Category: Cognitive Dysfunction

The relations among body consciousness, somatic symptom report, and information processing speed inchronic fatigue syndrome

Abstract:

OBJECTIVE: The aim of this study was to assess the potential influence of body consciousness and levels of somatic symptom report upon information processing speed in patients with chronic fatigue syndrome (CFS).

BACKGROUND: According to a model of a fixed information processing capacity, it was predicted that in a group of patients with CFS, high body consciousness in combination with a high report of somatic symptoms would affect information-processing speed negatively.

METHODS: Information- and motor-processing speed were simultaneously measured with a simple- and a choice-reaction time task, whereas cognitive complaints were rated with two questionnaires. The hypothesized influence of private body consciousness and somatic symptom report upon information-processing speed was tested in a model. A symptom-validity test was used to screen for possible illness behavior.

RESULTS: Private body consciousness was directly related to information-processing speed and somatic symptom report. Somatic symptom report was related to both test performance and memory and concentration complaints.

CONCLUSIONS: Levels of private body consciousness directly affected somatic symptom report and information-processing speed. This finding supports the role of attentive processes in CFS, and offers, besides possible cerebral dysfunction, an alternative explanation for slowing of information processing in CFS.

 

Source: van der Werf SP, de Vree B, van Der Meer JW, Bleijenberg G. The relations among body consciousness, somatic symptom report, and information processing speed in chronic fatigue syndrome. Neuropsychiatry Neuropsychol Behav Neurol. 2002 Mar;15(1):2-9. http://www.ncbi.nlm.nih.gov/pubmed/11877546

 

Information processing in chronic fatigue syndrome: a preliminary investigation of suggestibility

Abstract:

This study examines the effects of certain types of information processing on the subjective experience of cognitive deficits in persons with chronic fatigue syndrome (CFS).

Two groups of participants, persons with CFS and a group of healthy controls, were administered a symptom inventory and measures of intellectual functioning, memory, automatic processing, and suggestibility. The groups differed significantly on number and severity of reported symptoms and on measures of global suggestibility and automatic processing, but not on measures of intellectual functioning and memory.

Suggestibility was related to number and severity of reported symptoms, as well as the inability to inhibit the automatic processing of information. Implications of these findings are discussed, as well as directions for future research and treatment of symptoms associated with CFS.

 

Source: DiClementi JD, Schmaling KB, Jones JF. Information processing in chronic fatigue syndrome: a preliminary investigation of suggestibility. J Psychosom Res. 2001 Nov;51(5):679-86. http://www.ncbi.nlm.nih.gov/pubmed/11728509

 

Intraindividual variability in cognitive performance in persons with chronic fatigue syndrome

Abstract:

Studies of cognitive performance among persons with chronic fatigue syndrome (CFS) have yielded inconsistent results. We sought to contribute to findings in this area by examining intraindividual variability as well as level of performance in cognitive functioning.

A battery of cognitive measures was administered to 14 CFS patients and 16 healthy individuals on 10 weekly occasions. Analyses comparing the two groups in terms of level of performance defined by latency and accuracy scores revealed that the CFS patients were slower but not less accurate than healthy persons.

The CFS group showed greater intraindividual variability (as measured by intraindividual standard deviations and coefficients of variation) than the healthy group, although the results varied by task and time frame. Intraindividual variability was found to be stable across time and correlated across tasks at each testing occasion. Intraindividual variability also uniquely differentiated the groups. The present findings support the proposition that intraindividual variability is a meaningful indicator of cognitive functioning in CFS patients.

 

Source: Fuentes K, Hunter MA, Strauss E, Hultsch DF. Intraindividual variability in cognitive performance in persons with chronic fatigue syndrome. Clin Neuropsychol. 2001 May;15(2):210-27. http://www.ncbi.nlm.nih.gov/pubmed/11528543

 

Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders

Abstract:

OBJECTIVE: To identify antinuclear antibodies (ANA) specific for chronic fatigue syndrome (CFS), and in related conditions such as fibromyalgia (FM) or psychiatric disorders.

METHODS: One hundred and fourteen CFS patients and 125 primary and secondary FM patients were selected based on criteria advocated by the Centers for Disease Control and Prevention and by the American College of Rheumatology, respectively. As controls, healthy subjects and patients with either various psychiatric disorders or diffuse connective tissue diseases were included. Autoantibodies were examined by immunoblot utilizing HeLa cell extracts as the antigen.

