Characterizing the Neuropsychological profile and Examining the Role of Cognitive Reserve in Pediatric-Onset Multiple Sclerosis Using a Computerized Battery

Multiple sclerosis (MS) is a chronic demyelinating and degenerative condition of the central nervous system. While the majority of affected individuals show their first symptoms between the ages of 25-35 years, 3-5% of people have a pediatric-onset (POMS) of the disease, with a first attack occurring prior to age at 18. POMS leads to a range of physical and cognitive symptoms that impact everyday functioning and development, however, further research is needed to understand the cognitive profile and predict outcomes.

The overall objective of this program of research was to better understand processes facilitating protection against the cognitive presentation of neuropathology in POMS, with a specific focus on cognitive reserve (CR) and its domain-specificity. Areas of deficit in POMS were first clarified, with delineation of dysfunction in speed and accuracy across cognitive domains using a computerized neurocognitive battery. In Study 1, we found that deficits in working memory, attention/inhibition, visuospatial processing, verbal recognition memory and verbal reasoning exist separately from and in addition to slowed speed of processing in individuals affected by POMS. Furthermore, we found that individuals with POMS are afforded some protection by CR (as estimated by parental education) in Study 2, however, these affects appeared weaker than what has been observed in adults. CR effects were strongest for tasks of executive functioning, where patients demonstrated greatest deficit relative to controls, and were not observed for tasks of information processing speed, potentially owing to differential availability of compensatory strategies in these networks.

These findings highlight differences in vulnerability to cognitive dysfunction in individuals with POMS, given impacts of the disease on developing functions and reserves. We propose that cognitive screening should be expanded beyond assessment of simple processing speed to identify a greater proportion of youth affected by the cognitive sequelae of MS. While the mechanisms contributing to the development of CR remain to be elucidated, engagement in a range of physically and cognitively enriching activities, as well as a focus on mental health may be helpful towards better cognitive outcomes for youth with POMS. Further research is needed with direct comparison to adults with MS to understand how the developmental context influences the profile of cognitive deficits and role of protective factors in POMS.