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Pediatric MS causes more deficits than other myelin disorders
By LOIS BAKER
Contributing Editor
Pediatric multiple sclerosis researchers at UB are working to define and better understand previously unappreciated and uncommon types of childhood demyelinating disorders, including MS, to improve treatment approaches.
In the first comparison of children with MS with those diagnosed with conditions called monophasic demyelinating disorders, they have shown that children with MS have greater social and cognitive deficits and that the specific cognitive areas affected are similar to those found in adult MS patients.
Joy B. Parrish, clinical instructor of neurology and lead researcher on the study, presented the results at the 2008 American Academy of Neurology meeting.
“A monophasic disorder means that there is just one occurrence of demyelination,” said Parrish, “while MS is characterized by recurrent demyelinating events.” Demyelination occurs when the body's immune system attacks the myelin, the sheath that protects and insulates nerve fibers. Breaks in the myelin disrupt the flow of electrical impulses, causing loss of sensation and coordination.
“There are several specific monophasic disorders, such acute disseminated encephalomyelitis [ADEM] and optic neuritis,” she noted. Optic neuritis is an inflammation of the optic nerve that can result in a complete or partial loss of vision.
“It could be the case that if a patient with a monophasic disorder had another demyelinating event, they would meet criteria for MS, but there are specific diseases and disorders in which there are recurrent demyelinating events that do not meet criteria for MS,” said Parrish.
“In other words, some patients with a monophasic disorder will have another event, but some will not, and some with another demyelinating event will be diagnosed with MS, but not all.”
The main purpose of the study was to describe areas of cognitive functioning that may be impacted by both monophasic disorders and MS because of limited research examining cognitive functioning in children with MS or other demyelinating disorders, Parish noted.
The study also compared the groups with recurrent demyelinating events who are diagnosed with MS and those with only one demyelinating event to determine if having multiple events further impacts functioning.
Ten children with MS were in the study, along with 12 children with monophasic demyelinating disorders. Results showed that MS patients performed worse on tests of working memory, phonemic decoding (the ability to hear specific sounds and represent those sounds with symbols), processing speed and visual-motor sequencing (integrating perceptual and motor skills), despite comparable IQ.
Children with MS had more trouble making decisions and carrying them out, known as "executive function," than children with monophasic demyelinating disorders, parents and teachers reported, and they had more difficulty with physical, emotional, social and school functioning.
“These preliminary findings are consistent with adult MS literature, suggesting specific deficits in processing speed and working memory,” noted Parrish. “The greater deficits in MS patients may reflect greater lesion burden, early brain atrophy or other disease processes that distinguish these disorders. “Worse perceived quality of life found in MS children possibly reflects neurocognitive difficulties and self-image concerns.
“Longitudinal assessment and examination of associated neuroimaging findings will improve our understanding of the progression and unique features of each disorder,” Parrish said.
Eluen A. Yeh, Lisa A. Jackson, Ralph H.B. Benedict and Bianca Weinstock-Guttman, all from UB, were major contributors to the study.
The research was supported by a grant from the National Multiple Sclerosis Society to Weinstock-Guttman.