Category: Cognitive Dysfunction

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

 

Quality of attention in chronic fatigue syndrome: subjective reports of everyday attention and cognitive difficulty, and performance on tasks of focused attention

Abstract:

Patients with chronic fatigue syndrome (also known as post-viral fatigue syndrome or myalgic encephalomyelitis) commonly report cognitive difficulties concerning attention, concentration and memory. In this study, patients were compared with matched controls on two questionnaires which assess subjective difficulties with attention and general cognitive functioning, and on two tasks requiring focused attention.

Patients reported significantly greater difficulty with attention on the Everyday Attention Questionnaire and more cognitive symptoms on the Profile of Fatigue-Related Symptoms. The objective tests did not clearly indicate a deficit in patients’ focused attention; patients tended to perform less well on the Embedded Figures Test and the Stroop Colour-Word Interference Test, but these differences were not significant.

There was, however, evidence of psychomotor retardation, with patients having longer response times for word reading and colour naming in the Stroop test. Difficulties in interpreting findings for both subjective and objective cognitive measures are discussed.

 

Source: Ray C, Phillips L, Weir WR. Quality of attention in chronic fatigue syndrome: subjective reports of everyday attention and cognitive difficulty, and performance on tasks of focused attention. Br J Clin Psychol. 1993 Sep;32 ( Pt 3):357-64. http://www.ncbi.nlm.nih.gov/pubmed/8251968

 

Behavioural problems associated with the chronic fatigue syndrome

Abstract:

Disturbances of memory, concentration and motor function are often reported by patients with the chronic fatigue syndrome (CFS). The present study objectively evaluated these behavioural problems using a computerized test battery measuring memory, attention and motor skills.

Fifty-seven CFS patients were compared with 19 matched controls and all subjects completed the performance test battery and filled in questionnaires measuring psychopathology and mood. The patients reported significantly higher levels of depression, anxiety, physical symptoms and cognitive failures than the controls. Similarly, they reported more negative affect at the time of testing.

The patients were slower on psychomotor tasks, showed increased visual sensitivity and impaired attention. Digit span and free recall were not impaired but retrieval from semantic memory and logical reasoning were slower. None of the performance differences between patients and controls could be attributed to differences in psychopathology. These results agree with recent findings from other laboratories, and it is now time to consider the nature of the neurological dysfunction underlying these effects.

 

Source: Smith AP, Behan PO, Bell W, Millar K, Bakheit M. Behavioural problems associated with the chronic fatigue syndrome. Br J Psychol. 1993 Aug;84 ( Pt 3):411-23. http://www.ncbi.nlm.nih.gov/pubmed/8401992

 

Cognitive impairment in patients with chronic fatigue: a preliminary study

Erratum in: J Neurol Neurosurg Psychiatry 1993 Oct;56(10):1142

Abstract:

Subjective impairment of memory and concentration is a frequent complaint in sufferers from chronic fatigue. To study this, 65 general practice attenders identified as having chronic fatigue were administered a structured psychiatric interview and a brief screening battery of cognitive tests.

Subjective cognitive impairment was strongly related to psychiatric disorder, especially depressed mood, but not fatigue, anxiety, or objective performance. Simple tests of attention and concentration showed some impairment but this was influenced by both fatigue and depression.

Subjects with high levels of fatigue performed less well on a memory task requiring cognitive effort, even in the absence of depression. There was no evidence for mental fatiguability. The relationship between depression, fatigue, and cognitive function requires further research.

 

Source: McDonald E, Cope H, David A. Cognitive impairment in patients with chronic fatigue: a preliminary study. J Neurol Neurosurg Psychiatry. 1993 Jul;56(7):812-5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1015065/ (Full article)

 

Analysis of neuropsychological functioning in patients with chronic fatigue syndrome

Abstract:

Memory impairment dominates the cognitive complaints of patients with chronic fatigue syndrome (CFS). Twenty CFS patients were available for studies with a clinical and experimental battery composed of memory and cognitive tests. The results on objective testing indicated that the CFS patients had some mild memory impairment, but only on tasks requiring conceptually driven encoding and retrieval processes. There were no associations between the nature of the precipitating illness, self ratings of fatigue, physical findings, or laboratory determination and objective memory performance or self report of memory functioning. These generally negative results indicate that memory impairment in CFS patients is typically mild and involves memory processes that participate in conceptualising information.

