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)

Prognosis in chronic fatigue syndrome: a prospective study on the natural course

Abstract:

OBJECTIVE: To determine spontaneous improvement after a follow up interval of 18 months in patients with chronic fatigue syndrome and to identify factors that predict improvement.

METHODS: A longitudinal study was used. Of 298 initially assessed self referred patients fulfilling criteria for chronic fatigue syndrome, 246 patients completed self report questionnaires at follow up (response rate 83%). A multidimensional assessment method was used, measuring behavioural, emotional, cognitive, and social functioning. Comparison data from 53 healthy subjects matched for age, sex, and educational level were available.

RESULTS: Three per cent of patients reported complete recovery and 17% reported improvement. At follow up, there were considerable problems at work and consumption of medication was high. Subjective improvement was confirmed by dimensional change: at follow up recovered patients had similar scores to healthy subjects and improved patients showed significant improvement on four out of seven outcome measures and had higher scores than healthy subjects in all dimensions. Sociodemographic variables or treatment by specialists and alternative practitioners did not predict improvement. Predictors of improvement were: subjective sense of control over symptoms, less fatigue, shorter duration of complaints, and a relative absence of physical attributions.

CONCLUSION: The improvement rate in patients with a relatively long duration of complaints is small. Psychological factors are related to improvement, especially cognitive factors.

 

Source: Vercoulen JH, Swanink CM, Fennis JF, Galama JM, van der Meer JW, Bleijenberg G. Prognosis in chronic fatigue syndrome: a prospective study on the natural course. J Neurol Neurosurg Psychiatry. 1996 May;60(5):489-94. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486359/ (Full article)

Neuropsychological deficits in chronic fatigue syndrome: artifact or reality?

Chronic fatigue syndrome is an illness characterised by extreme fatigue of uncertain origin which has been present for at least six months. The fatigue should have a sudden onset and be severe enough to substantially reduce the patient’s day to day activities. A number of other symptoms are associated with chronic fatigue syndrome including complaints of impaired memory, difficulty making decisions, poor attention, and reduced concentration. Many patients complain that it is these cognitive symptoms which cause them the greatest frustration and disability.

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486357/pdf/jnnpsyc00017-0004.pdf

 

Source: Moss-Morris R, Petrie KJ, Large RG, Kydd RR. Neuropsychological deficits in chronic fatigue syndrome: artifact or reality? J Neurol Neurosurg Psychiatry. 1996 May;60(5):474-7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486357/

 

Neuroimaging in chronic fatigue syndrome

The link between viral infection, the brain, and fatiguing illnesses has a long history. This combination forced itself on the medical imagination after events in Austria in the winter of 1916-17. A virulent form of influenza was noted, characteristically, to produce lethargy and later, to leave a host of neurological deficits in its wake. By the spring of 1918 several English cases of encephalitis lethargica had been reported and in the next year the disease was notifiable. The peak of the epidemic occurred in 1924 in the United Kingdom, at which time the Board of Control reported that many cases had been admitted to hospital with psychiatric disturbances.1 Hence the notion that apparent psychiatric illnesses may be misdiagnosed manifestations of a postinfectious cerebral disease began; it refuses to disappear.23

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486356/pdf/jnnpsyc00017-0001.pdf

 

Source: Cope H, David AS. Neuroimaging in chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1996 May;60(5):471-3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC486356/

 

‘Seronegative’ Sjögren’s syndrome manifested as a subset of chronic fatigue syndrome

Abstract:

We determined the extent to which chronic fatigue syndrome (CFS) patients with sicca symptoms fulfil the diagnostic criteria for Sjögren’s syndrome (SS). Three sets of diagnostic criteria for SS, formulated by the Japanese, Europeans and Fox, were used. One-third of the CFS patients with sicca symptoms fulfilled the diagnostic criteria for SS. However, they were ‘seronegative’, differing from the ordinary primary SS.

 

Source: Nishikai M1, Akiya K, Tojo T, Onoda N, Tani M, Shimizu K. ‘Seronegative’ Sjögren’s syndrome manifested as a subset of chronic fatigue syndrome. Br J Rheumatol. 1996 May;35(5):471-4. http://rheumatology.oxfordjournals.org/content/35/5/471.long (Full article)

 

A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome

Abstract:

PURPOSE: To assess possible triggers and cofactors for chronic fatigue syndrome (CFS) and to compare levels of selected cytokines between cases and an appropriately matched control group.

