Longitudinal Analysis of the Relation Between Clinical Impairment and Gray Matter Degeneration in Spinocerebellar Ataxia Type 7 Patients

In vivo assessment of neurodegeneration in Spinocerebellar Ataxia type 7

“…Furthermore, global WM microstructural abnormality, as measured by pFA, trended most toward significant correlation with ataxia severity as compared to microstructural abnormality in the cerebrum, brainstem, or cerebellum alone. If the abnormality we are measuring directly led to the development of symptoms, we would reasonably expect to see more non-motor/non-visual symptoms (although see( Contreras et al, 2020 , Chirino et al, 2018 ); which report correlations between GM volume and cognitive function). Given that pMD and pFA are nonspecific measures of tissue microstructure, it is certainly possible we are measuring changes resulting from multiple factors.…”

“…Other studies employing VBM to study SCA7 have reported volume loss in even more cortical regions ( Alcauter et al, 2011 , Hernandez-Castillo et al, 2013 , Hernandez-Castillo et al, 2016 , Contreras et al, 2020 ). However, it is worth noting that three of these studies had a sample size of 20 or more patients ( Hernandez-Castillo et al, 2013 , Hernandez-Castillo et al, 2016 , Contreras et al, 2020 ).…”

“…VBM, which measures differences in relative brain volume on a voxel-wise basis ( Ashburner and Friston, 2000 ), has detected gray matter (GM) atrophy not only in the cerebellum, but also in many cortical areas including the sensorimotor cortices, motor association areas, cuneus, precuneus, insula, inferior frontal gyrus, medial frontal gyrus, inferior parietal lobule, and temporal regions. ( Alcauter et al, 2011 , Hernandez-Castillo et al, 2018 , Hernandez-Castillo et al, 2013 , Hernandez-Castillo et al, 2016 , Contreras et al, 2020 ). DTI, which is typically used to assess WM microstructural integrity via measures of water diffusivity ( Basser et al, 1994 , Pierpaoli et al, 1996 ), has detected microstructural abnormalities in the cerebellar WM, cerebellar peduncles, brainstem, cerebral peduncles, and several cerebral WM tracts including the internal and external capsules, corona radiata, optical radiation, corpus callosum, and miscellaneous temporal, occipital, parietal, and frontal WM in patients ( Alcauter et al, 2011 , Hernandez-Castillo et al, 2016 ).…”