Category: Cognitive Dysfunction

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

 

Associations Between Cognitive Performance and Pain in Chronic Fatigue Syndrome: Comorbidity with Fibromyalgia Does Matter

Abstract:

BACKGROUND: In addition to the frequently reported pain complaints, performance-based cognitive capabilities in patients with chronic fatigue syndrome (CFS) with and without comorbid fibromyalgia (FM) are significantly worse than those of healthy controls. In various chronic pain populations, cognitive impairments are known to be related to pain severity. However, to the best of our knowledge, the association between cognitive performance and experimental pain measurements has never been examined in CFS patients.

OBJECTIVES: This study aimed to examine the association between cognitive performance and self-reported as well as experimental pain measurements in CFS patients with and without FM.

STUDY DESIGN: Observational study.

SETTING: The present study took place at the Vrije Universiteit Brussel and the University of Antwerp.

METHODS: Forty-eight (18 CFS-only and 30 CFS+FM) patients and 30 healthy controls were studied. Participants first completed 3 performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, experimental pain measurements (pressure pain thresholds [PPT], temporal summation [TS], and conditioned pain modulation [CPM]) took place and participants were asked to fill out 3 questionnaires to assess self-reported pain, fatigue, and depressive symptoms.

RESULTS: In the CFS+FM group, the capacity of pain inhibition was significantly associated with cognitive inhibition. Self-reported pain was significantly associated with simple reaction time in CFS-only patients. The CFS+FM but not the CFS-only group showed a significantly lower PPT and enhanced TS compared with controls.

LIMITATIONS: The cross-sectional nature of this study does not allow for inferences of causation.

CONCLUSIONS: The results underline disease heterogeneity in CFS by indicating that a measure of endogenous pain inhibition might be a significant predictor of cognitive functioning in CFS patients with FM, while self-reported pain appears more appropriate to predict cognitive functioning in CFS patients without FM.

 

Source: Ickmans K, Meeus M, De Kooning M, Lambrecht L, Pattyn N, Nijs J. Associations Between Cognitive Performance and Pain in Chronic Fatigue Syndrome: Comorbidity with Fibromyalgia Does Matter. Pain Physician. 2015 Sep-Oct;18(5):E841-52. http://www.painphysicianjournal.com/current/pdf?article=MjQxOA%3D%3D&journal=91 (Full article as PDF file)

 

The impact of chronic fatigue syndrome on cognitive functioning in adolescents

Abstract:

Chronic fatigue syndrome (CFS) is characterized by persistent fatigue and severe disability. Most adolescent patients report attention and concentration problems, with subsequent poor performance at school. This study investigated the impact of CFS on intellectual capacity by (1) assessing discrepancies between current intelligence quotient (IQ) and school level and (2) exploring differences in current IQ and pre-CFS school performance, compared with healthy individuals. Current data was cross-sectionally gathered and compared with retrospective pre-CFS school performance data. Fifty-nine CFS adolescents and 40 controls were evaluated on performance on age-appropriate intelligence tests and school level. Current IQ scores of CFS adolescents were lower than expected on the basis of their school level. Furthermore, there was a difference in intelligence performance across time when current IQ scores were compared with pre-CFS cognitive achievement. Healthy controls did not show any discrepancies.

CONCLUSION: According to their pre-CFS intelligence assessments, CFS patients started with appropriate secondary school levels at the age of 12. Our data suggest that CFS may be accompanied by a decline in general cognitive functioning. Given the critical age for intellectual development, we recommend a timely diagnosis followed by appropriate treatment of CFS in adolescents.

WHAT IS KNOWN: Adolescent chronic fatigue syndrome (CFS) is a debilitating condition with major impact on social and intellectual development. Most patients report concentration problems, with subsequent poor performance at school. Little is known about the influence of CFS on intellectual performances.

WHAT IS NEW: IQ scores of CFS adolescents are lower than the IQ scores of healthy peers with an equivalent school level. There is a decrease in intelligence performance across time when current IQ scores are compared with pre-CFS cognitive achievement. Healthy controls do not show any discrepancies between their current IQ, school level and previous cognitive functioning. This suggest that adolescent CFS may be accompanied by a decline in general cognitive functioning.

