Generation of classification criteria for chronic fatigue syndrome using an artificial neural network and traditional criteria set

Abstract:

OBJECTIVE: The definition of chronic fatigue syndrome (CFS) is still disputed and no validated classification criteria have been published. Artificial neural networks (ANN) are computer-based models that can help to evaluate complex correlations. We examined the utility of ANN and other conventional methods in generating classification criteria for CFS compared to other diseases with prominent fatigue, systemic lupus erythematosus (SLE) and fibromyalgia syndrome (FMA).

PATIENTS AND METHODS: Ninety-nine case patients with CFS, 41 patients with SLE and 58 with FMA were recruited from a generalist outpatient population. Clinical symptoms were documented with help of a predefined questionnaire. The patients were randomly divided into two groups. One group (n = 158) served to derive classification criteria sets by two-fold cross-validation, using a) unweighted application of criteria, b) regression coefficients, c) regression tree analysis, and d) artificial neural networks in parallel. These criteria were validated with the second group (n = 40).

RESULTS: Classification criteria developed by ANN were found to have a sensitivity of 95% and a specificity of 85%. ANN achieved a higher accuracy than any of the other methods.

CONCLUSION: We present validated criteria for the classification of CFS versus SLE and FMA, comparing different classification approaches. The most accurate criteria were derived with the help of ANN. We therefore recommend the use of ANN for the classification of syndromes with complex interrelated symptoms like CFS.

 

Sour ce: Linder R, Dinser R, Wagner M, Krueger GR, Hoffmann A. Generation of classification criteria for chronic fatigue syndrome using an artificial neural network and traditional criteria set. In Vivo. 2002 Jan-Feb;16(1):37-43. http://www.ncbi.nlm.nih.gov/pubmed/11980359

 

Dry eyes and mouth syndrome–a subgroup of patients presenting with sicca symptoms

Abstract:

OBJECTIVE: To evaluate the characteristics of patients presenting with symptoms suggestive of Sjögren’s syndrome (SS) but failing to satisfy diagnostic criteria.

METHODS: Clinical, serological and histological data were collected on 34 patients presenting with dry eyes and/or mouth who did not satisfy the Vitali criteria for the diagnosis of SS. They were compared with 136 patients with primary SS, 38 patients with secondary SS, and 13 patients without SS. Questionnaires on symptoms from each group were compared with 43 healthy controls.

RESULTS: The 34 patients who did not satisfy the diagnostic criteria for SS or any other connective tissue disease were designated dry eyes and mouth syndrome (DEMS). Their demography including age was similar to that of a primary SS group and there was no more atrophy seen on their biopsies compared with SS and non-SS controls. They scored highly on visual analogue scales of symptoms but had few objective signs. All were negative for anti-Ro and anti-La although the prevalence of antinuclear antibodies (19%) was increased compared with a normal population. There was no excess of SS-associated tissue types.

CONCLUSION: There was no evidence that age, salivary gland atrophy or subclinical SS accounted for the symptoms in DEMS. Most of the patients fitted into a spectrum of disease which tended more towards fibromyalgia and/or chronic fatigue syndrome.

Comment in: Dry eyes and mouth syndrome or sicca, asthenia and polyalgia syndrome? [Rheumatology (Oxford). 2003]

 

Source: Price EJ, Venables PJ. Dry eyes and mouth syndrome–a subgroup of patients presenting with sicca symptoms. Rheumatology (Oxford). 2002 Apr;41(4):416-22. http://rheumatology.oxfordjournals.org/content/41/4/416.long (Full article)

 

 

 

The case definition of chronic fatigue syndrome

Abstract:

The 1994 case definition of chronic fatigue syndrome is widely used not only for diagnosis but also for clinical and laboratory-based observations of this clinical entity. The criteria for the 1994 case definition are based primarily on symptoms and not on physical signs or chemical or immunological tests. This situation has resulted in conflicting clinical and laboratory observations that in all likelihood is due to different populations of patients being studied in different centers.

Based on some of the recent publications, there appears to be an emerging picture of this disease entity that we propose could be used to subgroup chronic fatigue syndrome into four different subclasses. These subclasses would consist of chronic fatigue with primarily nervous system disorders such as impaired memory or concentration and headache, chronic fatigue with primarily endocrine system disorders such as unrefreshing sleep and postexertional malaise, chronic fatigue with musculoskeletal system disorders such as muscle pain and joint pain, and chronic fatigue with immune system/infectious disorders such as sore throat and tender lymph nodes.

It is suggested that if clinical and laboratory-based studies on chronic fatigue syndrome were conducted on more homogeneous subgroups of patients, the data from one center to the other might not be as conflicting and more insights can be shed on the nature of this clinical condition.

 

Source: Tan EM, Sugiura K, Gupta S. The case definition of chronic fatigue syndrome. J Clin Immunol. 2002 Jan;22(1):8-12. http://www.ncbi.nlm.nih.gov/pubmed/11958593

 

Editorial on CFS was biased, inaccurate, and misleading

EDITOR—As a member of the chief medical officer’s working group on chronic fatigue syndrome, I consider that Straus has failed to appreciate the difficulties of deciding what constitutes evidence in an illness as uncertain and heterogeneous as this.1 He also misunderstood, or took out of context, some of the key conclusions and recommendations in the chief medical officer’s report.

