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M.E. (and ICD-CFS) Articles, Research and Books
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Research topics: General Articles and Research Overviews, Immune System Research, Viral Research, Cardiac Research, Exercise Research, Muscle Research, Metabolic Research, Neurological and Cognitive Research, Genetic Research, Neuroendocrine Research, and Miscellaneous Research.
Article topics: The Definitions of M.E., On 'fatigue', CBT, GET and the unscientific 'behavioural' paradigm of M.E., On 'stress', M.E. Outbreaks, On the Name Myalgic Encephalomyelitis, M.E. and Other Illnesses, Children with M.E., The Severity of M.E., M.E. Fatalities, Activism Articles, Articles sorted by Author, Articles sorted by Country and Historical, Political and Medical Overviews.
On this page: Neurological and Cognitive Research and Relevant Books - page 2 of 3
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Neurological and Cognitive Research - continued
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Attention and Information Processing Efficiency in Patients with Chronic Fatigue Syndrome. Michiels V, de Gucht V, Cluydts R, Fischler B Free University of Brussels (VUB), Belgium Journal of Clinical and Experimental Neuropsychology (ISSN 1380-3395) 1999 Oct;21(5):709-729 NLM citation: PMID: 10572289
In a study of attentional tests and a verbal memory tasks administered to 29 people with Chronic Fatigue Syndrome and 22 healthy controls, the authors found evidence of a global non-modality-specific attentional dysfunction in patients with CFS.
Working memory deficits associated with chronic fatigue syndrome.Dobbs BM, Dobbs AR, Kiss I. J Int Neuropsychol Soc 2001 Mar;7(3):285-93 Department of Psychology, University of Alberta, Edmonton, Canada. bdobbs@ualberta.caNLM Citation: PMID: 11311029
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 [syndrome] 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.
Influence of exhaustive treadmill exercise on cognitive functioning in chronic fatigue syndrome. LaManca JJ, Sisto SA, DeLuca J, Johnson SK, Lange G, Pareja J, Cook S, Natelson BH. Chronic Fatigue Syndrome Cooperative Research Center, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, USA.
The purpose of this study was to determine the effect of exhaustive exercise on cognitive performance of patients with chronic fatigue syndrome (CFS) and sedentary healthy controls (CON). Subjects were 19 women with CFS and 20 CON. A test battery consisting of 4 cognitive tests (CTB) was given pre-, immediately post-, and 24 hours post-treadmill exercise to exhaustion. No differences were seen on the CTB pre-exercise. CFS patients improved at a slower rate than CON on the Symbol Digit Modalities Test (SDMT), Stroop Word Test (SWT), and Stroop Color Test (SCT). When compared with CON, a lower number of correct responses was seen for the CFS immediately postexercise on the SDMT (61 +/- 3 vs 66 +/- 2), SWT (137 +/- 6 vs 146 +/- 6), and SCT (99 +/- 4 vs 107 +/- 3), and 24 hours postexercise on the SDMT (64 +/- 3 vs 69 +/- 2), SWT (134 +/- 7 vs 148 +/- 5), and SCT (101 +/- 4 vs 106 +/- 3). We conclude that after physically demanding exercise, CFS subjects demonstrated impaired cognitive processing compared with healthy individuals.
Relationships of cognitive difficulties to immune measures, depression and illness burden in CFS. Lutgendorf S, Klimas NG, Antoni M, Brickman A, Fletcher MA University of Miami School of Medicine, Miami, Florida, USA. Journal of Chronic Fatigue Syndrome 1995; 1(2): 23-41.
