Category: Cognitive Dysfunction

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

Abstract:

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.

 

Source: Attree EA, Dancey CP, Pope AL. An assessment of prospective memory retrieval in women with chronic fatigue syndrome using a virtual-reality environment: an initial study. Cyberpsychol Behav. 2009 Aug;12(4):379-85. doi: 10.1089/cpb.2009.0002. https://www.ncbi.nlm.nih.gov/pubmed/19591619

 

An investigation into the cognitive deficits associated with chronic fatigue syndrome

Abstract:

This study addresses, among other things, the debate as to whether cognitive deficits do occur with a diagnosis of Chronic Fatigue Syndrome (CFS). Previous studies have indicated a potential mismatch between subjective patient ratings of impairment and clinical assessment.

In an attempt to tackle some of the methodological problems faced by previous research in this field, this study recruited a large sample of CFS patients where adequate diagnosis had been made and administered an extensive battery of measures. In doing so this study was able to replicate previous published evidence of clear cognitive impairment in this group and demonstrate also that these deficits occurred independent of psychopathology.

The conclusion drawn is that cognitive impairments can be identified if appropriate measures are used. Furthermore, the authors have shown that performance changes in these measures have been used to assess both efficacy of a treatment regime and rates of recovery.

 

Source: Thomas M, Smith A. An investigation into the cognitive deficits associated with chronic fatigue syndrome. Open Neurol J. 2009 Feb 27;3:13-23. doi: 10.2174/1874205X00903010013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682840/ (Full article)

 

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

Abstract:

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.

 

Source: Dickson A, Toft A, O’Carroll RE. Neuropsychological functioning, illness perception, mood and quality of life in chronic fatigue syndrome, autoimmune thyroid disease and healthy participants. Psychol Med. 2009 Sep;39(9):1567-76. doi: 10.1017/S0033291708004960. Epub 2009 Jan 15. https://www.ncbi.nlm.nih.gov/pubmed/19144216

 

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

Abstract:

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.

 

Source: Majer M, Welberg LA, Capuron L, Miller AH, Pagnoni G, Reeves WC. Neuropsychological performance in persons with chronic fatigue syndrome: results from a population-based study. Psychosom Med. 2008 Sep;70(7):829-36. doi: 10.1097/PSY.0b013e31817b9793. Epub 2008 Jul 7. https://www.ncbi.nlm.nih.gov/pubmed/18606722

 

A twin study of cognitive function in chronic fatigue syndrome: the effects of sudden illness onset

Abstract:

Variable reports of neuropsychological deficits in individuals with chronic fatigue syndrome (CFS) may, in part, be attributable to methodological limitations. In this study, these limitations were addressed by controlling for genetic and environmental influences and by assessing the effects of comorbid depression and mode of illness onset. Specifically, the researchers conducted a co-twin control study of 22 pairs of monozygotic twins, in which 1 twin met strict criteria for CFS and the co-twin was healthy.

Twins underwent a structured psychiatric interview and comprehensive neuropsychological assessment evaluating 6 cognitive domains. Results indicated that twin groups had similar intellectual and visual memory functioning, but fatigued twins exhibited decreases in motor functions (p = .05), speed of information processing (p = .02), verbal memory (p = .02), and executive functioning (p = .01). Major depression did not affect neuropsychological functioning among fatigued twins, although twins with sudden illness onset demonstrated slowed information processing compared with those with gradual onset (p = .01).

Sudden onset CFS was associated with reduced speed of information processing. If confirmed, these findings suggest the need to distinguish illness onset in future CFS studies and may have implications for treatment, cognitive rehabilitation, and disability determination.

 

Source: Claypoole KH, Noonan C, Mahurin RK, Goldberg J, Erickson T, Buchwald D. A twin study of cognitive function in chronic fatigue syndrome: the effects of sudden illness onset. Neuropsychology. 2007 Jul;21(4):507-13. https://www.ncbi.nlm.nih.gov/pubmed/17605583

 

School phobia and childhood chronic fatigue syndrome (CCFS)

Abstract:

Chronic fatigue occurring in previously healthy children and adolescents is a vexing problem encountered by pediatric practitioners and the impact of fatigue in youngsters should not be underestimated. In its severe form, it is often associated with mood disorders. Findings in children and adolescent cases suggest that severe unexplained fatigue might precede the development of fatigue-related illness, such as childhood chronic fatigue syndrome (CCFS). This is a disabling condition characterized by severe disabling fatigue and a combination of symptoms, the prominent features being self-reported impairments in concentration and short-term memory, sleep disturbances and autonomic symptoms that cannot be explained by medical or psychiatric illness. We have encountered such patients with these complaints; their major symptoms include: general fatigue, fever, headache (not migraine), and memory disturbance. From our clinical experience, we have inferred that patients with CCFS might experience changes in brain function levels, which induce an autonomic imbalance and engender symptoms such as general fatigue, higher-order level cognitive dysfunction, and memory disturbance.

