Risks for Developing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in College Students Following Infectious Mononucleosis: A Prospective Cohort Study.

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) involves severe fatigue, unrefreshing sleep, and cognitive impairment, leading to functional difficulties; prior studies have not evaluated risk factors with behavioral and immune data collected before developing ME/CFS. Up to 5% of university students develop infectious mononucleosis (IM) annually, and 9-12% meet criteria for ME/CFS 6 months later. We sought to determine predictors of ME/CFS. METHODS: We enrolled college students at the start of the school year (time 1), identified those who developed IM (time 2), and followed them for 6 months (time 3), identifying 3 groups: those who developed ME/CFS, severe ME/CFS (meeting >1 set of criteria), and who were asymptomatic. We conducted 8 behavioral and psychological surveys and analyzed cytokines at 3 time points. RESULTS: 238 of the 4501 students (5.3%) developed IM; 6 months later, 55 of the 238 (23%) met criteria for ME/CFS and 157 (66%) were asymptomatic. 67 of the 157 asymptomatic students served as controls. Students with severe ME/CFS were compared with students who were asymptomatic at 3 time points. The former group was not different from the latter group at time 1 (prior to developing IM) in stress, coping, anxiety, or depression but were different in several behavioral measures and had significantly lower levels of IL-6 and IL-13. At time 2 (when they developed IM), the 2 ME/CFS groups tended to have more autonomic complaints and behavioral symptoms while the severe-ME/CFS group had higher levels of IL-12 and lower levels of IL-13 than the recovered group. CONCLUSIONS: At baseline, those who developed ME/CFS had more physical symptoms and immune irregularities, but not more psychological symptoms, than those who recovered.

A reexamination of the cognitive behavioral model of chronic fatigue syndrome.

OBJECTIVE: The cognitive behavioral model of chronic fatigue syndrome (CFS) suggests that cognitions and reduced activity level perpetuate the fatigue and impairment that individuals with CFS experience. The two empirical evaluations of this model resulted in conflicting findings. The current study examines the influence of case definition fulfillment on the applicability of this model to CFS. METHOD: A moderated mediation analysis was conducted on 990 individuals with CFS to reexamine the behavioral pathway of this model. Case definition fulfillment was entered as a moderator. RESULTS: Findings were generally inconsistent with the cognitive behavioral model of CFS. Case definition fulfillment significantly moderated the relation between activity level and physical impairment (ß = -0.08, p = 0.03); individuals who met more stringent case definitions demonstrated a weaker relation between activity level and impairment. CONCLUSIONS: This model may not accurately represent the experience of individuals with CFS, particularly those who fulfill more stringent case definitions.

Defining Essential Features of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

Considerable debate surrounds the search for the defining features of patients with Myalgic Encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Current case definitions were created through clinical consensus. Failure to operationalize these case definitions has led to considerable variability in the identification of patients. In addition, some case definitions (e.g., Fukuda et al., 1994) do not require cardinal symptoms of this illness, where as other case definitions do require core symptoms of this illness (Carruthers et al., 2003, 2011), and these latter case criteria appear to identify a more impaired group of patients. Criterion variance is most likely to occur when operationally explicit criteria do not exist for diagnostic categories (Spitzer, Endicott, & Robins, 1978), or when there are varying criteria for contrasting case definitions, which is an impediment to the research in this field. To deal with this problem, it is possible to differentiate those that meet more loosely defined criteria from those that are more narrowly and defined, thus differentiating CFS from ME. In order to progress the search for biological markers and effective treatments, essential features need to be operationalized and broadly used in order to increase the probability that individuals included in samples have the same underlying illness.

Activity measurement in pediatric chronic fatigue syndrome.

