TGI Friday! Our weeklyround-up of recently published research abstracts and related items | 14 June 2013

June 14, 2013

From the Saudi Journal of Medicine and Medical Sciences Volume 1, Issue 1, Page 11-13, 3 June 2013. Full article available to read from the web or as a pdf download.

Myalgic encephalomyelitis/chronic fatigue syndrome: Review of history, clinical features, and controversies

Nigel Speight
Consultant Paediatrician, Durham, United Kingdom


Myalgic encephalomyelits/chronic fatigue syndrome (ME/CFS) has been both a medical mystery and a source of controversy in Western medicine for over 50 years. This article reviews the major historical developments over this period, describes the clinical pattern and spectrum of severity, and then explores the current major controversies surrounding the subject.

From Frontiers in Physiology, 30 May 2013.

Multiscale analysis of heart rate variability in non-stationary environments

Jianbo Gao(1,2), Brian M. Gurbaxani(3), Jing Hu(1), Keri J. Heilman(4), Vincent A. Emanuele II(3), Greg F. Lewis(4,5), Maria Davila(4), Elizabeth R. Unger(3) and Jin-Mann S. Lin(3)
1 PMB Intelligence LLC, West Lafayette, IN, USA
2 Mechanical and Materials Engineering, Wright State University, Dayton, OH, USA
3 Chronic Viral Diseases Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
4 College of Medicine, Brain-Body Center, University of Illinois, Chicago, IL, USA
5 Research Triangle Institute, Raleigh, NC, USA


Heart rate variability (HRV) is highly non-stationary, even if no perturbing influences can be identified during the recording of the data. The non-stationarity becomes more profound when HRV data are measured in intrinsically non-stationary environments, such as social stress.

In general, HRV data measured in such situations are more difficult to analyze than those measured in constant environments. In this paper, we analyze HRV data measured during a social stress test using two multiscale approaches, the adaptive fractal analysis (AFA) and scale-dependent Lyapunov exponent (SDLE), for the purpose of uncovering differences in HRV between chronic fatigue syndrome (CFS) patients and their matched-controls.

CFS is a debilitating, heterogeneous illness with no known biomarker. HRV has shown some promise recently as a non-invasive measure of subtle physiological disturbances and trauma that are otherwise difficult to assess. If the HRV in persons with CFS are significantly different from their healthy controls, then certain cardiac irregularities may constitute good candidate biomarkers for CFS.

Our multiscale analyses show that there are notable differences in HRV between CFS and their matched controls before a social stress test, but these differences seem to diminish during the test. These analyses illustrate that the two employed multiscale approaches could be useful for the analysis of HRV measured in various environments, both stationary and non-stationary.

From Comprehensive Psychiatry, 5 June 2013

The role of neuroticism, perfectionism and depression in chronic fatigue syndrome. A structural equation modeling approach

Sergi Valero(a), Naia Sáez-Francàs(a), Natalia Calvo(a), José Alegre(b), Miquel Casas(c,a),
(a) Department of Psychiatry, Hospital Universitari Vall d’Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Passeig de la Vall d’Hebron 119–129, 08035 Barcelona, Catalonia, Spain
(b) Department of Internal Medicine, Hospital Universitari Vall D´Hebron, Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Passeig de la Vall d’Hebron 119–129, 08035 Barcelona, Catalonia, Spain
© Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Campus de Bellaterra s/n 08193, Bellaterra, Catalonia, Spain



Previous studies have reported consistent associations between Neuroticism, maladaptive perfectionism and depression with severity of fatigue in Chronic Fatigue Syndrome (CFS). Depression has been considered a mediator factor between maladaptive perfectionism and fatigue severity, but no studies have explored the role of neuroticism in a comparable theoretical framework. This study aims to examine for the first time, the role of neuroticism, maladaptive perfectionism and depression on the severity of CFS, analyzing several explanation models.


A sample of 229 CFS patients were studied comparing four structural equation models, testing the role of mediation effect of depression severity in the association of Neuroticism and/or Maladaptive perfectionism on fatigue severity.


The model considering depression severity as mediator factor between Neuroticism and fatigue severity is the only one of the explored models where all the structural modeling indexes have fitted satisfactorily (Chi square = 27.01, p = 0.079; RMSE = 0.047, CFI = 0.994; SRMR = 0.033). Neuroticism is associated with CFS by the mediation effect of depression severity. This personality variable constitutes a more consistent factor than maladaptive perfectionism in the conceptualization of CFS severity.


CFS, Chronic fatigue syndrome;
RMSE, Root Mean Squared Error;
CFI, Confirmatory Fit Index;
SRMR, Standardized Root Mean Residual;
FIS, Fatigue Impact Scale;
U-FIS, Unidimensional Fatigue Impact Scale;
ZKPQ, Zuckerman–Kuhlman Personality Questionnaire;
MPS-F, Frost Multidimensional Perfectionism Scale;
HADS, Hospital Anxiety–Depression Scale

From the European Journal of Pediatrics, June 2013

Clinical Practice: Chronic fatigue syndrome

Charlotte L. Werker(1), Sanne L. Nijhof(1), Elise M. van de Putte(1,2)
1) Department of Pediatrics, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands.
2) Department of Pediatrics, University Medical Centre, Utrecht≤ Office KE 04.133.1, Postbox 85090, 3508 AB Utrecht, The Netherlands.


