Category: Cognitive Dysfunction

A Concurrent Cognitive Task Does Not Perturb Quiet Standing in Fibromyalgia and Chronic Fatigue Syndrome

Abstract:

BACKGROUND AND OBJECTIVES: Cognitive complaints are common in fibromyalgia (FM) and chronic fatigue syndrome (CFS). Fatigue as well as pain may require greater effort to perform cognitive tasks, thereby increasing the load on processing in the central nervous system and interfering with motor control.

METHODS: The effect of a concurrent arithmetic cognitive task on postural control during quiet standing was investigated in 75 women (aged 19-49 years) and compared between FM, CFS, and matched controls (n=25/group). Quiet standing on a force plate was performed for 60 s/condition, with and without a concurrent cognitive task. The center of pressure data was decomposed into a slow component and a fast component representing postural sway and adjusting ankle torque.

RESULTS: Compared to controls, CFS and FM displayed lower frequency in the slow component (p < 0.001), and CFS displayed greater amplitude in the slow (p=0.038 and p=0.018) and fast (p=0.045) components. There were no interactions indicating different responses to the added cognitive task between any of the three groups.

CONCLUSION: Patients displayed insufficient postural control across both conditions, while the concurrent cognitive task did not perturb quiet standing. Fatigue but not pain correlated with postural control variables.

Source: Rasouli O, Fors EA, Vasseljen O, Stensdotter AK. A Concurrent Cognitive Task Does Not Perturb Quiet Standing in Fibromyalgia and Chronic Fatigue Syndrome. Pain Res Manag. 2018 Aug 7;2018:9014232. doi: 10.1155/2018/9014232. eCollection 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6109464/ (Full article)

Patients with chronic fatigue syndrome do not score higher on the autism-spectrum quotient than healthy controls: Comparison with autism spectrum disorder

Abstract:

Clinically, there is an overlap of several symptoms of chronic fatigue syndrome (CFS) and autism spectrum disorder (ASD), including fatigue; brain “fog”; cognitive impairments; increased sensitivity to sound, light, and odour; increased pain and tenderness; and impaired emotional contact.

Adults with CFS (n = 59) or ASD (n = 50) and healthy controls (HC; n = 53) were assessed with the Autism-Spectrum Quotient (AQ) in a cross-sectional study. Non-parametric analysis was used to compare AQ scores among the groups. Univariate analysis of variance (ANCOVA) was used to identify if age, sex, or diagnostic group influenced the differences in scores. Patients with ASD scored significantly higher on the AQ than the CFS group and the HC group. No differences in AQ scores were found between the CFS and HC groups. AQ results were influenced by the diagnostic group but not by age or sex, according to ANCOVA. Despite clinical observations of symptom overlap between ASD and CFS, adult patients with CFS report few autistic traits in the self-report instrument, the AQ. The choice of instrument to assess autistic traits may influence the results.

Source: Bileviciute-Ljungar I, Maroti D, Bejerot S. Patients with chronic fatigue syndrome do not score higher on the autism-spectrum quotient than healthy controls: Comparison with autism spectrum disorder. Scand J Psychol. 2018 May 8. doi: 10.1111/sjop.12451. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29738079

Altered right anterior insular connectivity and loss of associated functions in adolescent chronic fatigue syndrome

Abstract:

Impairments in cognition, pain intolerance, and physical inactivity characterize adolescent chronic fatigue syndrome (CFS), yet little is known about its neurobiology. The right dorsal anterior insular (dAI) connectivity of the salience network provides a motivational context to stimuli. In this study, we examined regional functional connectivity (FC) patterns of the right dAI in adolescent CFS patients and healthy participants.

