What lies beneath: White matter microstructure in pediatric myalgic encephalomyelitis/chronic fatigue syndrome using diffusion MRI.

Recent studies in adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) suggest that changes in brain white matter microstructural organization may correlate with core ME/CFS symptoms, and represent a potential biomarker of disease. However, this has yet to be investigated in the pediatric ME/CFS population. We examined group differences in macrostructural and microstructural white matter properties, and their relationship with clinical measures, between adolescents recently diagnosed with ME/CFS and healthy controls. Forty-eight adolescents (25 ME/CFS, 23 controls, mean age 16 years) underwent brain diffusion MRI, and a robust multi-analytic approach was used to evaluate white and gray matter volume, regional brain volume, cortical thickness, fractional anisotropy, mean/axial/radial diffusivity, neurite dispersion and density, fiber density, and fiber cross section. From a clinical perspective, adolescents with ME/CFS showed greater fatigue and pain, poorer sleep quality, and poorer performance on cognitive measures of processing speed and sustained attention compared with controls. However, no significant group differences in white matter properties were observed, with the exception of greater white matter fiber cross section of the left inferior longitudinal fasciculus in the ME/CFS group compared with controls, which did not survive correction for intracranial volume. Overall, our findings suggest that white matter abnormalities may not be predominant in pediatric ME/CFS in the early stages following diagnosis. The discrepancy between our null findings and white matter abnormalities identified in the adult ME/CFS literature could suggest that older age and/or longer illness duration influence changes in brain structure and brain-behavior relationships that are not yet established in adolescence.

Health, Wellbeing, and Prognosis of Australian Adolescents with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Case-Controlled Follow-Up Study.

BACKGROUND: The purpose of this study was to follow-up an Australian cohort of adolescents newly-diagnosed with ME/CFS at a tertiary paediatric ME/CFS clinic and healthy controls over a mean period of two years (range 1-5 years) from diagnosis. Objectives were to (a) examine changes over time in health and psychological wellbeing, (b) track ME/CFS symptomatology and fulfillment of paediatric ME/CFS diagnostic criteria over time, and (c) determine baseline predictors of ME/CFS criteria fulfilment at follow-up. METHODS: 34 participants aged 13-18 years (25 ME/CFS, 23 controls) completed standardised questionnaires at diagnosis (baseline) and follow-up assessing fatigue, sleep quality and hygiene, pain, anxiety, depression, and health-related quality of life. ME/CFS symptomatology and diagnostic criteria fulfilment was also recorded. RESULTS: ME/CFS patients showed significant improvement in most health and psychological wellbeing domains over time, compared with controls who remained relatively stable. However, fatigue, pain, and health-related quality of life remained significantly poorer amongst ME/CFS patients compared with controls at follow-up. Sixty-five percent of ME/CFS patients at baseline continued to fulfil ME/CFS diagnostic criteria at follow-up, with pain the most frequently experienced symptom. Eighty-two percent of patients at follow-up self-reported that they still had ME/CFS, with 79% of these patients fulfilling criteria. No significant baseline predictors of ME/CFS criteria fulfilment at follow-up were observed, although pain experienced at baseline was significantly associated with criteria fulfilment at follow-up (R = 0.6, p = 0.02). CONCLUSIONS: The majority of Australian adolescents with ME/CFS continue to fulfil diagnostic criteria at follow-up, with fatigue, pain, and health-related quality of life representing domains particularly relevant to perpetuation of ME/CFS symptoms in the early years following diagnosis. This has direct clinical impact for treating clinicians in providing a more realistic prognosis and highlighting the need for intervention with young people with ME/CFS at the initial diagnosis and start of treatment.