OBJECTIVES: Individuals with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) experience debilitating symptoms, including post-exertional malaise, an intensification of symptoms after physical or cognitive exertion. Previous studies found differences in the activity levels and patterns of activity among individuals with ME and CFS, compared to healthy controls; however, limited research exists on the activity levels of pediatric patients. The objective of this study was to examine differences in activity between healthy children and youth with ME and CFS. METHODS: The present study examines the objective (i.e., ActiGraphy) and self-reported levels of activity among children (ages 5 to 17) enrolled in a community-based study of pediatric CFS. RESULTS: Children with ME and CFS evidenced lower activity levels than healthy control children. Moreover, participants with ME and CFS evidenced increased nighttime activity and delayed initiation of daytime activity. Participants' self-reported activity data significantly correlated with their ActiGraph data, suggesting that children with ME and CFS are able to accurately describe their activity level. DISCUSSION: This study highlights differences in activity level and diurnal/nocturnal activity patterns between healthy children and those with ME and CFS. These differences should be considered in identifying appropriate supports and accommodations for children with ME and CFS.

Patient-Reported Experiences With Median Arcuate Ligament Syndrome: Resilience and Resources Required.

Objective: Median arcuate ligament syndrome (MALS) is a vascular condition that is treated surgically. MALS is a diagnosis of exclusion and therefore often requires that pediatric patients undergo an exhaustive number of tests and potential experiences with misdiagnosis before receiving an accurate diagnosis and treatment. The purpose of the current mixed-methods study was to assess the pediatric patient- and parent-reported experience of (a) coping with and managing symptoms associated with MALS and (b) the diagnostic, treatment, and recovery process for pediatric MALS. Methods: Nine postsurgical pediatric patients (M age = 20.11 ± 3.59; all <18 at time of surgery) and 6 parents participated in semistructured focus groups and completed self-report questionnaires about their experiences and current functioning. Results: Four themes emerged: (a) the impact of MALS (physical and psychosocial), (b) uncertainties and feeling misunderstood, (c) extensive medical tests, and (d) mental health impacts, with an additional three themes related to specific querying (i.e., appreciation, recommendations, and interdisciplinary treatment team). With the exception of variable long-term physical impacts, patients and their parents reported fairly consistent experiences, and the content of these themes was consistent with self-reported quantitative data. Conclusions: The current study highlights the resilience and resources seemingly required for effective diagnosis and intervention for pediatric MALS. The need for increased knowledge about MALS, the inclusion of an interdisciplinary treatment team, and long-term follow-up for pediatric patients with MALS are implicated.

The development of an instrument to assess post-exertional malaise in patients with myalgic encephalomyelitis and chronic fatigue syndrome.

Post-exertional malaise, or a variation of this term, is a key symptom of myalgic encephalomyelitis and chronic fatigue syndrome, as this symptom is mentioned in almost all myalgic encephalomyelitis and chronic fatigue syndrome case definitions. Until now there has not been a comprehensive questionnaire to assess post-exertional malaise. To rectify this situation, in this article we describe the development of a new questionnaire, called the DePaul Post-Exertional Malaise Questionnaire, which was based on input from hundreds of patients. Preliminary validation was provided by the findings of significant and predictable relationships between different domains of this post-exertional malaise questionnaire and physical functioning.

The Prevalence of Pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in a Community­Based Sample.

BACKGROUND: Most pediatric prevalence studies of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have been based upon data from tertiary care centers, a process known for systematic biases such as excluding youth of lower socioeconomic status and those less likely to have access to health care. In addition, most pediatric ME/CFS epidemiologic studies have not included a thorough medical and psychiatric examination. The purpose of this study was to determine the prevalence of pediatric ME/CFS from an ethnically and sociodemographically diverse community-based random sample. METHOD: A sample of 10,119 youth aged 5-17 from 5622 households in the Chicagoland area were screened. Following evaluations, a team of physicians made final diagnoses. Youth were given a diagnosis of ME/CFS if they met criteria for three selected case definitions. A probabilistic, multi-stage formula was used for final prevalence calculations. RESULTS: The prevalence of pediatric ME/CFS was 0.75%, with a higher percentage being African American and Latinx than Caucasian. Of the youth diagnosed with ME/CFS, less than 5% had been previously diagnosed with the illness. CONCLUSIONS: Many youth with the illness have not been previously diagnosed with ME/CFS. These findings point to the need for better ways to identify and diagnose youth with this illness.

