Category: Neurology

Neuroimaging and the case of chronic fatigue syndrome

Abstract:

This article analyzes the use of neuroimaging in research into chronic fatigue syndrome. It reviews some works published in the 1990 s and investigates a specific aspect of these studies, namely the search for a cerebral abnormality, in the form of an altered activation pattern, which could provide a pattern for diagnosis and treatment of the disease. The understanding of chronic fatigue syndrome as a disease reduced to some cerebral findings is analyzed, arguing in favor of a broader vision of this disease that includes psychosocial elements of the patient’s life as opposed to entirely somatic explanations.

 

Source: Ortega F, Zorzanelli R. Neuroimaging and the case of chronic fatigue syndrome. Cien Saude Colet. 2011 Apr;16(4):2123-32. [Article in Portuguese]http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-81232011000400012&lng=en&nrm=iso&tlng=en (Full article)

 

A brain MRI study of chronic fatigue syndrome: evidence of brainstem dysfunction and altered homeostasis

Abstract:

To explore brain involvement in chronic fatigue syndrome (CFS), the statistical parametric mapping of brain MR images has been extended to voxel-based regressions against clinical scores.

Using SPM5 we performed voxel-based morphometry (VBM) and analysed T(1) – and T(2) -weighted spin-echo MR signal levels in 25 CFS subjects and 25 normal controls (NC). Clinical scores included CFS fatigue duration, a score based on the 10 most common CFS symptoms, the Bell score, the hospital anxiety and depression scale (HADS) anxiety and depression, and hemodynamic parameters from 24-h blood pressure monitoring. We also performed group × hemodynamic score interaction regressions to detect locations where MR regressions were opposite for CFS and NC, thereby indicating abnormality in the CFS group.

In the midbrain, white matter volume was observed to decrease with increasing fatigue duration. For T(1) -weighted MR and white matter volume, group × hemodynamic score interactions were detected in the brainstem [strongest in midbrain grey matter (GM)], deep prefrontal white matter (WM), the caudal basal pons and hypothalamus. A strong correlation in CFS between brainstem GM volume and pulse pressure suggested impaired cerebrovascular autoregulation.

It can be argued that at least some of these changes could arise from astrocyte dysfunction. These results are consistent with an insult to the midbrain at fatigue onset that affects multiple feedback control loops to suppress cerebral motor and cognitive activity and disrupt local CNS homeostasis, including resetting of some elements of the autonomic nervous system (ANS).

Copyright © 2011 John Wiley & Sons, Ltd.

 

Source: Barnden LR, Crouch B, Kwiatek R, Burnet R, Mernone A, Chryssidis S, Scroop G, Del Fante P. A brain MRI study of chronic fatigue syndrome: evidence of brainstem dysfunction and altered homeostasis. NMR Biomed. 2011 Dec;24(10):1302-12. doi: 10.1002/nbm.1692. Epub 2011 May 11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4369126/ (Full article)

 

Increased HDAC in association with decreased plasma cortisol in older adults with chronic fatigue syndrome

Abstract:

Hypocortisolism is a frequent finding in individuals with chronic fatigue syndrome (CFS) with other research findings implying potential dysregulation of glucocorticoid signaling. Glucocorticoid signaling is under the influence of several pathways, several of which are of interest in the study of CFS. Oxidative stress and decreased antioxidant capacity are known to disrupt the hypothalamic-pituitary-adrenal (HPA) axis (Epel et al., 2004) and the presence of histone deacetylases (HDAC) could also impact glucocorticoid signaling.

The intent of this pilot study was to investigate the relationship among oxidative stress elements, select HDAC’s (2/3) and glucocorticoid receptor signaling in an elderly sample with CFS. Findings suggest increased histone deacetylase activity, lower total antioxidant power, in the context of decreased plasma cortisol and increased plasma dehydroepiandrosterone concomitant with decreased expression of the encoding gene for the glucocorticoid receptor. These findings support the presence of HPA axis dysregulation in elderly individuals with CFS.

Copyright © 2011 Elsevier Inc. All rights reserved.

 

Source: Jason L, Sorenson M, Sebally K, Alkazemi D, Lerch A, Porter N, Kubow S. Increased HDAC in association with decreased plasma cortisol in older adults with chronic fatigue syndrome. Brain Behav Immun. 2011 Nov;25(8):1544-7. doi: 10.1016/j.bbi.2011.04.007. Epub 2011 Apr 28. https://www.ncbi.nlm.nih.gov/pubmed/21549189

 

The cerebralization of fatigue: an analysis of the cerebral hypothesis in the case of chronic fatigue syndrome

Abstract:

The article analyzes a number of conditions that allowed the brain to become established as an etiological hypothesis in the case of chronic fatigue syndrome (CFS), together with other hypotheses related to organic causes, such as viruses and immunity. It also addresses the process of cerebralization of personhood, which grew out of the use of neuroimaging for research and diagnostic purposes and according to which the brain constitutes the prime place for looking for the cause of the diseases – including CFS – within the context of a somatic culture, intensified at the end of the twentieth century.

