Abstracts

Rationale: Functional Magnetic Resonance Imaging (fMRI) is a neuroimaging technique commonly used to localize language and motor areas in the presurgical workup for epilepsy surgery. However, fMRI requires the subject’s cooperation and comprehension. Considering that patients with cognitive delay may have behavior problems, performing fMRI may become a challenging task. We demonstrate here the feasibility to perform fMRI in epileptic patients with cognitive impairment. Methods: Fifteen epileptic patients underwent language or motor fMRI for surgical planning. Eight patients underwent language task for fMRI, 4 patients underwent both language and motor tasks, and 3 patients underwent only motor task. Language tasks were constituted of the tasks of verbal fluency. In the first task, the patients were asked to quietly generate as many elements as possible from a specific category (eg. fruits) until cued to stop. In the second task, patients were asked to think silently of as many words as possible starting with a specified letter. The motor tasks were finger tapping or flexion and extension finger, depending of motor impairment. Images were acquired in a 1.5T scanner (Siemens, Magneton-Vision) with EPI-BOLD sequences. Statistical maps were analyzed in Brain Voyager QX 1.8 software, using the GLM. In both tasks, paradigms of six blocks of 27 seconds of rest were interleaved with five blocks of activity. Results: All patients presented mental retardation with IQ < 69, mean IQ 59 (range 46-69), mean age 17,1 (range 5-31 years), mean years of school variable 3,4 years (range 1-7). Three patients were left handed and 12 right handed. Our results showed activation in at least one task in 12 (80%) patients, and no activation in 3 patients (20%), probably due to movement artifacts. The most activated brain regions during language tasks were frontal and prefrontal-areas Brodmann 9, 44, 45, 46, 47 and in temporal-areas Brodmann 21, 22, 41 and 42, and the activated regions during motor tasks were perirolandic areas. Conclusions: Our study demonstrated the feasibility to perform fMRI in epileptic patients with cognitive impairment. This successful approach was probably due to the patient’s training before the scanning, but also depending on a minimum collaboration of them. In this setting, patients with more severe cognitive impairments may not be able to undergo fMRI. Nevertheless, fMRI should always be tried in epileptic patients with mild and moderate cognitive impairments as their findings could avoid postsurgical language and motor deficits.