 

Source: Grafman J, Schwartz V, Dale JK, Scheffers M, Houser C, Straus SE. Analysis of neuropsychological functioning in patients with chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1993 Jun;56(6):684-9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC489620/ (Full article)

 

Memory deficits associated with chronic fatigue immune dysfunction syndrome

Abstract:

Performance on tests of memory in 39 patients who met Center for Disease Control (CDC) criteria for chronic fatigue immune dysfunction syndrome (CFIDS) was compared with 23 depressed patients (DSM-III-R) and 129 healthy controls.

Although the CFIDS patients had normal neuropsychological profiles, they significantly overestimated their ability (metamemory), performed significantly worse on tests of recall as context increased (e.g., recognition), made more errors when rehearsal was prevented, and had delayed mental scanning as memory load increased.

The overall pattern indicated that CFIDS patients had a significant memory deficit, far worse than implied by CDC criteria. The pattern for CFIDS patients was consistent with temporal-limbic dysfunction and significantly different than depressed patients and control subjects.

 

Source: Sandman CA, Barron JL, Nackoul K, Goldstein J, Fidler F. Memory deficits associated with chronic fatigue immune dysfunction syndrome. Biol Psychiatry. 1993 Apr 15-May 1;33(8-9):618-23. http://www.ncbi.nlm.nih.gov/pubmed/8329493

 

Information processing efficiency in chronic fatigue syndrome and multiple sclerosis

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.

RESULTS: The mean number of correctly identified responses collapsed across the four PASAT trials was significantly different across groups (F[2,31] = 4.03; P < .05). While the CFS and MS groups did not differ from each other, subjects with CFS (SEM, 124.2 +/- 6.4) and subjects with MS (SEM, 112.9 +/- 10.9) scored significantly below controls (SEM, 146.4 +/- 6.4) (Fisher’s Protected Least Significant Difference test; P < .05). There were significant differences among the three groups on mean Digit Span Test performance (F[2,31] = 5.5; P < .01). While the CFS and MS group did not differ significantly from each other, only the CFS group was significantly lower than control (Fisher’s Protected Least Significant Difference test; P < .05). Mean performance on the Similarities test did not differ among the three groups (F = 0.58). In addition, there were significant differences among the three groups in mean BDI scores (F[2,31] = 7.6; P < .01). The CFS and MS groups did not differ significantly from each other, and both groups showed a statistically significantly elevated mean BDI score relative to the control group (Fisher’s Protected Least Significant Difference test; P < .05). No significant correlations were found between BDI scores and PASAT total scores (CFS, r = -.21; MS, r = .13; control, r = .27), or between BDI and Digit Span Test (CFS, r = -.32; MS, r = -.40; control, r = -.19). Results of the PASAT and Digit Span Test were significantly correlated in the CFS group (r = .71; P < .01), but not in the MS (r = .06) or control groups (r = .49).

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. Selective impairment in information processing efficiency may lie at the root of other cognitive complaints made by patients with CFS.

 

Source: DeLuca J, Johnson SK, Natelson BH. Information Processing Efficiency in Chronic Fatigue Syndrome and Multiple Sclerosis.Arch Neurol. 1993;50(3):301-304. doi:10.1001/archneur.1993.00540030065016. http://archneur.jamanetwork.com/article.aspx?articleid=592247

 

Neuropsychological and psychiatric abnormalities in myalgic encephalomyelitis: a preliminary report

Abstract:

Ten patients attending one general medical hospital clinic who fulfilled operational criteria for the diagnosis of myalgic encephalomyelitis (ME) and with a history longer than three months, underwent a series of standardized neuropsychological and psychiatric tests. Nine were able to complete the tests and were individually matched with a normal control group for age, sex, educational background and premorbid intelligence. The ME subjects showed inferior performance to the controls on two tests of verbal memory. Their personality scores displayed less extraversion and less psychoticism. This is the first report of objective neuropsychological abnormalities in patients with ME, suggesting a discrete deterioration of short-term memory. The findings may also suggest a concurrent psychiatric component of the condition, but the direction of causality remains to be clarified.

 

Source: Riccio M, Thompson C, Wilson B, Morgan DJ, Lant AF. Neuropsychological and psychiatric abnormalities in myalgic encephalomyelitis: a preliminary report. Br J Clin Psychol. 1992 Feb;31 ( Pt 1):111-20. http://www.ncbi.nlm.nih.gov/pubmed/1559114