The diagnosis chronic fatigue syndrome (CFS) was conceptualized in the mid-1980s. It is a clinically defined condition characterized by severe and disabling new onset fatigue with at least four additional symptoms: impaired memory or concentration, sore throat, tender cervical or axillary lymph nodes, muscle pain, multi-joint pain, new headaches, unrefreshing sleep or post-exertion malaise.

Chronic fatigue syndrome in adolescents is a rare condition compared to symptomatic fatigue. The estimated prevalence of adolescent CFS ranges between 0.11 and 1.29 % in Dutch, British, and US populations.

Diagnosis of the chronic fatigue syndrome is established through exclusion of other medical and psychiatric causes of chronic fatiguing illness. Taking a full clinical history and a full physical examination are therefore vital.

In adolescence, CFS is associated with considerable school absence with long-term detrimental effects on academic and social development. One of the most successful potential treatments for adolescents with CFS is cognitive behavioural therapy, which has been shown to be effective after 6 months in two thirds of the adolescents with CFS. This treatment effect sustains at 2–3-year follow-up.

In conclusion, the diagnosis CFS should be considered in any adolescent patient with severe disabling long-lasting fatigue. Cognitive behavioural therapy is effective in 60–70 % of the patients. Prompt diagnosis favours the prognosis.

From the Journal of Clinical Rheumatology, 5 Junen 2013 [Epub ahead of print]

Cognitive performance is of clinical importance, but is unrelated to pain severity in women with chronic fatigue syndrome.

Ickmans K, Meeus M, Kos D, Clarys P, Meersdom G, Lambrecht L, Pattyn N, Nijs J.
Pain in Motion Research Group (PIM), Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Building L, Pleinlaan 2, 1050, Brussels, Belgium.


In various chronic pain populations, decreased cognitive performance nis known to be related to pain severity. Yet, this relationship has not been investigated in patients with chronic fatigue syndrome (CFS).

This study investigated the relationship between cognitive performance and (1) pain severity, (2) level of fatigue, and (3) self-reported symptoms and health status in women with CFS.

Examining the latter relationships is important for clinical practice, since people with CFS are often suspected to exaggerate their symptoms. A sample of 29 female CFS patients and 17 healthy controls aged 18 to 45 years filled out three questionnaires (Medical Outcomes Study 36-Item Short-Form Health Survey, Checklist Individual Strength (CIS), and CFS Symptom List) and performed three performance-based cognitive tests (psychomotor vigilance task, Stroop task, and operation span task), respectively.

In both groups, pain severity was not associated with cognitive performance. In CFS patients, the level of fatigue measured with the CFS Symptom List, but not with the CIS, was significantly correlated with sustained attention. Self-reported mental health was negatively correlated with all investigated cognitive domains in the CFS group.

These results provide evidence for the clinical importance of objectively measured cognitive problems in female CFS patients. Furthermore, a state-like measure (CFS Symptom List) appears to be superior over a trait-like measure (CIS) in representing cognitive fatigue in people with CFS.

Finally, the lack of a significant relationship between cognitive performance and self-reported pain severity suggests that pain in CFS might be unique.

From the Journal of Psychosomatic Research, 3 June 2013

Differences in physical functioning between relatively active and passive patients with Chronic Fatigue Syndrome

Desirée C.W.M. Vos-Vromans, Ivan P.J. Huijnen, Albère J.A. Köke, Henk A.M. Seelen, et al.
Revant Rehabilitation Centre Breda, Brabantlaan 1, 4817 JW Breda, The Netherlands



According to the Cognitive behavioral therapy (CBT) protocol for patients with Chronic Fatigue Syndrome (CFS), therapists are advised to categorize patients in relatively active and passive patients. However, evidence to support the differences in physical functioning between these subgroups is limited. Using the baseline data from a multicentre randomized controlled trial (FatiGo), the differences in actual and perceived physical functioning between active and passive patients with CFS were evaluated.


Sixty patients, who received CBT during the FatiGo trial were included. Based on the expert opinion and using the definitions of subgroups defined in the CBT protocols, the therapist categorized the patient. Data from an activity monitor was used to calculate actual physical functioning, physical activity, daily uptime, activity fluctuations and duration of rest during daily life. Perceived physical functioning was assessed by measuring physical activity, physical functioning and functional impairment with the Checklist Individual Strength, Short Form-36 and Sickness-Impact Profile 8.


Relatively active patients have a significantly higher daily uptime and show significantly less fluctuations in activities between days. Passive patients experience a significantly lower level of physical functioning and feel more functionally impaired in their mobility. However, no significant differences were found in the other actual or perceived physical functioning indices.


A clear difference in actual and perceived physical functioning between relatively active and passive patients with CFS as judged by their therapists could not be found. Future research is needed to form a consensus on how to categorize subgroups of patients with CFS.

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