Children who develop multiple sclerosis (MS) at an early age are more likely to have a low IQ and be worse at thinking skills and paying attention, according to research published in Neurology.
The study, conducted by Maria Pia Amato MD of the University of Florence, compared 63 children under the age of 18 who had MS to 57 of similar ages who were healthy.
Participants were asked to take 17 tests to measure their intelligence, memory, language abilities and thinking skills.
Five of those with MS had IQs of less than 70 and 31 per cent met the criteria for cognitive impairment by failing at least three of the tests.
None of the healthy children had an IQ below 70 and less than five per cent failed three or more tests.
Ms Amato said children may be particularly susceptible to language problems when the disease occurs during a critical phase for language development.
"It's possible that MS can show an even more dramatic effect on the thinking skills and intelligence in children than in adults, since the disease might affect the brain at a time when it is still developing," she said.
"We need to understand how the disease affects kids so we can help them manage their difficulties and academic challenges."
An estimated 85,000 people in the UK have MS according to the Multiple Sclerosis Society.