PATIENTS AND METHODS: We conducted a case-control study of 47 cases of CFS obtained through a regional CFS research program maintained at a tertiary care medical center. One age-, gender-, and neighborhood-matched control was identified for each case through systematic community telephone sampling. Standardized questionnaires were administered to cases and controls. Sera were assayed for transforming growth factor-beta (TGF-beta), interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and antibody to Borrelia burgdorferi and Babesia microti.

RESULTS: Cases were more likely to have exercised regularly before illness onset than controls (67% versus 40%; matched odds ratio (MOR) = 3.4; 95% CI = 1.2 to 11.8; P = 0.02). Female cases were more likely to be nulliparous prior to onset of CFS than controls (51% versus 31%; MOR = 8.0; 95% CI = 1.03 to 170; P = 0.05). History of other major factors, including silicone-gel breast implants (one female case and one female control), pre-morbid history of depression (15% of cases, 11% of controls) and history of allergies (66% of cases, 51% of controls) were similar for cases and controls. However, cases were more likely to have a diagnosis of depression subsequent to their diagnosis of CFS compared to a similar time frame for controls (MOR = undefined; 95% CI lower bound = 2.5; P < 0.001). Positive antibody titers to B burgdorferi (one case and one control) and B microti (zero cases and two controls) were also similar.

CONCLUSIONS: Further investigation into the role of prior routine exercise as a cofactor for CFS is warranted. This study supports the concurrence of CFS and depression, although pre-morbid history of depression was similar for both groups.

Comment in: Etiology of chronic fatigue syndrome. [Am J Med. 1997]

 

Source: MacDonald KL, Osterholm MT, LeDell KH, White KE, Schenck CH, Chao CC, Persing DH, Johnson RC, Barker JM, Peterson PK. A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome. Am J Med. 1996 May;100(5):548-54. http://www.ncbi.nlm.nih.gov/pubmed/8644768

 

Short-term night-shift working mimics the pituitary-adrenocortical dysfunction in chronic fatigue syndrome

Abstract:

The purpose of this study was to determine whether a short period (5 days) of night-shift work affected the pituitary-adrenal responses to CRH. Ten nurses (8 female and 2 male; age 28.1 +/- 1.7 yr: mean +/- SEM) working at the Royal Liverpool University Hospital, and who regularly undertook periods of night and day shift work were enrolled.

Measurements were made of basal ACTH and cortisol concentrations, and their responses to iv ovine CRH (1 microgram.kg-1). Basal ACTH concentrations were higher during the night shift than during the day shift (12.9 +/- 5.1 pmol.L-1 vs. 4.7 +/- 1.2 pmol.L-1, P < 0.01) whereas cortisol concentrations were lower (551 +/- 48 nmol.L – 1 vs. 871 +/- 132 nmol.L – 1, P < 0.01). After CRH injection, ACTH concentrations remained consistently higher during the night shift, but the integrated increase in ACTH concentration was lower (P < 0.05) than during the day shift. Conversely, the increase in cortisol concentration was greater during the night shift than the day shift (283 +/- 53 nmol.L-1 vs. 134 +/- 41 nmol.L-1, P < 0.05).

We conclude that the pituitary-adrenal responses to CRH are markedly disrupted after only 5 days of nighttime work. These abnormalities mimic those previously observed in patients with chronic fatigue syndrome. Neuroendocrine abnormalities reported to be characteristic of chronic fatigue syndrome may be merely the consequence of disrupted sleep and social routine.

 

Source: Leese G, Chattington P, Fraser W, Vora J, Edwards R, Williams G. Short-term night-shift working mimics the pituitary-adrenocortical dysfunction in chronic fatigue syndrome. J Clin Endocrinol Metab. 1996 May;81(5):1867-70. http://www.ncbi.nlm.nih.gov/pubmed/8626849

 

Reduced oxidative muscle metabolism in chronic fatigue syndrome

Abstract:

The purpose of this study was to determine if chronic fatigue syndrome (CSF) is characterized by abnormalities in oxidative muscle metabolism. Patients with CFS according to Centers for Disease Control (CDC) criteria (n = 22) were compared to normal sedentary subjects (n = 15).

