Category: Cognitive Dysfunction

Cognitive performance and complaints of cognitive impairment in chronic fatigue syndrome (CFS)

Abstract:

Patients with chronic fatigue syndrome (CFS) complain that they have difficulties with concentration and memory but studies to date have not found consistent objective evidence of performance deficits.

Two groups of CFS patients, depressed and non-depressed, and healthy controls, were asked about concentration problems in general and specifically when reading. CFS subjects were more likely than controls to report that they had concentration problems when reading, that they needed to re-read text and that they failed to take in what they were reading.

Subjects then performed a task in which their reading behaviour and text recall was measured. While all CFS subjects complained of general cognitive failures and of difficulties with reading, only depressed CFS subjects recalled significantly less of the text than controls. Severity of complaints about reading problems was not related to amount of text recalled, but was related to severity of depressed mood. However, subjects were able to evaluate accurately their ability to remember the text immediately after reading it and before being tested for recall.

Additionally, subjects performed a paired-associate learning task on which no significant differences between the subject groups was found. It is concluded that deficits in cognitive functioning in CFS patients are more likely to be found on naturalistic than on laboratory tasks.

 

Source: Wearden A, Appleby L. Cognitive performance and complaints of cognitive impairment in chronic fatigue syndrome (CFS). Psychol Med. 1997 Jan;27(1):81-90. http://www.ncbi.nlm.nih.gov/pubmed/9122311

 

Cognitive slowing and working memory difficulties in chronic fatigue syndrome

Abstract:

OBJECTIVE: Patients with chronic fatigue syndrome (CFS) commonly report problems with attention, memory, learning, and speed of cognitive processing. This study attempted to evaluate these complaints using objective test criteria.

METHOD: A test battery composed of six tests assessing these cognitive functions was given on two consecutive days. Twenty CFS patients were compared with 20 healthy control subjects and 14 patients with a history of major depression or dysthymia matched by age, intelligence, education level, and sex.

RESULTS: Compared with control subjects, CFS patients consistently scored lower on tests in which motor and cognitive processing speeds were a critical factor, eg, reaction-time tasks. They also had more difficulty on working-memory tests in which rapid cognitive processing speed is also an important factor. The effort made on the first day of testing did not result in a decline in cognitive function on the following day. CFS patients did not qualify as having affective disorder by several different diagnostic criteria. Nonetheless, CFS patients’ test performances did not differ from patients with a history of major depression or dysthymia.

CONCLUSIONS: It is concluded that, although CFS and major depression and dysthymia have distinct clinical features, these disorders have slowed motor and cognitive processing speed in common.

Comment in: Cognitive slowing in chronic fatigue syndrome (CFS) [Psychosom Med. 1997]

 

Source: Marshall PS, Forstot M, Callies A, Peterson PK, Schenck CH. Cognitive slowing and working memory difficulties in chronic fatigue syndrome. Psychosom Med. 1997 Jan-Feb;59(1):58-66. http://www.ncbi.nlm.nih.gov/pubmed/9021867

 

Cognitive functioning in patients with chronic fatigue syndrome

Abstract:

A comprehensive battery of neuropsychological tests was administered to 35 outpatients suffering from Chronic Fatigue Syndrome (CFS). They were compared to 33 normal controls matched for age, gender, intelligence, and education.

The patients displayed psychomotor slowing and impaired attention. The learning rate of verbal and visual material for patients with CFS was slower, and delayed recall of verbal and visual information was impaired. Because there was a high variability in cognitive impairment within the CFS group, it would be inappropriate to generalize results to the entire CFS population. Two neuropsychological variables indicating aspects of psychomotor performance and verbal memory were found to discriminate best between patients and controls.

 

Source: Michiels V, Cluydts R, Fischler B, Hoffmann G, Le Bon O, De Meirleir K. Cognitive functioning in patients with chronic fatigue syndrome. J Clin Exp Neuropsychol. 1996 Oct;18(5):666-77. http://www.ncbi.nlm.nih.gov/pubmed/8941852

 

Cognitive deficits in patients with chronic fatigue syndrome

Abstract:

Twenty-nine subjects with chronic fatigue syndrome (CFS) and 25 healthy control subjects were administered a lengthy neuropsychological battery that included standard neuropsychological tests and a computerized set of tasks that spanned the same areas of ability.