 

Source: Tomoda A. School phobia and childhood chronic fatigue syndrome (CCFS). Nihon Rinsho. 2007 Jun;65(6):1121-33. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/17561707

 

The effect of cognitive behaviour therapy for chronic fatigue syndrome on self-reported cognitive impairments and neuropsychological test performance

Abstract:

BACKGROUND: Patients with chronic fatigue syndrome (CFS) often have concentration and memory problems. Neuropsychological test performance is impaired in at least a subgroup of patients with CFS. Cognitive behavioural therapy (CBT) for CFS leads to a reduction in fatigue and disabilities.

AIM: To test the hypothesis that CBT results in a reduction of self-reported cognitive impairment and in an improved neuropsychological test performance.

METHODS: Data of two previous randomised controlled trials were used. One study compared CBT for adult patients with CFS, with two control conditions. The second study compared CBT for adolescent patients with a waiting list condition. Self-reported cognitive impairment was assessed with questionnaires. Information speed was measured with simple and choice reaction time tasks. Adults also completed the symbol digit-modalities task, a measure of complex attentional function.

RESULTS: In both studies, the level of self-reported cognitive impairment decreased significantly more after CBT than in the control conditions. Neuropsychological test performance did not improve.

CONCLUSIONS: CBT leads to a reduction in self-reported cognitive impairment, but not to improved neuropsychological test performance. The findings of this study support the idea that the distorted perception of cognitive processes is more central to CFS than actual cognitive performance.

 

Source: Knoop H, Prins JB, Stulemeijer M, van der Meer JW, Bleijenberg G. The effect of cognitive behaviour therapy for chronic fatigue syndrome on self-reported cognitive impairments and neuropsychological test performance. J Neurol Neurosurg Psychiatry. 2007 Apr;78(4):434-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2077788/ (Full article)

 

Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: new trends and future directions

Abstract:

Fibromyalgia (FM) and chronic fatigue syndrome (CFS) patients often have memory and cognitive complaints. Objective cognitive testing demonstrates long-term and working memory impairments. In addition, CFS patients have slow information-processing, and FM patients have impaired control of attention, perhaps due to chronic pain. Neuroimaging studies demonstrate cerebral abnormalities and a pattern of increased neural recruitment during cognitive tasks. Future work should focus on the specific neurocognitive systems involved in cognitive dysfunction in each syndrome.

 

Source: Glass JM. Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: new trends and future directions. Curr Rheumatol Rep. 2006 Dec;8(6):425-9. https://www.ncbi.nlm.nih.gov/pubmed/17092441

 

Probing the working memory system in chronic fatigue syndrome: a functional magnetic resonance imaging study using the n-back task

Abstract:

OBJECTIVE: Up to 90% of patients with chronic fatigue syndrome (CFS) report substantial cognitive difficulties. However, objective evidence supporting these claims is inconsistent. The present functional magnetic resonance imaging study examined the neural correlates of working memory in patients with CFS compared with controls.

METHODS: Seventeen patients with CFS and 12 healthy control subjects were scanned while performing a parametric version of the n-back task (0-, 1-, 2-, and 3-back).

RESULTS: Both groups performed comparably well and activated the verbal working memory network during all task levels. However, during the 1-back condition, patients with CFS showed greater activation than control subjects in medial prefrontal regions, including the anterior cingulate gyrus. Conversely, on the more challenging conditions, patients with CFS demonstrated reduced activation in dorsolateral prefrontal and parietal cortices. Furthermore, on the 2- and 3-back conditions, patients but not control subjects significantly activated a large cluster in the right inferior/medial temporal cortex. Trend analyses of task load demonstrated statistically significant differences in brain activation between the two groups as the demands of the task increased.

CONCLUSIONS: These results suggest that patients with CFS show both quantitative and qualitative differences in activation of the working memory network compared with healthy control subjects. It remains to be determined whether these findings stay stable after successful treatment.

 

Source: Caseras X, Mataix-Cols D, Giampietro V, Rimes KA, Brammer M, Zelaya F, Chalder T, Godfrey EL. Probing the working memory system in chronic fatigue syndrome: a functional magnetic resonance imaging study using the n-back task. Psychosom Med. 2006 Nov-Dec;68(6):947-55. Epub 2006 Nov 1. https://www.ncbi.nlm.nih.gov/pubmed/17079703

 

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

Abstract:

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.

 

Source: Capuron L, Welberg L, Heim C, Wagner D, Solomon L, Papanicolaou DA, Craddock RC, Miller AH, Reeves WC. Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome. Neuropsychopharmacology. 2006 Aug;31(8):1777-84. Epub 2006 Jan 4. http://www.nature.com/npp/journal/v31/n8/full/1301005a.html (Full article)