Children with multiple sclerosis (MS) recover more quickly and “significantly better” from relapses than do adults — patients with disease onset at age 18 or older, researchers reported.
The study, “Improved relapse recovery in paediatric compared to adult multiple sclerosis,” was published in the journal Brain.
Relapses and incomplete relapse recovery contribute to increasing disability in MS. In fact, data suggest that patients who fail to recover completely from a first relapse are at greater risk of transitioning more quickly to secondary progressive MS.
Age is known to affect relapse frequency, with children likely to experience two to three times more relapses than adults.
But disability worsening, as measured by increasing expanded disability status scale (EDSS) scores, is typically slower in pediatric patients.
Researchers at Massachusetts General Hospital and colleagues investigated how age affects relapse recovery in a large group of children and adults with MS.
They analyzed data on 632 adults, ages 18 or older, with MS (76.7% women) enrolled in the Comprehensive Longitudinal Investigation of Multiple Sclerosis at Brigham and Women’s Hospital (CLIMB) study, and 132 children (65.6% girls) in the U.S. Network of Paediatric Multiple Sclerosis Centers (NPMSC) registry. Disability was evaluated based on EDSS scores determined within 30 days of relapse onset, and again six months later.
Specifically, researchers looked for changes in EDSS scores between the attack (baseline scores) and those at a six-month follow-up exam. Improvements in EDSS were defined as a decline in these scores at follow-up compared with baseline.
Changes in four functional systems were also assessed: vision, pyramidal function (a measure of fine motor skills), brainstem function, and cerebellar function. The brainstem is a region at the base of the brain that regulates vital functions (e.g., heart rate, respiration), as well as sensory perception and movement. The cerebellum region of the brain coordinates voluntary movements, such as balance, coordination, and speech.
At the time of a relapse, the median EDSS was 2.0 in both groups, meaning minimal disability in one functional system. Changes in EDSS at follow-up, however, were significantly lower in children compared to adults.
Results showed that recovery in EDSS scores drop by 0.15 points for every additional 10 years of age. This age-dependent recovery was also seen with functioning of the brainstem and cerebellar brain regions. Among younger patients, improvements in EDSS scores were more pronounced in boys.
Improvements after a relapse were also seen to significantly differ between these patient groups, with children showing significant improvements in EDSS scores, and in pyramidal, brainstem, and cerebellar function after a relapse compared with adults.
Finally, researchers asked “whether patients returned to normal after a relapse.” Around 20% of those under age 20 saw their EDSS scores return to normal, or an EDSS of zero at follow-up, with this percentage decreasing for every 10-year increase in age. With every 10 additional years, the probability of a patient’s EDSS not returning to normal rose by 1.33 times.
These results show that “children recover significantly better from relapses than adults with multiple sclerosis, despite the prior observations that younger age is associated with a higher relapse rate at baseline,” the researchers wrote.
Multiple factors may account for this age difference in recovery, they added, ranging from a “differing intensity or composite of immunological insult,” to “lesser axonal damage or demyelination in children” or better remyelination.
“This study serves as a basis to investigate age-associated recovery, which may lead to new insights and therapeutic targets for relapse-related disability and progressive multiple sclerosis,” the team concluded.