The primary significant differences between patients and controls were found on tests of learning and memory. These differences remained when the degree of psychiatric symptomatology in the subjects was covaried. Patients on and off psychoactive medications did not differ in their performance on these tasks.

These results suggest that at least a subset of CFS patients may experience significant impairments in learning and memory.

 

Source: Marcel B, Komaroff AL, Fagioli LR, Kornish RJ 2nd, Albert MS. Cognitive deficits in patients with chronic fatigue syndrome. Biol Psychiatry. 1996 Sep 15;40(6):535-41. http://www.ncbi.nlm.nih.gov/pubmed/8879474

 

Research on cognitive complaints and cognitive functioning in patients with chronic fatigue syndrome (CFS): What conclusions can we draw?

Abstract:

People with chronic fatigue syndrome (CFS) complain of difficulties with concentration and memory yet studies suggest that they do not suffer gross deficits in cognitive functioning. Depressed patients make similar cognitive complaints, and there is symptomatic overlap between CFS and depression.

Cognitive complaints and depressed mood are positively correlated in CFS patients but, except on tasks which are particularly sensitive to depression, cognitive performance and depression are not.

The inconsistency between cognitive complaints and results of tests of cognitive functioning resembles that found in other subject groups and may be due in part to the inappropriate use of laboratory memory tests for assessing “everyday” cognitive functioning.

Even when cognitive capacity is intact, cognitive performance may be affected by factors such as arousal, mood, and strategy. In CFS patients, everyday cognitive tasks may require excessive processing resources leaving patients with diminished spare attentional capacity or flexibility.

 

Source: Wearden AJ, Appleby L. Research on cognitive complaints and cognitive functioning in patients with chronic fatigue syndrome (CFS): What conclusions can we draw? J Psychosom Res. 1996 Sep;41(3):197-211. http://www.ncbi.nlm.nih.gov/pubmed/8910243

 

Selective impairment of auditory processing in chronic fatigue syndrome: a comparison with multiple sclerosis and healthy controls

Abstract:

The most consistent deficit observed in individuals with Chronic Fatigue Syndrome has been in efficiency of information processing. To examine the possibility of a modality-specific impairment, the present study examined subjects with Chronic Fatigue Syndrome, multiple sclerosis, and healthy controls on an auditory-versus visual-paced serial-addition test. 20 subjects with Chronic Fatigue Syndrome, 20 subjects with clinically definite Multiple Sclerosis, and 20 sedentary healthy controls were compared.

One-half of the subjects in each group were administered the Paced Auditory Serial Addition Test and the other half were administered the Paced Visual Serial Addition Test. The group with Chronic Fatigue Syndrome was differentially impaired on the auditory relative to the visual processing task. The group with Multiple Sclerosis was equally impaired on both versions of the task. The results are discussed within the framework of Baddeley’s model of working memory.

 

Source: Johnson SK, DeLuca J, Diamond BJ, Natelson BH. Selective impairment of auditory processing in chronic fatigue syndrome: a comparison with multiple sclerosis and healthy controls. Percept Mot Skills. 1996 Aug;83(1):51-62. http://www.ncbi.nlm.nih.gov/pubmed/8873173

 

Memory, attention, and executive function in chronic fatigue syndrome

Abstract:

OBJECTIVES: To examine cognitive function in chronic fatigue syndrome.

METHODS: Twenty patients with chronic fatigue syndrome recruited from primary care and 20 matched normal controls were given CANTAB computerised tests of visuospatial memory, attention, and executive function, and verbal tests of letter and category fluency and word association learning.

RESULTS: Patients with chronic fatigue syndrome were impaired, predominantly in the domain of memory but their pattern of performance was unlike that of patients with amnesic syndrome or dementia. They were normal on tests of spatial pattern recognition memory, simultaneous and delayed matching to sample, and pattern-location association learning. They were impaired on tests of spatial span, spatial working memory, and a selective reminding condition of the pattern-location association learning test. An executive test of planning was normal. In an attentional test, eight subjects with chronic fatigue syndrome were unable to learn a response set; the remainder exhibited no impairment in the executive set shifting phase of the test. Patients with chronic fatigue syndrome were also impaired on verbal tests of unrelated word association learning and letter fluency.

