Cognitive Behavioral Therapy -- thought by some to be the "cure" for CFS proved to be a failure in this test. Patients complained less about their impairments but the actual objectively-measured impairments themselves did not improve.
Proving once again what patients have been saying for years: you can tell us that we are not sick, you can try to make us believe that we are not sick, but in the long run, all the talking and positive thinking does not change the reality, because this is a virus, not a psychological problem, and viruses cannot be cured by talking about your problems.
To tell a CFS patient that their problems are all in their head is as insulting as telling a cancer patient they don't need surgery, just a head-shrinker.
* * *
Source: Journal of Neurology, Neurosurgery, and Psychiatry
Vol. 78, #4, pp 434-436
Date: March 21, 2007
URL: http://jnnp.bmj.com/cgi/content/full/78/4/434
http://www.jnnp.com
[Short report]
The effect of cognitive behaviour therapy for chronic fatigue syndrome on
self-reported cognitive impairments and neuropsychological test performance
---------------------------------------------------------------------------
Hans Knoop, Judith B Prins, Maja Stulemeijer, Jos W M van der Meer, Gijs
Bleijenberg
Hans Knoop, Gijs Bleijenberg, Expert Centre Chronic Fatigue, Radboud
University Nijmegen Medical Centre, Nijmegen, The Netherlands
Judith B Prins, Maja Stulemeijer, Department of Medical Psychology, Radboud
University Nijmegen Medical Centre, Nijmegen, The Netherlands
Jos W M van der Meer, Department of Internal Medicine, Radboud University
Nijmegen Medical Centre, Nijmegen, The Netherlands
Correspondence to: H Knoop, Expert Centre Chronic Fatigue, Radboud University
Nijmegen Medical Centre, P O Box 9011, 6525 EC Nijmegen, The Netherlands;
j.knoop@nkcv.umcn.nl
Received 26 June 2006
Revised 14 November 2006
Accepted 15 November 2006
Abstract
Background
Patients with chronic fatigue syndrome (CFS) often have concentration and
memory problems. Neuropsychological test performance is impaired in at least
a subgroup of patients with CFS. Cognitive behavioural therapy (CBT) for CFS
leads to a reduction in fatigue and disabilities.
Aim
To test the hypothesis that CBT results in a reduction of self-reported
cognitive impairment and in an improved neuropsychological test performance.
Methods
Data of two previous randomised controlled trials were used. One study
compared CBT for adult patients with CFS, with two control conditions. The
second study compared CBT for adolescent patients with a waiting list
condition. Self-reported cognitive impairment was assessed with
questionnaires. Information speed was measured with simple and choice
reaction time tasks. Adults also completed the symbol digit-modalities task,
a measure of complex attentional function.
Results
In both studies, the level of self-reported cognitive impairment decreased
significantly more after CBT than in the control conditions. Neuropsychological
test performance did not improve.
Conclusions
CBT leads to a reduction in self-reported cognitive impairment, but not to
improved neuropsychological test performance. The findings of this study
support the idea that the distorted perception of cognitive processes is more
central to CFS than actual cognitive performance.
Abbreviations: CBT, cognitive behavioural therapy; CFS, chronic fatigue
syndrome; CIS, checklist individual strength; CIS-conc, checklist individual
strength-concentration; SDMT, symbol digit modalities task; SIP-ab, sickness
impact profile-alertness behaviour; SOCI, self-observation of cognitive
impairment
--------------------------------------------------------------------------------
Chronic fatigue syndrome (CFS) is characterised by severe fatigue, lasting
longer than 6 months and leading to functional impairment. The fatigue is not
the result of a known organic disease or ongoing exertion, and not alleviated
by rest. According to the Centre for Disease Control definition of CFS,
impaired concentration and/or memory is an additional symptom criterion.1 The
level of self-reported cognitive impairments in CFS is high2 and contributes
to the social and occupational dysfunctions of patients with CFS.3
Studies evaluating neuropsychological functioning in patients with CFS with
neuropsychological tests yielded conflicting results.4 Reduced speed of
(complex) information processing is the most consistently found impairment.3
5 6 However, several studies found no cognitive impairments7 and other
studies identified a subset of patients with defective performance.8 9
Fatigue-related cognitions and behaviour can perpetuate CFS.10 Several
controlled trials have shown that cognitive behavioural therapy (CBT) aimed
at these perpetuating factors leads to a reduction in fatigue and
disabilities.11
The first hypothesis tested was that CBT for CFS also results in a reduction
of self-reported cognitive impairments. The second hypothesis was that the
neuropsychological test performance of patients with CFS improves after CBT.
Data of two previous CBT trials12 13 were used to test the hypotheses.
