Neurocognitive impairment in childhood chronic fatigue syndrome

Abstract:

Neurocognitive impairment is a feature of childhood chronic fatigue syndrome (CCFS). Several studies have demonstrated reduced attention control in CCFS patients in switching and divided attention tasks. In students, the extent of deterioration in task performance depends on the level of fatigue.

Poor performance in switching and divided attention is common in both fatigued students and CCFS patients. Additionally, attentional functions show dramatic development from childhood to adolescence, suggesting that abnormal development of switching and divided attention may be induced by chronic fatigue.

The brain structures associated with attentional control are situated in the frontal and parietal cortices, which are the last to mature, suggesting that severe fatigue in CCFS patients and students may inhibit normal structural and functional development in these regions. A combination of treatment with cognitive behavioral therapy and antidepressant medication is effective to improve attentional control processing in CCFS patients. Studies identifying the features of neurocognitive impairment in CCFS have improved our current understanding of the neurophysiological mechanisms of CCFS.

 

Source: Mizuno K, Watanabe Y. Neurocognitive impairment in childhood chronic fatigue syndrome. Front Physiol. 2013 Apr 19;4:87. doi: 10.3389/fphys.2013.00087. ECollection 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3630366/ (Full article)

 

Depression in paediatric chronic fatigue syndrome

Abstract:

OBJECTIVE: To describe the prevalence of depression in children with chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and investigate the relationship between depression in CFS/ME and clinical symptoms such as fatigue, disability, pain and school attendance.

DESIGN: Cross-sectional survey data using the Hospital Anxiety and Depression Scale (HADS) collected at assessment.

SETTING: Specialist paediatric CFS/ME service in the South West.

PATIENTS: Children aged 12-18 years with CFS/ME.

MAIN OUTCOME MEASURE: Depression was defined as scoring >9 on the HADS depression scale.

RESULTS: 542 subjects had complete data for the HADS and 29% (156/542) (95% CI 25% to 33%) had depression. In a univariable analysis, female sex, poorer school attendance, and higher levels of fatigue, disability, pain, and anxiety were associated with higher odds of depression. Age of child and duration of illness were not associated with depression. In a multivariable analysis, the factors most strongly associated with depression were disability, with higher scores on the physical function subscale of the 36 item Short Form (SF-36).

CONCLUSIONS: Depression is commonly comorbid with CFS/ME, much more common than in the general population, and is associated with markers of disease severity. It is important to screen for, identify and treat depression in this population.

 

Source: Bould H, Collin SM, Lewis G, Rimes K, Crawley E. Depression in paediatric chronic fatigue syndrome. Arch Dis Child. 2013 Jun;98(6):425-8. doi: 10.1136/archdischild-2012-303396. Epub 2013 Apr 25. https://www.ncbi.nlm.nih.gov/pubmed/23619200

 

Could mitochondrial dysfunction be a differentiating marker between chronic fatigue syndrome and fibromyalgia?

Abstract:

Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are complex and serious illnesses that affect approximately 2.5% and 5% of the general population worldwide, respectively. The etiology is unknown; however, recent studies suggest that mitochondrial dysfunction has been involved in the pathophysiology of both conditions. We have investigated the possible association between mitochondrial biogenesis and oxidative stress in patients with CFS and FM.

We studied 23 CFS patients, 20 FM patients, and 15 healthy controls. Peripheral blood mononuclear cell showed decreased levels of Coenzyme Q10 from CFS patients (p<0.001 compared with controls) and from FM subjects (p<0.001 compared with controls) and ATP levels for CFS patients (p<0.001 compared with controls) and for FM subjects (p<0.001 compared with controls).

On the contrary, CFS/FM patients had significantly increased levels of lipid peroxidation, respectively (p<0.001 for both CFS and FM patients with regard to controls) that were indicative of oxidative stress-induced damage. Mitochondrial citrate synthase activity was significantly lower in FM patients (p<0.001) and, however, in CFS, it resulted in similar levels than controls. Mitochondrial DNA content (mtDNA/gDNA ratio) was normal in CFS and reduced in FM patients versus healthy controls, respectively (p<0.001). Expression levels of peroxisome proliferator-activated receptor gamma-coactivator 1-alpha and transcription factor A, mitochondrial by immunoblotting were significantly lower in FM patients (p<0.001) and were normal in CFS subjects compared with healthy controls.