Abstract: OBJECTIVE. We related the subjective assessment of cognitive difficulties with lymphocyte phenotypes, cell-mediated immunity (CMI), cytokine and neopterin levels in patients with chronic fatigue syndrome (CFS), in order to determine if CFS patients complaining of greater cognitive difficulties would show greater impairments in cell-mediated immunity and a greater degree of immune system dysregulation, and to determine if these cognitive difficulties would correlate with the other non-affective measures of CFS-associated illness burden. We also assessed whether these relationships would hold independent of depression in two ways, by statistically covarying depression severity scores and by comparing subsets of CFS patients with and without a concurrent diagnosis of major depressive disorder. DESIGN. A case series of CFS patients. SETTING. Outpatient tertiary referral clinic at the University of Miami School of Medicine, Miami, FL. PATIENTS. Consecutive sample of 65 patients who were referred as CFS to the University of Miami Diagnostic Immunology Clinic, who met the Centers for Disease Control and Prevention (CDC) criteria for diagnosis of CFS and consented to participate. MAIN MEASURES. Self-assessment of cognitive difficulties, depression and illness burden, clinician-assessed depression and CFS symptoms, lymphocyte phenotype, proliferative response to mitogens, serum levels of cytokines and neopterin.
RESULTS. Among CFS patients, high Cognitive Difficulty Scale (CDS) scores were significantly related to lower lymphocyte proliferative responses to mitogens, higher neopterin levels, and higher CD4 and lower CD8 lymphocyte counts. These relationships, with the exception of T cell subset percentages, were maintained when depression severity was used as a co-variate. High CDS scores were also significantly related to lower Karnofsky scores, and greater illness burden as measured by the Sickness Impact Profile. Evidence is presented that CFS patients with higher cognitive difficulty scores have more immune and clinical dysfunction than those with less cognitive difficulty, and that these relationships are independent of depression . These observations provide support for the concept that although both cognitive difficulties and immunologic abnormalities, such as immune activation and impaired cell-mediated immunity, may represent secondary sequelae to the same event(s), they are not likey to be secondary sequelae to depression.
Attention and information processing efficiency in patients with Chronic Fatigue Syndrome.Michiels V; de Gucht V; Cluydts R; Fischler B Free University of Brussels (VUB), Belgium.J Clin Exp Neuropsychol 1999 Oct; 21(5):709-29 (ISSN: 0168-8634)
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. Unique NLM Identifier: 20042376
Impaired associative learning in chronic fatigue syndrome. Servatius RJ; Tapp WN; Bergen MT; Pollet CA; Drastal SD; Tiersky LA; Desai P; Natelson BH New Jersey Medical School, Department of Neuroscience, East Orange 07019, USA.Neuroreport 1998 Apr 20;9(6):1153-7 (ISSN: 0959-4965)
Patients with chronic fatigue syndrome (CFS) report cognitive difficulties (impaired attention, memory and reasoning). Neuropsychological tests have failed to consistently find cognitive impairments to the degree reported by CFS patients. We tested patients with CFS and sedentary controls in protocols designed to measure sensory reactivity and acquisition of the classically conditioned eyeblink response. Patients with CFS exhibited normal sensitivity and responsivity to acoustic stimuli. However, CFS patients displayed impaired acquisition of the eyeblink response using a delayed-type conditioning paradigm. Sensitivity and responsivity to the airpuff stimulus were normal. In the absence of sensory/motor abnormalities, impaired acquisition of the classically conditioned eyeblink response indicates an associative deficit. These data suggest organic brain dysfunction within a defined neural substrate in CFS patients.
Unique NLM Identifier: 98263991 Grant ID: UOI-AI32247-AI-NIAID
Detection of Intracranial Abnormalities in Patients with Chronic Fatigue Syndrome: comparison of MR Imaging and SPECT. Schwartz, R. B.,Garada,B.M., Komaroff A. L. et al: American Journal of Roentgenology 1994:162:935-941
"in addition to CNS lupus, other inflammatory vascular.. conditions can appear similar to CFS (ME) clinically and radiologically……As with any chronic inflammatory condition affecting the CNS, the T2-bright foci on MR in CFS (ME) may represent perivascular cellular infiltrate and / or reactive demyelination of the surrounding white matter. Alternatively, these abnormalities may reflect the result of a vasculopathy specifically involving the small vessels of the cerebral white matter; indeed, the distribution of lesions on MR in CFS (ME) is similar to that observed in occlusive arteriolar disease of any origin. The cortical defects measured with SPECT likewise may result from decreased flow through cortical arterioles owing to vasculitis. Specifically, on the basis of our observations, the white matter abnormalities seen on MR images may represent ... chronic demyelination, which appears to be irreversible".