Myalgic encephalomyelitis and chronic fatigue syndrome case definitions: effects of requiring a substantial reduction in functioning.

BACKGROUND: Current case definitions for myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) require an individual to report a 'substantial reduction' in activity levels, when compared to premorbid functioning. However, little guidance is provided on how to measure these reductions, as well as what level of reduction should be deemed 'substantial,' leading to inconsistencies in how this criterion is applied across research settings. PURPOSE: The current study examined the influence of substantial reduction criterion on case definitions. METHOD: The current study analyzed an international convenience sample of 1002 individuals with ME or CFS, 53 healthy controls, and 260 controls with other chronic illnesses. RESULTS: Findings indicated that the utility of the substantial reduction criterion varied by case definition, with more stringent case definitions not needing this criterion to identify cases. CONCLUSION: These results suggest that the requirement of a substantial reduction in functioning may be redundant when case definitions specify that individuals must endorse a set of core symptoms at specified frequency and severity levels.

The development of a short form of the DePaul Symptom Questionnaire.

PURPOSE/OBJECTIVE: The DePaul Symptom Questionnaire (DSQ) is a widely used instrument that assesses common symptoms of myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). The DSQ has strong psychometric properties; however, it consists of 99 items, and the energy limitations and cognitive difficulties experienced by individuals with ME and CFS may hinder their ability to easily complete the questionnaire. METHOD: The current study examined symptom prevalence and discriminative ability to develop a short form of the DSQ (DSQ-SF). RESULTS: The resulting short form questionnaire consists of 14 items that were highly prevalent among individuals with ME and CFS. Additionally, the items demonstrated the ability to differentiate individuals with ME and CFS from adult controls and, to a lesser extent, individuals with multiple sclerosis. CONCLUSIONS/IMPLICATIONS: The DSQ-SF may serve as an effective, brief screening tool for symptoms of ME and CFS. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Differentiating Post-Polio Syndrome from Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

BACKGROUND: Overlapping and concomitant symptoms among similar chronic illnesses have created difficulties for diagnosis and further treatment. Three such chronically fatiguing illnesses, Post-polio syndrome (PPS), Myalgic Encephalomyelitis (ME) and chronic fatigue syndrome (CFS) fall under this category. PURPOSE: The aim of this study is to examine and distinguish between core symptoms found in these illnesses (i.e. muscle pain/weakness, fatigue or exhaustion, and autonomic symptoms) via three methods of analysis (DePaul Symptom Questionnaire 2 (DSQ-2), Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and machine learning techniques). RESULTS: Items assessing onset and severity for individuals who reported having PPS were found to have experienced an onset of PPS related symptoms roughly 30 years after the onset of Polio. Items found in the DSQ-2, SF-36 compared all illness groups and found that participants with ME/CFS were more functionally impaired across symptoms than those with PPS. Across all analyses, three domains most commonly differentiated the illnesses (neurocognitive, Post-exertional malaise, and neuroendocrine). CONCLUSION: Examining functional impairment amongst chronically fatiguing illnesses using multiple methods of analysis can be an important factor in distinguishing similar illnesses. These findings support further analysis of analogous symptomatology among other chronic illnesses to assist in diagnosis.

The DePaul Symptom Questionnaire-2: A Validation Study.