 

Source: Ortega F, Zorzanelli R. The cerebralization of fatigue: an analysis of the cerebral hypothesis in the case of chronic fatigue syndrome. Hist Cienc Saude Manguinhos. 2010 Jun;17(2):289-305. [Article in Portuguese] http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-59702010000200002&lng=en&nrm=iso&tlng=en (Full article)

 

Cerebral blood flow is reduced in chronic fatigue syndrome as assessed by arterial spin labeling

Abstract:

BACKGROUND: Chronic fatigue syndrome is diagnosed by a set of clinical criteria and therefore is probably heterogeneous. Earlier reports tested the hypothesis that the syndrome had a neurological substrate by doing studies of cerebral blood flow (CBF) but with discrepant results. One possible reason for the discrepancy was that relative CBF was assessed. We found reduced CBF in an earlier study of absolute CBF using xenon-CT. The purpose of this study was to use a second method of assessing CBF and to look within the study group for heterogeneity of responses.

METHOD: Eleven CFS patients and 10 age matched healthy controls underwent neuroimaging using arterial spin labeling to determine their regional and global absolute CBF. A template was constructed based on the control data, and individual patient montages were compared on a case by case basis to determine if differences in regions of interest occurred.

RESULTS: The patients as a group had significantly lower global CBF than the controls. The reduction in CBF occurred across nearly every region assessed. Nine of the 11 patients showed these reductions compared to the average control data, while two patients showed actual increases relative to the controls.

CONCLUSION: The data extend our earlier observation that CFS patients as a group have broad decreases in CBF compared to healthy controls. However, as expected, the effect was not homogeneous in that 2 of the 11 patients studied showed actual increases in CBF relative to controls.

Copyright © 2010 Elsevier B.V. All rights reserved.

 

Source: Biswal B, Kunwar P, Natelson BH. Cerebral blood flow is reduced in chronic fatigue syndrome as assessed by arterial spin labeling. J Neurol Sci. 2011 Feb 15;301(1-2):9-11. doi: 10.1016/j.jns.2010.11.018. Epub 2010 Dec 16.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139492/ (Full article)

 

No differences in cardiovascular autonomic responses to mental stress in chronic fatigue syndrome adolescents as compared to healthy controls

Abstract:

Chronic fatigue syndrome (CFS) is a disabling disease with unknown etiology. There is accumulating evidence of altered cardiovascular autonomic responses to different somatic stressors, in particular orthostatic stress, whereas autonomic responses to mental stress remain to be investigated. In this study, we explored cardiovascular autonomic responses to a simple mental stress test in CFS patients and healthy controls.

A consecutive sample of 13 patients with CFS, aged 12 to 18 years, and a volunteer sample of 53 healthy control subjects of equal age and gender distribution were included. Blood pressure, heart rate and acral skin blood flow were continuously recorded during an arithmetic exercise.

At baseline, heart rate was significantly higher among CFS patients than controls (p = 0.02). During the arithmetic exercise, however, there were no significant differences in the responses between the two groups.

In conclusion, CFS patients have unaltered autonomic responses to simple mental stress as compared to healthy control subjects.

 

Source: Egge C, Wyller VB. No differences in cardiovascular autonomic responses to mental stress in chronic fatigue syndrome adolescents as compared to healthy controls. Biopsychosoc Med. 2010 Dec 14;4:22. doi: 10.1186/1751-0759-4-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3012010/ (Full article)

 

Elevated nocturnal blood pressure and heart rate in adolescent chronic fatigue syndrome

Abstract:

AIM: To compare ambulatory recordings of heart rate (HR) and blood pressure in adolescents with chronic fatigue syndrome (CFS) and healthy controls. We hypothesized both HR and blood pressure to be elevated among CFS patients.

METHODS: Forty-four CFS patients aged 12-18 years were recruited from our paediatric outpatient clinic. The controls were 52 healthy adolescents having similar distribution of age and gender. 24-h ambulatory blood pressure and HR were recorded using a validated, portable oscillometric device.

RESULTS: At night (sleep), HR, mean arterial blood pressure and diastolic blood pressure were significantly higher in CFS patients as compared with controls (p < 0.01). During daytime, HR was significantly higher among CFS patients (p < 0.05), whereas blood pressures were equal among the two groups.

CONCLUSIONS: The findings support previous experimental evidence of sympathetic predominance of cardiovascular control in adolescent CFS patients. Also, the findings prompt increased focus on cardiovascular risk assessment and suggest a possible target for therapeutic intervention.

© 2010 The Author(s)/Acta Paediatrica © 2010 Foundation Acta Paediatrica.

