Thursday March 30 7:44 PM ET
NEW YORK, Mar 30 (Reuters Health) -- Over time, the brains of multiple sclerosis (MS) patients shrink, and in some patients the degree of shrinkage can predict the worsening of symptoms, researchers report.
"Our major findings were that total brain (shrinkage) was significantly greater in the patients with MS than in the (healthy) control subjects," according to Dr. Robert L. Grossman from the University of Pennsylvania in Philadelphia, and associates.
The authors used sophisticated magnetic resonance imaging (MRI) software to determine the percentage of area within the skull occupied by brain tissue (PBV, a measure of brain atrophy or shrinkage) in 36 patients with MS and in 20 healthy individuals. The MS patients were retested over periods ranging from 1 to 7 years. The authors also compared the MRI results with disability scores measured by the expanded disability status scale (EDSS).
At the outset of the study, the average PBV was significantly smaller in the MS patients (85.5%) than in the controls (88.2%), the authors report.
There were no significant differences in any measure between the two types of MS patients (27 patients with relapsing-remitting MS and 9 patients with secondary progressive MS), according to the results.
The average PBV fell significantly over time for all patients (1.6% loss per year), for patients with relapsing-remitting MS (1.5% loss per year), and for patients with secondary progressive MS (2.0% loss per hear), the researchers observe.
Only for the patients with secondary progressive MS, though, did EDSS scores change in line with their brain shrinkage, the report indicates.
Even though they did not measure brain shrinkage in the control subjects over time, the investigators explain, the average loss of brain tissue in MS patients (about 18 mL or two-thirds of an ounce a year) appears to be nine times greater than that seen with normal aging (0.7-2.0 mL per year), but less than half that with Alzheimer's disease (40.0 mL per year).
Chronic, progressive brain shrinkage in patients with long-standing
MS may be a predictor of increasing disability, Grossman and colleagues
conclude. "Longitudinal (measurement) of brain volume loss in patients
with MS may therefore represent a sensitive and highly reproducible means
of following and predicting clinical response to drug therapy in MS treatment
SOURCE: Radiology 2000;214:665-670.