Intrahemispheric and interhemispheric structural network abnormalities in PLS and ALS

Authors

  • Federica Agosta,

    1. Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Sebastiano Galantucci,

    1. Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
    2. Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Nilo Riva,

    1. Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Adriano Chiò,

    1. Department of Neuroscience, Università degli Studi di Torino, Turin, Italy
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  • Stefano Messina,

    1. Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano – Department of Pathophysiology and Tranplantation, “Dino Ferrari” Center, Università degli Studi di Milano, Milan, Italy
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  • Sandro Iannaccone,

    1. Department of Clinical Neurosciences, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Andrea Calvo,

    1. Department of Neuroscience, Università degli Studi di Torino, Turin, Italy
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  • Vincenzo Silani,

    1. Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano – Department of Pathophysiology and Tranplantation, “Dino Ferrari” Center, Università degli Studi di Milano, Milan, Italy
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  • Massimiliano Copetti,

    1. Biostatistics Unit, IRCCS-Ospedale Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
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  • Andrea Falini,

    1. Department of Neuroradiology, CERMAC, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Giancarlo Comi,

    1. Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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  • Massimo Filippi

    Corresponding author
    1. Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
    2. Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
    • Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute, San Raffaele University, Via Olgettina, 60, 20132 Milan, Italy. E-mail: m.filippi@hsr.it

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Abstract

Using diffusion tensor (DT) magnetic resonance imaging (MRI), damage to brain intrahemispheric and interhemispheric connections was assessed in 26 sporadic primary lateral sclerosis (PLS) patients compared with 28 sporadic amyotrophic lateral sclerosis (ALS) patients with similar disability and 35 healthy controls. DT MRI diagnostic accuracy in distinguishing the two motor neuron disease (MND) variants was tested. PLS and ALS patients showed a distributed pattern of abnormalities of the motor system, including the corticospinal tracts and corpus callosum (CC). PLS versus ALS patients showed a more severe damage to the motor CC fibers and subcortical white matter (WM) underlying the primary motor cortices. Both patient groups showed an extra-motor damage, which was more severe in PLS. This did not appear to be driven by longer disease duration in PLS. In PLS patients, damage to the CC mid-body correlated with the severity of upper motor neuron clinical burden. CC fractional anisotropy values had the highest accuracy in distinguishing PLS from controls and ALS. PLS and ALS share an overlapped pattern of WM abnormalities. This underscores that PLS, despite its distinct clinical phenotype and long survival, still lies within the wider MND spectrum. Whether CC diffusivity may be a novel marker to increase confidence in an early diagnostic separation of PLS from ALS still needs to be investigated. Hum Brain Mapp 35:1710–1722, 2014. © 2013 Wiley-Periodicals, Inc.

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