CFS patients were also tested before and 2 days after a maximal treadmill test. Muscle oxidative capacity was measured as the maximal rate of postexercise phosphocreatine (PCr) resynthesis using the ADP model (Vmax) in the calf muscles using 31P magnetic resonance spectroscopy. Vmax was significantly reduced in CFS patients (39.6 +/- 2.8 mmol/L/min, mean +/- SE) compared to controls (53.8 +/- 2.8 mmol/L/min). Two days postexercise there was no change in resting inorganic phosphate (Pi)/PCr or Vmax in the CFS patients (n = 14).

In conclusion, oxidative metabolism is reduced in CFS patients compared to sedentary controls. In addition, a single bout of strenuous exercise did not cause a further reduction in oxidative metabolism, or alter resting Pi/PCr ratios.

Comment in: Chronic fatigue syndrome and skeletal muscle mitochondrial function. [Muscle Nerve. 1997]

 

Source: McCully KK, Natelson BH, Iotti S, Sisto S, Leigh JS Jr. Reduced oxidative muscle metabolism in chronic fatigue syndrome. Muscle Nerve. 1996 May;19(5):621-5. http://www.ncbi.nlm.nih.gov/pubmed/8618560

 

Cognitive behaviour therapy for the chronic fatigue syndrome. Patients’ beliefs about their illness were probably not a major factor

Comment on: Cognitive behaviour therapy for the chronic fatigue syndrome: a randomized controlled trial. [BMJ. 1996]

 

EDITOR,-Michael Sharpe and colleagues’ study confirms that the best medical advice for patients with the chronic fatigue syndrome is not “nothing can be done” or that “the disease will burn itself out.”‘ The study produced improvement in 73% of the patients, which is comparable to the 80% improvement produced by my management techniques.2 3 Interestingly, my approach seems to be fundamentally different from that of Sharpe and colleagues.

You can read the full comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2350897/pdf/bmj00539-0053d.pdf

 

Source: Ho-Yen DO. Cognitive behaviour therapy for the chronic fatigue syndrome. Patients’ beliefs about their illness were probably not a major factor. BMJ. 1996 Apr 27;312(7038):1097-8. http://www.ncbi.nlm.nih.gov/pubmed/8616430

 

Cognitive behaviour therapy for the chronic fatigue syndrome. Essential elements of the treatment must be identified

Comment on: Cognitive behaviour therapy for the chronic fatigue syndrome: a randomized controlled trial. [BMJ. 1996]

 

EDITOR,-We have several practical and theoretical concerns about Michael Sharpe and colleagues’ study of cognitive behaviour therapy in the chronic fatigue syndrome.’ The authors managed to obtain almost 100% uptake of treatment and compliance among patients who were attending an infectious diseases clinic and were strongly convinced that their chronic fatigue had a physical cause. We would struggle to engage our patients similarly, even with two hours for an initial appointment, and we could not offer them anything approaching an hour of treatment a week for four months. The difference between what was provided in the study and what clinicians can routinely offer their patients makes it important to identify the essential elements of the treatment.

The package given included cognitive techniques such as “question[ing] a simple disease explanation,” “strategies to reduce excessive perfectionism and self criticism,” and a problem solving approach of “gradual and consistent increases in activity.” The continuing improvement after the end oftreatment is unusual for the cognitive psychotherapies and suggests that the behavioural component was most effective. We find it puzzling, therefore, that the authors attribute the beneficial effects of treatment to “a specific effect on illness perpetuating beliefs and coping behaviour,” particularly as these attitudes did not change substantially. The patients would inevitably report less avoidance of exercise if they were complying with the study. After treatment at least half of the patients still believed that the illness was physical (from tables 2 and 5), and the vast majority still applied the damaging label of “myalgic encephalomyelitis”2 to their condition.

You can read the full comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2350875/pdf/bmj00539-0053b.pdf

 

Source: Lawrie SM. Cognitive behaviour therapy for the chronic fatigue syndrome. Cognitive behavior therapy. Essential elements of the treatment must be identified. BMJ. 1996 Apr 27;312(7038):1097; author reply 1098. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2350875/