The level of spinal cord involvement influences the pattern of movement-associated cortical recruitment in patients with isolated myelitis Maria A. Rocca, a,b Federica Agosta, a,b Vittorio Martinelli, b Andrea Falini, c Giancarlo Comi, b and Massimo Filippi a,b, * a Neuroimaging Research Unit, Scientific Institute and University Ospedale San Raffaele, Milan, Italy b Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy c Department of Neuroradiology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy Received 18 August 2005; revised 6 October 2005; accepted 10 October 2005 Available online 22 November 2005 Using fMRI, an increased recruitment of the ipsilateral primary sensorimotor cortex (SMC), supplementary motor area, and middle frontal gyrus has been detected in patients with cervical cord myelitis of possible demyelinating origin. The aim of this study was to evaluate, using fMRI, whether the level of cord involvement influences cortical reorganization by comparing patients with isolated myelitis of the cervical and the dorsal portions of the cord, and to investigate whether the extent of cortical reorganization is associated with the extent of cervical cord pathology measured using magnetization transfer (MT) MRI. We studied 24 right-handed patients (14 with a previous involvement of the cervical cord and 10 with an involvement of the dorsal cord) in a chronic and clinically stable phase following an isolated myelitis of possible demyelinating origin and 15 sex- and age-matched healthy controls. During a single session, we obtained fMRI during repetitive flexion – extension of the last four fingers of the right and left hands and cervical cord MT MRI. Average cord MTR was lower in patients with cervical ( P < 0.0001) and dorsal ( P = 0.0001) myelitis than in controls. Compared to controls and for both tasks, patients with myelitis had an increased recruitment of the ipsilateral primary SMC, which was independent of the level of cord involvement. On the contrary, patients with cervical myelitis had a more widespread recruitment of frontal and parietal regions, whereas those with dorsal myelitis had a more widespread recruitment of temporal and cerebellar regions. Strong correlations (r values ranging from À0.72 to À0.88) were found between relative activations of cortical areas and the severity of cervical cord damage. Patients with isolated myelitis have different patterns of movement-associated cortical activations accord- ing to the level of cord involvement. This ‘‘level-dependent’’ functional reorganization of the cortex is likely to have an adaptive role in limiting the clinical outcome of cord damage and should be considered when designing rehabilitation strategies for these patients. D 2005 Elsevier Inc. All rights reserved. Introduction Several fMRI studies have detected brain functional cortical changes after spinal cord injury, such as in case of isolated myelitis (Bruehlmeier et al., 1998; Cramer et al., 2001; Mikulis et al., 2002; Sabbah et al., 2002; Rocca et al., 2003), Devic’s neuromyelitis optica (NMO) (Rocca et al., 2004), and MS (Filippi et al., 2002). Some of these studies (Filippi et al., 2002; Rocca et al., 2003, 2004) have also shown a strong correlation between the extent of these cortical functional changes and the severity of spinal cord damage, suggesting a possible adaptive role of brain plasticity in limiting the clinical consequences of cord damage. The aim of the current study was to evaluate, using fMRI, whether the level of cord involvement influences the pattern of movement-associated cortical activations. To this aim, we assessed and compared patients with isolated myelitis of the cervical and the dorsal portions of the cord during the performance of simple motor tasks with their clinically unaf- fected upper limbs. We also attempted to collect further evidence for a potential adaptive role of cortical reorganization in these patients by investigating the magnitude of the correlation between the extent of brain functional recruitment and the extent of cervical cord damage, measured using magnetization transfer (MT) MRI. 1053-8119/$ - see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.neuroimage.2005.10.013 * Corresponding author. Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Via Olgettina, 60, 20132 Milan, Italy. Fax: +39 02 26433054. E-mail address: m.filippi@hsr.it (M. Filippi). Available online on ScienceDirect (www.sciencedirect.com). www.elsevier.com/locate/ynimg NeuroImage 30 (2006) 879 – 884