TGI Good Friday! Our regular round-up of recently published research abstracts | 29 March 2013

From Fatigue: Biomedicine, Health & Behaviour, 20 March 2013.

Contrasting chronic fatigue syndrome versus myalgic encephalomyelitis/chronic fatigue syndrome

Leonard A. Jason(a), Abigail Brown(a), Meredyth Evans(a), Madison Sunnquist(a) & Julia L. Newton(b)
(a) DePaul University, Centre for Community Research, Chicago, USA (b) Newcastle University, Newcastle-upon-Tyne, UK

Abstract

BACKGROUND

Much debate is transpiring regarding whether chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME) are different illnesses. Several prior studies that compared the Fukuda et al. CFS criteria to the Canadian ME/CFS criteria found that the Canadian criteria identified patients with more functional impairments and greater physical, mental, and cognitive problems than those who met Fukuda et al. criteria. These samples were located in the Chicago metropolitan area, so the results could not be generalized to other locations. In addition, past studies used a symptom questionnaire that was not specifically developed to tap the Canadian criteria.

PURPOSE

The present comparative study of CFS and ME/CFS criteria was intended to correct the limitations of prior studies.

METHODS

This article used data from three distinct samples to compare patients who met criteria for the ME/CFS Canadian clinical case definition to those who met the Fukuda et al. CFS case definition.

RESULTS

Findings indicated that fewer individuals met the Canadian criteria than the Fukuda et al. criteria. Those who met the Canadian criteria evidenced more severe symptoms and physical functioning impairment.

CONCLUSIONS

Future research should continue to compare existing case definitions and determine which criteria best select for this illness.


From J Transl Med, 20 March 2013 [Epub ahead of print]. Full text available,

Screening NK-, B- and T-cell phenotype and function in patients suffering from Chronic Fatigue Syndrome.

Curriu M (1), Carrillo J(1), Massanella M(1), Rigau J(2), Alegre J(3), Puig J(4), Garcia-Quintana AM(5), Castro-Marrero J(3), Negredo E(4), Clotet B(1,4), Cabrera C (1), Blanco J(1,6).
1 Institut de recerca de la sida, IrsiCaixa-HIVACAT, Institut d’Investigació en Ciències de la Salut Germans Trias I Pujol|, Badalona, Spain
2 CFS Clinic, Tarragona, Spain
3 CFS Unit, Institut de Recerca Vall d’Hebron, Barcelona, Spain
4 Fundació Lluita contra la SIDA, Hospital Germans Trias I Pujol, Badalona, Spain
5 CFS Unit, Delfos Clinic, Barcelona, Spain
6 Institut de Recerca de la sida, IrsiCaixa/Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, Hospital Universitari Germans Trias i Pujol, Badalona 08916, Spain

Abstract

BACKGROUND

Chronic Fatigue Syndrome (CFS) is a debilitating neuro-immune disorder of unknown etiology diagnosed by an array of clinical manifestations. Although several immunological abnormalities have been described in CFS, their heterogeneity has limited diagnostic applicability.

METHODS

Immunological features of CFS were screened in 22 CFS diagnosed individuals fulfilling Fukuda criteria and 30 control healthy individuals. Peripheral blood T, B and NK cell function and phenotype were analyzed by flow cytometry in both groups.

RESULTS

CFS diagnosed individuals showed similar absolute numbers of T, B and NK cells, with minor differences in the percentage of CD4+ and CD8+ T cells. B cells showed similar subset frequencies and proliferative responses between groups. Conversely, significant differences were observed in T cell subsets. CFS individuals showed increased levels of T regulatory cells (CD25+/FOXP3+) CD4 T cells, and lower proliferative responses in vitro and in vivo. Moreover, CD8 T cells from the CFS group showed significantly lower activation and frequency of effector memory cells. No clear signs of T-cell immunosenescence were observed. NK cells from CFS individuals displayed higher expression of NKp46 and CD69 but lower expression of CD25 in all NK subsets defined. Overall, T cell and NK cell features clearly clustered CFS individuals.