Grief in M.E. sufferers
Grief is the most common cause of mood change in CFS. The change in quality of life with CFS is profound; patients must adapt every aspect of existence and often resist acceptance of this unwanted change22,23. Grief cannot begin until a diagnosis is made and other diagnoses are ruled out. Diagnosis frees the patient to begin the process of grieving. Grief is not a disorder. It is a normal developmental process which enables people to deal with overwhelming loss. It is an understandable reaction to a serious, uncertain, stigmatizing and chronic disorder. Grief is therefore common during the initial post diagnostic period and may recur each time there are new changes in health or life situation.
A chronic illness characterized by fatigue, neurologic and immunologic disorders, and active human herpesvirus type 6 infection. Buchwald D, Cheney PR, Peterson DL, Henry B, Wormsley SB, Geiger A, Ablashi DV, Salahuddin SZ, Saxinger C, Biddle R, et al. Annals of Internal Medicine 1992; 116(2): 103-13.
Abstract: OBJECTIVE: To conduct neurologic, immunologic, and virologic studies in patients with a chronic debilitating illness of acute onset. DESIGN: Cohort study with comparison to matched, healthy control subjects. PATIENTS: We studied 259 patients who sought care in one medical practice; 29% of the patients were regularly bedridden or shut-in. MAIN OUTCOME MEASURES: Detailed medical history, physical examination, conventional hematologic and chemistry testing, magnetic resonance imaging (MRI) studies, lymphocyte phenotyping studies, and assays for active infection of patients' lymphocytes with human herpesvirus type 6 (HHV-6). MAIN RESULTS: Patients had a higher mean (± SD) CD4/CD8 T-cell ratio than matched healthy controls (3.16 ± 1.5 compared with 2.3 ± 1.0, respectively; P less than 0.003). Magnetic resonance scans of the brain showed punctate, subcortical areas of high signal intensity consistent with edema or demyelination in 78% of patients (95% CI, 72% to 86%) and in 21% of controls (CI, 11% to 36%) (P less than 10(-9)). Primary cell culture of lymphocytes showed active replication of HHV-6 in 79 of 113 patients (70%; CI, 61% to 78%) and in 8 of 40 controls (20%; CI, 9% to 36%) (P less than 10(-8], a finding confirmed by assays using monoclonal antibodies specific for HHV-6 proteins and by polymerase chain reaction assays specific for HHV-6 DNA. CONCLUSIONS: Neurologic symptoms, MRI findings, and lymphocyte phenotyping studies suggest that the patients may have been experiencing a chronic, immunologically mediated inflammatory process of the central nervous system. The active replication of HHV-6 most likely represents reactivation of latent infection, perhaps due to immunologic dysfunction. Our study did not directly address whether HHV-6, a lymphotropic and gliotropic virus, plays a role in producing the symptoms or the immunologic and neurologic dysfunction seen in this illness. Whether the findings in our patients, who came from a relatively small geographic area, will be generalizable to other patients with a similar syndrome remains to be seen.
Brainstem perfusion is impaired in chronic fatigue syndrome. Costa DC, Tannock C, Brostoff J. Quarterly Journal of Medicine 1995; 88(11): 767-73.
Abstract: We looked for brain perfusion abnormalities in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). An initial pilot study revealed widespread reduction of regional brain perfusion in 24 ME/CFS patients, compared with 24 normal volunteers. Hypoperfusion of the brainstem (0.72 ± 0.05 vs. 0.80 ± 0.04, p <0.0001) was marked and constant. We then tested whether perfusion to the brainstem in ME/CFS patients differs from that in normals, patients with major depression, and others with epilepsy. Data from a total of 146 subjects were included in the present study: 40 normal volunteers, 67 patients with ME/CFS (24 in the pilot study, 16 with no psychiatric disorders, 13 with ME/CFS and depression, 14 with ME/CFS and other psychiatric disorders), 10 epileptics, 20 young depressed patients and 9 elderly depressed individuals. Brain perfusion ratios were calculated using 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) and single-photon emission tomography (SPECT) with a dedicated three-detector gamma camera computer/system (GE Neurocam). Brain-stem hypoperfusion was confirmed in all ME/CFS patients. Furthermore, the 16 ME/CFS patients with no psychiatric disorders and the initial 24 patients in the pilot study showed significantly lower brainstem perfusion (0.71 ± 0.03) than did depressed patients (0.77 ± 0.03; ANOVA, p < 0.0001). Patients with ME/CFS have a generalized reduction of brain perfusion, with a particular pattern of hypoperfusion of the brainstem.