Although it was agreed that evidence should not just be limited to the results of randomised controlled trials, the findings of the York systematic review were frequently cited. It was therefore disingenuous of Straus to state that information from this review did not influence the report’s conclusions about a wide range of therapeutic interventions. It did.

Equally, it would have been a serious omission if the report had failed to refer to the feedback from patients contained in three large surveys on attitudes to management, as well as two events where patients and carers met with the working group. All three surveys concluded that graded exercise as is currently being done made more people worse than any other intervention. Pacing, however, was found to be beneficial by around 90% of respondents. By dismissing such views as anecdote, Straus fails to appreciate that the Department of Health is encouraging patients to enter into a therapeutic relationship with the medical profession in the management of chronic conditions such as this.2

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1122848/

 

Source: Shepherd C. Editorial on CFS was biased, inaccurate, and misleading. BMJ. 2002 Apr 13;324(7342):914. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1122848/ (Full article)

 

Role of pathological delayed-type hypersensitivity in chronic fatigue syndrome: importance of the evaluation of lymphocyte activation by flow cytometry and the measurement of urinary neopterin

Abstract:

Chronic fatigue syndrome or benign myalgic encephalomyelitis has been extensively described and investigated. Although numerous immunological abnormalities have been linked with the syndrome, none have been found to be specific.

This article describes the detection of delayed-type hypersensitive responses to certain common environmental antigens in almost fifty per cent of patients with this syndrome. Such hypersensitivity can be detected by the intradermal administration of antigens derived from commensal organisms like the yeast Candida albicans, and then monitoring for a systemic reaction over the following six to forty eight hours. This approach can be consolidated by performing lymphocyte activation tests in parallel and measuring in vitro T-cell activation by Candida albicans antigens by three-colour flow cytometry based on CD3, CD4 and either CD69 or CD25.

Another useful parameter is the kinetics of neopterin excretion in the urine over the course of the skin test. The results showed that the intensity of the DTH response correlated with the number of T-cells activated in vitro. Various factors have been implicated in the fatigue of many patients, notably lack of sleep. However, it remains difficult to establish causality in either one direction or the other. This work is in the spirit of a multifactorial approach to the group of conditions referred to as “chronic fatigue syndrome”.

 

Source: Brunet JL, Fatoohi F, Liaudet AP, Cozon GJ. Role of pathological delayed-type hypersensitivity in chronic fatigue syndrome: importance of the evaluation of lymphocyte activation by flow cytometry and the measurement of urinary neopterin. Allerg Immunol (Paris). 2002 Feb;34(2):38-44. [Article in French] http://www.ncbi.nlm.nih.gov/pubmed/11933752

 

Brainstem conundrum: the Chiari I malformation

Abstract:

PURPOSE: To describe the Chairi I Malformation in relation to the anatomy of the brain and spinal cord, the common manifestations of the condition, diagnostic considerations, and management for the primary care provider.

DATA SOURCES: Extensive review of the world-wide scientific literature on the condition, supplemented with actual case studies.

CONCLUSIONS: The adult Chairi I Malformation is an insidious congenital brainstem anomaly that consists of caudal displacement of the cerebellar tonsils, brainstem and fourth ventricle into the upper cervical space, resulting in overcrowding of the posterior fossa.

IMPLICATIONS FOR PRACTICE: Due to the vague, and often ambiguous presenting symptoms of Chiari I Malformation, many patients are misdiagnosed with conditions such as multiple sclerosis, fibromyalgia, chronic fatigue syndrome, or psychiatric disorders. Patients frequently experience symptoms months to years prior to accurate diagnosis and often incur irreversible neurologic deficits.

 

Source: Mueller D. Brainstem conundrum: the Chiari I malformation. J Am Acad Nurse Pract. 2001 Apr;13(4):154-9. http://www.ncbi.nlm.nih.gov/pubmed/11930527

 

Evaluating attributions for an illness based upon the name: chronic fatigue syndrome, myalgic encephalopathy and Florence Nightingale disease

Abstract:

In recent years, considerable discussion has occurred about stigma surrounding the name given to an illness currently known as chronic fatigue syndrome (CFS). Although patients and medical personnel have expressed varying opinions on this issue, no studies have evaluated how beliefs about the illness change based upon the type of name used for diagnostic purposes. Proposals have been put forth to rename the illness with an eponym (a famous patient’s or researcher’s name) or with a less trivial sounding, more medically based type of name.

In this study, attributions about CFS were measured in three groups of medical trainees. All groups read the same case study of a person with classic symptoms of chronic fatigue syndrome, with the only difference being in the type of name given. Trainees then were asked to provide attributions about certain aspects of the illness, including its cause, severity, and prognosis.

