Superior Cerebellar Peduncle Atrophy Predicts Cognitive Impairment in Relapsing Remitting Multiple Sclerosis Patients with Cerebellar Symptoms: A DTI Study

Background: Using Diffusion Tensor Imaging (DTI), we tested the hypothesis that cerebellar abnormalities in fractional anisotropy (FA) may be involved in cognitive dysfunctions in Relapsing-Remitting (RR)-Multiple Sclerosis (MS). Objective: The aim of our study was to investigate the microstructural integrity in MS of regions that connect in both feedforward and feedback pathways to cortical areas, i.e., Superior Cerebellar Peduncles (SCP), Middle Cerebellar Peduncles (MCP), Dentate nuclei (DN) and Thalamus (Th). Patients and methods: We studied 46 patients with RR-MS (21 with cerebellar signs and 25 without) and 23 normal subjects. All subjects underwent cognitive testing. Results: In patients with a cerebellar phenotype, cognitive performance in all considered domains was from moderately to strongly related (p<0.05) to abnormalities of SCP (r=0.119 to 0.735) and Thalamus (r=0.477 to 0.602). Discussion: Our study showed an important correlation between cognitive testing and FA values of SCP and thalamus in cerebellar MS patients. We found not only the involvement of thalamus but also of SCP that is an important link between cerebellar nuclei and thalamus, suggesting that a disconnection is present also out of the thalamus. These results suggest that SCP and thalamic damage is a clinically relevant biomarker of the neurodegenerative cerebellar process in MS.