TGI Friday! Our weekly round-up of recently published research abstracts | 17 March 2017


Staff working for the UK ME/CFS Biobank at the London School of Hygiene and Tropical Medicine have had another paper published in a peer-reviewed journal.
 
Here, the team – whose running costs are currently funded wholly by the ME Association’s Ramsay Research Fund – ask whether long-running disputes about selection bias and disease misrepresentation are holding back progress in ME/CFS research.


From the Journal of Health Psychology (open access piece), 1 March 2017.

How have selection bias and disease misclassification undermined the validity of myalgic encephalomyelitis/chronic fatigue syndrome studies?

Luis Nacul, Eliana M Lacerda, Caroline C Kingdon, Hayley Curran, Erinna W Bowman
‘Cure ME’ Team at the London School of Hygiene and Tropical Medicine.

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome has been a controversial diagnosis, resulting in tensions between patients and professionals providing them with care. A major constraint limiting progress has been the lack of a ‘gold standard’ for diagnosis; with a number of imperfect clinical and research criteria used, each defining different, though overlapping, groups of people with myalgic encephalomyelitis or chronic fatigue syndrome.

We review basic epidemiological concepts to illustrate how the use of more specific and restrictive case definitions could improve research validity and drive progress in the field by reducing selection bias caused by diagnostic misclassification.


From the Journal of Child Psychology and Psychiatry, and Allied Disciplines, 9 March 2017.

Stress vulnerability in adolescents with chronic fatigue syndrome: Experimental study investigating heart rate variability and skin conductance responses

Katharine A. Rimes(*), Kate Lievesley, Trudie Chalder
Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
* Corresponding author. Institute of Psychiatry, Psychology and Neuroscience, King’s College London, De Crespigny Park, London SE5 8AF, UK

Abstract

BACKGROUND

Stress vulnerability has been implicated in adolescent chronic fatigue syndrome (CFS), but has rarely been investigated directly. This study compared psychological and physiological responses to a laboratory social performance task in adolescents with CFS with chronic illness (asthma) and healthy control groups.

METHODS

Adolescents with CFS (n=60), adolescents with asthma (n=31) and healthy adolescents (n=78) completed questionnaires before and after a social performance task. Skin conductance responses (SCR; mean SCR and Max-Min) and heart rate variability (low frequency/high frequency; LF/HF and root mean square difference of successive RR intervals; RMSSD) was measured before, during and after the task.

RESULTS

Baseline heart rate variability (HRV) (RMSSD) was significantly lower in the CFS and Asthma groups than the HC. During the speech, the CFS and Asthma groups had higher HRV (LF/HF) than the HC, adjusting for baseline LF/HF. Although the asthma group showed a subsequent reduction in HRV during recovery, the CFS group did not. Similarly, during recovery after the task, the CFS group showed a continued increase in skin conductance (Min-Max), unlike the Asthma and HC groups. Compared to control groups, adolescents with CFS expected to find the task more difficult, were more anxious beforehand and afterwards, rated it as more difficult, evaluated their performance more negatively and had lower observer ratings of performance. Parents of adolescents with CFS expected that their child would perform less well in the task than parents of control participants.

CONCLUSIONS

Adolescents with CFS showed autonomic nervous system responses that are consistent with chronic stress vulnerability, difficulty coping with acute stress and slower recovery after acute stress. Self-report measures also indicated greater trait, pre- and posttask anxiety in the CFS group.


From BMC Psychology (open access), 6 March 2017.

Patterns of control beliefs in chronic fatigue syndrome: results of a population-based survey

Johanna M. Doerr(†,1), (Daniela S. Jopp†,2) Michael Chajewski(2), Urs M. Nater(1)
1) Clinical Biopsychology, Dept. of Psychology, University of Marburg
2) Dept. of Psychology, Fordham University

Abstract

BACKGROUND

Chronic fatigue syndrome (CFS) represents a unique clinical challenge for patients and health care providers due to unclear etiology and lack of specific treatment. Characteristic patterns of behavior and cognitions might be related to how CFS patients respond to management strategies.

METHODS

This study investigates control beliefs in a population-based sample of 113 CFS patients, 264 individuals with insufficient symptoms or fatigue for CFS diagnosis (ISF), and 124 well individuals.

RESULTS

Controlling for personality and coping, individuals with low confidence in their problem-solving capacity were almost 8 times more likely to be classified as ISF and 5 times more likely to be classified as CFS compared to being classified as well. However there was a wide distribution within groups and individuals with “low confidence” scores were found in 31.7% of Well individuals. Individuals with low levels of anxiety and who were more outgoing were less likely to be classified as ISF or CFS.

