title: Relationship between structural brainstem and brain plasticity and lower-limb training in spinal cord injury: a longitudinal pilot study.
abstract: Rehabilitative training has shown to improve significantly motor outcomes and functional walking capacity in patients with incomplete spinal cord injury (iSCI). However, whether performance improvements during rehabilitation relate to brain plasticity or whether it is based on functional adaptation of movement strategies remain uncertain. This study assessed training improvement-induced structural brain plasticity in chronic iSCI patients using longitudinal MRI. We used tensor-based morphometry (TBM) to analyze longitudinal brain volume changes associated with intensive virtual reality (VR)-augmented lower limb training in nine traumatic iSCI patients. The MRI data was acquired before and after a 4-week training period (16-20 training sessions). Before training, voxel-based morphometry (VBM) and voxel-based cortical thickness (VBCT) assessed baseline morphometric differences in nine iSCI patients compared to 14 healthy controls. The intense VR-augmented training of limb control improved significantly balance, walking speed, ambulation, and muscle strength in patients. Retention of clinical improvements was confirmed by the 3-4 months follow-up. In patients relative to controls, VBM revealed reductions of white matter volume within the brainstem and cerebellum and VBCT showed cortical thinning in the primary motor cortex. Over time, TBM revealed significant improvement-induced volume increases in the left middle temporal and occipital gyrus, left temporal pole and fusiform gyrus, both hippocampi, cerebellum, corpus callosum, and brainstem in iSCI patients. This study demonstrates structural plasticity at the cortical and brainstem level as a consequence of VR-augmented training in iSCI patients. These structural changes may serve as neuroimaging biomarkers of VR-augmented lower limb neurorehabilitation in addition to performance measures to detect improvements in rehabilitative training.
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland ; University College Physiotherapy Thim van der Laan Landquart, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Villiger
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Grabher
authors.affiliation: Institute of Neuroinformatics, University of Zurich and ETH Zurich Zurich, Switzerland.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Hepp-Reymond
authors.affiliation: Institute of Neuroinformatics, University of Zurich and ETH Zurich Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kiper
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland.
authors.forename: Armin
authors.initials: A
authors.lastname: Curt
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Bolliger
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland.
authors.forename: Sabina
authors.initials: S
authors.lastname: Hotz-Boendermaker
authors.affiliation: Institute of Neuroradiology, University Hospital Zurich, University of Zurich Zurich, Switzerland.
authors.forename: Spyros
authors.initials: S
authors.lastname: Kollias
authors.affiliation: Institute of Neuroinformatics, University of Zurich and ETH Zurich Zurich, Switzerland.
authors.forename: Kynan
authors.initials: K
authors.lastname: Eng
authors.affiliation: Spinal Cord Injury Center Balgrist, University of Zurich Zurich, Switzerland ; Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK ; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Freund
keywords: lower limb; spinal cord injury; structural plasticity; tensor-based morphometry; virtual reality-augmented neurorehabilitation; voxel-based morphometry