Category: Cognitive Dysfunction

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

 

P300 assessment of chronic fatigue syndrome

Abstract:

The P3(00) event-related brain potential (ERP) was elicited with an auditory tone-discrimination paradigm in 25 patients diagnosed with chronic fatigue syndrome (CFS) and 25 matched normal control subjects. Target stimulus probability was varied systematically (0.20, 0.50, 0.80) in different task conditions. No differences between the CFS and control subjects were found for either P3 amplitude or latency. No group effects were observed for the N1, P2, and N2 components. Despite the attentional and immediate memory deficits reported in CFS, the P3 ERP from auditory stimuli does not reliably discriminate CFS from matched control subjects.

 

Source: Polich J, Moore AP, Wiederhold MD. P300 assessment of chronic fatigue syndrome. J Clin Neurophysiol. 1995 Mar;12(2):186-91. http://www.ncbi.nlm.nih.gov/pubmed/7797633

 

Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression

Abstract:

To examine the degree and nature of cognitive impairments in chronic fatigue syndrome, a comprehensive neuropsychological battery was given to patients with chronic fatigue syndrome, multiple sclerosis, depressed patients, and healthy controls. The battery included tests of attention and concentration, information processing speed, verbal and visual memory, intellectual ability, and concept formation. Measures of depression and anxiety were also obtained.

The chronic fatigue syndrome group did not differ from the depressed group in overall neuropsychological performance, but differed from the multiple sclerosis and control groups. The most significant impairment was in information processing speed in the chronic fatigue syndrome group. Depression and anxiety were not related to neuropsychological performance. The influence of reduced information processing on other areas of cognition is discussed.

 

Source: DeLuca J, Johnson SK, Beldowicz D, Natelson BH. Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression. J Neurol Neurosurg Psychiatry. 1995 Jan;58(1):38-43. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1073266/ (Full article)

 

Cognitive functioning of patients with chronic fatigue syndrome

Abstract:

Neuropsychological problems are a distressing and frequent component of the symptom complex associated with chronic fatigue syndrome. Objective assessment of these difficulties is essential to understanding the nature of this illness. Results of the studies discussed in this paper suggest that impaired information processing, rather than primary memory dysfunction, may be at the root of the cognitive problems that afflict so many patients with CFS.

 

Source: Johnson SK, DeLuca J, Fiedler N, Natelson BH. Cognitive functioning of patients with chronic fatigue syndrome. Clin Infect Dis. 1994 Jan;18 Suppl 1:S84-5. http://www.ncbi.nlm.nih.gov/pubmed/8148459