BACKGROUND: The DePaul Symptom Questionnaire (DSQ) was developed to assess the symptomatology and case definition fulfillment of individuals with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). The questionnaire was recently revised to improve its psychometric properties, increase its diagnostic reliability, and assess symptoms required by case definitions. The resulting instrument was named the DSQ-2. PURPOSE: The current study sought to evaluate the utility and reliability of the new and revised items in the DSQ-2. METHOD: A cross-sectional sample of 399 adults with ME or CFS was recruited to complete the DSQ-2. RESULTS: Descriptive analyses of the DSQ-2 suggest that the new and revised items enhance the instrument's ability to assess certain symptom domains and evaluate recent case definitions. Additionally, an exploratory factor analysis resulted in an eight-factor solution: post-exertional malaise, cognitive impairment, fever and flu, pain, sleep disruption, orthostatic intolerance, genitourinary issues, and temperature intolerance. The items within each factor demonstrated strong internal consistency reliability (Cronbach's alphas = .73-.91). CONCLUSION: These analyses indicate that the DSQ-2 offers a more thorough and precise understanding ME and CFS symptomology and case definition fulfillment.

Deconstructing post-exertional malaise: An exploratory factor analysis.

Post-exertional malaise is a cardinal symptom of myalgic encephalomyelitis and chronic fatigue syndrome. There are two differing focuses when defining post-exertional malaise: a generalized, full-body fatigue and a muscle-specific fatigue. This study aimed to discern whether post-exertional malaise is a unified construct or whether it is composed of two smaller constructs, muscle fatigue and generalized fatigue. An exploratory factor analysis was conducted on several symptoms that assess post-exertional malaise. The results suggest that post-exertional malaise is composed of two empirically different experiences, one for generalized fatigue and one for muscle-specific fatigue.

Approaching recovery from myalgic encephalomyelitis and chronic fatigue syndrome: Challenges to consider in research and practice.

There are unique methodological challenges to studying and assessing recovery in myalgic encephalomyelitis and chronic fatigue syndrome. This study explored these challenges through interviewing 13 physicians who treat myalgic encephalomyelitis and chronic fatigue syndrome. Our deductive thematic analysis produced four themes to consider when approaching recovery: lifespan differences in the illness experience; the heterogeneity of myalgic encephalomyelitis and chronic fatigue syndrome-case definitions, etiological stance, and misdiagnosis; patient follow-up and selection bias; and assessment logistics. We discuss how researchers and clinicians can use these considerations when working with patients, drafting recovery criteria, and interpreting treatment outcomes.

Defining and measuring recovery from myalgic encephalomyelitis and chronic fatigue syndrome: the physician perspective.

PURPOSE: To inform an operationalised definition of recovery from myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) for research and practice. Without a consensus on defining and measuring recovery, there will continue to be controversy amongst researchers, clinicians, and patients when interpreting treatment outcomes. METHOD: This study explores physicians' views on recovery from ME and CFS. We conducted semi-structured interviews with 10 physician participants who are experts in the ME and CFS field. Our deductive thematic analysis, using a realist perspective, provided a framework for differentiating recovery and significant improvement. RESULTS: Physicians conceptualised recovery as complete symptom remission and a return to premorbid functioning (adjusted for with age), whereas they viewed significant improvement as a substantial reduction in symptoms with considerable functional gains, where patients may operate in daily life but still must cope or be treated. CONCLUSIONS: Our findings provide recommendations and approaches for measuring: daily functioning, symptomatology, quality of life, and physical functioning. Implications for rehabilitation Physicians viewed recovery as complete symptom remission and a return to premorbid functioning (adjusted for with age). Recovery from myalgic encephalomyelitis and chronic fatigue syndrome should be viewed as multidimensional, considering patients' daily life, psychosocial functioning, and overall physical functioning. These findings can improve practitioner-client interactions, as they provide recommendations for measuring recovery in research and practice.

The 'cognitive behavioural model' of chronic fatigue syndrome: Critique of a flawed model.