MATERIALS AND METHODS
Patients
The first study from which data were used compared the effects of CBT for
adults with CFS with natural course and support groups12 in a multicentre
randomised controlled trial. Assessments were done at baseline, and at 8 and
14 months. An intention-to-treat analysis showed a reduction in fatigue and
functional impairment after CBT. In two of the three participating treatment
centres, neuropsychological tests were part of the assessments. Consequently,
data from neuropsychological test performance were available for a subset of
233 (78 CBT; 76 natural course; 79 support group) of the total group of 278
patients. The mean (SD) age of this group was 36.8 (10.2) years, 182 (78%)
were female and median illness duration was 41 months. The second study was a
randomised controlled trial comparing CBT for adolescents with CFS13 with a
waiting list condition. A total of 69 patients were randomly assigned to the
conditions. Assessments were done at baseline and at 5 months. The results
showed a greater decrease in fatigue and functional impairment in the CBT
group. Neuropsychological data of 67 patients were available (33 CBT; 34
waiting list). The mean (SD) age of the group was 15.6 (1.3) years, 59 (88%)
were female and median illness duration was 18 months.
Questionnaires assessing self-reported cognitive impairments
Checklist individual strength-concentration
In both studies, the severity of concentration problems over the past 2 weeks
was assessed with the subscale concentration of the checklist individual
strength (CIS) that consists of five items on a seven-point scale. The score
can range between 5 and 35.3 12 13
Sickness impact profile-alertness behaviour
In adults, the self-observed effect of cognitive impairments on daily
functioning was assessed with the subscale sickness impact profile-alertness
behaviour (SIP-ab) of the sickness impact profile.14 The subscale has 10
items, each item is weighed and the score can range between 0 and 777. No
such instrument was available for adolescents.
Self-observation of cognitive impairment
In adolescents, the frequency of cognitive impairments was determined with a
structured diary. Patients rated both concentration and memory impairment
separately on a daily self-observation list four times a day for 12 days
(0=no impairment; 1=impaired). The percentage of concentration problems and
memory problems (both number of assessments with a problem divided by 48
times 100) were added and then divided by two to calculate the mean
percentage of incidents of cognitive impairment.
Neuropsychological tests
Reaction time task
The reaction time task consisted of two subtests, simple and choice reaction
time tasks. Both are described in detail elsewhere.8 15 In a previous study,
the reaction times of patients with CFS were slower than that of healthy
controls on both tasks.8
Symbol digit modalities task
The symbol digit modalities task (SDMT)16 was used in the adult study as a
measure of complex attention. In previous studies, patients with CFS scored
lower than a matched healthy control group.8 9
Statistical analysis
Statistical analysis was performed using SPSS V.12.01. Significance was
assumed at p,0.05. A multivariate analysis of variance was performed with
self-reported cognitive impairment and reaction time as dependent variables
and treatment as fixed factor. Univariate tests and post hoc analysis are
reported if the multivariate test was significant. For the SDMT, a univariate
analysis was performed, as data were available for a subset of 174 patients
as the SDMT was added later to the test battery. In the adult study, the
dependent variables were the change scores at 14 months from baseline and in
the adolescent study, it was at 5 months from baseline. Reaction times were
transformed by a logarithm transformation. For adults, if data at 14 months
were missing and data 8-months post-treatment were available, the second were
used. In all other cases, missing data were replaced with estimates derived
by single imputation (missing variable analysis regression in SPSS with
baseline value as predictor). For significant treatment effects, effect sizes
were calculated.
RESULTS
Nineteen adult patients (8%) had missing checklist individual
strength-concentration (CIS-conc) and SIP-ab post-treatment data. One patient
had missing data on both reaction time tasks at baseline, for 44 (19%)
patients only baseline data and for 30 (17%) patients only a baseline SDMT
score was available. Two adolescent patients had no SOCI scores at baseline.
For 4 (6%) patients the CIS-conc and SOCI at second assessment were missing.
Two patients had no baseline reaction time and for 13 (20%) adolescents the
reaction times at the second assessment were missing.
In both studies, there were more data missing from neuropsychological tests
than from questionnaires as some patients were willing to mail the
questionnaires, but refused to undergo a second neuropsychological
assessment.
Self-reported cognitive impairments
Adults
The multivariate test (Pillai's trace) showed a significant change in
self-reported cognitive impairments (F(4,460)=4.76; p=0.001). The univariate
tests showed a significant effect of treatment on the change in CIS-conc and
SIP-ab (F(2,230)=8.94; p<0.001 and F(2,230)=4.42; p=0.013). Following CBT,
the decrease in CIS was significantly greater than in both the natural course
(p,0.001) and the support group (p=0.001; table 1). There was a significantly
greater decrease in SIP-ab score after CBT compared with natural course
(p=0.004). The difference between CBT and support group failed to reach
significance (p=0.055).
Adolescents
The multivariate test showed a significant treatment effect on self-reported
cognitive impairments (F2,62=5.03; p=0.009). Univariate tests showed that the
decrease in the CIS-conc and SOCI score was significantly larger in the CBT
group (F(1,63)=6.4; p=0.014 and F(1,63)=6.28; p=0.015).