Assesment of regional cerebral perfusion by 99Tcm-HMPAO SPECT in chronic fatigue syndrome. Ichise M, Salit IE, Abbey SE, Chung DG, Gray B, Kirsh JC, Freedman M. Nuclear Medicine Communications 1992; 13(10): 767-72.
Abstract: Chronic fatigue syndrome (CFS) is a severely disabling illness of uncertain aetiology. It is characterized by a chronic, sustained or fluctuating sense of debilitating fatigue without any other known underlying medical conditions. It is also associated with both somatic and neuropsychological symptoms. Both physical and laboratory findings are usually unremarkable. Regional cerebral blood flow (rCBF) was assessed in 60 clinically defined CFS patients and 14 normal control (NC) subjects using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) single photon emission computed tomography (SPECT). Compared with the NC group, the CFS group showed significantly lower cortical/cerebellar rCBF ratios, throughout multiple brain regions (P <0.05). Forty-eight CFS subjects (80%) showed at least one or more rCBF ratios significantly less than normal values. The major cerebral regions involved were frontal (38 cases, 63%), temporal (21 cases, 35%), parietal (32 cases, 53%) and occipital lobes (23 cases, 38%). The rCBF ratios of basal ganglia (24 cases, 40%) were also reduced. 99Tcm-HMPAO brain SPECT provided objective evidence for functional impairment of the brain in the majority of the CFS subjects. The findings may not be diagnostic of CFS but 99Tcm-HMPAO SPECT may play an important role in clarifying the pathoaetiology of CFS. Further studies are warranted.
Gait abnormalities in chronic fatigue syndrome. Natelson BH, Sisto SA, Tapp WN. Journal of the Neurological Sciences 1995; 131(2): 156-61.
Abstract: To evaluate our clinical impression that patients with the chronic fatigue syndrome (CFS) did not walk normally, we assessed gait kinematics at slow walking speeds (i.e., 0.45, 0.89 and 1.34 m/sec) and 30 m run time speeds on CFS patients and on a comparison group of sedentary controls. Run time was significantly slower for CFS than control subjects (p <0.001). There was a significant interaction (p < 0.01) between group and speed for maximum hip angle during stance and swing phase with hip angle being significantly larger at 1.34 m/sec for CFS than controls subjects for both cases (p < 0.05). Knee flexion during stance and swing phases was significantly larger for controls than CFS subjects at 0.45 m/sec (p < 0.01). Ratio of stride length divided by leg length was significantly larger for the control subjects than for the CFS subjects with differences occurring at 0.45 and 0.89 m/sec (p < 0.01) but not 1.34 m/sec. The data indicate that CFS patients have gait abnormalities when compared to sedentary controls. These could be due to balance problems, muscle weakness, or central nervous system dysfunction; deciding which will require further research. Evaluation of gait may be a useful tool to measure outcome following therapeutic interventions.
A controlled study of brain magnetic resonance imaging in patients with the chronic fatigue syndrome. Natelson BH, Cohen JM, Brassloff I, Lee HJ. Journal of the Neurological Sciences 1993; 120(2): 213-7.
Abstract: Two neuroradiologists compared the brain MR scans of 52 patients with the CDC criteria for the chronic fatigue syndrome (CFS) with those of 52 age and sex matched controls who had undergone imaging because of histories of head trauma or headache. CFS patients had significantly more abnormal scans than controls—27% vs 2%. Abnormalities seen were foci of increased white matter T2 signal in 9 CFS patients and one control and ventricular or sulcal enlargement in 5 CFS patients. Follow up of patients with subcortical signal hyperintensities revealed 3 who had symptoms suggestive of other known medical causes of what appeared to be CFS. The data indicate that some CFS patients have some organic problem manifesting itself on neuroimaging. But, finding MR abnormalities should warn the physician that the patient's symptoms may be secondary to some other medical illness and not simply primary CFS.