These data lead to the hypothesis that mitochondrial dysfunction-dependent events could be a marker of differentiation between CFS and FM, indicating the mitochondria as a new potential therapeutic target for these conditions.

 

Source: Castro-Marrero J, Cordero MD, Sáez-Francas N, Jimenez-Gutierrez C, Aguilar-Montilla FJ, Aliste L, Alegre-Martin J. Could mitochondrial dysfunction be a differentiating marker between chronic fatigue syndrome and fibromyalgia? Antioxid Redox Signal. 2013 Nov 20;19(15):1855-60. doi: 10.1089/ars.2013.5346. Epub 2013 May 29. https://www.ncbi.nlm.nih.gov/pubmed/23600892

 

Moderators of the treatment response to guided self-instruction for chronic fatigue syndrome

Abstract:

OBJECTIVE: The efficiency and efficacy of guided self-instruction for chronic fatigue syndrome (CFS) can be enhanced if it is known which patients will benefit from the intervention. This study aimed to identify moderators of treatment response.

METHODS: This study is a secondary analysis of two randomized controlled trials evaluating the efficacy of guided self-instruction for CFS. A sample of 261 patients fulfilling US Center for Disease Control and Prevention criteria for CFS was randomly allocated to guided self-instruction or a wait list. The following potential treatment moderators were selected from the literature: age, fatigue severity, level of physical functioning, pain, level of depressive symptoms, self-efficacy with respect to fatigue, somatic attributions, avoidance of activity, and focus on bodily symptoms. Logistic and linear regression analyses were used with interaction term between treatment response and the potential moderator.

RESULTS: Age, level of depression, and avoidance of activity moderated the response to guided self-instruction. Patients who were young, had low levels of depressive symptoms, and who had a low tendency to avoid activity benefited more from the intervention than older patients and patients with high levels of depressive symptoms and a strong tendency to avoid activity.

CONCLUSION: Guided self-instruction is exclusively aimed at cognitions and behaviours that perpetuate fatigue. Patients with severe depressive symptom may need more specific interventions aimed at the reduction of depressive symptoms to profit from the intervention. Therefore we suggest that patients with substantial depressive symptoms be directly referred to regular cognitive behaviour therapy.

Copyright © 2013 Elsevier Inc. All rights reserved.

 

Source: Tummers M, Knoop H, van Dam A, Bleijenberg G. Moderators of the treatment response to guided self-instruction for chronic fatigue syndrome. J Psychosom Res. 2013 May;74(5):373-7. doi: 10.1016/j.jpsychores.2013.01.007. Epub 2013 Mar 5. https://www.ncbi.nlm.nih.gov/pubmed/23597323

 

Cognitive behavior therapy in patients with chronic fatigue syndrome: the role of illness acceptance and neuroticism

Abstract:

OBJECTIVE: Increasing the quality of life (QoL) of patients with chronic fatigue is challenging because recovery is seldom achieved. Therefore, it is important to identify processes that improve QoL. This study examined the extent of improvement related to cognitive behavior group therapy (CBT), and whether improvement is affected by initial levels of acceptance and neuroticism.

METHODS: Eighty CFS patients followed CBT, and self-reported (pre-post design) on mental and physical QoL (MQoL and PQoL), fatigue, acceptance, and neuroticism. The extent of improvement was analyzed using t-tests, effect sizes, and clinically significant change criteria. Whether acceptance and neuroticism at baseline predicted changes was analyzed by means of correlation and regression analyses.

RESULTS: Significant improvement was found for all variables. The effect size for MQoL and PQoL was small; for acceptance and fatigue, effect size was moderate. About 20% (MQoL) to 40% (fatigue) of the participants clinically improved. Pre-treatment level of acceptance was negatively correlated with changes in MQoL, not with PQoL changes. Neuroticism pre-treatment was positively related with MQoL changes. Regression analysis showed an effect of acceptance on changes in MQoL beyond the effect of neuroticism.

CONCLUSIONS: Although CBT is an evidence-based treatment, the sizes of the effects are often small regarding QoL. Our study also revealed small effect sizes. Our study showed that patient characteristics at baseline were significantly associated with MQoL outcome; indicating that CFS patients with high neuroticism or with a low acceptance show more improvement in MQoL. We propose to specifically target acceptance and neuroticism before treatment in order to maximize clinical relevance.

Copyright © 2013 Elsevier Inc. All rights reserved.