 

Source: Hurum H, Sulheim D, Thaulow E, Wyller VB. Elevated nocturnal blood pressure and heart rate in adolescent chronic fatigue syndrome. Acta Paediatr. 2011 Feb;100(2):289-92. doi: 10.1111/j.1651-2227.2010.02073.x. Epub 2010 Nov 17. https://www.ncbi.nlm.nih.gov/pubmed/21059182

 

Increased ventricular lactate in chronic fatigue syndrome measured by 1H MRS imaging at 3.0 T. II: comparison with major depressive disorder

Abstract:

Chronic fatigue syndrome (CFS), a complex illness characterized by fatigue, impaired concentration, and musculoskeletal pain, is often misdiagnosed as a psychiatric illness due to the overlap of its symptoms with mood and anxiety disorders. Using proton magnetic resonance spectroscopic imaging ((1)H MRSI), we previously measured levels of the major brain metabolites in CFS, in generalized anxiety disorder (GAD), and in healthy control subjects, and found significantly higher levels of ventricular cerebrospinal fluid (CSF) lactate in CFS compared to the other two groups.

In the present study, we sought to assess the specificity of this observation for CFS by comparing ventricular lactate levels in a new cohort of 17 CFS subjects with those in 19 healthy volunteers and in 21 subjects with major depressive disorder (MDD), which, like GAD, is a neuropsychiatric disorder that has significant symptom overlap with CFS.

Ventricular CSF lactate was significantly elevated in CFS compared to healthy volunteers, replicating the major result of our previous study. Ventricular lactate measures in MDD did not differ from those in either CFS or healthy volunteers. We found a significant correlation between ventricular CSF lactate and severity of mental fatigue that was specific to the CFS group.

In an exploratory analysis, we did not find evidence for altered levels of the amino acid neurotransmitters, gamma-aminobutyric acid (GABA) and glutamate + glutamine (‘Glx’), in CFS compared to MDD or healthy controls. Future (1)H MRS studies with larger sample sizes and well-characterized populations will be necessary to further clarify the sensitivity and specificity of neurometabolic abnormalities in CFS and MDD.

 

Source: Murrough JW, Mao X, Collins KA, Kelly C, Andrade G, Nestadt P, Levine SM, Mathew SJ, Shungu DC. Increased ventricular lactate in chronic fatigue syndrome measured by 1H MRS imaging at 3.0 T. II: comparison with major depressive disorder. NMR Biomed. 2010 Jul;23(6):643-50. doi: 10.1002/nbm.1512. https://www.ncbi.nlm.nih.gov/pubmed/20661876

 

EEG findings in burnout patients

Abstract:

The concept of burnout remains enigmatic since it is only determined by behavioral characteristics. Moreover, the differential diagnosis with depression and chronic fatigue syndrome is difficult.

EEG-related variables in 13 patients diagnosed with burnout syndrome were compared with 13 healthy comparison subjects in order to explore the existence of neurobiological markers for burnout.

Burnout patients showed reduced P300 amplitude, a lower alpha peak frequency and reduced beta power. These EEG-related differences in burnout patients differ from those described in the literature in depression and chronic fatigue patients. Our preliminary findings suggest that burnout might be considered as a separate clinical syndrome.

 

Source: van Luijtelaar G, Verbraak M, van den Bunt M, Keijsers G, Arns M. EEG findings in burnout patients. J Neuropsychiatry Clin Neurosci. 2010 Spring;22(2):208-17. doi: 10.1176/appi.neuropsych.22.2.208. https://www.ncbi.nlm.nih.gov/pubmed/20463115

 

Sex differences in plasma prolactin response to tryptophan in chronic fatigue syndromepatients with and without comorbid fibromyalgia

Abstract:

BACKGROUND: Some think chronic fatigue syndrome (CFS) and fibromyalgia (FM) are variants of the same illness process. This would imply that CFS patients with and without comorbid FM have similar biological underpinnings. To test this, we compared serotonergic-based responses, plasma prolactin (PRL), and self-reported measures of fatigue to intravenous infusion of tryptophan among patients with CFS alone, CFS + FM, and healthy controls.

METHODS: Men and women with CFS alone or CFS + FM and healthy subjects, none with current major depressive disorder (MDD), were given 120 mg of L-tryptophan per kg lean body mass intravenously (i.v.). Before and after tryptophan infusion, blood samples were collected, and plasma PRL, tryptophan, and kynurenine concentrations were determined.

RESULTS: Women with CFS alone, but not CFS + FM, showed upregulated plasma PRL responses compared with controls. There were no differences among groups of men. Plasma tryptophan and kynurenine concentrations did not differ among groups.

CONCLUSIONS: These results indicate that women with CFS alone have upregulated serotonergic tone that is not seen in those with comorbid FM. The lack of effect in men suggests a mechanism that might explain, in part, the increased prevalence of CFS in women. The data support the interpretation that CFS in women is a different illness from FM.

 

Source: Weaver SA, Janal MN, Aktan N, Ottenweller JE, Natelson BH. Sex differences in plasma prolactin response to tryptophan in chronic fatigue syndrome patients with and without comorbid fibromyalgia. J Womens Health (Larchmt). 2010 May;19(5):951-8. doi: 10.1089/jwh.2009.1697. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875960/ (Full article)