Fatigue and its relationships with cognitive functioning and depression in paediatric multiple sclerosis

Background: There is limited information on fatigue and its clinical and psychosocial correlates in children and adolescents with multiple sclerosis (MS). Objective: To assess the relationships between fatigue, cognitive functioning and depression in paediatric MS. Methods: The study cohort consisted of patients with MS recruited for an Italian collaborative study on cognitive and psychosocial functioning in paediatric MS. The present assessment included evaluation of fatigue on the Pediatric Quality of Life Inventory-Multidimensional Fatigue Scale, cognitive functioning on an extensive neuropsychological battery and depression on the Children's Depression Inventory (CDI). A psychiatric interview through the Kiddie-SADS-Present and Lifetime Version was also administered. Results: In total, 57 patients with relapsing-remitting MS were compared with 70 healthy controls. Percentages of fatigued patients ranged from 9% to 14% according to self-reports, and from 23% to 39% according to parent reports. Fatigue was significantly related with higher scores on the CDI (p < 0.03). Higher levels of self-reported cognitive fatigue were associated with impaired performance on a problem-solving test, whereas higher levels of parent-reported cognitive fatigue were associated with impairment on tests of verbal learning, processing speed, complex attention and verbal comprehension. Conclusions: Our data show that fatigue can affect a sizeable proportion of paediatric MS patients, and confirm the association between fatigue and depressive symptoms in MS. They also highlight the difficulties of fatigue assessment in the paediatric population and provide a few clues to further research in the field