Patients with pediatric-onset multiple sclerosis (MS) not only have lower cognitive scores in adulthood than patients with adult-onset MS, but cognitive scores declined faster.
While cognitive impairment is common in patients with multiple sclerosis (MS), few studies have examined cognitive outcomes for patients with pediatric-onset MS (POMS) as they enter adulthood. New research has found that patients with POMS are more likely to experience cognitive impairment in adulthood than patients with adult-onset MS (AOMS).
The study compared long-term cognitive outcomes of POMS with those observed in AOMS, which is more common. The study included 5704 patients with MS, 300 of whom had POMS, as defined as having MS onset before 18 years of age. The results of the study were published in JAMA Neurology.
The study included individuals from the Swedish MS Registry. Their cognition was measured using the Symbol Digit Modalities Test (SDMT). The first SDMT assessment was considered the baseline visit and only patients who had at least 2 SDMT scores were included in the study. Patients younger than age 18 and older than age 55 were excluded from the study.
A total of 46,429 SDMT scores were analyzed. SDMT scores range from 0 to 120 with higher scores indicating greater information-processing efficiency. The mean baseline SDMT score was 51.0 and the median follow-up time was 3 years.
The researchers found that SDMT scores between the POMS and AOMS groups were comparable at younger than 30 years; however, the scores began to diverge after that. By age 35, the mean SDMT score for the AOMS group was 60.9 compared with 51.1 for the POMS group; the gap widened slightly at 40 years of age with a mean SDMT score for the AOMS group of 57.5, compared with 46.4 for the POMS group.
During the follow-up time, 70.7% of patients with POMS and 59.8% of patients with AOMS met the definition for cognitive impairment. As time went on, SDMT scores of patients with POMS declined faster than scores for patients with AOMS.
“Cognition is a critical component of a person’s ability to work and engage in society, as well as their overall quality of life,” the authors wrote. “Children and adolescents who develop MS should be monitored closely for cognitive changes and helped to manage the difficulties and challenges that MS poses on scholastic and work-related achievements, with a view to the long-term consequences of MS as they reach adulthood.”
McKay KA, Manouchehrinia A, Berrigan L, Fisk JD, Olsson T, Hillert J. Long-term cognitive outcomes in patients with pediatric-onset vs adult-onset multiple sclerosis [published online June 17, 2019]. JAMA Neurol. doi:10.1001/jamaneurol.2019.1546.