To examine cognitive deficits in people with chronic fatigue syndrome (CFS) and their relationship to psychological status, CFS symptoms, and everyday functioning.
The current study compared the cognitive performance (reaction time, attention, memory, motor functioning, verbal abilities, and visuospatial abilities) of a sample with CFS (n = 50) with that of a sample of healthy controls (n = 50), all of whom had demonstrated high levels of effort and an intention to perform well, and examined the extent to which psychological status, CFS symptoms, and everyday functioning were related to cognitive performance.
The CFS group showed impaired information processing speed (reaction time), relative to the controls, but comparable performance on tests of attention, memory, motor functioning, verbal ability, and visuospatial ability. Moreover, information processing speed was not related to psychiatric status, depression, anxiety, the number or severity of CFS symptoms, fatigue, sleep quality, or everyday functioning.
A slowing in information processing speed appears to be the main cognitive deficit seen in persons with CFS whose performance on effort tests is not compromised. Importantly, this slowing does not appear to be the consequence of other CFS-related variables, such as depression and fatigue, or motor speed.
"Therefore, it seems patients with CFS may experience memory deficits with or without comorbid depression. Other studies have suggested that the appearance of memory difficulties in patients with CFS is the result of impairments with information processing (Cockshell and Mathias, 2013) rather than actual memory deficits. "
[Show abstract][Hide abstract] ABSTRACT: Chronic fatigue syndrome (CFS) is characterized by fatigue, sleep dysfunction, and cognitive deficits (Fukuda et al., 1994). Research surrounding cognitive functioning among patients with CFS has found difficulty with memory, attention, and information processing. A similar disorder, postural tachycardia syndrome (POTS), is characterized by increased heart rate, fatigue, and mental cloudiness (Raj et al., 2009). Potential implications of cognitive deficits for patients with CFS and/or POTS are discussed, including difficulties with school and/or employment. A few biological theories (i.e., kindling, impairments in the central nervous system, and difficulty with blood flow) have emerged as potential explanations for the cognitive deficits reported in both CFS and POTS Future research should continue to examine possible explanations for cognitive impairments in CFS and POTS, and ultimately use this information to try and reduce cognitive impairments for these patients.
Frontiers in Physiology 05/2013; 4:113. DOI:10.3389/fphys.2013.00113 · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Both good physical and cognitive functioning have a positive influence on the execution of activities of daily living. Patients with chronic fatigue syndrome (CFS) as well as patients with fibromyalgia (FM) have marked cognitive deficits. Furthermore, a good physical and functional health status may have a positive impact on a variety of cognitive skills. A link that has already been observed in young and old healthy individuals, but in patients with CFS evidence is limited.
To examine whether recovery of upper limb muscle function could be a significant predictor of cognitive performance in patients with CFS and CFS with comorbid FM. Furthermore, this study determined whether cognitive performance is different in CFS patients with and without comorbid FM.
A case-control design.
Eighteen patients with CFS-only, 30 patients with CFS+FM, and 30 healthy inactive controls were studied. Participants first completed three performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, they performed a fatiguing upper limb exercise test with subsequent recovery measures.
Recovery of upper limb muscle function was found to be a significant predictor of cognitive performance in patients with CFS. Patients with CFS+FM, but not patients with CFS-only showed significantly decreased cognitive performance compared with the controls.
The cross-sectional nature of this study does not allow for inferences of causation.
The results suggest that a better physical health status could predict better mental health in patients with CFS. Furthermore, they underline disease heterogeneity, suggesting that reducing this in future research is important to better understand and uncover mechanisms regarding the nature of divers impairments in these patients.
[Show abstract][Hide abstract] ABSTRACT: Objective:
The purpose of this study was to examine the relationship between subjective and objective assessments of memory and attention in people with chronic fatigue syndrome (CFS), using tests that have previously detected deficits in CFS samples and measures of potential confounds.
Fifty people with CFS and 50 healthy controls were compared on subjective (memory and attention symptom severity, Cognitive Failures Questionnaire, Everyday Attention Questionnaires) and objective (California Verbal Learning Test, Rey-Osterreith Complex Figure Test, Paced Auditory Serial Addition Test, Stroop task) measures of memory and attention. Fatigue, sleep, depression, and anxiety were also assessed.
The CFS group reported experiencing more cognitive problems than the controls, but the two groups did not differ on the cognitive tests. Scores on the subjective and objective measures were not correlated in either group. Depression was positively correlated with increased severity of cognitive problems in both the CFS and control groups.
There is little evidence for a relationship between subjective and objective measures of cognitive functioning for both people with CFS and healthy controls, which suggests that they may be capturing different constructs. Problems with memory and attention in everyday life are a significant part of CFS. Depression appears to be related to subjective problems but does not fully explain them.
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