Results suggested that, across name conditions, most trainees appeared to consider the symptom complex of CFS a serious illness resulting in poor quality of life. In addition, findings indicated that the name, chronic fatigue syndrome, may be regarded less seriously than the Myalgic Encephalopathy name with respect to some important aspects of the illness. In this study, specialty of medical trainee also played a role in how the illness was perceived.

 

Source: Jason LA, Taylor RR, Plioplys S, Stepanek Z, Shlaes J. Evaluating attributions for an illness based upon the name: chronic fatigue syndrome, myalgic encephalopathy and Florence Nightingale disease. Am J Community Psychol. 2002 Feb;30(1):133-48. http://www.ncbi.nlm.nih.gov/pubmed/11928774

 

Chronic fatigue syndrome: evaluation and treatment

Abstract:

Severe fatigue is a common complaint among patients. Often, the fatigue is transient or can be attributed to a definable organic illness. Some patients present with persistent and disabling fatigue, but show no abnormalities on physical examination or screening laboratory tests. In these cases, the diagnosis of chronic fatigue syndrome (CFS) should be considered. CFS is characterized by debilitating fatigue with associated myalgias, tender lymph nodes, arthralgias, chills, feverish feelings, and postexertional malaise. Diagnosis of CFS is primarily by exclusion with no definitive laboratory test or physical findings. Medical research continues to examine the many possible etiologic agents for CFS (infectious, immunologic, neurologic, and psychiatric), but the answer remains elusive. It is known that CFS is a heterogeneous disorder possibly involving an interaction of biologic systems. Similarities with fibromyalgia exist and concomitant illnesses include irritable bowel syndrome, depression, and headaches. Therefore, treatment of CFS may be variable and should be tailored to each patient. Therapy should include exercise, diet, good sleep hygiene, antidepressants, and other medications, depending on the patient’s presentation.

Comment in:

Differential diagnosis for chronic fatigue syndrome. [Am Fam Physician. 2003]

Chronic fatigue syndrome and depression. [Am Fam Physician. 2002]

 

Source: Craig T, Kakumanu S. Chronic fatigue syndrome: evaluation and treatment. Am Fam Physician. 2002 Mar 15;65(6):1083-90. http://www.aafp.org/afp/2002/0315/p1083.html (Full article)

 

Cellular immunity in monozygotic twins discordant for chronic fatigue syndrome

Abstract:

Studies elsewhere have suggested that immune dysfunction may be common in patients with chronic fatigue syndrome (CFS). The objective of this study was to assess the nature and extent of abnormalities in lymphocyte cell surface markers and NK cell activity in patients with CFS while controlling for genetic factors. A co-twin control study of immune system parameters was conducted for 22 pairs of monozygotic twins discordant for CFS and 9 healthy pairs of twins.

The CFS twins had greater numbers of CD62L(+) T cells in several T cell subsets, although these differences did not achieve statistical significance. Significantly greater variability was noted in twins discordant for CFS than in the concordant healthy twins for 20 of 48 variables examined. The monozygotic co-twin control design is of unique value because of its ability to control for genetic influences on CFS; however, additional studies will be required to further assess immune dysregulation in this illness.

 

Source: Sabath DE, Barcy S, Koelle DM, Zeh J, Ashton S, Buchwald D. Cellular immunity in monozygotic twins discordant for chronic fatigue syndrome. J Infect Dis. 2002 Mar 15;185(6):828-32. Epub 2002 Feb 28. http://jid.oxfordjournals.org/content/185/6/828.long (Full article)

 

Prognosis of chronic fatigue in a community-based sample

Abstract:

OBJECTIVE: This study examined predictors of fatigue severity and predictors of continued chronic fatigue status at wave 2 follow-up within a random, community-based sample of individuals previously evaluated in a wave 1 prevalence study of chronic fatigue and chronic fatigue syndrome that originally took place between 1995 and 1997.

METHODS: Wave 1 data were from a larger community-based prevalence study of chronic fatigue syndrome. In the present study, a second wave of data were collected by randomly selecting a sample of participants from the wave 1 sample of 18,675 adults and readministering a telephone screening questionnaire designed to assess symptoms of chronic fatigue syndrome.

RESULTS: Findings revealed that wave 1 fatigue severity was a predictor of fatigue severity at wave 2 in the overall sample of individuals with and without chronic fatigue. In the smaller sample of individuals with chronic fatigue, wave 1 fatigue severity, worsening of fatigue with physical exertion, and feeling worse for 24 hours or more after exercise significantly predicted continued chronic fatigue status (vs. improvement) at wave 2 follow-up.

CONCLUSIONS: These findings underscore the prognostic validity of postexertional malaise in predicting long-term chronic fatigue and also highlight the importance of using population-based, representative random samples when attempting to identify long-term predictors of chronic fatigue at follow-up.

 

Source: Taylor RR, Jason LA, Curie CJ. Prognosis of chronic fatigue in a community-based sample. Psychosom Med. 2002 Mar-Apr;64(2):319-27. http://www.ncbi.nlm.nih.gov/pubmed/11914449