Neuropsychological test performance
Adults
There was no significant effect of treatment on either reaction time task
(F(4,458)=0.44; p=0.783). There was no significant treatment effect on the
SDMT (F(2,171)=0.73; p=0.484).
Adolescents Multivariate tests showed no significant treatment effect on
either reaction time task (F(2,62)=0.34; p=0.714).
DISCUSSION
The hypothesis that self-reported cognitive impairments decrease after CBT in
patients with CFS was confirmed. Only one comparison in the adult study,
measuring cognitive impairments more indirectly, showed an effect in the
expected direction without reaching significance. The results of the original
adolescent study13 already indicated that concentration problems decrease
after CBT. In that study, the concentration problems were assessed with a
single item evaluating these problems retrospectively over a period of 6
months. This assessment can be easily influenced by situational circumstances
and memory biases, which can be prevented by the use of a diary as in the
present study. No support could be found for the hypothesis that
neuropsychological test performance improves after CBT.
A methodological problem is that in a substantial part of the patients the
neuropsychological data of the second assessment were missing. Furthermore,
in our analysis we assumed that dropout occurred at random, whereas patients
may drop out for non-random reasons. We repeated the analyses, but only on
patients who completed both assessments. Again, there was no significant
treatment effect. Our interpretation is that this indicates that improvement
in self-reported cognitive impairments after CBT is independent of the change
in neuropsychological test performance.
A discrepancy between subjectively reported disabilities versus objectively
measured performance is not limited to the current study. Mahurin et al17
found that the objective cognitive functioning of monozygotic twins
discordant for CFS did not differ, whereas the twin with CFS reported more
cognitive impairments. Metzger and Denney18 showed that patients with CFS
underestimated their cognitive performance. In the study by Vercoulen et al,8
most patients with CFS reported concentration and memory problems, whereas
only a small percentage showed an impaired performance. Given the fact that
patients with CFS perceive their cognitive processes as impaired but
underestimate their actual performance, one would expect that an effective
treatment of CFS would lead to a more accurate perception of one's
performance. The results of the present study are consistent with this
prediction. CBT resulted in decreased complaints about cognitive functioning,
but not in a change in performance. This is also in line with the hypothesis
that a distorted perception of symptoms and performance is a crucial element
of CFS.10
ACKNOWLEDGEMENTS
The authors thank Theo Fiselier for contributing to the selection of
adolescent patients with CFS, Lammy Elving for contributing to the selection
of adult patients and Ria te Winkel and Lida Nabuurs for assisting in data
collection.
Funding: The Health Insurance Council (College van Zorgverzekeraars) funded
the adult CBT study. The Children's Welfare Stamps Netherlands (Stichting
Kinderpostzegels Nederland) and the ME Foundation (ME Stichting) funded the
adolescent CBT study.
Competing interests: none.
TABLE
Table 1 Estimated treatment effect in change score (95% CI) on the dependent variables
------------------------------------------------------------------------------------------------------
Self-reported cognitive impairments
Adults CBT Natural course Support group
CIS-conc -7.4 (-9.1 to -5.7)+ -2.7 (-4.4 to -1.0)** -3.4 (-5.1 to -1.8)**
SIP-ab -116 (-156 to -76)++ -31 (-72 to -10)** -61 (-100 to -21)
Adolescents CBT Waiting list
CIS-conc -6.8 (-10.5 to -3.5)+++ -0.9 (-4.2 to +2.5)*
SOCI -7.9 (-12.8 to -2.9)1 0.9 (-4.1 to +6.0)*
------------------------------------------------------------------------------------------------------
Neuropsychological test performance
Adults CBT Natural course Support group
Simple reaction time (ms) 9 (-9 to 27) -5 (-23 to 14) 6 (-12 to 24)
Choice reaction time (ms) -24 (-51 to 3) -27 (-54 to 1) -26 (-53 to 1)
SDMT 2.8 (0.8 to 4.8) 2.3 (0.2 to 4.4) 4 (2 to 6)
Adolescents CBT Waiting list
Simple reaction time (ms) -30 (-53 to -8) -18 (-41 to 4)
Choice reaction time (ms) -12 (-29 to 6) -10 (-28 to 8)
------------------------------------------------------------------------------------------------------
CBT, cognitive behavioural therapy; CIS-conc, checklist individual strength-concentration; SDMT,
symbol digit modalities task; SIP-ab, sickness impact profile-alertness behaviour; SOCI, self-
observation of cognitive impairment.
* Significantly different from the CBT condition, p,0.05.
** Significantly different from the CBT condition, p,0.01.
+ Cohen's d based on change within treatment condition=1.3.
++ Cohen's d=0.6.
+++ Cohen's d=0.4.
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