Eighteen adolescent patients with CFS and 18 aged-matched healthy adolescent control participants underwent resting-state functional magnetic resonance imaging. The right dAI region of interest was examined in a seed-to-voxel resting-state FC analysis using SPM and CONN toolbox. Relative to healthy adolescents, CFS patients demonstrated reduced FC of the right dAI to the right posterior parietal cortex (PPC) node of the central executive network. The decreased FC of the right dAI-PPC might indicate impaired cognitive control development in adolescent CFS. Immature FC of the right dAI-PPC in patients also lacked associations with three known functional domains: cognition, pain and physical activity, which were observed in the healthy group. These results suggest a distinct biological signature of adolescent CFS and might represent a fundamental role of the dAI in motivated behavior.

Source: Wortinger LA, Glenne Øie M, Endestad T, Bruun Wyller V. Altered right anterior insular connectivity and loss of associated functions in adolescent chronic fatigue syndrome. PLoS One. 2017 Sep 7;12(9):e0184325. doi: 10.1371/journal.pone.0184325. ECollection 2017. https://www.ncbi.nlm.nih.gov/pubmed/28880891

Prevalence of and risk factors for severe cognitive and sleep symptoms in ME/CFS and MS

Abstract:

BACKGROUND: There are considerable phenotypic and neuroimmune overlaps between myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis (MS). While the precise aetiologies of both MS and ME/CFS are unclear, evidence suggests that deterioration in cognitive function is widely prevalent in patients with either condition. Little is known about differing risk factors or exposures, which may lead to severe cognitive or sleep symptoms. This study aims to gauge the extent of cognitive and sleep symptoms in ME/CFS and MS patients participating in the UK ME/CFS Biobank and identify the characteristics of those experiencing severe symptoms.

METHODS: This was a cross-sectional study of 395 UK ME/CFS Biobank participants, recruited from primary care and the community, using similar standardised protocols, and matched by age, sex and geographical area. Data were collected from participants using a standardized written questionnaire at clinical visits. Cognitive symptoms included problems with short-term memory, attention, and executive function. Sleep symptoms included unrefreshing sleep and poor quality or inadequate duration of sleep. All participants reported symptoms based on an ordinal severity scale. Multivariable logistic regression was carried out in the ME/CFS group to investigate socio-demographic factors associated with severe symptoms.

RESULTS: All cognitive and sleep symptoms were more prevalent in the ME/CFS group, with 'trouble concentrating' (98.3%) the most commonly reported symptom. Severe symptoms were also more commonly reported in the ME/CFS group, with 55% reporting 'severe, unrefreshing sleep'. Similarly, in the MS group, the most commonly reported severe symptoms were sleep-related. Logistic regression analysis revealed that ME/CFS patients aged over 50 years were more than three times as likely to experience severe symptoms than those younger than 30 (OR 3.23, p = 0.031). Current smoking was associated with severe symptoms, increasing the risk by approximately three times (OR 2.93, p = 0.003) and those with household incomes of more than £15,000 per year were less likely to experience severe symptoms compared to those earning less than this (OR 0.31, p = 0.017).

CONCLUSIONS:Cognitive and sleep symptoms are more common in ME/CFS patients than in MS patients and healthy controls, providing further support for existing evidence of central nervous system abnormalities in ME/CFS. Our findings suggest that people with ME/CFS who are smokers, or have a low income, are more likely to report severe cognitive and sleep symptoms. Future research should aim to develop strategies to prevent the progression of severe cognitive and sleep symptoms through early interventions that prioritise patients identified as being at highest risk.

Source: Jain V, Arunkumar A, Kingdon C, Lacerda E, Nacul L. Prevalence of and risk factors for severe cognitive and sleep symptoms in ME/CFS and MS. BMC Neurol. 2017 Jun 20;17(1):117. doi: 10.1186/s12883-017-0896-0. https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-017-0896-0 (Full article)

Chronic fatigue syndrome: System under stress

Australian researchers have discovered for the first time that reduced heart rate variability — or changes in heart beat timing — best predicts cognitive disturbances, such as concentration difficulties commonly reported by people with chronic fatigue syndrome (CFS). This adds to the growing body of evidence linking autonomic nervous system imbalance to symptoms of this poorly understood disorder.

The findings are reported in the journal PLOS ONE.

