FMRI Correlates of Sustained Attention in Pediatric Multiple Sclerosis (P2.250)

OBJECTIVE: To assess fMRI abnormalities during a sustained attention task in pediatric patients MS and their correlations with cognitive dysfunction. BACKGROUND: The Continuous Performance Test (CPT) is commonly administered to test sustained attention and vigilance in pediatric populations. DESIGN/METHODS: fMRI scans were acquired in 58 pediatric MS patients and 14 matched healthy controls (HCs) during the administration of the Conners’ CPT (inter-stimulus interval=1, 2, 4 s). Patients with > 2 abnormal tests at neuropsychological evaluation were classified as cognitively impaired (CI). Areas showing increasing activations/deactivations with increasing task difficulty were identified creating a “load” linear contrast (SPM8). RESULTS: Twenty (34.5[percnt]) pediatric MS patients were CI. During the “load” condition, all participants showed activations of bilateral parietal regions, middle frontal gyrus, supplementary motor area (SMA), right lingual gyrus and precuneus. Compared to HC, MS patients had increased activation of left insula, anterior cingulate cortex and right inferior frontal gyrus, and a reduced activation of right precuneus and paracentral lobule. Compared to HC and CI, CP MS patients showed increased activation of left thalamus, inferior temporal and lingual gyri. Compared to the other two groups, CI MS patients had increased recruitment of the bilateral superior medial frontal gyrus, left SMA and right inferior frontal gyrus and cerebellum. They also experienced a reduced activation of the right postcentral gyrus (PCG). Better performance during CPT correlated with increased activity if the right precuneus and PCG, while worse CPT performance correlated with increased activity in frontal regions. CONCLUSIONS: During an attentive task, CI and CP pediatric MS patients recruited different brain area with increasing task demand. The increased fMRI activity in frontal regions seen in CI MS patients is likely to be a maladaptive mechanism, associated to cognitive impairment. Study Supported by: Partially supported by a grant from Italian Ministry of Health (GR-2009-1529671).