Paediatric-onset MS impairs information processing in adulthood
Adults who developed multiple sclerosis (MS) in childhood or adolescence had significantly higher odds of impairment and greater decline over time in information-processing efficiency than adults who developed MS later in life, independent of age or disease duration, a large population-based longitudinal cohort study has shown.
The study compared long-term information-processing efficiency between patients with paediatric-onset MS (POMS) and adult-onset MS (AOMS) using data collected between April 2016 and April 2018 by the Swedish MS Registry, which collates information from all 64 neurology clinics in Sweden. Information-processing efficiency was measured every 6 or 12 months using Symbol Digit Modalities Test (SDMT). Registered cases with definite MS and at least two recorded SDMT scores were included in the study. Among the 5,704 patients aged 18–55 years at baseline (median age, 25.6 years for POMS group and 38.3 years for AOMS group; 70.4 percent female) who met the inclusion criteria, 300 (5.3 percent) had POMS. [JAMA Neurol 2019, doi: 10.1001/jamaneurol.2019.1546]
“During the median follow-up period of 3.0 years in adulthood, 70.7 percent of patients with POMS and 59.8 percent of patients with AOMS met the definition for cognitive impairment,” the investigators reported.
After adjustment for sex, age, disease duration, disease course, total number of SDMTs completed, oral or visual SDMT form, and disease-modifying therapy exposure, the SDMT scores for patients with POMS were significantly lower than those of patients with AOMS (β coefficient, −3.59; 95 percent confidence interval [CI], −5.56 to −1.54).
Furthermore, the SDMT scores of patients with POMS declined faster than those of patients with AOMS (β coefficient, −0.30; 95 percent CI, −0.42 to −0.17]), independent of age, disease duration or treatment status. The odds of cognitive impairment were also significantly elevated in the POMS group (odds ratio, 1.44; 95 percent CI, 1.06 to 1.98).
“The differences observed in information-processing efficiency between the POMS and AOMS groups may be a consequence of the heightened inflammation and axonal loss that has been reported in POMS,” the investigators suggested.
“Inflammation of the brain during critical developmental periods, including myelinogenesis in adolescence, may irreparably damage neural networks involved in cognition,” they added.
“We aimed to explore changes in cognitive function over time in adults with POMS relative to adults with AOMS,” stated the investigators. According to them, the study provides the first population-based and longitudinal evidence of the cognitive consequences of POMS for adults.
The investigators concluded that since cognition is a critical component of a person’s ability to work and engage in society, as well as a factor of overall quality of life, children and adolescents who develop MS should be monitored closely for cognitive changes and aided in managing the difficulties that MS poses on educational and work-related achievements.