Chronic fatigue syndrome is characterised by medically unexplained, disabling fatigue and neuropsychiatric symptoms of at least six months’ duration. The disturbance underlying the symptoms in CFS is still poorly understood.

“We have studied autonomic function in CFS for some time and our findings clearly indicate a loss of integrity in stress-responsive neural and physiological systems in CFS. Patients with this condition are hyper-responsive to challenges arising both from within the body and from the environment,” says lead researcher, Associate Professor Ute Vollmer-Conna of the University of New South Wales in Sydney, Australia.

“Even when they sleep, their stress-responsive neural systems are on high alert, signalling that it is not safe to relax. I think this condition may be understood by analogy to post-traumatic stress disorder, just that in CFS the original trauma is most likely a physiological, internal one, such as a severe infection.”

In a study of 30 patients with CFS and 40 healthy individuals, UNSW researchers recorded the heart beats of participants (via ECG) and analysed cardiac responses to cognitive challenges, and associations with mental performance outcomes.

The patients with CFS performed with similar accuracy, but they took significantly longer to complete the tests than people without the condition. They also had greater heart rate reactivity; low and unresponsive heart rate variability; and prolonged heart rate-recovery after the cognitive challenge.

Resting heart rate variability (an index of vagus nerve activity) was identified as the only significant predictor of cognitive outcomes, while current levels of fatigue and other symptoms did not relate to cognitive performance.

“This is the first demonstration of an association between reduced cardiac vagal tone and cognitive impairment in CFS. Our findings confirm previous reports of a significant loss of vagal modulation, which becomes particularly apparent when dealing with challenging tasks. The current results are consistent with the notion that CFS represents a ‘system under stress’,” Associate Professor Vollmer-Conna says.

The findings could lead to new ways to improve cognitive difficulties in people with CFS, including biofeedback assisted retraining of autonomic functioning, the researchers say.

Journal Reference: Alison Beaumont, Alexander R. Burton, Jim Lemon, Barbara K. Bennett, Andrew Lloyd, Uté Vollmer-Conna. Reduced Cardiac Vagal Modulation Impacts on Cognitive Performance in Chronic Fatigue Syndrome. PLoS ONE, 2012; 7 (11): e49518 DOI: 10.1371/journal.pone.0049518

 

Source: University of New South Wales. “Chronic fatigue syndrome: System under stress.” ScienceDaily. ScienceDaily, 15 November 2012. https://www.sciencedaily.com/releases/2012/11/121115133806.htm

 

Neural Consequences of Post-Exertion Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Post exertion malaise is one of the most debilitating aspects of Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, yet the neurobiological consequences are largely unexplored. The objective of the study was to determine the neural consequences of acute exercise using functional brain imaging.

Fifteen female Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients and 15 healthy female controls completed 30 minutes of submaximal exercise (70% of peak heart rate) on a cycle ergometer. Symptom assessments (e.g. fatigue, pain, mood) and brain imaging data were collected one week prior to and 24 hours following exercise.

Functional brain images were obtained during performance of: 1) a fatiguing cognitive task – the Paced Auditory Serial Addition Task, 2) a non-fatiguing cognitive task – simple number recognition, and 3) a non-fatiguing motor task – finger tapping. Symptom and exercise data were analyzed using independent samples t-tests. Cognitive performance data were analyzed using mixed-model analysis of variance with repeated measures. Brain responses to fatiguing and non-fatiguing tasks were analyzed using linear mixed effects with cluster-wise (101-voxels) alpha of 0.05.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients reported large symptom changes compared to controls (effect size ≥0.8, p<0.05). Patients and controls had similar physiological responses to exercise (p>0.05). However, patients exercised at significantly lower Watts and reported greater exertion and leg muscle pain (p<0.05).

For cognitive performance, a significant Group by Time interaction (p<0.05), demonstrated pre- to post-exercise improvements for controls and worsening for patients. Brain responses to finger tapping did not differ between groups at either time point. During number recognition, controls exhibited greater brain activity (p<0.05) in the posterior cingulate cortex, but only for the pre-exercise scan. For the Paced Serial Auditory Addition Task, there was a significant Group by Time interaction (p<0.05) with patients exhibiting increased brain activity from pre- to post-exercise compared to controls bilaterally for inferior and superior parietal and cingulate cortices.

