Multiple sclerosis symptoms may be single or multiple and could range from mild to severe intensity with the duration also differing. Experts share that multiple sclerosis activity possibly augments during spring and summer months. They compared MRI brain scans of 44 individuals from 1991 to 1993 to the weather data collected during the same period. Participants enlisted for the study aged between 25 and 52 years with who experienced multiple sclerosis.

Each individual included in the analysis had eight weekly scans. Further, they underwent eight scans every other week continued by six monthly check-ups for an average of 22 scans per person. The weather information gathered for the study included daily temperature, solar radiation and precipitation measurements for the Boston area.

“Our results showed that the appearance of lesions on brain scans was two to three times higher in the months of March to August, compared to other months of the year,” remarked study author Dominik Meier, PhD, of Brigham and Women’s Hospital in Boston and a member of the American Academy of Neurology.

After around one year, 310 new lesions were examined among 31 people however, thirteen people had no new lesions during the analysis. Experts not only observed greater lesions during spring and summer, they also revealed that warmer temperatures and solar radiations were associated to disease activity. Besides, there was no relation observed between precipitation and lesions.

“This is an important study because it analyzes records from the early 1990’s, before medications for relapsing MS were approved, so medicines likely could not affect the outcome. A study like this probably won’t be able to be repeated,” commented Anne Cross, MD, with the Washington University School of Medicine in St. Louis, who wrote an editorial about the study. Cross is also a member of the American Academy of Neurology. “Future studies should further explore how and why environmental factors play a role in MS.”

Scientists share that clinical trials usually adopt MRI to evaluate the efficiency of a drug and the analysis generally last between six to twelve months. If the analysis was carried out from spring to winter, it may show that lesions lowered due to drug effect, but apparently the main reason may be change of season. The opposite may occur if the analysis began in winter and lasted through the spring and summer.

These findings were published in the August 31, 2010 issue of Neurology.