Cognitive slowing and working memory difficulties in chronic fatigue syndrome

Free-water-corrected diffusion and adrenergic/muscarinic antibodies in myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND AND PURPOSE

Free-water-corrected diffusion tensor imaging (FW-DTI), a new analysis method for diffusion MRI, can indicate neuroinflammation and degeneration. There is increasing evidence of autoimmune etiology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We used FW-DTI and conventional DTI to investigate microstructural brain changes related to autoantibody titers in patients with ME/CFS.

METHODS

We prospectively examined 58 consecutive right-handed ME/CFS patients who underwent both brain MRI including FW-DTI and a blood analysis of autoantibody titers against β1 adrenergic receptor (β1 AdR-Ab), β2 AdR-Ab, M3 acetylcholine receptor (M3 AchR-Ab), and M4 AchR-Ab. We investigated the correlations between these four autoantibody titers and three FW-DTI indices-free water (FW), FW-corrected fractional anisotropy (FAt), and FW-corrected mean diffusivity-as well as two conventional DTI indices-fractional anisotropy (FA) and mean diffusivity. The patients' age and gender were considered as nuisance covariates. We also evaluated the correlations between the FW-DTI indices and the performance status and disease duration.

RESULTS

Significant negative correlations between the serum levels of several autoantibody titers and DTI indices were identified, mainly in the right frontal operculum. The disease duration showed significant negative correlations with both FAt and FA in the right frontal operculum. The changes in the FW-corrected DTI indices were observed over a wider extent compared to the conventional DTI indices.

CONCLUSIONS

These results demonstrate the value of using DTI to assess the microstructure of ME/CFS. The abnormalities of right frontal operculum may be a diagnostic marker for ME/CFS.

Systematic review and meta-analysis of cognitive impairment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is commonly associated with cognitive complaints. To bring out the neuropsychological symptomatology inherent to ME/CFS, we conducted a systematic review according to PRISMA and MOOSE guidelines of the literature through the analysis of 764 studies published between 1988 and 2019 by using PubMed Central website and Clarivate analytics platform. We performed a meta-analysis to delineate an idea of the neuropsychological profile inherent in ME/CFS. The clinical picture typically affects visuo-spatial immediate memory (g = - 0.55, p = 0.007), reading speed (g = - 0.82, p = 0.0001) and graphics gesture (g = - 0.59, p = 0.0001). Analysis also revealed difficulties in several processes inherent in episodic verbal memory (storage, retrieval, recognition) and visual memory (recovery) and a low efficiency in attentional abilities. Executive functions seemed to be little or not affected and instrumental functions appeared constantly preserved. With regard to the complexity and heterogeneity of the cognitive phenotype, it turns out that determining a sound clinical picture of ME/CFS cognitive profile must go through a neuropsychological examination allowing a complete evaluation integrating the notion of agreement between the choice and the number of tests and the complexity intrinsic to the pathology.

Cognitive dysfunction in ulcerative colitis patients in remission and its comparison with patients with irritable bowel syndrome and healthy controls

BACKGROUND

There is a paucity of research concerning cognitive impairments in Inflammatory bowel disease - ulcerative colitis (IBD-UC) and irritable bowel syndrome (IBS). Studies on cognitive dysfunction in patients with IBD-UC have either been small or have shown conflicting results. This study is conducted to examine the evidence of cognitive dysfunction in IBD-UC patients in remission and compare the evident cognitive deficit with IBS patients and healthy controls.

METHODS

This single-centre cross-sectional observational study enrolled a total of 90 participants, 29 in ulcerative colitis (UC) in remission group, 31 in IBS group and 30 in healthy control group. Assessment of cognition with the help of cognitive function tests mini-mental state examination (MMSE), Montreal Cognitive Assessment (MoCA) test and p300 was performed in all participants.

RESULTS

A statistically significant number of the participants in IBD-UC in remission group had MMSE and MoCA score below the lower limit of normal, in comparison to the healthy control and IBS groups. The mean peak latency of the p300 wave was statistically significantly increased in people in the IBD-UC group, in comparison to the healthy control and IBS groups.

CONCLUSION

Patients with IBD-UC in remission show impairments in cognitive functioning compared to the IBS and healthy control groups as assessed on cognitive function testing on MMSE, MoCA and mean peak latency of the p300 wave. This impairment in cognitive function is unlikely to be due to premorbid levels of intellectual functioning and is likely to have impact on health-related quality of life.

Impacts of trait anxiety on visual working memory, as a function of task demand and situational stress

Higher trait anxiety can impair cognitive functioning via attention, but relatively little is known about the impacts on visual working memory. These were investigated using previously validated visual feature binding tasks. In Study 1, participants' memory for visual features (shapes) and feature bindings (coloured shapes) was assessed. Stimulus presentation was simultaneous or sequential, varying attentional demand, and participants were grouped according to trait cognitive anxiety (low, moderate, high). No reliable effect of trait anxiety, either cognitive or somatic, was found on memory accuracy, but moderate trait cognitive anxiety was associated with faster correct response times (i.e. increased efficiency) when stimuli were sequentially presented. In Study 2, the role of situational stress was explored during a simultaneously presented task. Higher trait cognitive and somatic anxiety were both associated with poorer efficiency during both shape and binding memory tasks. Trait somatic anxiety also predicted poorer binding effectiveness (i.e. accuracy), in those reporting higher state cognitive anxiety. Situational stress predicted binding effectiveness, but never interacted with trait anxiety, and was therefore not necessary to observe these trait anxiety-visual working memory relationships. Trait cognitive and somatic anxiety, and situational stress, therefore each influence visual working memory performance.

Changes in Working Memory Performance Over an Academic Semester in Student Pharmacists

Objective. To preliminarily assess changes in Doctor of Pharmacy students' working memory performance over the course of an academic semester and to determine whether any observed changes were associated with fluctuations in stress and fatigue. Methods. Twenty-three PharmD students were recruited for this pilot study. At baseline, data were collected on students' personality, stress, fatigue, and working memory performance using two measures, the operation span and the symmetry span. Approximately every four weeks throughout the semester students' fatigue and stress levels were reassessed and they completed the two measures of working memory. A repeated measures analysis of variance was used to assess trends over time, and correlation analysis was used to assess potential relationships between working memory and other variables. Results. The operation span, a measure of general working memory resources, showed a significant quadratic trend over time. Irrespective of time, some associations between working memory performance and fatigue were seen. Significant correlations between fatigue and the extraversion personality trait were identified. The symmetry span, a measure of visuospatial resources, did not show trends over time nor did it correlate with fatigue, stress, or personality factors. Conclusion. Pharmacy students' working memory performance may fluctuate over the course of a semester, but more research is needed to identify factors that may influence this fluctuation.