Changes in brain activity were significantly related to symptoms for patients (p<0.05). Acute exercise exacerbated symptoms, impaired cognitive performance and affected brain function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients.

These converging results, linking symptom exacerbation with brain function, provide objective evidence of the detrimental neurophysiological effects of post-exertion malaise.

Published by Elsevier Inc.

 

Source: Cook DB, Light AR, Light KC, Broderick G, Shields MR, Dougherty RJ, Meyer JD, VanRiper S, Stegner AJ, Ellingson LD, Vernon SD. Neural Consequences of Post-Exertion Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Brain Behav Immun. 2017 Feb 16. pii: S0889-1591(17)30051-X. doi: 10.1016/j.bbi.2017.02.009. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28216087

 

Low putamen activity associated with poor reward sensitivity in childhood chronic fatigue syndrome

Abstract:

Motivational signals influence a wide variety of cognitive processes and components of behavioral performance. Cognitive dysfunction in patients with childhood chronic fatigue syndrome (CCFS) may be closely associated with a low motivation to learn induced by impaired neural reward processing. However, the extent to which reward processing is impaired in CCFS patients is unclear.

The aim of the present functional magnetic resonance imaging (fMRI) study was to determine whether brain activity in regions related to reward sensitivity is impaired in CCFS patients. fMRI data were collected from 13 CCFS patients (mean age, 13.6 ± 1.0 years) and 13 healthy children and adolescents (HCA) (mean age, 13.7 ± 1.3 years) performing a monetary reward task. Neural activity in high- and low-monetary-reward conditions was compared between CCFS and HCA groups. Severity of fatigue and the reward obtained from learning in daily life were evaluated by questionnaires.

Activity of the putamen was lower in the CCFS group than in the HCA group in the low-reward condition, but not in the high-reward condition. Activity of the putamen in the low-reward condition in CCFS patients was negatively and positively correlated with severity of fatigue and the reward from learning in daily life, respectively.

We previously revealed that motivation to learn was correlated with striatal activity, particularly the neural activity in the putamen. This suggests that in CCFS patients low putamen activity, associated with altered dopaminergic function, decreases reward sensitivity and lowers motivation to learn.

 

Source: Mizuno K, Kawatani J, Tajima K, Sasaki AT, Yoneda T, Komi M, Hirai T, Tomoda A, Joudoi T, Watanabe Y. Low putamen activity associated with poor reward sensitivity in childhood chronic fatigue syndrome. Neuroimage Clin. 2016 Sep 26;12:600-606. eCollection 2016. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043413/ (Full article)

 

Cognitive Dysfunction in Chronic Fatigue Syndrome: a Review of Recent Evidence

Abstract:

Cognitive difficulties represent a common and debilitating feature of the enigmatic chronic fatigue syndrome (CFS). These difficulties manifest as self-reported problems with attention, memory, and concentration and present objectively as slowed information processing speed particularly on complex tasks requiring sustained attention. The mechanisms underlying cognitive dysfunction remain to be established; however, alterations in autonomic nervous system activity and cerebral blood flow have been proposed as possibilities.

Heterogeneity in the experience of cognitive impairment, as well as differences in the methods utilised to quantify dysfunction, may contribute to the difficulties in establishing plausible biological underpinnings. The development of a brief neurocognitive battery specifically tailored to CFS and adoption by the international research community would be beneficial in establishing a profile of cognitive dysfunction. This could also provide better insights into the underlying biological mechanisms of cognitive dysfunction in CFS and enhance the development of targeted treatments.

