Neuropsychological functioning in pediatric multiple sclerosis: A longitudinal investigation of cognitive performance and the contribution of primary clinical factors
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that has been historically regarded as an adult medical condition. In recent years, however, the occurrence of MS among pediatric patients has been increasingly recognized, with an estimated one-third of patients exhibiting significant cognitive impairments. With that said, research devoted to understanding the nature, prevalence, and severity of MS symptomology in pediatric patients remains limited. To date, only two longitudinal studies exploring the evolution of cognitive functioning among pediatric cohorts have been published. Moreover, while adult studies have investigated the impact of neurologic impairment, disease duration, and relapse rate on cognitive performance, the relationship between primary clinical factors and cognitive dysfunction in pediatric patients remains elusive. The present study assessed individual and group-level changes in cognitive functioning in a cohort of pediatric MS patients (n = 20) across a mean period of 14.65 months using a brief neuropsychological battery. The study employed the Reliable Change Index (RCI) and Binomial Probability Distribution (BPD) methods in addition to a repeated measures multivariate analysis of variance (MANOVA) to accomplish this goal. The study also explored the relationship between cognitive performance and various clinical factors, including age at onset, relapse rate, disease duration, fatigue, and depression using a stepwise linear regression analysis. Examination of individual cognitive trajectories revealed more improvements than declines in performance, although 45% of participants met criteria for significant cognitive impairment. Declines in working memory, visual scanning and sustained attention, immediate verbal learning, and visual perception were most pronounced; whereas, motor-based processing speed and verbal fluency were largely preserved. Group-level analyses revealed significant declines in working memory, with noted improvements in visual scanning and motor speed. Several relevant clinical variables were noted to predict performance on Digit Span, SDMT, CVLT, TMT A, GPT, and Beery VMI. The directionality and interpretability of these predictive relationships, however, varied widely. Taken together, this study contributes to what is known about the impact of pediatric MS and associated clinical factors on cognitive functioning across time. Results support the use of routine neuropsychological screenings to monitor functioning and inform educational and treatment planning.