Vest Test Ices MS Symptoms
But study critics throw cold water on results
MONDAY, Sept. 10, 2001 (HealthDayNews) -- Can a vest like the one used to cool astronauts in space help multiple sclerosis (MS) patients? A tiny Dutch study says yes, but critics say the study was poorly designed and too small to draw any conclusions as to why.
The 10-person study found that the $1,195 cooling vest helps MS patients with muscle strength, fatigue and balance. The findings will be published tomorrow in Neurology, the scientific journal of the American Academy of Neurology.
About 80 percent of MS patients say their symptoms get worse when it's hot and get better when they feel cooler. NASA originally developed cooling garments to dissipate the body heat of astronauts in space by circulating coolant fluid. In later research, a variation of the cooling garments seemed to help relieve symptoms in MS patients.
In this latest study, researchers at University Hospital in Groningen, Netherlands, documented the responses of 10 patients (five men and five women, ages 21 to 55) who wore cooling vests for an hour. Half of the patients received a high level of cooling, with the vest temperature set at 45°F. The other half experienced lesser cooling at a temperature of 79°F. The vest temperatures of the groups were then reversed.
Researchers tested the subjects' fatigue level, balance and muscle strength before cooling and three hours after. On average, balance improved by 20 percent for patients who received the higher cooling while muscle strength improved by an average of 10 percent. They also felt less tired.
"We were unable to detect any lowering of the core body temperature -- not unexpected because our body has compensatory mechanisms to keep temperature within normal limits," says study author Dr. Jacques De Keyser, a neurologist.
But perhaps more notably, he says much less nitric oxide was made by their white blood cells. MS patients normally have much higher levels of the compound, but it decreased by 41 percent in those who had the coolest vests. This may mean that less nitric oxide, not body temperature, relieved their symptoms. "In addition, improvement of symptoms persisted for hours after cooling. This was the reason for us to suspect a metabolic mechanism," says De Keyser. "Cooling may improve symptoms through reducing leukocyte nitric oxide production in MS patients."
Nitric oxide plays many roles in human biology; it is a critical regulator of blood flow and clotting; it's a main nerve messenger chemical controlling erectile function, and it's a major factor in inflammation and immunity.
Other experts in the field are divided about the findings. "It's an extraordinarily small study and appears to be poorly designed," says Stephen Reingold, vice president for research programs at the National Multiple Sclerosis Society.
"I don't think this study breaks a lot of new ground in terms of therapeutic applications," says Dr. Aaron Miller, director of the division of neurology and of the MS Care Center at Maimonides Medical Center in Brooklyn, N.Y. "What's different is that it suggests a mechanism of action for these vests that's not related to core body temperature."
The issue seems not to be whether the expensive cooling uniforms will help MS patients, but whether nitric oxide is a fruitful area for more research. If so, it may lead to developing drugs that can tinker with that mechanism.
"This is fascinating," says Dr. Jack Burks, clinical professor of medicine (neurology) at the University of Nevada School of Medicine and medical director of the Washoe Institute for Neurosciences in Reno. "This makes more sense than the current thinking on cooling, because the core temperature doesn't decrease all that much even though patients consider themselves helped. It makes sense that this could happen. It seems like a reasonable hypothesis to me."
Others are more circumspect in their praise. "We don't know everything about nitric oxide. It has good aspects and bad aspects," says Dr. Pierre Duquette, professor of neurology at the University of Montreal. "If you start lowering it, you will hurt other cell processes."
"Nitric oxide is an interesting hypothesis, but there's no data to definitively support the hypothesis," says Reingold. "It's a small, hot area of research, but the connection between cooling and nitric oxide as having an impact on conduction is more hypothetical than real. It may have a role; it may not."
What To Do
For more information on cooling vests and cooling technologies, visit MSAA.