Functional MRI (fMRI) has shown that cognitive rehabilitation changes brain function and improves cognitive performance in patients with relapsing-remitting multiple sclerosis (MS), according to a study published in the March issue of Radiology.
“These results prompt the use of specific computer-based rehabilitation programs to treat deficits in selected neuropsychological domains in patients with relapsing-remitting MS,” Massimo Filippi, MD, professor of neurology at San Raffaele Vita-Salute University in Milan, said in a statement. “They also suggest that fMRI might provide useful metrics to monitor the effects of rehab in MS.”
Filippi and colleagues studied 20 patients with relapsing-remitting MS, randomized into two groups, with half receiving a 12-week program of computer-assisted cognitive rehabilitation of attention and information processing and executive function, and the other half serving as a control with no cognitive rehabilitation. All patients underwent neuropsychological assessment and MRI exams at baseline and after 12 weeks.
The rehabilitation program included a day-planning task, which employed realistic simulations of a set of scheduled dates and duties to address the patient's ability to organize, plan and develop solution strategies; and an attention task requiring the patient to simulate driving a train, carefully observing the control panel of the train and the countryside while encountering several distractions at increasing levels of difficulty.
As compared to their performance at baseline, the patients in the treatment group improved in tests of attention and information processing and executive functions. The fMRI results showed modifications in activity in several brain regions—the posterior cingulate cortex, anterior cingulum and dorsolateral prefrontal cortex, among others—in the rehabilitation group, compared to the non-rehabilitation group. These fMRI modifications were correlated with cognitive improvement.
Analysis after cognitive rehabilitation found no structural changes in the gray matter or normal-appearing white matter of the brain in the treatment group.
Since active fMRI results are greatly influenced by individual task performance, the researchers also performed resting-state fMRI. Significant treatment effects were seen in several cognitive-related resting-state networks, indicating an increase in activity over time in the treatment group but decreasing activity in the control group.
“In healthy individuals, resting-state network activity tends to remain stable over a period of several weeks, while a reduction of activity within selected regions at rest has been associated with worsening of cognitive performance after three years in patients with mild cognitive impairment,” wrote the authors. “As a consequence, the increased activity we found at rest in our patients might reflect the occurrence of compensatory mechanisms.”
The authors were surprised to find no structural changes in gray matter and normal-appearing white matter in the treatment patients. Recent research had demonstrated a positive correlation between an increase in gray matter volumes and fMRI activation after two weeks of mirror reading in healthy subjects.
“Such a negative finding might reflect an impairment of structural plasticity in these patients, which is likely caused by the MS pathologic process,” wrote the authors. “On the basis of our findings, we speculate that the lack of a concomitant modification of functional and structural plasticity might contribute to explain the relatively short persistence of the positive effects of rehabilitation usually observed in patients with MS.”