Sleep Disturbances in Pediatric Chronic Fatigue Syndrome: A Review of Current Research

Abstract

Objective: Children and adolescents with chronic fatigue syndrome (CFS) frequently report sleep disturbances. However, little is known about the nature and severity of sleep disturbance and factors associated with sleep problems in pediatric CFS. The purpose of this review was to synthesize and critically appraise existing literature relating to sleep disturbances in pediatric CFS. Methods: Embase, CINAHL, PsychINFO, PubMed. and Medline databases were searched to retrieve all studies that included an assessment of sleep in pediatric CFS. Two reviewers independently assessed eligibility, extracted data, and systematically assessed reporting quality. Results: Six studies were included and these were mostly case-controlled designs. Findings varied across studies; however, most studies found that children and adolescents with CFS had signifi cantly more sleep disturbances when compared to healthy controls. Signifi cant methodological variations and limitations were apparent. Conclusions: This review suggests that children and adolescents with CFS experience sleep disturbances. However, results need to be interpreted cautiously given the limited evidence available and its overall low quality. More research is required to elucidate the nature and extent of sleep disturbance in pediatric CFS and should focus on (1) identifying the specifi c types, causes, and severity of sleep disturbances; (2) the specifi c consequences of sleep disturbances; and (3) Originally thought to occur only in adults, it is becoming increasingly recognized within the pediatric population with estimates of incidence ranging from 0.001% to 2%.2-5 With typical age of onset in mid to late adolescence, the effect of CFS often occurs in the critical stages of higher education where missed schooling due to illness can have a major effect on future academic and social outcomes. Sleep problems are commonly reported by children and adolescents with CFS. 6It is well accepted that adequate amount and quality of sleep is crucial for healthy child development and the functional consequences of poor sleep for children and adolescents are well known.7 Although studies show that most children and adolescents with CFS complain of sleep disturbances, 6 the type and severity of sleep disturbance that these children and adolescents experience has not been well characterized. There has been limited investigation of factors that might contribute to sleep disturbances (physiological, psychological, and social) in this group, as well as little or no evidence supporting the effi cacy of sleep interventions in children and adolescents with CFS. Therefore, there is little guidance for clinicians in how to best manage sleep disturbances in this population, which may potentially exacerbate disease burden in this already vulnerable group.

Sleep Quality in Adolescents With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME)

“…17 Subjective measures are often inexpensive, easily administered, and provide detailed descriptions of sleep characteristics, whereas objective measures such as actigraphy can provide additional impartial information about sleep quality. 17 A recent systematic review 12 found that, since 1987 (ie, the year in which the official diagnosis of CFS/ME was first published), only 6 studies have investigated sleep in children and adolescents younger than 19 years with a diagnosis of CFS/ ME. The studies are characterized by wide variation with respect to the inclusion criteria employed (ie, some have used different case definitions of CFS/ME), sample size (ie, ranging from n = 3 to n = 57), 12 method used to assess sleep (ie, actigraphy, polysomnography, core body temperature, sleep/wake diary), sleep outcomes (ie, total sleep time, sleep efficiency, sleep latency), time frame of data collection (ie, polysomnography for 1 night, actigraphy for 2 weeks), and the investigation of biological factors that potentially underlie sleep disturbances (ie, core body temperature, cortisol levels, melatonin levels).…”

“…Increased objective sleep disturbance in participants with CFS/ME in comparison with healthy controls was a common finding in previous studies. 12 Compared with controls, children and adolescents with CFS/ME showed significantly longer total sleep time, 18 more disrupted sleep and reduced sleep efficiency, 18,19 reduced rapid eye movement (REM) and non-REM stage 2 sleep, 20 delayed time of appearance of the lowest core body temperature and lower amplitude of changes in circadian core body temperature, 21 higher levels of melatonin in the first part of the night and early morning, 22 and temporal differences in bouts of actual rest during time in bed. 19 Nevertheless, children and adolescents with CFS/ME have also been shown to have objective sleep parameters that are comparable to healthy controls such as actual sleep time, 20,22 sleep onset latency, 20,22 REM latency, and the amount of non-REM stage 1 sleep.…”

“…20 The inconsistency in findings may relate to the variable methodologies and measures employed. For instance, of the 6 studies in the recent systematic review, 12 2 studies used actigraphy, 2 studies used polysomnography, and 2 studies used a sleep/wake diary. Importantly, the use of actigraphy in pediatric CFS/ME studies is relatively rare, despite it being recommended as a more ecologically valid and sensitive measure of sleep quality and routine because it is performed in a naturalistic setting (ie, in the individual's home).…”

“…Of note, none of the 6 pediatric CFS/ME studies conducted to date have comprehensively investigated both an objective and validated subjective (selfreport) measure of sleep disturbance. 12 In addition, it is also worth investigating other factors that may be associated with sleep quality such as demographic characteristics (ie, age, sex) and illness characteristics (ie, illness duration, factors that trigger illness, comorbid psychopathology) because these may aid in the identification of individuals with CFS/ME who are especially vulnerable to sleep disturbance. Snodgrass and colleagues reported that no previous study had investigated these characteristics in a pediatric CFS/ ME cohort, despite previous research suggesting that they may play a role in other chronic conditions.…”

“…Snodgrass and colleagues reported that no previous study had investigated these characteristics in a pediatric CFS/ ME cohort, despite previous research suggesting that they may play a role in other chronic conditions. 12,29,30 For instance, selfreported variations in presleep rumination have been shown to predict an increase in actigraphy-measured sleep onset latency 31 suggesting that anxiety-related symptomatology may influence sleep quality in some individuals. Indeed, Knight and colleagues found that 17% of adolescents with CFS/ME had comorbid anxiety based on a retrospective review of medical records, although rates are estimated to be as high as 50% when based on diagnostic interviews and self-report questionnaires.…”