CONCLUSIONS

Our findings suggest that alterations in T-cell phenotype and proliferative response along with the specific signature of NK cell phenotype may be useful to identify CFS individuals. The striking down modulation of T cell mediated immunity may help to understand intercurrent viral infections in CFS.


From Clinical Epidemiology, 26 March 2013.

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

Samantha Johnston(1), Ekua W Brenu (1), Donald Staines(1,2) Sonya Marshall-Gradisnik(1)
(1) Griffith Health Institute, School of Medical Sciences, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Parklands, QLD,
Australia;
(2) Gold Coast Public Health Unit, Queensland Health, Robina, QLD, Australia

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 I2 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 todifferences 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.


From J Pain Res. 6 March 2013

Self-regulatory fatigue in chronic multisymptom illnesses: scale development, fatigue, and self-control.

Nes LS(1,3), Ehlers SL(1), Whipple MO(2), Vincent A(2).
(1) Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA ;
(2) Fibromyalgia and Chronic Fatigue Clinic, General Internal Medicine, Mayo Clinic, Rochester, MN, USA;
(3) Center for Shared Decision Making and Collaborative Care Research, Oslo University Hospital, Oslo, Norway.

Abstract

BACKGROUND

Self-regulatory capacity involves ability to regulate thoughts, emotions, and behavior. Chronic multisymptom illnesses such as fibromyalgia and chronic fatigue syndrome are accompanied by numerous challenges, and have recently been associated with self-regulatory fatigue (SRF). Chronic multisymptom illnesses are also frequently associated with physical fatigue, and through development of a scale measuring SRF, the current study aimed to examine how SRF can be distinguished from physical fatigue. The study also sought to distinguish SRF from self-control.

METHODS

Two self-regulation researchers developed 30 items related to self-regulatory capacity. These items were distributed to patients (n = 296) diagnosed with chronic multisymptom illness together with validated measures of physical fatigue and self-control. A principal factor analysis was employed to examine factor structures, identify inter-item relationships, and aid in scale development.

RESULTS

The final proposed scale consisted of 18 items measuring self-regulatory capacity (SRF-18) with cognitive, emotional, and behavioral SRF components. Internal consistency and reliability was acceptable (Cronbach’s á = 0.81). The final scale was moderately correlated with self-control (r = -0.48) and highly correlated with physical fatigue (r = 0.75), although more so with emotional (r = 0.72) and mental (r = 0.65) than physical (r = 0.46) fatigue components.

CONCLUSION

The current study suggests a new scale for measurement of SRF in chronic multisymptom illness. Although cross-validation studies are necessary, such a scale may contribute to a better understanding of the concept of self-regulation and the role of SRF in chronic illness. Although related to physical fatigue and self-control, the results point to SRF as a distinct construct.


Neuropsychology, 27 March 2013

Cognitive deficits in chronic fatigue syndrome and their relationship to psychological status, symptomatology, and everyday functioning.

Cockshell SJ, Mathias JL.
School of Psychology.

Abstract

OBJECTIVE

To examine cognitive deficits in people with chronic fatigue syndrome (CFS) and their relationship to psychological status, CFS symptoms, and everyday functioning.

METHOD

The current study compared the cognitive performance (reaction time, attention, memory, motor functioning, verbal abilities, and visuospatial abilities) of a sample with CFS (n = 50) with that of a sample of healthy controls (n = 50), all of whom had demonstrated high levels of effort and an intention to perform well, and examined the extent to which psychological status, CFS symptoms, and everyday functioning were related to cognitive performance.

RESULTS

The CFS group showed impaired information processing speed (reaction time), relative to the controls, but comparable performance on tests of attention, memory, motor functioning, verbal ability, and visuospatial ability. Moreover, information processing speed was not related to psychiatric status, depression, anxiety, the number or severity of CFS symptoms, fatigue, sleep quality, or everyday functioning.

CONCLUSION

A slowing in information processing speed appears to be the main cognitive deficit seen in persons with CFS whose performance on effort tests is not compromised. Importantly, this slowing does not appear to be the consequence of other CFS-related variables, such as depression and fatigue, or motor speed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).


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