slow processing speed – Page 3 – American ME and CFS Society

Psychomotor function and response inhibition in chronic fatigue syndrome

Abstract:

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.

Source: Van Den Eede F, Moorkens G, Hulstijn W, Maas Y, Schrijvers D, Stevens SR, Cosyns P, Claes SJ, Sabbe BG. Psychomotor function and response inhibition in chronic fatigue syndrome. Psychiatry Res. 2011 Apr 30;186(2-3):367-72. doi: 10.1016/j.psychres.2010.07.022. Epub 2010 Aug 24. https://www.ncbi.nlm.nih.gov/pubmed/20797797

Cognitive functioning in chronic fatigue syndrome: a meta-analysis

Abstract:

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.

Comment in: Letter to the Editor: Plausible explanations for neurocognitive deficits in ME/CFS, aggravation of neurocognitive impairment induced by exertion. [Psychol Med. 2010]

Source: Cockshell SJ, Mathias JL. Cognitive functioning in chronic fatigue syndrome: a meta-analysis. Psychol Med. 2010 Aug;40(8):1253-67. doi: 10.1017/S0033291709992054. Epub 2010 Jan 5. https://www.ncbi.nlm.nih.gov/pubmed/20047703

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

Neuropsychological deficits in patients with chronic fatigue syndrome

Abstract:

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.

Source: Busichio K, Tiersky LA, Deluca J, Natelson BH. Neuropsychological deficits in patients with chronic fatigue syndrome. J Int Neuropsychol Soc. 2004 Mar;10(2):278-85. http://www.ncbi.nlm.nih.gov/pubmed/15012848

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

Abstract:

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.

Source: Deluca J, Christodoulou C, Diamond BJ, Rosenstein ED, Kramer N, Natelson BH. Working memory deficits in chronic fatigue syndrome: differentiating between speed and accuracy of information processing. J Int Neuropsychol Soc. 2004 Jan;10(1):101-9. http://www.ncbi.nlm.nih.gov/pubmed/14751012

Validation of a telephone cognitive assessment test battery for use in chronic fatigue syndrome

Abstract:

We compared a computerized version of the Cognitive Drug Research (CDR) cognitive assessment test battery and a completely automated telephone version of the same battery. These assessed aspects of attention, working memory and long-term memory. Both methods were used to assess the cognitive performance of a cohort of 30 people with confirmed chronic fatigue syndrome (CFS) and a group of 30 healthy controls matched for age and education.

The CFS group had significantly slower reaction times on all four cognitive measures on both the computerized and telephone tests. The mood data followed similar patterns in the computer and telephone assessments. The results from both forms of the test battery confirmed the pattern and severity of cognitive impairment in CFS. Furthermore, the two methods of testing were similarly sensitive in detecting cognitive deficits. The incapacitating nature of CFS may cause problems for researchers if the restrictions to mobility affect the representativeness of the study group. The findings of the present study support the use of a fully automated telephone cognitive testing system for detecting deficits in CFS.

Source: McCue P, Scholey AB, Herman C, Wesnes KA. Validation of a telephone cognitive assessment test battery for use in chronic fatigue syndrome. J Telemed Telecare. 2002;8(6):337-43. http://www.ncbi.nlm.nih.gov/pubmed/12537921

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

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

Attention and information processing efficiency in patients with Chronic Fatigue Syndrome

Abstract:

In this study a battery of attentional tests and a verbal memory task were administered to outpatients with Chronic Fatigue Syndrome (CFS) in order to evaluate aspects of attention that have not been explored in this group to date. In addition, this study was designed to further examine memory function and to extend the few reports investigating the rate of cognitive processing independent of motor speed and the possibility of a modality-specific impairment of information processing.

Twenty-nine patients with CFS and 22 healthy controls matched for age, gender, intelligence, and education were included in this study. The results show that patients with CFS do not seem to be impaired for modification of phasic arousal level, nor for visual selective attention requiring shifting of attention in the visuospatial field.

The results further support the presence of reduced information processing speed and efficiency, and strengthen the evidence of a global non-modality-specific attentional dysfunction in patients with CFS. In this study the poor performance of patients with CFS on recall of verbal information was due to poor initial storage rather than to a retrieval failure.

Source: Michiels V, de Gucht V, Cluydts R, Fischler B. Attention and information processing efficiency in patients with Chronic Fatigue Syndrome. J Clin Exp Neuropsychol. 1999 Oct;21(5):709-29. http://www.ncbi.nlm.nih.gov/pubmed/10572289

Cognitive deficits in patients suffering from chronic fatigue syndrome, acute infective illness or depression

Abstract:

BACKGROUND: Patients with chronic fatigue syndrome (CFS) report neuro-psychological symptoms as a characteristic feature. We sought to assess cognitive performance in patients with CFS, and compare cognitive performance and subjective workload experience of these patients with that of two disease comparison groups (non-melancholic depression and acute infection) and healthy controls.

METHOD: A computerized performance battery employed to assess cognitive functioning included tests of continuous attention, response speed, performance accuracy and memory. Severity of mood disturbance and subjective fatigue were assessed by questionnaire.

RESULTS: All patient groups demonstrated increased errors and slower reaction times, and gave higher workload ratings than healthy controls. Patients with CFS and non-melancholic depression had more severe deficits than patients with acute infection. All patient groups reported more severe mood disturbance and fatigue than healthy controls, but patients with CFS and those with acute infection reported less severe mood disturbance than patients with depression.

CONCLUSIONS: As all patients demonstrated similar deficits in attention and response speed, it is possible that common pathophysiological processes are involved. The differences in severity of mood disturbance, however, suggest that the pathophysiological processes in patients with CFS and acute infection are not simply secondary to depressed mood.

Source: Vollmer-Conna U, Wakefield D, Lloyd A, Hickie I, Lemon J, Bird KD, Westbrook RF. Cognitive deficits in patients suffering from chronic fatigue syndrome, acute infective illness or depression. Br J Psychiatry. 1997 Oct;171:377-81. http://www.ncbi.nlm.nih.gov/pubmed/9373430