 

Source: Nijhof LN, Nijhof SL, Bleijenberg G, Stellato RK, Kimpen JL, Hulshoff Pol HE, van de Putte EM. The impact of chronic fatigue syndrome on cognitive functioning in adolescents. Eur J Pediatr. 2016 Feb;175(2):245-52. doi: 10.1007/s00431-015-2626-1. Epub 2015 Sep 3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4724362/ (Full article)

 

Computerized training improves verbal working memory in patients with myalgic encephalomyelitis/chronic fatigue syndrome: A pilot study

Abstract:

OBJECTIVE: Patients with myalgic encephalomyelitis/chronic fatigue syndrome experience cognitive difficulties. The aim of this study was to evaluate the effect of computerized training on working memory in this syndrome.

DESIGN: Non-randomized (quasi-experimental) study with no-treatment control group and non-equivalent dependent variable design in a myalgic encephalomyelitis/chronic fatigue syndrome-cohort.

SUBJECTS: Patients with myalgic encephalomyelitis/chronic fatigue syndrome who participated in a 6-month outpatient rehabilitation programme were included in the study. Eleven patients who showed signs of working memory deficit were recruited for additional memory training and 12 patients with no working memory deficit served as controls.

METHODS: Cognitive training with computerized working memory tasks of increasing difficulty was performed 30-45 min/day, 5 days/week over a 5-week period. Short-term and working memory tests (Digit Span – forward, backward, total) were used as primary outcome measures. Nine of the 11 patients were able to complete the training.

RESULTS: Cognitive training increased working memory (p = 0.003) and general attention (p = 0.004) to the mean level. Short-term memory was also improved, but the difference was not statistically significant (p = 0.052) vs prior training. The control group did not show any significant improvement in primary outcome measures.

CONCLUSION: Cognitive training may be a new treatment for patients with myalgic encephalomyelitis/chronic fatigue syndrome.

 

Source: Maroti D, Westerberg AF, Saury JM, Bileviciute-Ljungar I. Computerized training improves verbal working memory in patients with myalgic encephalomyelitis/chronic fatigue syndrome: A pilot study. J Rehabil Med. 2015 Aug 18;47(7):665-8. doi: 10.2340/16501977-1976. https://www.medicaljournals.se/jrm/content/abstract/10.2340/16501977-1976 (Full article)

 

The association between daytime napping and cognitive functioning in chronic fatigue syndrome

Abstract:

OBJECTIVES: The precise relationship between sleep and physical and mental functioning in chronic fatigue syndrome (CFS) has not been examined directly, nor has the impact of daytime napping. This study aimed to examine self-reported sleep in patients with CFS and explore whether sleep quality and daytime napping, specific patient characteristics (gender, illness length) and levels of anxiety and depression, predicted daytime fatigue severity, levels of daytime sleepiness and cognitive functioning, all key dimensions of the illness experience.

METHODS: 118 adults meeting the 1994 CDC case criteria for CFS completed a standardised sleep diary over 14 days. Momentary functional assessments of fatigue, sleepiness, cognition and mood were completed by patients as part of usual care. Levels of daytime functioning and disability were quantified using symptom assessment tools, measuring fatigue (Chalder Fatigue Scale), sleepiness (Epworth Sleepiness Scale), cognitive functioning (Trail Making Test, Cognitive Failures Questionnaire), and mood (Hospital Anxiety and Depression Scale).

RESULTS: Hierarchical Regressions demonstrated that a shorter time since diagnosis, higher depression and longer wake time after sleep onset predicted 23.4% of the variance in fatigue severity (p <.001). Being male, higher depression and more afternoon naps predicted 25.6% of the variance in objective cognitive dysfunction (p <.001). Higher anxiety and depression and morning napping predicted 32.2% of the variance in subjective cognitive dysfunction (p <.001). When patients were classified into groups of mild and moderate sleepiness, those with longer daytime naps, those who mainly napped in the afternoon, and those with higher levels of anxiety, were more likely to be in the moderately sleepy group.

CONCLUSIONS: Napping, particularly in the afternoon is associated with poorer cognitive functioning and more daytime sleepiness in CFS. These findings have clinical implications for symptom management strategies.

 

Source: Gotts ZM, Ellis JG, Deary V, Barclay N, Newton JL. The association between daytime napping and cognitive functioning in chronic fatigue syndrome. PLoS One. 2015 Jan 9;10(1):e0117136. doi: 10.1371/journal.pone.0117136. ECollection 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4289075/ (Full article)

 

Neuropsychological impairment in female patients with chronic fatigue syndrome: a preliminary study

Abstract:

This study examines neuropsychological impairments associated with chronic fatigue syndrome (CFS) and explores their association with related clinical factors.

