DALLAS March 20, 2008 A bodysuit that heats or cools a patient, combined with painless measurements of eye movements, is providing multiple sclerosis researchers at UT Southwestern Medical Center with a new tool to study the mysterious link between body temperature and severity of MS symptoms.
The researchers studied an aspect of MS called Uhthoffs phenomenon, named for the German ophthalmologist who reported in 1889 that some people have temporary vision problems after exercise or in hot weather. This and other symptoms of MS, such as fatigue or problems with coordination, worsen in the heat for most people with the disease.
Although doctors and researchers have long known about Uhthoffs phenomenon, there has been no way to objectively measure its severity or how it is related to body temperature.
The UT Southwestern study, available online and appearing in the March 25 edition of the journal Neurology, demonstrated that as body temperature rises, the severity of an eye-movement disorder called INO, or internuclear ophthalmoparesis, also increases. When a person with INO looks rapidly from one object to another, one eye moves more slowly than the other. Normally, the eyes move at the same speed.
INO can serve as an easy-to-measure canary in a coal mine, acting as a surrogate for other heat-related symptoms that are harder to measure, such as fatigue, mental confusion or bladder or bowel problems, said Dr. Elliot Frohman, professor of neurology and ophthalmology, director of the Multiple Sclerosis Program and Multiple Sclerosis Clinical Center at UT Southwestern and senior author of the study.
The researchers tools were a whole-body suit, riddled with tubes for circulation of water, that can change body temperature; a pill-like thermometer that measures core body temperature after being swallowed; and an infrared camera that painlessly tracks eye movements.
The study, conducted at UT Southwester
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UT Southwestern Medical Center