Topographic distribution of cortical thinning in subtypes of multiple system atrophy

Despite the predominant degeneration of subcortical structures, recent studies have suggested the evidence of cortical involvement in multiple system atrophy (MSA). This study aimed to identify the different topographic pattern of cortical thinning in MSA according to clinical subtypes, and the association of cortical thinning with cerebellar atrophy and other disease related metrics.

We used cortical thickness analysis in 53 non-demented probable MSA patients (29 with MSA-C, 24 with MSA-P) and 35 healthy subjects and modeled local cortical thickness as a linear association with cerebellar volume and disease related metrics including age, disease duration, cognition and disease severity.

We found five clusters (left ventromedial prefrontal, bilateral ventrolateral prefrontal cortex, right parahippocampal and lingual gyrus) exhibiting significant cortical thinning in MSA-C and two clusters (right primary sensory motor and left ventromedial prefrontal cortex) exhibiting a thinning tendency in MSA-P compared with the control group. In correlation analysis, we identified no cluster exhibiting a significant correlation with cerebellar atrophy in both of the MSA groups. However, cortical thickness in right parahippocampalgyrus and left ventrolateral prefrontal cortex showed significant negative correlation with International Cooperative Ataxia Rating Scale subscore of speech disorder in MSA-C group.

We identified different topographic distributions of cortical thinning in MSA subtypes. Our study suggests that cortical thinning of MSA occurs independently of cerebellar atrophy as a primary disease process rather than secondary deafferentation.