RESULTS: Autoantibodies to a 68/48 kDa protein were present in 13.2 and 15.6% of patients with CFS and primary FM, respectively. In addition, autoantibodies to a 45 kDa protein were found in 37.1 and 21.6% of the patients with secondary FM and psychiatric disorders, respectively. Meanwhile, these two autoantibodies were not found at all in connective tissue disease patients without FM, nor in healthy subjects (P<0.05). As a group, the anti-68/48 kDa-positive CFS patients presented more frequently with hypersomnia (P<0.005), short-term amnesia (P<0.07) or difficulty in concentration (P<0.05) than those CFS patients without the antibodies.

CONCLUSIONS: The presence of the anti-68/48 kDa protein antibodies in a portion of both CFS and primary FM patients suggests the existence of a common immunological background. These antibodies may find utility as possible markers for a clinicoserological subset of CFS/FM patients with hypersomnia and cognitive complaints.

 

Source: Nishikai M, Tomomatsu S, Hankins RW, Takagi S, Miyachi K, Kosaka S, Akiya K. Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders. Rheumatology (Oxford). 2001 Jul;40(7):806-10. http://rheumatology.oxfordjournals.org/content/40/7/806.long (Full article)

 

Divided attention deficits in patients with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) patients and controls were compared on a variety of mood state, personality, and neuropsychological measures, including memory, word finding, and attentional tasks that required participants to focus, sustain, or divide their attention, or to perform a combination of these functions.

CFS patients demonstrated a selective deficit on 3 measures of divided attention. Their performance on the other neuropsychological tests of intelligence, fluency, and memory was no different than that of normal controls despite their reports of generally diminished cognitive capacity. There was an inverse relation between CFS patient fatigue severity and performance on 1 of the divided attention measures.

Given these findings, it is probable that CFS patients will report more cognitive difficulties in real-life situations that cause them to divide their effort or rapidly reallocate cognitive resources between 2 response channels (vision and audition).

 

Source: Ross S, Fantie B, Straus SF, Grafman J. Divided attention deficits in patients with chronic fatigue syndrome. Appl Neuropsychol. 2001;8(1):4-11. http://www.ncbi.nlm.nih.gov/pubmed/11388122

 

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

Abstract:

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.

 

Source: Daly E, Komaroff AL, Bloomingdale K, Wilson S, Albert MS. Neuropsychological function in patients with chronic fatigue syndrome, multiple sclerosis, and depression. Appl Neuropsychol. 2001;8(1):12-22. http://www.ncbi.nlm.nih.gov/pubmed/11388119

 

Working memory deficits associated with chronic fatigue syndrome

Abstract:

Cognitive impairments are among the most frequently reported and least investigated components of the chronic fatigue syndrome (CFS). As part of a multifaceted study of the CFS, the present study investigated the cognitive functioning of chronic fatigue patients.

The performance of 20 CFS patients was compared to that of controls (N = 20) on 4 tests of working memory (WM). Digit Span Forward was used to assess the storage capacity of WM. Multiple aspects of central executive functioning were assessed using several standard measures: Digit Span Backward, and Trails A and Trails B. More recently developed measures of WM were used to assess control of processing under temporal demands (working memory task) and resistance to interference (a sustained attention task).

Deficits were restricted to more demanding tasks, requiring resistance to interference and efficient switching between processing routines. The overall results clearly implicate deficits in the control aspects of central executive function in CFS.

 

Source: Dobbs BM, Dobbs AR, Kiss I. Working memory deficits associated with chronic fatigue syndrome. J Int Neuropsychol Soc. 2001 Mar;7(3):285-93. http://www.ncbi.nlm.nih.gov/pubmed/11311029

 

Neuropsychological functioning in chronic fatigue syndrome: a review

Abstract:

OBJECTIVE: In this paper we review critically the current status of neurocognitive studies in patients with chronic fatigue syndrome (CFS).

METHOD: CFS literature was monitored as part of a large research project which involved several neuropsychological and psychopathological studies. The literature survey was the result of several consecutive searches on Medline and PsycInfo databases.

