P 33. Investigation of microstructural alterations of ALS-specific tracts in asymptomatic ALS-mutation carriers

Abstract

Introduction. Neuropathological studies in amyotrophic lateral sclerosis (ALS) show that ALS may disseminate in a sequential regional pattern during four disease stages. The in vivo transfer of this propagation scheme can be performed by diffusion tensor imaging (DTI) based analysis of specific tracts [1]. This study investigates if these alterations can already be detected in asymptomatic ALS mutation carriers. Methods. The analysis of fractional anisotropy (FA) was performed by whole brain-based spatial statistics (WBSS) as well as by a tract-of-interest (TOI)-analysis for 45 positively tested asymptomatic ALS mutation carriers vs age- and gender-matched controls to detect specific white matter alterations. Furthermore, a longitudinal analysis was performed with a time-interval of 300 days of data of 20 positively tested asymptomatic ALS mutation carriers. Results. Neither WBSS nor TOI-based analysis were able to detect significant characteristic alteration patterns for asymptomatic ALS mutation carriers. Discussion. This study shows that microstructural alterations in ALS specific tracts in asymptomatic mutation carriers are not detectable by DTI-based analyses. That way, these tract alterations seem to be detectable with the beginning of the symptomatic stage. [1] Kassubek J, et al. J Neurol Neurosurg Psychiatry 2018; 89:374–381.