OBJECTIVE: To test the hypothesis that axonal damage extending into primarily normal-appearing white matter is clinically important by comparing the concentrations of N-acetylaspartate (NAA) bilaterally within the internal capsule with lateralization of motor impairment in patients with multiple sclerosis (MS) and persistent asymmetrical motor deficit. DESIGN: We performed magnetic resonance spectroscopy and T2-weighted imaging of the internal capsule, calculated central motor conduction times, and related these results to measures of motor function asymmetry in 12 patients with MS. RESULTS: Levels of NAA from normal-appearing white matter of the internal capsule in patients with MS were significantly lower than those in control subjects (P = .05). Side-to-side differences in NAA levels were also significantly greater in patients with MS than in controls (P = .01). There was a correlation between asymmetry in motor function for the left and right limbs and asymmetry of internal capsule NAA concentrations (r = 0.60; P = .04). This correlation seemed slightly stronger when tests specifically of arm and hand motor asymmetry were considered alone. Central motor conduction times were abnormal in most patients with MS and showed a side-to-side difference that also correlated with asymmetry in motor function. CONCLUSION: Our demonstration of a graded association between NAA concentrations within primarily normal-appearing white matter of a specific tract and functional impairments referable to that tract suggests that axonal pathology distant from macroscopic lesions might be an important determinant of disability in MS.
OBJECTIVE: To test the hypothesis that axonal damage extending into primarily normal-appearing white matter is clinically important by comparing the concentrations of N-acetylaspartate (NAA) bilaterally within the internal capsule with lateralization of motor impairment in patients with multiple sclerosis (MS) and persistent asymmetrical motor deficit. DESIGN: We performed magnetic resonance spectroscopy and T2-weighted imaging of the internal capsule, calculated central motor conduction times, and related these results to measures of motor function asymmetry in 12 patients with MS. RESULTS: Levels of NAA from normal-appearing white matter of the internal capsule in patients with MS were significantly lower than those in control subjects (P = .05). Side-to-side differences in NAA levels were also significantly greater in patients with MS than in controls (P = .01). There was a correlation between asymmetry in motor function for the left and right limbs and asymmetry of internal capsule NAA concentrations (r = 0.60; P = .04). This correlation seemed slightly stronger when tests specifically of arm and hand motor asymmetry were considered alone. Central motor conduction times were abnormal in most patients with MS and showed a side-to-side difference that also correlated with asymmetry in motor function. CONCLUSION: Our demonstration of a graded association between NAA concentrations within primarily normal-appearing white matter of a specific tract and functional impairments referable to that tract suggests that axonal pathology distant from macroscopic lesions might be an important determinant of disability in MS.
Authors: Daniel S Reich; Seth A Smith; Kathleen M Zackowski; Eliza M Gordon-Lipkin; Craig K Jones; Jonathan A D Farrell; Susumu Mori; Peter C M van Zijl; Peter A Calabresi Journal: Neuroimage Date: 2007-08-15 Impact factor: 6.556
Authors: Ponnada A Narayana; Juan J Herrera; Kurt H Bockhorst; Emilio Esparza-Coss; Ying Xia; Joel L Steinberg; F Gerard Moeller Journal: Psychiatry Res Date: 2014-01-23 Impact factor: 3.222
Authors: Melissa Cambron; Miguel D'Haeseleer; Guy Laureys; Ralph Clinckers; Jan Debruyne; Jacques De Keyser Journal: J Cereb Blood Flow Metab Date: 2012-01-04 Impact factor: 6.200