Sixty-eight women with CFS were assessed with a neuropsychological battery. Raw scores were adjusted for age and gender and were converted to T scores according to normative data extracted from a local sample of 250 healthy subjects. Neuropsychological dysfunction was calculated using summary impairment indexes (proportion of test scores outside normal limits-T score <40-for each cognitive domain). Finally, a linear regression was calculated to identify predictors of cognitive deficit, including intrinsic factors of the disease (level of fatigue and length of illness) and extrinsic factors (emotional factors, age, and education).

Approximately 50% of scores showed impairment in attention and motor functioning, and nearly 40% showed impairment in speed information processing and executive functioning. Fatigue predicted attention and executive functioning impairment, and emotional factors predicted verbal memory dysfunction.

According to our findings, cognitive dysfunction in CFS could be explained by pathophysiological processes of the disease. One implication of this would be the need to identify homogeneous subgroups of patients with CFS by taking into account common factors, which, in turn, would help to identify more specific cognitive profiles, which could then serve to implement appropriate therapeutic measures accordingly.

 

Source: Santamarina-Perez P, Eiroa-Orosa FJ, Rodriguez-Urrutia A, Qureshi A, Alegre J. Neuropsychological impairment in female patients with chronic fatigue syndrome: a preliminary study. Appl Neuropsychol Adult. 2014;21(2):120-7. doi: 10.1080/09084282.2013.771264. Epub 2013 Aug 13. https://www.ncbi.nlm.nih.gov/pubmed/24826505

 

Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by persistent emotional, mental, and physical fatigue accompanied by a range of neurological, autonomic, neuroendocrine, immune, and sleep problems. Research has shown that psychosocial factors such as anxiety and depression as well as the symptoms of the illness, have a significant impact on the quality of life of people with ME/CFS. In addition, individuals may suffer from deficits in memory and concentration. This study set out to explore the relationships between variables which have been found to contribute to cognitive performance, as measured by prospective and retrospective memory, and cognitive failures.

METHODS: Eighty-seven people with ME/CFS answered questionnaires measuring fatigue, depression, anxiety, social support, and general self-efficacy. These were used in a correlational design (multiple regression) to predict cognitive function (self-ratings on prospective and retrospective memory), and cognitive failures.

RESULTS: Our study found that fatigue, depression, and general self-efficacy were directly associated with cognitive failures and retrospective (but not prospective) memory.

CONCLUSION: Although it was not possible in this study to determine the cause of the deficits, the literature in this area leads us to suggest that although the pathophysiological mechanisms of ME/CFS are unclear, abnormalities in the immune system, including proinflammatory cytokines, can lead to significant impairments in cognition. We suggest that fatigue and depression may be a result of the neurobiological effects of ME/CFS and in addition, that the neurobiological effects of the illness may give rise to both fatigue and cognitive deficits independently.

 

Source: Attree EA, Arroll MA, Dancey CP, Griffith C, Bansal AS. Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome. Psychol Res Behav Manag. 2014 Feb 25;7:67-76. doi: 10.2147/PRBM.S50645. ECollection 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3940708/ (Full article)

 

Rebuttal to Ickmans et al. association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome

Dear Editor:

In a study recently published in Journal of Rehabilitation Research and Development, Ickmans et al. [1] found a substantially deteriorated physical exercise capacity in myalgic encephalopathy/chronic fatigue syndrome (ME/CFS), as established by a cardiopulmonary exercise test (peak oxygen uptake [VO2max]: 19.1 ± 4.6 mL/min/kg, peak heart rate: 145.1 ± 22.4 beats per minute [bpm], peak workload: 114.2 ± 31.3 W, compared with 27.2 ± 5.6 mL/min/ kg, 170.0 ± 36.2 bpm, and 114.2 ± 31.3 W, respectively, in sedentary controls). Ickmans et al. Also observed various cognitive deficits in ME/CFS, e.g., prolonged choice and simple reaction times in various Stroop subtests and the psychomotor vigilance task test (PVT), more errors of omission in the PVT, and worse letter recall scores on the operation span task test, indicative for working memory impairment and reduced psychomotor speed.

You can read the rest of this letter here:  http://www.rehab.research.va.gov/jour/2013/509/pdf/pagevii.pdf 

Comment on: Association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome. [J Rehabil Res Dev. 2013]

 

Source: Twisk F. Rebuttal to Ickmans et al. association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome. J Rehabil Res Dev. 2013;50(9):vii-viii. http://www.rehab.research.va.gov/jour/2013/509/pdf/pagevii.pdf (Full article)