 

Source: Poppe C, Petrovic M, Vogelaers D, Crombez G. Cognitive behavior therapy in patients with chronic fatigue syndrome: the role of illness acceptance and neuroticism. J Psychosom Res. 2013 May;74(5):367-72. doi: 10.1016/j.jpsychores.2013.02.011. Epub 2013 Mar 25. https://www.ncbi.nlm.nih.gov/pubmed/23597322

 

Couples’ experiences of interacting with outside others in chronic fatigue syndrome: a qualitative study

Abstract:

OBJECTIVES: Social isolation and stigma are frequently reported by patients with chronic fatigue syndrome/myalgic encephalomyelitis and relationships in the home environment with those close to the patients (their ‘significant others’) may thus be particularly important. Rather little attention has yet been paid to the beliefs and experiences of ‘significant others’ themselves in this context. This study sought to explore in-depth the beliefs and experiences of both patients and ‘significant others’ in relation to chronic fatigue syndrome/myalgic encephalomyelitis.

METHODS: In-depth interviews using a semi-structured interview schedule designed around the core constructs of the Common-Sense Model of self-regulation were conducted with two patients with chronic fatigue syndrome/myalgic encephalomyelitis and their spouses. Interpretative Phenomenological Analysis was used to analyse interview data.

RESULTS: Experiences of social interactions in relation to chronic fatigue syndrome/myalgic encephalomyelitis with others outside of the relationship dyad emerged as a key issue for all participants when reflecting on their experiences of living with the condition. These concerns are presented under two themes: interactions with healthcare professionals and interactions with the social world.

CONCLUSIONS: It is evident that significant others play an important role in the lived experience of chronic fatigue syndrome/myalgic encephalomyelitis. For both patients and significant others, the wider social world and interactions with outside others may be important influences on dyadic coping in chronic fatigue syndrome/myalgic encephalomyelitis. Both future research and treatment interventions could usefully include a ‘significant other’ perspective.

 

Source: Brooks J, King N, Wearden A. Couples’ experiences of interacting with outside others in chronic fatigue syndrome: a qualitative study. Chronic Illn. 2014 Mar;10(1):5-17. doi: 10.1177/1742395312474478. Epub 2013 Apr 12. https://www.ncbi.nlm.nih.gov/pubmed/23585635

Examining the energy envelope and associated symptom patterns in chronic fatigue syndrome: does coping matter?

Abstract:

OBJECTIVE/Hypothesis: The objective of this study was to examine sub-types of individuals with chronic fatigue syndrome based on variables that are associated with the energy envelope theory and to examine the role of coping strategies in explaining the differences found between the subtypes.

METHODS: Cluster analysis was used. Grouping variables included physical functioning, post-exertional malaise severity, and the extent to which an individual was outside of the energy envelope. These clusters were evaluated using discriminant function analysis to determine whether they could be differentiated based on coping styles.

RESULTS: Cluster analysis identified three groups. Clusters 1 and 2 were consistent with the energy envelope theory. However, Cluster 3 was characterized by patients with the most impairment, but they were to a lesser extent exceeding their energy envelope. Coping strategies explained a small percentage (10%) of the variance in differentiating the clusters.

DISCUSSION: Energy maintenance may be associated with improved functioning and less severe symptoms for some. However, patients in Cluster 3 were closer to remaining within their energy envelope and also used higher levels of adaptive coping but were more impaired than Cluster 2. This suggests that adaptive coping strategies were not associated with improved health, as members of Cluster 3 were severely limited in functioning.

 

Source: Brown AA, Evans MA, Jason LA. Examining the energy envelope and associated symptom patterns in chronic fatigue syndrome: does coping matter? Chronic Illn. 2013 Dec;9(4):302-11. doi: 10.1177/1742395313478220. Epub 2013 Apr 12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3893101/ (Full article)

 

Detection of mycotoxins in patients with chronic fatigue syndrome

Abstract:

Over the past 20 years, exposure to mycotoxin producing mold has been recognized as a significant health risk. Scientific literature has demonstrated mycotoxins as possible causes of human disease in water-damaged buildings (WDB). This study was conducted to determine if selected mycotoxins could be identified in human urine from patients suffering from chronic fatigue syndrome (CFS).

Patients (n = 112) with a prior diagnosis of CFS were evaluated for mold exposure and the presence of mycotoxins in their urine. Urine was tested for aflatoxins (AT), ochratoxin A (OTA) and macrocyclic trichothecenes (MT) using Enzyme Linked Immunosorbent Assays (ELISA). Urine specimens from 104 of 112 patients (93%) were positive for at least one mycotoxin (one in the equivocal range).