CONCLUSION: Patients with chronic fatigue syndrome have reduced attentional capacity resulting in impaired performance on effortful tasks requiring planned or self ordered generation of responses from memory.

Source: Joyce E, Blumenthal S, Wessely S. Memory, attention, and executive function in chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1996 May;60(5):495-503. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486360/ (Full article)

Neurocognitive functioning in chronic fatigue syndrome

Abstract:

Although substantial research has been conducted on chronic fatigue syndrome (CFS) over the past decade, the syndrome remains poorly understood. The most recent case definition describes CFS as being characterized both by disabling fatigue and by subjective reports of difficulty with concentration and “short-term” memory. However, research into the neurocognitive and psychological functioning of individuals with CFS has provided mixed objective results. The current paper reviews studies that have examined the neurocognitive and/or psychological functioning of individuals with CFS. Changes in research design and instruments employed to study individuals with CFS are suggested.

 

Source: DiPino RK, Kane RL. Neurocognitive functioning in chronic fatigue syndrome. Neuropsychol Rev. 1996 Mar;6(1):47-60. http://www.ncbi.nlm.nih.gov/pubmed/9144668

 

An assessment of cognitive function and mood in chronic fatigue syndrome

Abstract:

Data were gathered regarding the associates of chronic fatigue syndrome (CFS) with: (1) speed of cognitive processing, (2) motor speed, (3) ability to sustain attention, and (4) mood. Patients were given a brief neuropsychological test battery before and after double-blind treatment with terfenadine or placebo and completed a daily mood rating scale (Positive and Negative Affect Schedule) during the study.

CFS patients exhibited slower cognitive processing and motor speed and lower positive affect, as compared to data reported from previous studies of healthy subjects and other patient groups; however, CFS patients did not exhibit deficits in sustained attention in comparison to other groups.

The CFS patients’ ability to attend to verbal versus figural stimuli and mood ratings were different from those reported in studies of patients with depression. Because of methodological limitations, these findings are preliminary, but they encourage further assessment of cognitive dysfunction and mood in CFS.

 

Source: Marshall PS, Watson D, Steinberg P, Cornblatt B, Peterson PK, Callies A, Schenck CH. An assessment of cognitive function and mood in chronic fatigue syndrome. Biol Psychiatry. 1996 Feb 1;39(3):199-206. http://www.ncbi.nlm.nih.gov/pubmed/8837981

 

Cognitive functioning and magnetic resonance imaging in chronic fatigue

Abstract:

BACKGROUND: This study examines whether cognitive dysfunction in chronic fatigue may be accounted for by depression and anxiety or is due to brain pathology evident on magnetic resonance imaging (MRI).

METHOD: Twenty-six subjects with chronic fatigue, with and without coexisting depression, and 18 age-matched normal controls were recruited from primary care following a presumed viral illness six months previously. Comparison was made with 13 psychiatric controls with depressive illness on standardised cognitive tests. MRI determined the presence of cerebral white-matter lesions.

RESULTS: No substantial differences in performance were shown between subjects with chronic fatigue, most of whom met the criteria for chronic fatigue syndrome, and controls. Subjective cognitive dysfunction increased with psychopathology. White-matter lesions were found in a minority from all groups. Improvement in fatigue and depression coincided with improved performance on cognitive measures.

CONCLUSIONS: Subjective complaints of cognitive impairment are a prominent feature of chronic fatigue, but objective cognitive and MRI abnormalities are not. Such complaints probably reflect psychopathology rather than a post-viral process.

 

Source: Cope H, Pernet A, Kendall B, David A. Cognitive functioning and magnetic resonance imaging in chronic fatigue. Br J Psychiatry. 1995 Jul;167(1):86-94. http://www.ncbi.nlm.nih.gov/pubmed/7551617