Children who develop multiple sclerosis, a disease that usually strikes during childhood, are more likely to have low IQ scores and cognitive problems, new research shows.

An unpredictable disease of the central nervous system, multiple sclerosis can range from relatively benign to somewhat disabling to devastating, as communication between the brain and other parts of the body is disrupted.

Health experts believe MS is an autoimmune disease – one in which the body, through its immune system, launches a defensive attack against its own tissues. In the case of MS, it is the nerve-insulating myelin that comes under assault. The degeneration of myelin affects nerves by lessening their ability to conduct signals. These problems in nerve transmission cause complications in movement, sensation, cognition, vision and other functions.

MS is also known to cause muscle weakness, severe fatigue, loss of balance and coordination, and depression. Which symptoms affect which patients depends upon the particular nerve transmissions that are interrupted.

According to the U.S. National Institute of Neurological Disorders and Stroke, an estimated 250,000 to 350,000 Americans are believed to have MS. Pediatric MS affects about 8,000-10,000 people under age 18 in the U.S., according to the National Multiple Sclerosis Society.

For the study, a team at the University of Florence in Italy, led by Maria Pia Amato, M.D., measured memory, attention and language abilities in 63 MS patients and 57 healthy controls younger than 18 years of age. The researchers also assessed fatigue and depression in patients and the control group.

In the MS group, the IQ scores were lower than in the placebo group, 5 MS children had an IQ below 70 vs. none of the placebo group. Fifteen of the MS group had an IQ between 70 and 89, vs. 2 children in the placebo group. A total of 19 children with MS (31 percent) met the criteria for cognitive impairment by failing at least three of the tests, while less than five percent of the healthy children failed at least three tests.

The study noted language difficulties in about 30 percent of the children with MS. Language problems are uncommon in adults with the disease.

“Since the disease occurs during a critical phase for language development, children may be particularly vulnerable to language problems. Even subtle language difficulties are likely to have important functional consequences. Therefore…assessment of language function in pediatric MS deserves particular attention in future studies,” Amato wrote.

Also, MS negatively affected school and everyday activities in 56 percent of the subjects. Three fourths of the patients met criteria for significant fatigue. Additionally, patients had a depression prevalence of 6 percent.

Amato said that treatment of very young children may be more effective, given the fact that their brain is in a continuous development.

“I would like to highlight that treatment and support may help the subjects and the families to cope with their psychosocial difficulties. Therefore, early recognition of problems and intervention strategies, both rehabilitative and pharmacological, may lead to a better outcome,” she said, as quoted by Reuters.

The study, supported in part by a grant from Biogen-Dompe, a manufacturer of medications fro MS, was published in the May 13, 2008 issue of Neurology, the medical journal of the American Academy of Neurology.