Brain White Matter Tract Microstructural Alterations in Multiple Sclerosis Patients with Depression and Fatigue: A Diffusion Tensor MRI Study (P6.126)

OBJECTIVE: To investigate the topographical pattern of damage to the brain white matter (WM) in MS patients with and without depression and fatigue, by using diffusion tensor (DT) MRI. BACKGROUND: Depression and fatigue frequently co-occur in MS patients, and it has been postulated that they might share common pathophysiologic substrates. DESIGN/METHODS: Brain dual-echo and DT MRI scans were acquired on a 3.0 T scanner from 147 MS patients and 90 gender and age-matched healthy controls (HC). Patients were stratified by the presence of depression (92 depressed [D], 55 non depressed [nD]) and fatigue (81 fatigued [F], 16 non fatigued [nF]) using the Mongomery-Asberg Depression Rating Scale (MADRS) and the Fatigue Severity Scale (FSS), respectively. Whole-brain voxel-wise comparisons of WM fractional anisotropy (FA) were performed using tract-based spatial statistics (TBSS). Track-specific comparisons were run within brain main WM tracts using the standard-space templates provided in the Johns Hopkins Medical Institute tractography atlas. RESULTS: Demographics, disease duration and disability did not differ between D and nD patients, whereas F patients had higher EDSS scores than nF ones. Whole-brain voxel-wise comparisons of FA values between D/nD and F/nF patients yielded no significant results. Patients with concomitant D and F had reduced FA of the forceps minor. Reduced FA of the right anterior thalamic radiation and right uncinate fasciculus were found in F-MS compared with nF-MS patients after correcting for MADRS. After correcting for FSS, no significant differences were found between D/nD-MS patients. CONCLUSIONS: MS patients with co-occurrence of D and F share more severe microstructural alterations of the in the forceps minor compared patients without these symptoms. Abnormalities of the anterior thalamic radiation and uncinate fasciculus were linked to F. Study Supported by: Italian Ministry of Health (GR-2008-1138784).