Cognitive functioning is impaired in patients with chronic fatigue syndrome devoid of psychiatric disease. Deluca J, Johnson SK, Ellis SP, Natelson BH. Journal of Neurology Neurosurgery and Psychiatry 1997; 62: 151-55.
Abstract: OBJECTIVE: To examine the effect of the presence or absence of psychiatric disease on cognitive functioning in chronic fatigue syndrome. METHODS: Thirty six patients with chronic fatigue syndrome and 31 healthy controls who did not exercise regularly were studied. Subgroups within the chronic fatigue syndrome sample were formed based on the presence or absence of comorbid axis I psychiatric disorders. Patients with psychiatric disorders preceding the onset chronic fatigue syndrome were excluded. Subjects were administered a battery of standardised neuropsychological tests as well as a structured psychiatric interview. RESULTS: Patients with chronic fatigue syndrome without psychiatric comorbidity were impaired relative to controls and patients with chronic fatigue syndrome with concurrent psychiatric disease on tests of memory, attention, and information processing. CONCLUSION: Impaired cognition in chronic fatigue syndrome cannot be explained solely by the presence of a psychiatric condition.
Information processing efficiency in chronic fatigue syndrome and multiple sclerosis. DeLuca J, Johnson SK, Natelson BH. Archives of Neurology 1993; 50(3): 301-4.
Abstract: OBJECTIVE—To compare the cognitive performance of subjects with chronic fatigue syndrome (CFS), multiple sclerosis (MS), and healthy controls. All subjects were matched for age, education, and verbal intelligence, as previous neuropsychological studies of CFS had not used appropriate control groups. DESIGN—Case-control design. All subjects were given a neuropsychological battery and the test scores were compared among the groups. SETTING—Subjects with CFS and subjects with MS were recruited from private and institutional practice and from the community. Healthy subjects were recruited from the community. PATIENTS/OTHER PARTICIPANTS—Twelve subjects (all female) with CFS participated in the study. Chronic fatigue syndrome was diagnosed in these patients in accordance with the requirements outlined by the Centers for Disease Control as modified subsequently to not exclude patients with concurrent depression and/or anxiety. All subjects with CFS were referred for a neuropsychological examination to assess persistent cognitive complaints. Eleven subjects (10 female, one male) with the diagnosis of clinically stable MS were chosen from clinics and the community because of complaints of mild to moderate cognitive impairment. The subjects with MS and 11 healthy volunteers (10 female, one male) were matched to the group with CFS by age, education, and estimated verbal intelligence (based on the Vocabulary subtest of the Wechsler Adult Intelligence Scale-Revised). The subjects with MS had a mean Kurtzke Expanded Disability Status Scale score of 4.95 (SD, 1.95; range, 2.0 to 7.5). As a result of the matching procedure, there were no differences among the three groups in age (F[2,31] = 0.32), education (F[2,31] = 0.80), and verbal intelligence (F[2,31] = 0.31). INTERVENTIONS—None. MAIN OUTCOME MEASURES—These measures included the Beck Depression Inventory (BDI), the Paced Auditory Serial Addition Test (PASAT), Digit Span Test, and the Similarities Test of Verbal Abstract Reasoning. CONCLUSIONS—These results indicate that subjects with CSF and subjects with MS show significant impairment on a test of complex concentration when compared with appropriate controls. The data suggest that subjects with CFS and subjects with MS have difficulty on tasks that require the simultaneous processing of complex cognitive information.
AACFS CONFERENCE REPORT - JANUARY 2001
On MRI there are small areas of high signal in the white matter,.. SPECT scans are more physiologic and show a "tattered" signal in CFS. A functional MRI gives a better picture of the physiology. The brain appears to be working harder than in a healthy person doing the same task. Other parts of the brain seem to be brought in to "help".
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Neurological and Cognitive Research - continued
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Page 3: Neurological and Cognitive Research (continued) and Relevant Books
Page 1: Neurological and Cognitive Research
Page 2: Neurological and Cognitive Research (continued)
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