RESULTS: The neurocognitive studies are reviewed in terms of scientifically accepted aspects of attention and memory. In addition, we review possible explanations for cognitive dysfunction in CFS. This is preceded with a discussion of the methodological limitations that are considered to explain inconsistencies across neuropsychological studies in CFS.

CONCLUSION: The current research shows that slowed processing speed, impaired working memory and poor learning of information are the most prominent features of cognitive dysfunctioning in patients with CFS. Furthermore, to this date no specific pattern of cerebral abnormalities has been found that uniquely characterizes CFS patients. There is no overwhelming evidence that fatigue is related to cognitive performance in CFS, and researchers agree that their performance on neuropsychological tasks is unlikely to be accounted solely by the severity of the depression and anxiety.

 

Source: Michiels V, Cluydts R. Neuropsychological functioning in chronic fatigue syndrome: a review. Acta Psychiatr Scand. 2001 Feb;103(2):84-93. http://www.ncbi.nlm.nih.gov/pubmed/11167310

 

Abnormal neuropsychological findings are not necessarily a sign of cerebral impairment: a matched comparison between chronic fatigue syndrome and multiple sclerosis

Abstract:

OBJECTIVE: The aim of this study was to assess the potential impact of effort in comparative studies assessing neurocognitive dysfunction in patients with and without a neurologic diagnosis.

BACKGROUND: It was hypothesized that a subgroup within a group of patients with prominent neurocognitive complaints but without a neurologic diagnosis would have impaired performance on a task originally designed to detect malingering.

METHOD: We compared the neuropsychological performance of a group of 40 patients with a definite diagnosis of multiple sclerosis (MS) with that of 67 patients with chronic fatigue syndrome (CFS). The Amsterdam Short-Term Memory Test, a forced-choice memory task, served as measure to detect submaximal effort. In addition, we administered a regular neuropsychological task generally considered to be sensitive for cognitive deterioration.

RESULTS: Compared with the MS group (13%), a larger proportion of the matched CFS group (30%) obtained scores indicative of reduced effort. In contrast, the proportions of patients scoring below the cutoff value on a conventional neuropsychological test did not differ significantly (17% of MS patients and 16% of CFS patients).

CONCLUSIONS: The results obtained raise the question of to what extent abnormal test findings in the absence of documented neurologic impairment should be interpreted as a sign of cerebral impairment. The suggestion has been made to screen more often for biased results in comparative research studies so as to enhance valid interpretation of neuropsychological findings.

 

Source: van der Werf SP, Prins JB, Jongen PJ, van der Meer JW, Bleijenberg G. Abnormal neuropsychological findings are not necessarily a sign of cerebral impairment: a matched comparison between chronic fatigue syndrome and multiple sclerosis. Neuropsychiatry Neuropsychol Behav Neurol. 2000 Jul;13(3):199-203. http://www.ncbi.nlm.nih.gov/pubmed/10910092

 

The difference in patterns of motor and cognitive function in chronic fatigue syndrome and severe depressive illness

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) and major depressive disorder (MDD) share many symptoms and aetiological factors but may have different neurobiological underpinnings. We wished to determine the profile of the biological variables disturbed in CFS and MDD, and identify any critical factors that differentiate the disorders.

METHODS: Thirty patients with CFS, 20 with MDD and 15 healthy controls matched group-wise for age and sex were recruited. Subjects were given a detailed battery of motor and cognitive tests, including measures of psychomotor speed, memory and maximal voluntary muscle contraction in both the morning and evening that were balanced to avoid order effects.

RESULTS: CFS patients generally performed worse on cognitive tests than healthy controls, but better than patients with MDD. Both patient groups had markedly impaired motor function compared with healthy controls. MDD subjects showed a significantly greater diurnal improvement in maximal voluntary contraction than healthy controls.

CONCLUSIONS: Patients with CFS and MDD show similarly substantial motor impairment, but cognitive deficits are generally more marked in MDD. Diurnal changes in some functions in MDD may differentiate the disorder from CFS.

 

Source: Lawrie SM, MacHale SM, Cavanagh JT, O’Carroll RE, Goodwin GM. The difference in patterns of motor and cognitive function in chronic fatigue syndrome and severe depressive illness. Psychol Med. 2000 Mar;30(2):433-42. http://www.ncbi.nlm.nih.gov/pubmed/10824663