Almost 30% of the cases had more than one mycotoxin present. OTA was the most prevalent mycotoxin detected (83%) with MT as the next most common (44%). Exposure histories indicated current and/or past exposure to WDB in over 90% of cases. Environmental testing was performed in the WDB from a subset of these patients.

This testing revealed the presence of potentially mycotoxin producing mold species and mycotoxins in the environment of the WDB. Prior testing in a healthy control population with no history of exposure to a WDB or moldy environment (n = 55) by the same laboratory, utilizing the same methods, revealed no positive cases at the limits of detection.

 

Source: Brewer JH, Thrasher JD, Straus DC, Madison RA, Hooper D. Detection of mycotoxins in patients with chronic fatigue syndrome. Toxins (Basel). 2013 Apr 11;5(4):605-17. doi: 10.3390/toxins5040605. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705282/ (Full article)

 

Caught in the thickness of brain fog: exploring the cognitive symptoms of Chronic Fatigue Syndrome

Abstract:

Chronic Fatigue Syndrome (CFS) is defined as greater than 6 months of persistent fatigue that is experienced physically and cognitively. The cognitive symptoms are generally thought to be a mild cognitive impairment, but individuals with CFS subjectively describe them as “brain fog.” The impairment is not fully understood and often is described as slow thinking, difficulty focusing, confusion, lack of concentration, forgetfulness, or a haziness in thought processes.

Causes of “brain fog” and mild cognitive impairment have been investigated. Possible physiological correlates may be due to the effects of chronic orthostatic intolerance (OI) in the form of the Postural Tachycardia Syndrome (POTS) and decreases in cerebral blood flow (CBF). In addition, fMRI studies suggest that individuals with CFS may require increased cortical and subcortical brain activation to complete difficult mental tasks.

Furthermore, neurocognitive testing in CFS has demonstrated deficits in speed and efficiency of information processing, attention, concentration, and working memory. The cognitive impairments are then perceived as an exaggerated mental fatigue. As a whole, this is experienced by those with CFS as “brain fog” and may be viewed as the interaction of physiological, cognitive, and perceptual factors.

Thus, the cognitive symptoms of CFS may be due to altered CBF activation and regulation that are exacerbated by a stressor, such as orthostasis or a difficult mental task, resulting in the decreased ability to readily process information, which is then perceived as fatiguing and experienced as “brain fog.” Future research looks to further explore these interactions, how they produce cognitive impairments, and explain the perception of “brain fog” from a mechanistic standpoint.

 

Source: Ocon AJ. Caught in the thickness of brain fog: exploring the cognitive symptoms of Chronic Fatigue Syndrome. Front Physiol. 2013 Apr 5;4:63. doi: 10.3389/fphys.2013.00063. ECollection 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3617392/ (Full article)

 

The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis

Abstract:

PURPOSE: To perform a meta-analysis to examine variability among prevalence estimates for CFS/ME, according to the method of assessment used.

METHODS: Databases were systematically searched for studies on CFS/ME prevalence in adults that applied the 1994 Centers for Disease Control (CDC) case definition.1 Estimates were categorized into two methods of assessment: self-reporting of symptoms versus clinical assessment of symptoms. Meta-analysis was performed to pool prevalences by assessment using random effects modeling. This was stratified by sample setting (community or primary care) and heterogeneity was examined using the I (2) statistic.

RESULTS: Of 216 records found, 14 studies were considered suitable for inclusion. The pooled prevalence for self-reporting assessment was 3.28% (95% CI: 2.24-4.33) and 0.76% (95% CI: 0.23-1.29) for clinical assessment. High variability was observed among self-reported estimates, while clinically assessed estimates showed greater consistency.

CONCLUSION: The observed heterogeneity in CFS/ME prevalence may be due to differences in method of assessment. Stakeholders should be cautious of prevalence determined by the self-reporting of symptoms alone. The 1994 CDC case definition appeared to be the most reliable clinical assessment tool available at the time of these studies. Improving clinical case definitions and their adoption internationally will enable better comparisons of findings and inform health systems about the true burden of CFS/ME.

 

Source: Johnston S, Brenu EW, Staines D, Marshall-Gradisnik S. The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis. Clin Epidemiol. 2013;5:105-10. doi: 10.2147/CLEP.S39876. Epub 2013 Mar 26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3616604/ (Full article)