CONCLUSIONS

These findings suggest that fostering control beliefs could be an important focus for developing behavioral management strategies in CFS and other chronic conditions.


From Physiological Reports (open access), 7 March 2017.

Intermittent and graded exercise effects on NK cell degranulation markers LAMP‐1/LAMP‐2 and CD8+CD38+ in chronic fatigue syndrome/myalgic encephalomyelitis

Suzanne Broadbent, Rosanne Coutts
School of Health and Human Sciences, Southern Cross University, Lismore, Australia

Abstract


There is substantial evidence of immune system dysfunction in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) but little is understood of exercise training effects on lymphocyte function in this illness.

This study investigated whether graded and intermittent exercise improved CD8+ lymphocyte activation and natural killer cell degranulation markers compared to no exercise.

Twenty‐four chronic fatigue syndrome (CFS) patients (50.2 ± 10 year) were randomized to graded exercise (GE), intermittent exercise (IE) or usual care (UC) groups; a control group (CTL) of 18 matched sedentary non‐CFS/ME participants were included for immunological variable comparisons.

Main outcome measures were pre‐ and post-intervention expression of CD3+CD8+CD38+ and CD3−CD16+56+CD107a+ (LAMP‐1) CD107b+ (LAMP‐2) and aerobic exercise capacity. The postintervention percentage of NK cells expressing LAMP‐1 and ‐2 was significantly higher in IE compared to UC, and higher in GE compared to UC and CTL.

LAMP‐1 and LAMP‐2 expression (absolute numbers and percent positive) increased significantly pre‐to‐post-intervention for both GE and IE.

Pre-intervention, the absolute number of CD8+CD38+ cells was significantly lower in CTL compared to UC and IE. There were no significant pre‐ to post-intervention changes in CD8+CD38+ expression for any group. Aerobic exercise capacity was significantly improved by GE and IE.

Twelve weeks of GE and IE increased the expression of NK cell activation and degranulation markers, suggesting enhanced immunosurveillance.

Low‐intensity exercise may also reduce CD8+CD38+ expression, a marker of inflammation. Both GE and IE improved exercise capacity without worsening CFS/ME symptoms, and more robust trials of these exercise modalities are warranted.






From BioPsychoSocial Medicine (open access), 3 March 2017.

Development of a recumbent isometric yoga program for patients with severe chronic fatigue syndrome/myalgic encephalomyelitis: A pilot study to assess feasibility and efficacy

Takakazu Oka(1), Hisako Wakita(2) , Keishin Kimura(2)
1) Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Kyushu University, Japan
2) Japan Yoga Therapy Society

Abstract

BACKGROUND

Our previous randomized controlled trial demonstrated that isometric yoga in a sitting position reduces fatigue in patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). However, some patients experience difficulties sitting or practicing isometric yoga in a sitting position for long periods. To date, therapeutic interventions for patients with severe symptoms have not been established. Therefore, we developed a recumbent isometric yoga program, which takes approximately 20 min to complete, designed to reduce fatigue in patients with severe CFS/ME. The aim of this pilot study was to assess the feasibility, safety, and usefulness of this program.

METHODS

This pilot study included 12 adult patients with CFS/ME. Six patients were reluctant to practice isometric yoga in a sitting position because of the severity of their fatigue (group 1). The remaining six patients had previously practiced isometric yoga in a sitting position (group 2). For 3 months, the patients of both groups practiced recumbent isometric yoga every 2 to 4 weeks with a yoga instructor and at home on other days if they could. The short-term effects of isometric yoga on fatigue were assessed using the Profile of Mood Status (POMS) questionnaire immediately before and after their final session with the yoga instructor. The long-term effects of isometric yoga on fatigue were assessed using the Chalder Fatigue Scale (FS) questionnaire before and after the intervention period. Adverse events, satisfaction with the program, and preference of yoga position (sitting or recumbent) were also recorded.

RESULTS

All subjects completed the intervention. In both groups, the POMS fatigue score was significantly decreased after practicing the 20-min yoga program and the Chalder FS score was decreased significantly after the 3-month intervention period. There were no serious adverse events. All subjects in group 2 preferred the recumbent isometric yoga program over a sitting yoga program.

CONCLUSIONS

This study suggests that recumbent isometric yoga is a feasible and acceptable treatment for patients with CFS/ME, even for patients who experience difficulty practicing isometric yoga in the sitting position.