A unifying theory for cognitive abnormalities in functional neurological disorders, fibromyalgia and chronic fatigue syndrome: systematic review

BACKGROUND

Functional cognitive disorder (FCD) describes cognitive dysfunction in the absence of an organic cause. It is increasingly prevalent in healthcare settings yet its key neuropsychological features have not been reported in large patient cohorts. We hypothesised that cognitive profiles in fibromyalgia (FM), chronic fatigue syndrome (CFS) and functional neurological disorders (FNDs) would provide a template for characterising FCD.

METHODS

We conducted a systematic review of studies with cognition-related outcomes in FM, CFS and FND.

RESULTS

We selected 52 studies on FM, 95 on CFS and 39 on FND. We found a general discordance between high rates of subjective cognitive symptoms, including forgetfulness, distractibility and word-finding difficulties, and inconsistent objective neuropsychological deficits. Objective deficits were reported, including poor selective and divided attention, slow information processing and vulnerability to distraction. In some studies, cognitive performance was inversely correlated with pain, exertion and fatigue. Performance validity testing demonstrated poor effort in only a minority of subjects, and patients with CFS showed a heightened perception of effort.

DISCUSSION

The cognitive profiles of FM, CFS and non-cognitive FND are similar to the proposed features of FCD, suggesting common mechanistic underpinnings. Similar findings have been reported in patients with mild traumatic brain injury and whiplash. We hypothesise that pain, fatigue and excessive interoceptive monitoring produce a decrease in externally directed attention. This increases susceptibility to distraction and slows information processing, interfering with cognitive function, in particular multitasking. Routine cognitive processes are experienced as unduly effortful. This may reflect a switch from an automatic to a less efficient controlled or explicit cognitive mode, a mechanism that has also been proposed for impaired motor control in FND. These experiences might then be overinterpreted due to memory perfectionism and heightened self-monitoring of cognitive performance.

Emotional Regulation in Women with Chronic Fatigue Syndrome and Depression: Internal Representations and Adaptive Defenses

Chronic fatigue syndrome (CFS) presents challenges in differential diagnosis and treatment. Complicating diagnosis is that its symptoms overlap with those of depression. This study applies psychoanalytic concepts to understand emotional regulation (ER) in women with CFS and/or depression. One hundred eighty-six women were assigned to four groups and compared: (a) CFS plus high er depression (CFS-HD); (b) CFS plus lower depression (CFS-LD); (c) depressive disorder (DD); and (d) healthy controls (HC). ER was operationalized by measures of capacity to form internal representations and adaptive defenses. The study's premise was that difficulties metabolizing emotions psychologically would be associated with their greater somatic expression. Some support was found for the hypothesis that CFS participants would exhibit more impairment in representing emotions and in adaptive defenses compared to the DD and HC groups, but this held only for the CFS-HD group. Although CFS-LD participants were expected to be more purely somatizing than the CFS-HD group, they instead showed more sophisticated capacities for ER than that group and recalled less distressing early relationships, revealing more resilience. Still, however, we found support for somatization in some CFS sufferers: Within both the CFS-HD and the CFS-LD groups, weaknesses in representing emotions and in defensive functioning were associated with more severe physical symptoms. Clinically, the heterogeneity of CFS and those who suffer from it indicates the need for individual assessment and depression treatment.

Frailty, Frailty Components, and Oral Health: A Systematic Review

A systematic review was conducted to assess the relationship between frailty or one of its components and poor oral health. A search strategy was developed to identify articles related to the research question in the PubMed, EMBASE, Cochrane, LILACS, and SciELO databases that were published in English, Spanish, or Brazilian Portuguese from 1991 to July 2013. Thirty-five studies were identified, and 12 met the inclusion criteria, seven of which were cross-sectional and five were cohort studies. Of the 12 articles, five (41.7%) were rated good and seven (58.3%) as fair quality. The published studies applied different oral health and frailty criteria measures. Variations in definitions of outcome measures and study designs limited the ability to draw strong conclusions about the relationship between frailty or prefrailty and poor oral health. None of the studies that were evaluated longitudinally showed whether poor oral health increases the likelihood of developing signs of frailty, although the studies suggest that there may be an association between frailty and oral health. More longitudinal studies are needed to better understand the relationship between frailty and oral health.

Myalgic Encephalomyelitis: Symptoms and Biomarkers

Myalgic Encephalomyelitis (ME) continues to cause significant morbidity worldwide with an estimated one million cases in the United States. Hurdles to establishing consensus to achieve accurate evaluation of patients with ME continue, fueled by poor agreement about case definitions, slow progress in development of standardized diagnostic approaches, and issues surrounding research priorities. Because there are other medical problems, such as early MS and Parkinson's Disease, which have some similar clinical presentations, it is critical to accurately diagnose ME to make a differential diagnosis. In this article, we explore and summarize advances in the physiological and neurological approaches to understanding, diagnosing, and treating ME. We identify key areas and approaches to elucidate the core and secondary symptom clusters in ME so as to provide some practical suggestions in evaluation of ME for clinicians and researchers. This review, therefore, represents a synthesis of key discussions in the literature, and has important implications for a better understanding of ME, its biological markers, and diagnostic criteria. There is a clear need for more longitudinal studies in this area with larger data sets, which correct for multiple testing.

Association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome

Limited scientific evidence suggests that physical activity is directly related to cognitive performance in patients with chronic fatigue syndrome (CFS). To date, no other study has examined the direct relationship between cognitive performance and physical fitness in these patients. This study examined whether cognitive performance and physical fitness are associated in female patients with CFS and investigated the association between cognitive performance and physical activity level (PAL) in the same study sample. We hypothesized that patients who performed better on cognitive tasks would show increased PALs and better performance on physical tests. The study included 31 women with CFS and 13 healthy inactive women. Participants first completed three cognitive tests. Afterward, they undertook a test to determine their maximal handgrip strength, performed a bicycle ergometer test, and were provided with an activity monitor. In patients with CFS, lower peak oxygen uptake and peak heart rate were associated with slower psychomotor speed (p < 0.05). Maximal handgrip strength was correlated with working memory performance (p < 0.05). Both choice and simple reaction time were lower in patients with CFS relative to healthy controls (p < 0.05 and p < 0.001, respectively). In conclusion, physical fitness, but not PAL, is associated with cognitive performance in female patients with CFS.

Can recovery of peripheral muscle function predict cognitive task performance in chronic fatigue syndrome with and without fibromyalgia?

BACKGROUND

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 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 been observed in young and old individuals who are healthy, although evidence is limited in patients with CFS.

OBJECTIVE

The purpose of this study was to examine whether recovery of upper limb muscle function could be a significant predictor of cognitive performance in patients with CFS and in patients with CFS and comorbid fibromyalgia. Furthermore, this study determined whether cognitive performance is different between these patient groups.

DESIGN

A case-control design was used.