Chronic fatigue syndrome/myalgic encephalomyelitis is a debilitating illness that greatly impacts the lives of sufferers. A cognitive behavioural model attempts to explain illness onset and continuance with a hypothesis that the illness is perpetuated by patients' irrational beliefs and avoidance behaviours. This theory underpins the promotion of cognitive behavioural therapy, a treatment that aims to change beliefs and behaviours. This article reports on a detailed review of the cognitive behavioural model. Our review finds that the model lacks high-quality evidential support, conflicts with accounts given by most patients and fails to account for accumulating biological evidence of pathological and physiological abnormalities found in patients. There is little scientific credibility in the claim that psycho-behavioural therapies are a primary treatment for this illness.

Energy envelope maintenance among patients with myalgic encephalomyelitis and chronic fatigue syndrome: Implications of limited energy reserves.

OBJECTIVE: The Energy Envelope Theory of myalgic encephalomyelitis and chronic fatigue syndrome postulates that individuals with myalgic encephalomyelitis and chronic fatigue syndrome may experience some increase in functioning if their level of exertion consistently remains within the limits of their available energy. Findings of several studies support this theory; however, the current study is the first to explore how an individual's initial level of available energy may influence the relation between energy envelope maintenance and level of functioning. METHOD: The functioning, activity, and symptomatology of six groups of individuals with myalgic encephalomyelitis and chronic fatigue syndrome were compared. Groups were created based upon level of available energy (higher or lower) and energy envelope adherence (underextended, within, overextended). RESULTS: Results indicate that, as expected, individuals with myalgic encephalomyelitis and chronic fatigue syndrome who had higher available energy also had better functioning than individuals with lower available energy; however, this relation was less pronounced for individuals who were overexerting themselves. DISCUSSION: These results are consistent with the Energy Envelope Theory, and they suggest that overexertion was particularly impactful for individuals with higher levels of available energy.

The Development of the DePaul Symptom Questionnaire: Original, Expanded, Brief, and Pediatric Versions.

One of the key requirements of a reliable case definition is the use of standardized procedures for assessing symptoms. This article chronicles the development of the DePaul Symptom Questionnaire (DSQ) to assess symptoms of the major chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME) case definitions. The original questionnaire has been modified and expanded over time to more fully capture symptoms from various adult case definitions, and a brief as well as pediatric version have also been developed. The DSQ has demonstrated very good psychometric properties in terms of test-retest reliability and sensitivity/specificity, as well as construct, predictive, and discriminant validity. The DSQ allows for a clear characterization of a patient's illness and allows scientists and clinicians to improve diagnostic reliability and validity when employing case definitions of ME and CFS.

Latent class analysis of a heterogeneous international sample of patients with myalgic encephalomyelitis/chronic fatigue syndrome.

BACKGROUND: Individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) routinely display differences in symptomatology, as well as illness course, onset, duration, and functional disability. Given such diversity, previous work has attempted to identify symptom-based ME/CFS subtypes. However, results have been inconsistent. PURPOSE: This study sought to elucidate potential subtypes of ME/CFS as well as explore the impact of subtype membership on health functioning. METHODS: Twelve non-core (i.e., less frequently endorsed) symptoms were included in a latent class analysis of 1,210 adults with ME/CFS. Demographic and illness-related predictors of class membership were evaluated with a multinomial logistic regression. ANOVAs were then performed to determine if there were significant differences across class on the eight subscales of the Short-Form Health Survey (SF-36). RESULTS: A six-class solution was selected, which consisted of one class that was likely to endorse all non-core symptoms, one class that was unlikely to endorse any non-core symptoms, and four classes that were likely to endorse either one or two non-core symptom domains (i.e., circulatory/neuroendocrine impairment, orthostatic intolerance, and gastro-intestinal distress). Significant functioning differences by class were present for all SF-36 subscales. CONCLUSIONS: These results are suggestive of subtypes of ME/CFS and, if replicated, may assist physicians in providing tailored treatment to patients and allow researchers to form more homogeneous samples.