BANGKOK, THAILAND – Far from affecting only white matter, multiple sclerosis seems to strike at gray matter as well, causing atrophy of brain structures that correlates with disease duration and declining cognitive function.
“Traditionally, multiple sclerosis has been considered a white matter disease, but recent literature suggests an involvement of the gray matter as well, causing atrophy of particular brain regions,” Asaf Achiron said at the World Congress of Neurology.
Mr. Achiron, a fifth-year medical student, presented the results of an imaging study of 38 adults with relapsing-remitting multiple sclerosis, in which he tracked volumetric changes in specific brain regions as the disease progressed. The research was part of the Arrow Project, a student/professor collaboration in Tel Aviv University. Mr. Achiron's mentor, Dr. Ida Sarova-Pinhas, is a neurologist at The Chaim Sheba Medical Center, Tel Hashomer, Israel, and at Tel Aviv University.
The collaborators used a computerized imaging program called FreeSurfer to determine thickness and volume of the cerebral cortices, thalami, and hippocampi of their subjects. FreeSurfer is a set of automated tools that can reconstruct the brain's cortical surface from structural MRI data and overlay functional MRI data onto the reconstructed surface.
The study group consisted of 38 patients with relapsing-remitting MS, 24 of whom were women. Those with short disease duration (fewer than 5 years) were an average age of 33 years, with an average disease duration of 2 years. Those with longer disease duration (more than 5 years) were an average age of 36 years with an average disease duration of 11 years. Significant differences were found in the neurologic disability of those with shorter compared with longer disease duration.
In addition to undergoing MRI studies, the patients completed an online cognitive assessment called the Neurotrax Mindstreams Computerized Cognitive Battery (www.neurotrax.com
Mr. Achiron and Dr. Sarova-Pinhas found that, compared with patients with longer disease duration, patients with shorter duration disease had significantly larger volumetric measurements of the right cerebral cortex (274 vs. 245 cc) and left cerebral cortex (276 vs. 247 cc) and the right and left hippocampi (both 4.7 vs. 4.3 cc). While the differences were not significant, the right thalamus was larger in the group with shorter disease duration (7.4 vs. 7.0 cc), as was the left thalamus (7.8 vs. 7.4 cc).
“My feeling is that if we had a larger group, we might have reached significance,” in thalamic volume difference, Mr. Achiron said.
In the cognitive testing, patients with short duration of disease had significantly better scores in global cognition, visual spatial perception, and executive function than did those with longer disease duration.
“This loss of gray matter is a complement of the axonal loss and the genesis of symptomatic progression in MS,” Mr. Achiron said. “Identification of these specific areas of loss has clinical relevance for understanding the associated cognitive changes.”
FreeSurfer software, developed by the National Institutes of Health, is available for free download at http://surfer.nmr.mgh.harvard.edu/
The Arrow Project is a research program for medical students held in the Multiple Sclerosis Center at Sheba Medical Center, Tel Hashomer. Its aim is to strengthen students' knowledge and practice, and train them to be better physicians and researchers. Students are matched with a mentor and together, they choose a study topic and work on its design, literature review, and methodology.
This year, 10 students, including Mr. Achiron, are involved in the program (http://medical-students.ny.sheba.co.il/
◊ To watch a video interview of Mr. Achiron, go to www.youtube.com/watch?v=2gfzYiwacaw
Vitals
Major Finding: Volumetric measurements of the cerebral cortex and hippocampus declined with disease duration in multiple sclerosis.
Data Source: Imaging study of 38 adults with relapsing-remitting multiple sclerosis.
Disclosures: None.