METHODS

Seventy-eight participants were included in the study: 18 patients with CFS only (CFS group), 30 patients with CFS and comorbid fibromyalgia (CFS+FM group), and 30 individuals who were healthy and inactive (control group) 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, they performed a fatiguing upper limb exercise test, with subsequent recovery measures.

RESULTS

Recovery of upper limb muscle function was found to be a significant predictor of cognitive performance in patients with CFS. Participants in the CFS+FM group but not those in the CFS group showed significantly decreased cognitive performance compared with the control group.

LIMITATIONS

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

CONCLUSIONS

The results suggest that better physical health status could predict better mental health in patients with CFS. Furthermore, they underline disease heterogeneity, suggesting that reducing this factor in future research is important to better understand and uncover mechanisms regarding the nature of diverse impairments in these patients.

Cognitive impairments associated with CFS and POTS

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.

Antifatigue effects of Panax ginseng C.A. Meyer: a randomised, double-blind, placebo-controlled trial

The present study investigated the antifatigue effects of Panax ginseng C.A. Meyer in 90 subjects (21 men and 69 women) with idiopathic chronic fatigue (ICF) in a randomised, double-blind, placebo-controlled and parallel designed trial. A bespoke 20% ethanol extract of P. ginseng (1 g or 2 g day(-1)) or a placebo was administered to each group for 4 weeks, and then fatigue severity was monitored using a self-rating numeric scale (NRS) and a visual analogue scale (VAS) as a primary endpoint. Serum levels of reactive oxygen species (ROS), malondialdehyde (MDA), total glutathione (GSH) contents and glutathione reductase (GSH-Rd) activity were determined. After 4-week, P. ginseng administration decreased the total NRS score, but they were not statistically significant compared with placebo (P>0.05). Mental NRS score was significantly improved by P. ginseng administrations as 20.4 ± 5.0 to 15.1 ± 6.5 [95% CI 2.3 ~ 8.2] for 1 g and 20.7 ± 6.3 to 13.8 ± 6.2 [95% CI -0.1 ~ 4.2] for 2 g compared with placebo 20.9 ± 4.5 to 18.8 ± 2.9 [95% CI 4.1 ~ 9.9, P<0.01]. Only 2 g P. ginseng significantly reduced the VAS score from 7.3 ± 1.3 to 4.4 ± 1.8 [95% CI 0.7∼1.8] compared with the placebo 7.1 ± 1.0 to 5.8 ± 1.3 [95% CI 2.2 ~ 3.7, P<0.01]. ROS and MDA levels were lowered by P. ginseng compared to placebo. P. ginseng 1 g increased GSH concentration and GSH-Rd activity. Our results provide the first evidence of the antifatigue effects of P. ginseng in patients with ICF, and we submit that these changes in antioxidant properties contribute in part to its mechanism.

TRIAL REGISTRATION

Clinical Research Information Service (CRIS) KCT0000048.

Construct validity and test-retest reliability of the Fatigue Severity Scale in people with chronic neck pain

OBJECTIVE

To investigate an appropriate scoring system and unidimensionality using Rasch analysis, discriminant validity, and reliability of the Fatigue Severity Scale (FSS) in people with chronic neck pain.

DESIGN

Cross-sectional.

SETTING

Tertiary institution.

PARTICIPANTS

Patients with chronic neck pain (n=100) and asymptomatic controls (n=40).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The FSS.

RESULTS

Twenty-six of the 100 participants with chronic neck pain agreed to complete the FSS again within 1 week after the first administration for the assessment of the test-retest reliability. Two items obviously threatening unidimensionality were eliminated, and the 7-item FSS was developed through Rasch analyses. The 7-item FSS demonstrated the appropriateness of its 7-point scale and adequate internal consistency (Rasch-generated reliability, .83-.91). The 7-item FSS had a negligible floor effect (1%) and ceiling effect (2%). The item-person map demonstrated limited distribution of item difficulty in comparison with the distribution of person ability. The chronic neck pain group demonstrated significantly (P<.001) higher scores in the 7-item FSS than the control group, indicating discriminant validity. The 7-item FSS also demonstrated adequate test-retest reliability with a mean interval of 4.1 days (n=26) for each item (quadratic-weighted κ=.83-.94), and as a whole (intraclass correlation coefficient=.95). A 0-to-100 scale table reflecting Rasch scores was developed, and the minimum detectable change was 9.5 in the 0 to 100 scale.

CONCLUSION

The 7-item FSS appears unidimensional and reliable, and can be used quickly in clinical practice to gain a basic understanding of fatigue symptoms in people with chronic neck pain. Further, it is possible to modify the 7-item FSS to enhance discriminant ability within people with chronic neck pain by adding additional items, enlarging the distribution of item difficulty.

Contribution of Tactile and Kinesthetic Perceptions to Handwriting in Taiwanese Children in First and Second Grade

This study examined the contribution of tactile and kinesthetic perceptions to handwriting legibility and speed of 177 Taiwanese children in first and second grade. Five standardized instruments assessed tactile and kinesthetic perceptions using handwriting legibility and speed as outcome measures. Fine motor coordination, mental processing speed, age, and gender were measured and served as covariates. Pearson correlations and regression analyses examined the relationship between handwriting and tactile and kinesthetic perceptions. Handwriting speed and legibility both significantly correlated with tactile perception, kinesthetic perception, and covariates. Results from the regression analysis supported tactile and kinesthetic perceptions as being significant predictors of both handwriting speed ( F (6,170) = 25.87, p < .001, R = .477) and legibility ( F (6,170) = 11.043, p < .001, R = .280). Tactile perception contributed more to handwriting speed and legibility than kinesthetic perception. Tactile and kinesthetic perception should be assessed when evaluating handwriting. When children have difficulty writing quickly or legibly, professionals should assess children's tactile and kinesthetic abilities.

The relationship between cognitive functions, somatization and behavioural coping in patients with multiple functional somatic symptoms

BACKGROUND AND AIMS

Patients with multiple functional somatic symptoms (MFS) often express cognitive complaints. The aim of this descriptive study was to investigate whether these patients have cognitive deficits and whether the patients' cognitive functioning relates to their experience of physical and psychological distress and to their use of pain-related coping strategies.

METHODS

Neuropsychological assessment of verbal ability, psychomotor speed, attention, working memory, perceptual organization and memory, was conducted on 22 MFS patients and 27 healthy age- and gender-matched controls. Psychological distress, health anxiety, health status and pain coping were measured with questionnaires [Symptom Checklist 90-Revised (SCL-somatization, SCL-depression, SCL-anxiety), the Whiteley-7 scale, the Short Form (SF-36) and the Coping Strategies Questionnaire (CSQ)].

