into an interval scale which is assumed in the stats they are doing. Economists do this with something like the EQ5D scale by surveying a population and estimating a utility function that defines how different dimensions should be combined for a given population - but I think these are largely independant dimensions.

With the CFQ they have a a number of questions on physical fatigue, a different number of mental fatigue which are clearly correlated to a degree but not completely correlated. They then just sum these up and the bias in the number of questions weights physical fatigue as more important than mental fatigue.


Reading a bit more

A bi-factor model, containing a general fatigue factor, and two smaller group factors (physical and mental) most appropriately fitted the data. Items 6 and 7 correlated highly and appeared to measure something specific to weakness, rather than physical fatigue per se. Following examination of models with these items correlated, loaded onto a third group factor (weakness) or removed, model fit appeared most satisfactory when these items were removed. The two group-factors explained relatively low variance, whereas the general factor, with all 9-items loaded upon it, explained approximately 80% of the common variance. Therefore, whilst the CFQincludes two dimensions of fatigue, it remains sufficiently unidimensional for the total score (i.e. the sum-score) to be used as a reliable measure of general fatigue severity. The group factors remain only fragile indicators of separate constructs, namely, mental and physical fatigue. The saturation of total subscale scores by the general factor means the subscales would be unreliable indicators of the unique constructs, thus we recommend using the total score as a general fatigue measure in future studies. These findings support those of others20, 36, and casts significant doubt over the practical distinction between physical and mental constructs of fatigue in MS patients.

What they seem to be claiming is that there is a sufficient underlying factor of fatigue so that variations in mental and physical fatigue are small enough to be ignored. This may be because the scale is very course using a binomial marking scheme but I am still very suspicious particularly when measuring change (i.e. score at t0 as compared to score at t1) which I don't think they analyse.
 

Bob

Senior Member
Messages
16,455
Location
England (south coast)
The answer catagories are in the form of 'less than normal'; 'no more than usual'; 'more than usual'; 'much more than usual'
Any half-informed person with a modicum of common sense can see that the Chalder fatigue scale is a poorly designed and inadequate tool. It looks to me as if it's either been designed by very stupid people or by very clever people with an agenda; During the long course of a chronic illness, a patient will surely begin to be unable to recall precisely what 'healthy-normal' feels like, as 'healthy' becomes a distant memory, and as 'unhealthy' becomes the new 'normal' for them. For myself, for example, I've been ill for ten years, and it's difficult to easily recall those healthy summer days when I had boundless energy and could go for a long swim, followed by a walk, followed by a cycle in the sun etc. The new 'normal' is sitting on a sofa. So, if symptoms stay exactly the same, the Chalder fatigue scale will likely record a gradual improvement in health as the patient adjusts and acclimatises to their new situation, even without any improvement in symptoms, simply because of the inappropriate way the questions are worded. And/or the wording will cause consistent or sporadic confusion to the person answering the question unless the meaning of the questions have been repeatedly explained to them. So it's a perfect scale to use for a useless therapy if you want to demonstrate that the useless therapy is effective. It's such a basic common sense flaw that it shouldn't need a published paper to discredit this stupid scale. Then of course, there's the way the scale is inappropriate in terms of assessing severely affected patients, such that the scale can't record the difference between severe and very severe. This seems to cause bias in the scale such that deterioration can't be recorded in severely affected patients. So only improvements can be recorded in some patients. Again, this seems to be incredibly stupid or incredibly clever, depending on the agenda.
 
Last edited: