June 04, 2002
In a recent analysis, investigators attempted to measure whether altered cortical activation during a sustained attention task occurs along with a limited extent of neuropsychological problems in multiple sclerosis (MS) patients.
The group of researchers led by Dr. Wolfgang Staffen performed a psychometric assessment using the Wechsler Memory Scale (WMS) and the Multiple Sclerosis Functional Composite Score (MSFC) in 21 patients with clinically definite relapsing-remitting MS. Functional MRI was also performed during a Paced Visual Serial Addition Task (PVSAT), which is a visual analog of the Paced Auditory Serial Addition Task (PASAT).
All study participants were within 3 years of diagnosis and none of them were in relapse at the time of the study.
The patients were compared with a control group of 21 healthy volunteers who were matched for handedness, age, years of education, and sex.
Psychometric results showed that patients and controls had statistically significant differences in WMS general memory scores. However, no differences were noted for either the MSFC or PASAT scores.
Additionally, results from a group analysis of the functional imaging data during the PVSAT revealed different activation patterns for patients and controls.
The main activation in healthy volunteers was observed in the frontal part of the right gyrus cinguli (Brodmann area 32), whereas in MS patients, it was detected at the right hemispheric frontal cortex (Brodmann areas 6, 8, and 9). Moreover, the left hemispheric Brodmann area 39 was activated.
We interpret the different patterns of activation, accompanied with intact performance in a sustained attention task of our [MS] sample compared with healthy controls, as the consequence of compensatory mechanisms, the authors wrote. This is an expression of neuronal plasticity during early stages of a chronic disease. (Brain 2002;125:1275-82.)
© FWI 2002