RESULTS

For patients, a high score on the SCL-somatization subscale was associated with poor performance on tests of attention and psychomotor speed, and with a high score on the coping scale Increasing behavioural activities. A high score on this coping scale was associated with poor performance on tests of verbal ability and executive functioning. After controlling for years of education, controls performed significantly better than patients on verbal as well as performance IQ scales but not on tests of memory.

CONCLUSION

In the present study, we found that physical complaints are related to deficits in attention and psychomotor speed. Moreover, our results suggest that poor verbal skills may play a role in the development of MFS because of an increased tendency to apply behavioural/avoidant coping strategies. We suggest that treatment of MFS should involve training of attention as well as practicing the use of cognitive coping strategies.

Psychomotor function and response inhibition in chronic fatigue syndrome

Most research points to cognitive slowing in chronic fatigue syndrome (CFS), although there have been negative reports. The present study is one of few that examines fine motor processing and the inhibition of automatic responses in a well-characterised CFS population. A total of 35 female CFS patients without current major depression and 25 female controls performed two computerised figure-copying tasks. The cognitive and fine motor processing of visual-spatial information was measured by recording reaction time (RT) and movement time (MT), respectively. The inhibition of automatic responses was assessed by introducing 'conflicting patterns' (i.e., patterns that were difficult to draw from the preferred left to right). A multivariate general linear model was adopted for the statistical analysis of the movement recordings. As a result, CFS was significantly associated with longer RT and MT in the pooled and in the task-specific analyses. However, there was no interaction between disease status and conflicting character of the patterns. In conclusion, these performance data on the figure-copying tasks provide confirmatory evidence for psychomotor slowing in CFS, but not for a disturbed inhibition of automatic responses. Computerised figure-copying tasks may be promising tools for use in neurobiological research and clinical trials in CFS.

What to do about attention and memory problems in children with CFS/ME: a neuropsychological approach

Our recent research has shown that children with chronic fatigue syndrome/myalgic encephalomyopathy (CFS/ME) describe problems with focused attention, sustained attention, recall and stress. Neuropsychological testing demonstrated lower scores for sustained attention, switching attention, divided attention, auditory learning and immediate recall compared to normative data. This paper describes what is currently known about memory and attention problems in children with CFS/ME and suggests a variety of strategies that could be used to overcome these difficulties.

Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls

OBJECT

Chronic fatigue syndrome (CFS) patients report usually cognitive complaints. They also have frequently comorbid depression that can be considered a possible explanation for their cognitive dysfunction. We evaluated the cognitive performance of patients with CFS in comparison with a control group of healthy volunteers and a group of patients with MDD.

PATIENTS AND METHODS

Twenty-five patients with CFS, 25 patients with major depressive disorder (MDD), and 25 healthy control subjects were given standardized tests of attention, working memory, and verbal and visual episodic memory, and were also tested for effects related to lack of effort/simulation, suggestibility, and fatigue.

RESULTS

Patients with CFS had slower phasic alertness, and also had impaired working, visual and verbal episodic memory compared to controls. They were, however, no more sensitive than the other groups to suggestibility or to fatigue induced during the cognitive session. Cognitive impairments in MDD patients were strongly associated with depression and subjective fatigue; in patients with CFS, there was a weaker correlation between cognition and depression (and no correlation with fatigue).

CONCLUSIONS

This study confirms the presence of an objective impairment in attention and memory in patients with CFS but with good mobilization of effort and without exaggerated suggestibility.

[The role of depression in cognitive impairment in patients with chronic fatigue syndrome]

BACKGROUND AND OBJECTIVE

To analyze the role of depression in cognitive deficits of patients with chronic fatigue syndrome (CFS).

PATIENTS AND METHODS

57 women with CFS were assessed by neuropsychological tests that included measures of attention: CalCap, Mental control of the WMS-III, PASAT, forward and backward digits (WAIS-III), symbol digit modalities test (SDMT); executive functions: Stroop Test, Trail Making Test (TMT A y B), FAS, Tower of London; memory: Auditory-Verbal Learning Test (AVL), Rey Complex Figure (RCF), and psychomotor skills: Grooved Pegboard. The raw scores on the tests were adjusted according to normative data and transformed to T scores. The sample was divided into two groups based on the presence or absence of depression, assessed by clinical interview and administration of the Hospital Anxiety and Depression Scale (HADS). This study compared neuropsychological test scores between the two groups.

RESULTS

CFS patients showed cognitive deficit in attention and executive functions, regardless of the presence of depression. There were no significant differences between the two CFS groups.

CONCLUSIONS

The cognitive impairments in patients with CFS are not secondary to the presence of depression. These results should be taken into account in the implementation of therapeutic programs in these patients.

Cognitive functioning in chronic fatigue syndrome: a meta-analysis

BACKGROUND

Cognitive problems are commonly reported in persons with chronic fatigue syndrome (CFS) and are one of the most disabling symptoms of this condition. A number of cognitive deficits have been identified, although the findings are inconsistent and hindered by methodological differences. The current study therefore conducted a meta-analysis of research examining cognitive functioning in persons with CFS in order to identify the pattern and magnitude of any deficits that are associated with this condition.

METHOD

A comprehensive search of the PubMed and PsycINFO databases for studies that examined cognitive functioning in CFS between 1988 and 2008 identified 50 eligible studies. Weighted Cohen's d effect sizes, 95% confidence intervals and fail-safe Ns were calculated for each cognitive score.

RESULTS

Evidence of cognitive deficits in persons with CFS was found primarily in the domains of attention, memory and reaction time. Deficits were not apparent on tests of fine motor speed, vocabulary, reasoning and global functioning.

CONCLUSIONS

Persons with CFS demonstrate moderate to large impairments in simple and complex information processing speed and in tasks requiring working memory over a sustained period of time.

Orthostatic symptoms predict functional capacity in chronic fatigue syndrome: implications for management

OBJECTIVES

To establish the relationship between the functional impairment experienced by Chronic fatigue syndrome (CFS) patients and the symptoms frequently experienced by those with CFS; specifically cognitive impairment, fatigue and orthostatic symptoms.

DESIGN

Cross sectional questionnaire survey.

SETTING

Specialist CFS Clinical Service.

SUBJECTS

Ninety-nine Fukuda diagnosed CFS and 64-matched controls.

MAIN OUTCOME MEASURES

Symptom and functional assessment tools completed and returned by post included; PROMIS HAQ (Patient-Reported Outcomes Measurement Information System, Health Assessment Questionnaire), CFQ (Cognitive Failures Questionnaire), FIS (Fatigue Impact Scale) and OGS (Orthostatic Grading Scale) assessment tools.

RESULTS

CFS patients experience greater functional impairment than controls [mean (95% CI) PROMIS HAQ scores CFS 36 (31-42) vs. controls 6 (2-10); P < 0.0001], especially in the functional domains of activities and reach. Poorer functional ability impairment is significantly associated with greater cognitive impairment (P = 0.0002, r = 0.4), fatigue (P < 0.0001, r = 0.5) and orthostatic symptoms (P < 0.0001, r = 0.6). However, only orthostatic symptoms (OGS) independently associated with functional impairment (beta = 0.4, P = 0.01).

CONCLUSION

Treatment of orthostatic symptoms in CFS has the potential to improve functional capacity and so improve quality of life.

An assessment of prospective memory retrieval in women with chronic fatigue syndrome using a virtual-reality environment: an initial study

People with chronic fatigue syndrome (CFS) have increased rates of depression, anxiety, and illness intrusiveness; they may also suffer from cognitive problems such as retrospective memory (RM) deficits and concentration difficulties that can stem from diminished information-processing capability. We predicted that this diminished capacity may also lead to deficits in other cognitive functions, such as prospective memory (ProM). Event-, time-, and activity-based ProM was assessed in 11 women with CFS and 12 healthy women using a computer-generated virtual environment (VE). RM was assessed using a free-recall test, and subjective assessment of both ProM and RM was assessed by questionnaire. Groups were equivalent in age and measures of IQ. People with CFS performed slightly worse than healthy controls on both the event- and time-based ProM measures, although these were not statistically significant. However, the CFS group performed significantly worse than the healthy controls on both the free recall-task and on subjective assessment of both RM and ProM. Women with CFS do have some subtle decrements in memory, particularly RM. However, it is possible that the decrements found in the present sample would be greater in real life. Further studies utilizing both healthy controls and illness controls are now needed to ascertain how sensitive the VE measure is and to inform the development of tasks in the VE that place progressively increasing demands on working memory capacity.

Neuropsychological functioning, illness perception, mood and quality of life in chronic fatigue syndrome, autoimmune thyroid disease and healthy participants

BACKGROUND

This study attempted to longitudinally investigate neuropsychological function, illness representations, self-esteem, mood and quality of life (QoL) in individuals with chronic fatigue syndrome (CFS) and compared them with both healthy participants and a clinical comparison group of individuals with autoimmune thyroid disease (AITD).

METHOD

Neuropsychological evaluation was administered at two time points, five weeks apart. Twenty-one individuals with CFS, 20 individuals with AITD and 21 healthy participants were matched for age, pre-morbid intelligence, education level and socio-economic status (SES). All groups also completed measures of illness perceptions, mood, self-esteem and QoL at both time points.

RESULTS

The CFS group showed significantly greater impairment on measures of immediate and delayed memory, attention and visuo-constructional ability, and reported significantly higher levels of anxiety and depression. After controlling for the effects of mood, the CFS group still demonstrated significant impairment in attention. The CFS group also reported significantly lower self-reported QoL than the AITD and healthy participants. In terms of illness perceptions, the AITD group believed that their condition would last longer, that they had more treatment control over their condition, and reported less concern than the CFS group.

CONCLUSIONS

These results suggest that the primary cognitive impairment in CFS is attention and that this is not secondary to affective status. The lower treatment control perceptions and greater illness concerns that CFS patients report may be causally related to their affective status.

Words fail me: the verbal IQ deficit in inflammatory bowel disease and irritable bowel syndrome

BACKGROUND

Many chronic illnesses are accompanied by impaired cognitive functioning. In people with Inflammatory Bowel Disease (IBD), there is some research to suggest a decrement in verbal IQ (VIQ), when compared to people with Irritable Bowel Syndrome (IBS) and healthy controls. Although this is an important finding, it is necessary to ensure that such deficits are not due to methodological problems such as the failure to take into account pre-morbid functioning.

METHODS

A total of 88 people (IBD, N = 29; IBS, N = 29; Controls, N = 30) completed the Wechsler Abbreviated Scale of Intelligence (WASI), the Wechsler Test of Adult Reading (WATR), the Trait Rumination Questionnaire (TRQ), the Center for Epidemiologic Studies Depression Scale (CES-D), and the General Health Questionnaire (GHQ-12).

RESULTS

We found evidence of a VIQ decrement in both IBD and IBS groups when measured against both healthy controls and against their own pre-morbid IQ scores (WTAR-Predicted WAIS-III IQ measures). However, the decrement was larger (and of clinical significance) in the IBD group but not in the IBS group.

CONCLUSION

Some tentative evidence is presented which suggests that poor VIQ performance may be due in part to interference from excessive rumination.

Psychomotor functioning in chronic fatigue syndrome and major depressive disorder: a comparative study

BACKGROUND

Studies comparing chronic fatigue syndrome (CFS) and major depressive disorder (MDD) reported similarities as well as differences between the two disorders. However, whereas psychomotor symptoms have been studied extensively in MDD, such research in CFS is more limited. Moreover, the few studies that compared cognitive and motor performance in MDD and CFS yielded inconsistent results. This study hence directly compares fine psychomotor functioning in both syndromes.

METHODS

Thirty-eight patients diagnosed with CFS without a current major depressive episode (MDE), 32 MDD patients with a current MDE and 38 healthy controls performed two computerized copying tasks differing in complexity: a line-copying task that mainly requires motor effort and a figure-copying task requiring additional cognitive efforts. All participants were female. A multivariate general linear model was used to compute group differences.

RESULT

Overall, both patient groups performed more slowly than the controls. Compared to CFS patients, patients with MDD needed significantly more time to copy the single lines but no such between-group performance difference was observed for the figure reproductions. In this latter copying task, the increasing complexity of the figures resulted in prolonged reaction times for all three participant groups with the effect being larger and the magnitude similar for the two patient groups.

LIMITATIONS

All patients were female and most were on psychotropic medication.

CONCLUSIONS

Both the MDD and CFS patients tested demonstrated an overall fine motor slowing, with the motor component being more affected in the MDD patients than in the CFS patients while both patient groups showed similar cognitive impairments.

Disturbed cognitive functions after nasal provocation in patients with seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) reduces quality of life as a result of impaired psychological well-being and perceived impaired cognitive functioning. Few studies have measured cognitive functions objectively and it remains uncertain whether AR leads to an objective reduction in cognitive functions.

OBJECTIVE

The present study investigated whether AR is associated with a decrement in several aspects of cognitive functioning. Furthermore, the study investigated whether AR patients invest more 'mental effort' in order to achieve the same cognitive performances as healthy controls.

METHODS

Twenty five patients with seasonal allergic rhinitis (SAR) and 26 healthy controls, matched for age, education and sex, were tested on a battery of time-demanding and strenuous objective cognitive tests and subjective questionnaires, both before and after nasal provocation (NP). The cognitive functions assessed were sustained attention, short- and long-term memory and speed of information processing. Mental effort was assessed using visual rating scales.

RESULTS

Sustained but not short cognitive performance was impaired in patients after NP. Patients showed an increased effort on short cognitive tests.

CONCLUSION

SAR patients suffer from cognitive performance decrements that can be compensated by additional mental effort for short tasks only.

Neuropsychological performance in persons with chronic fatigue syndrome: results from a population-based study

OBJECTIVE

To examine the neuropsychological function characterized in subjects with chronic fatigue syndrome (CFS) at the same time controlling for relevant confounding factors. CFS is associated with symptoms of neuropsychological dysfunction. Objective measures of neuropsychological performance have yielded inconsistent results possibly due to sample selection bias, diagnostic heterogeneity, comorbid psychiatric disorders, and medication usage.

METHOD

CFS subjects (n = 58) and well controls (n = 104) from a population-based sample were evaluated, using standardized symptom severity criteria. Subjects who had major psychiatric disorders or took medications known to influence cognition were excluded. Neuropsychological function was measured using the Cambridge Neuropsychological Test Automated Battery (CANTAB).

RESULTS

Compared with controls, CFS subjects exhibited significant decreases in motor speed as measured in the simple and five-choice movement segments of the CANTAB reaction time task. CFS subjects also exhibited alterations in working memory as manifested by a less efficient search strategy on the spatial working memory task, fewer % correct responses on the spatial recognition task, and prolonged latency to a correct response on the pattern recognition task. A significantly higher percentage of CFS subjects versus controls exhibited evidence of neuropsychological impairment (defined by performance 1 standard deviation below the CANTAB normative mean) in tasks of motor speed and spatial working memory. Impairment in CFS subjects versus control subjects ranged from 20% versus 4.8% in five-choice movement time (p = .002) to 27.8% versus 10.6% in search strategy on the spatial working memory task (p = .006).

CONCLUSIONS

These results confirm and quantify alterations in motor speed and working memory in CFS subjects independent of comorbid psychiatric disease and medication usage.

Diagnostic and treatment challenges of chronic fatigue syndrome: role of immediate-release methylphenidate

Chronic fatigue syndrome (CFS) is a distinct entity belonging to the group of persistent fatigue that can be challenging to diagnose and to treat. It is characterized by a combination of prolonged fatigue, other nonspecific somatic manifestations and neuropsychological symptoms, including difficulties with concentration, short-term memory and thinking, as well as impaired attention and slowed processing speed. Neurostimulants increasing dopamine and norepinephrine activity, such as bupropion, dextroamphetamine and recently immediate-release methylphenidate have been advocated to improve neurocognitive deficits. The use of immediate-release methylphenidate in CFS has been shown in one small study. Using the positive results of this study and the well-known beneficial effects of the drug on a range of similar cognitive symptoms in attention-deficit/hyperactivity disorder, this perspective addresses CFS and other related disorders and provides a discussion on the potential promising role of methylphenidate in the therapeutic armamentarium of CFS.

A real-time assessment of the effect of exercise in chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) report substantial symptom worsening after exercise. However, the time course over which this develops has not been explored. Therefore, the objective of this study was to investigate the influence of exercise on subjective symptoms and on cognitive function in CFS patients in natural settings using a computerized ecological momentary assessment method, which allowed us to track the effects of exercise within and across days. Subjects were 9 female patients with CFS and 9 healthy women. A watch-type computer was used to collect real-time data on physical and psychological symptoms and cognitive function for 1week before and 2weeks after a maximal exercise test. For each variable, we investigated temporal changes after exercise using multilevel modeling. Following exercise, physical symptoms did get worse but not until a five-day delay in CFS patients. Despite this, there was no difference in the temporal pattern of changes in psychological symptoms or in cognitive function after exercise between CFS patients and controls. In conclusion, physical symptoms worsened after several days delay in patients with CFS following exercise while psychological symptoms or cognitive function did not change after exercise.

Psychomotor speed: possibly a new marker for overtraining syndrome

Overtraining syndrome (OTS) is a major threat for performance and health in athletes. OTS is caused by high levels of (sport-specific) stress in combination with too little regeneration, which causes performance decrements, fatigue and possibly other symptoms. Although there is general consensus about the causes and consequences, many different terminologies have been used interchangeably. The consequences of overreaching and overtraining are divided into three categories: (i) functional overreaching (FO); (ii) non-functional overreaching (NFO); and (iii) OTS. In FO, performance decrements and fatigue are reversed within a pre-planned recovery period. FO has no negative consequences for the athlete in the long term; it might even have positive consequences. When performance does not improve and feelings of fatigue do not disappear after the recovery period, overreaching has not been functional and is thus called NFO. OTS only applies to the most severe cases. NFO and OTS could be prevented using early markers, which should be objective, not manipulable, applicable in training practice, not too demanding, affordable and should be based on a sound theoretical framework. No such markers exist up to today. It is proposed that psychomotor speed might be such a marker. OTS shows similarities with chronic fatigue syndrome and with major depression (MD). Through two meta-analyses, it is shown that psychomotor slowness is consistently present in both syndromes. This leads to the hypothesis that psychomotor speed is also reduced in athletes with OTS. Parallels between commonly used models for NFO and OTS and a threshold theory support the idea that psychomotor speed is impaired in athletes with NFO or OTS and could also be used as an early marker to prevent NFO and/or OTS.

Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) frequently complain of cognitive dysfunction. However, evidence of cognitive impairment in CFS patients has been found in some, but not other, studies. This heterogeneity in findings may stem from the relative presence of mental fatigue in the patient populations examined. The present study assessed this possibility in a population-based sample of CFS patients. In all, 43 patients with CFS defined by the criteria of the 1994 research case definition using measurements recommended by the 2003 International CFS Study Group, and 53 age-, sex-, and race/ethnicity-matched nonfatigued subjects were included in the study. Mental fatigue was assessed using the mental fatigue subscale of the multidimensional fatigue inventory. Cognitive function was evaluated using an automated battery of computerized tests (Cambridge neuropsychological test automated battery (CANTAB)) that assessed psychomotor function, planning and problem-solving abilities, and memory and attentional performance. CFS patients with significant complaints of mental fatigue (score of mental fatigue 2 standard deviations above the mean of nonfatigued subjects) exhibited significant impairment in the spatial working memory and sustained attention (rapid visual information processing) tasks when compared to CFS patients with low complaints of mental fatigue and nonfatigued subjects. In CFS patients with significant mental fatigue, sustained attention performance was impaired only in the final stages of the test, indicating greater cognitive fatigability in these patients. CFS patients with low mental fatigue displayed performance comparable to nonfatigued subjects on all tests of the CANTAB battery. These findings show strong concordance between subjective complaints of mental fatigue and objective measurement of cognitive impairment in CFS patients and suggest that mental fatigue is an important component of CFS-related cognitive dysfunction.

Chronic fatigue syndrome: a systematic review

OBJECTIVE

A systematic review of the literature about chronic fatigue syndrome (CFS).

METHODS

A search of the Medline database (via Ovid and PubMed) with the key words chronic fatigue syndrome, diagnosis, classification, epidemiology, etiology, physiopathology, metabolism, microbiology, immunology, virology, psychology, drug therapy, rehabilitation, and therapy. The reference lists of each article were examined for additional related articles.

RESULTS

CFS was defined in 1988 by the US Centes for Disease Control and Prevention. The prevalence of chronic fatigue syndrome has ranged from 0.2% to 0.7% in the general population. In 1994, the definition of CFS was revised by Fukuda et al. Despite various research in several topics (e.g. infection, immune systems, neuroendocrinology, autonomic activity, neuromuscular involvement), the pathophysiology remains unknown.

CONCLUSION

CFS, with its various major clinical and functional impacts, should be associated with a "biopsychosocial model". Progressive muscular rehabilitation, combined with behavioral and cognitive treatment, is an essential part of therapy.

Chronic treatment with modafinil may not be beneficial in patients with chronic fatigue syndrome

Fourteen patients (7 male, 7 female, 22-63 years), classified as having chronic fatigue syndrome (CFS), but without concurrent major depression, significant sleepiness or use of psychoactive medication, completed a double-blind, placebo-controlled, crossover study of the effects of the selective wakefulness-promoting agent, modafinil (200 and 400mg/day). The treatment periods were each 20 days, with washout periods of 2 weeks. The primary aim was to determine effects on cognition and the secondary aim was to determine effects on self-ratings of fatigue, quality of life and mood. Modafinil had mixed effects in two cognitive tasks. In a test of sustained attention, treatment with 200mg reduced the latency to correctly detect sequences, but 400mg increased the number of missed targets. In a test of spatial planning, the 200mg dose resulted in a slower initial thinking time for the easiest part of the task, whereas 400mg reduced the initial thinking time for the hardest part of the test. Lastly, in a test of mental flexibility and one of motor speed, patients performed worse whilst on modafinil (400mg), compared with the placebo period. No effects were observed on the performance of other psychometric tests or on self-ratings of fatigue, quality of life or mood, but this may have been due to insufficient statistical power. It is discussed whether the limited and mixed cognitive effects that we observed could have occurred by chance, or whether a subgroup of CFS patients with daytime sleepiness would have shown greater benefits.

Cognitive Complaints Are Associated With Depression, Fatigue, Female Sex, and Pain Catastrophizing in Patients With Chronic Pain

OBJECTIVE

To examine the relation between demographic, pain-related, psychosocial, affective, and treatment factors and complaints of cognitive dysfunction among patients with chronic pain.

DESIGN

Cross-sectional survey.

SETTING

A university hospital outpatient multidisciplinary chronic pain program.

PARTICIPANTS

Chronic pain patients (N=222; 135 women, 87 men) completed a battery of psychometric questionnaires as part of an initial evaluation on referral to the program.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Cognitive impairment was assessed with items from the Brief Symptom Inventory; measures of depressive symptoms, pain intensity, posttraumatic stress disorder (PTSD), and pain catastrophizing were obtained from the Beck Depression Inventory (negative affect, negative self, somatic/physical function), McGill Pain Questionnaire, Modified Posttraumatic Chronic Pain Test, and Coping Strategies Questionnaire, respectively; and measures of subjective sleep disturbance, fatigue, opiate use, compensation/litigation status, pain location, and relevant demographic data were obtained from an open-ended questionnaire.

RESULTS

Correlational analysis indicated that female sex, pain intensity, PTSD symptoms, depressive symptoms, catastrophizing, pain location (neck), and fatigue were all positively related to cognitive complaints. Simultaneous regression analysis showed that all factors combined accounted for 52% of the variance in self-report of cognitive difficulties and that 6 variables had a significant unique contribution to the report of cognitive complaints in the following order of importance: depression-negative affect (beta=.28, P <.05), fatigue (beta=.17, P <.05), depression-somatic/physical function (beta=.16, P <.05), depression-negative self (beta=.14, P =.05), pain catastrophizing (beta=.12, P =.08), and female sex (beta=.12, P <.05).

CONCLUSIONS

Complaints of cognitive impairment among chronic pain patients appear to be associated with multiple factors, with particular attention to depressive symptoms, fatigue, and catastrophizing. Our results also suggest that women with chronic pain are particularly vulnerable to cognitive dysfunction.

Neuropsychological deficits in patients with chronic fatigue syndrome

The degree of neuropsychological dysfunction across multiple domains was examined in individuals suffering from chronic fatigue syndrome (CFS). In this descriptive study, a similar series of neuropsychological tests was administered to a group of CFS patients and healthy participants. More specifically, CFS patients (n = 141) who met the 1994 Case Definition criteria were compared to 76 healthy control participants on tests of memory, attention (concentration), speed of information processing, motor speed, and executive functioning. On the 18 measures administered, CFS patients scored 1 standard deviation below the healthy mean on nine measures and scored 2 standard deviations below the healthy mean on four of the measures. Moreover, results indicated that CFS patients were more likely than healthy controls to fail (1.6 SD below the healthy mean) at least one test in each of the following domains: attention, speed of information processing, and motor speed, but not on measures of memory and executive functioning. Finally, CFS patients demonstrated a greater total number of tests failed across domains.

Cognitive Processing in Monozygotic Twins Discordant for Chronic Fatigue Syndrome

Twenty-one pairs of monozygotic twins discordant for chronic fatigue syndrome (CFS) and 21 matched healthy control (HC) subjects were assessed with 5 untimed tests and 5 timed tests from the computer-based NeuroCognitive Assessment Battery (R. K. Mahurin, 1993). Random effects regression showed no difference between CFS and healthy twins on any of the cognitive tests. Further, the twin groups did not differ from the HC group on any content-dependent measure. In contrast, both sets of twins performed worse than the HC group on all speed-dependent tests except Finger Tapping. Self-rated fatigue and dysphoric mood were only weakly correlated with cognitive performance. These data point toward a shared genetic trait related to information processing that is manifest in the CFS context. The findings have implications for differentiating genetic and acquired vulnerability in the symptomatic expression of the disorder. ((c) 2004 APA, all rights reserved)

Working memory deficits in chronic fatigue syndrome: differentiating between speed and accuracy of information processing

To examine the relative influence of speed of information processing versus working memory ability, CFS participants with psychiatric comorbidity (CFS-Psych) and CFS without a psychiatric history (CFS-noPsych) were examined on tests of visual and auditory processing speed and visual and auditory working memory. Compared to healthy controls (HC) and a group of participants with rheumatoid arthritis (RA), the CFS-noPsych group displayed significantly reduced performance on tests of information processing speed, but not on tests of working memory. No significant differences were observed between the CFS-Psych group and any other group in the study. The implications of group heterogeneity on the understanding of cognitive impairment in CFS are discussed.

Neuropsychological impairment in fibromyalgia: relation to depression, fatigue, and pain

OBJECTIVE

The present study assessed the relationship of depression, pain, and fatigue to subjective cognitive complaints and objective impairment in patients with fibromyalgia (FM), patients with other chronic pain disorders, and healthy controls.

METHOD

Neuropsychological assessment was conducted on 28 FM patients, 27 chronic pain patients, and 21 healthy controls. Five FM patients and five chronic pain patients were excluded due to poor effort on cognitive tasks. Assessment included measures of depression, pain, fatigue, subjective cognitive complaints, memory, executive functioning, intellect, attention, and psychomotor speed. Analysis of covariance was used to assess group differences in cognitive complaints and cognitive test performance, after controlling for depression, pain, and fatigue. Hierarchical regression was used to assess whether objective test performance was related to subjective cognitive complaints, after controlling for depression, pain, and fatigue.

RESULTS

FM patients had more memory complaints and reported more fatigue, pain, and depression than other groups. Groups were not different in cognitive performance, after controlling for fatigue, pain, and depression; depression was related to memory performance and fatigue was related to psychomotor speed. Neuropsychological test results did not add significantly to the variance accounted for in subjective cognitive complaints, after accounting for depression, pain, and fatigue.

CONCLUSION

Psychological factors, particularly effort, depression, and fatigue, are important in understanding both subjective cognitive complaints and objective cognitive impairment in FM and other chronic pain disorders.

Cognitive function in people with chronic illness: inflammatory bowel disease and irritable bowel syndrome

Recent research has shown that people with chronic illnesses often experience cognitive deficits, such deficits may be specific to a particular type of illness, reflecting the disease process itself, or they may be deficits that are common across a number of chronic illnesses. Our study investigated whether people with an organic disease (Inflammatory Bowel Disease) show cognitive dysfunction relative to the control group and people with a functional illness (Irritable Bowel Syndrome), and if so, to elucidate the mechanisms by which such dysfunction occurs. A quasi-experimental design using three groups of participants provided scores on IQ, memory, and cognitive flexibility. Differences in absolute scores were slight. However, a noticeable interaction effect was found between group and IQ: The illness groups showed a deficit in verbal IQ relative to both their own performance IQ and to that of the control group's verbal IQ. This verbal deficit cannot be explained by depression, cognitive load, or medication.

Cognitive functioning in chronic fatigue syndrome and the role of depression, anxiety, and fatigue

OBJECTIVE

This study was designed to investigate the role of depression, anxiety, and fatigue in Chronic Fatigue Syndrome (CFS) sufferers' objective and subjective cognitive performance.

METHODS

Twenty-three CFS sufferers and 23 healthy control participants were compared on objective and subjective assessments of cognitive performance. Depression, anxiety, and fatigue were also evaluated.

RESULTS

CFS sufferers did not demonstrate any impairment in objective cognitive functioning compared to the control group, and objective performance was not related to their higher levels of depression or their level of fatigue. Depression scores only accounted for a small amount of the variance in CFS sufferers' lower subjective assessment of their cognitive performance compared to control participants. There were no differences between the groups on anxiety scores.

CONCLUSION

The results are discussed in terms of the heterogeneity of the CFS population and the complex interaction of symptomatological factors that characterise CFS.

Neuropsychological function in patients with chronic fatigue syndrome, multiple sclerosis, and depression

Patients with chronic fatigue syndrome (CFS), multiple sclerosis (MS), and major depression were compared with controls and with each other on a neuropsychological battery that included standard neuropsychological tests and a computerized set of tasks that spanned the same areas of ability. A total of 101 participants were examined, including 29 participants with CFS, 24 with MS, 23 with major depressive disorder, and 25 healthy controls. There were significant differences among the groups in 3 out of 5 cognitive domains: memory, language, and spatial ability. Assessment of psychiatric symptoms indicated that all 3 patient groups had a higher prevalence of depression than the controls. A total measure of psychiatric symptomatology also differentiated the patients from the controls. After covarying the cognitive test scores by a measure of depression, the patient groups continued to differ from controls primarily in the area of memory. The findings support the view that the cognitive deficits found in CFS cannot be attributed solely to the presence of depressive symptomatology in the patients.

Cardiovascular responses of women with chronic fatigue syndrome to stressful cognitive testing before and after strenuous exercise

OBJECTIVE

The purpose of this study was to compare the cardiovascular responses of patients with chronic fatigue syndrome (CFS) to healthy control subjects when performing stressful cognitive tasks before and after strenuous exercise.

METHOD

Beat-by-beat blood pressure and electrocardiogram were recorded on 19 women with CFS and 20 healthy nonexercising (ie, sedentary) women while they performed cognitive tests before, immediately after, and 24 hours after incremental exercise to exhaustion.

RESULTS

Diminished heart rate (p <.01) and systolic (p <.01) and diastolic (p <.01) blood pressure responses to stressful cognitive testing were seen in patients with CFS when compared with healthy, sedentary controls. This diminished stress response was seen consistently in patients with CFS across three separate cognitive testing sessions. Also, significant negative correlations between self-ratings of CFS symptom severity and cardiovascular responses were seen (r = -0.62, p <.01).

CONCLUSIONS

Women with CFS have a diminished cardiovascular response to cognitive stress; however, exercise did not magnify this effect. Also, the data showed that the patients with the lowest cardiovascular reactivity had the highest ratings of CFS symptom severity, which suggests that the individual response of the patient with CFS to stress plays a role in the common complaint of symptoms worsening after stress.

Chronic fatigue syndrome: an update

The chronic fatigue syndrome is characterised by a fatigue that is disproportionate to the intensity of effort that is undertaken, has persisted for 6 months or longer, and has no obvious cause. Unless there has been a long period of patient- or physician-imposed inactivity, objective data may show little reduction in muscle strength or peak aerobic power, but the affected individual avoids heavy activity. The study of aetiology and treatment has been hampered by the low disease prevalence (probably <0.1% of the general population), and (until recently) by a lack of clear and standardised diagnostic criteria. It is unclear how far the aetiology is similar for athletes and nonathletes. It appears that in top competitors, overtraining and/or a negative energy balance can be precipitating factors. A wide variety of other possible causes and/or precipitating factors have been cited in the general population, including psychological stress, disorders of personality and affect, dysfunction of the hypothalamic-pituitary-adrenal axis, hormonal imbalance, nutritional deficits, immune suppression or activation and chronic infection. However, none of these factors have been observed consistently. The prognosis is poor; often disability and impairment of athletic performance are prolonged. Prevention of overtraining by careful monitoring seems the most effective approach in athletes. In those where the condition is established, treatment should aim at breaking the vicious cycle of effort avoidance, deterioration in physical condition and an increase in fatigue through a combination of encouragement and a progressive exercise programme.