 

Source: Cvejic E, Birch RC, Vollmer-Conna U. Cognitive Dysfunction in Chronic Fatigue Syndrome: a Review of Recent Evidence. Curr Rheumatol Rep. 2016 May;18(5):24. doi: 10.1007/s11926-016-0577-9. https://www.ncbi.nlm.nih.gov/pubmed/27032787

 

Neurocognitive improvements after best-practice intervention for chronic fatigue syndrome: Preliminary evidence of divergence between objective indices and subjective perceptions

Abstract:

BACKGROUND: Neurocognitive difficulties are commonly reported by patients suffering from chronic fatigue syndrome (CFS). Moderate improvements from ‘best practice’ therapy are promising, but to date reported efficacy is based entirely on subjective measures. This is problematic, given the well-documented divergence between subjective perceptions and actual neurocognitive performance, including in this patient group.

MATERIAL AND METHODS: Subjective and objective measures of neurocognitive performance were obtained from 25 patients with well-characterized CFS before and after the completion of a 12-week graded-activity program incorporating a cognitive training component. Additionally, self-reported symptoms, cardiac autonomic activity (a relevant biomarker of stress responsivity), and their relation to neurocognitive improvements were examined.

RESULTS: Substantive post-intervention improvements in subjective (p=0.006) and objective (including faster responses speeds and greater accuracy, p’s<0.001) neurocognitive performance were documented. Participants also demonstrated reduced autonomic reactivity to the cognitive challenge at follow-up (p’s≤0.01). These improvements were accompanied by improvements in symptom ratings (p’s≤0.01). However, subjective ratings of neurocognitive difficulties, and CFS-related symptoms were not linked to objective performance improvements.

CONCLUSIONS: These initial data provide the first evidence of objective neurocognitive performance improvements accompanied by a significant reduction in responsiveness in stress-related neural pathways consequent to cognitive-behavioral/graded exercise therapy programs. These findings provide support for the effectiveness of such programs in remediating clinical status. These promising findings warrant further investigation, including replication in a larger sample utilizing more controlled study designs.

Copyright © 2016 Elsevier Inc. All rights reserved.

 

Source: Cvejic E, Lloyd AR, Vollmer-Conna U. Neurocognitive improvements after best-practice intervention for chronic fatigue syndrome: Preliminary evidence of divergence between objective indices and subjective perceptions. Compr Psychiatry. 2016 Apr;66:166-75. doi: 10.1016/j.comppsych.2016.02.002. Epub 2016 Feb 9. https://www.ncbi.nlm.nih.gov/pubmed/26995250

 

Neurocognitive complaints and functional status among patients with chronic fatigue syndrome and fibromyalgia

Abstract:

PURPOSE: The purpose of this study was to conduct a longitudinal examination of cognitive complaints and functional status in patients with chronic fatigue syndrome (CFS) alone and those who also had fibromyalgia (CFS/FM).

METHODS: A total of 93 patients from a tertiary care fatigue clinic were evaluated on four occasions, each 6 months apart. Each evaluation included a tender point assessment, and self-reported functional status and cognitive complaints.

RESULTS: Patients with CFS/FM reported significantly worse physical functioning, more bodily pain, and more cognitive difficulties (visuo-perceptual ability and verbal memory) than patients with CFS alone. Over time, bodily pain decreased only for participants with CFS alone. Verbal memory problems were associated with more bodily pain for both patient groups, whereas visuo-perceptual problems were associated with worse functional status for patients with CFS alone.

CONCLUSIONS: This study adds to the literature on functional status, longitudinal course, and cognitive difficulties among patients with CFS and those with CFS and FM. The results suggest that patients with CFS/FM are more disabled, have more cognitive complaints, and improve more slowly over time than patients with CFS alone. Specific cognitive difficulties are related to worse functional status, which supports the addition of cognitive difficulties to the FM case criteria.

 

Source: Schmaling KB, Betterton KL. Neurocognitive complaints and functional status among patients with chronic fatigue syndrome and fibromyalgia. Qual Life Res. 2016 May;25(5):1257-63. doi: 10.1007/s11136-015-1160-y. Epub 2015 Oct 15. https://www.ncbi.nlm.nih.gov/pubmed/26471263