MRI sub-study
CORTEX
A rs-fMRI scan was performed on a subgroup of five patients (four cases and one control) at the pre-intervention visit and at the post-intervention visit (after 30 days of therapy) to test the effects of visual training with the OPTIcTRAIN® software on the neural plasticity of the patients’ visual cortex. At both visits, T1-weighted and dMRI data were also acquired. Prior to MRI acquisition, patients signed a specific informed consent form after trained research staff verified that they met the necessary criteria for testing. All the MRI acquisitions took place on the Philips Achieva 3.0 T X-Series scanner at the Laboratory of Instrumental Techniques (LTI) of the Universidad de Valladolid.For the purposes of this study, brain grey matter morphometry, white matter diffusion and functional connectivity analyses were performed. To quantify the variation in the different metrics between the two acquisitions (before and after the intervention), we used a coefficient of variation defined as (For the analysis of brain grey matter, four parameters were selected: cortical curvature, cortical thickness, surface area and grey matter volume. These parameters were assessed in 34 bilateral cortical regions of interest (ROI). Moreover, the bilateral cerebellum and seven subcortical regions were exclusively analysed with the grey matter volume. The segmentation of the ROIs and the four morphometry parameters were obtained using the Freesurfer (v6.0.0) software standard pipeline for cortical parcellation. The aforementioned 84 regions were also employed to assess the functional connectivity.For the analysis of brain white matter diffusion, three types of parameters were extracted:Parameters related to the diffusion tensor (classical): fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD).Parameters related to the diffusion propagator calculated with the AMURA (Apparent Measures Using Reduced Acquisitions) technique [Advanced parameters of the diffusion propagator using AMURA [Specifically, the dMRI assessment was performed on 48 white matter regions, including some bilateral tracts such as the posterior corona radiata, posterior thalamic radiation (including optic radiation), and superior fronto-occipital fasciculus.