Cerebellar Evaluation In Parkinson'S Disease: Gray Matter Analysis And Its Association With Disease Severity

Background: The cerebellum has emerged as a structure potentially involved in Parkinson’s Disease (PD), however where within the cerebellum and when it is affected remains unclear.Objective: To evaluate the cerebellar gray matter (GM) of patients with tremor-predominant (PDT) and akinetic/rigidity-predominant PD (PDAR), and also to assess whether any identified GM change is associated with the severity of motor impairment.Methods: MRI scans of 66 patients were acquired. In the first analysis we compared 45 PDT to 45 healthy controls (HC) and 21 PDAR to 21 HC. We divided the PDT group into three groups according to the Hoehn and Yahr scale (HY) and compared each group with a matched HC group. Analysis I: 9 patients (HY:1 - 1.5); analysis II: 21 patients (HY: 2 - 2.5); analysis III: 15 patients (HY ≥ 3). For a specific evaluation of the cerebellum, we used the SUIT tool for voxel-based morphometry (Puncorrected < 0.001).Results: In PDT we observed GM atrophy in the lobule VI, lobule Crus I, and in the vermis. In the PDT subgroups analysis the groups I and II had no atrophy. Group III however, demonstrated a large GM decrease in the anterior lobe, in the crus I and in the lobules V, VI (including the vermis) and VIIIa. There were no significant changes in the cerebellar GM in PDAR.Conclusions: We demonstrated that cerebellar GM is affected in PDT patients only; they showed atrophy particularly in the anterior lobe and motor-related lobules and these changes seemed to parallel disease severity. Background: The cerebellum has emerged as a structure potentially involved in Parkinson’s Disease (PD), however where within the cerebellum and when it is affected remains unclear. Objective: To evaluate the cerebellar gray matter (GM) of patients with tremor-predominant (PDT) and akinetic/rigidity-predominant PD (PDAR), and also to assess whether any identified GM change is associated with the severity of motor impairment. Methods: MRI scans of 66 patients were acquired. In the first analysis we compared 45 PDT to 45 healthy controls (HC) and 21 PDAR to 21 HC. We divided the PDT group into three groups according to the Hoehn and Yahr scale (HY) and compared each group with a matched HC group. Analysis I: 9 patients (HY:1 - 1.5); analysis II: 21 patients (HY: 2 - 2.5); analysis III: 15 patients (HY ≥ 3). For a specific evaluation of the cerebellum, we used the SUIT tool for voxel-based morphometry (Puncorrected < 0.001). Results: In PDT we observed GM atrophy in the lobule VI, lobule Crus I, and in the vermis. In the PDT subgroups analysis the groups I and II had no atrophy. Group III however, demonstrated a large GM decrease in the anterior lobe, in the crus I and in the lobules V, VI (including the vermis) and VIIIa. There were no significant changes in the cerebellar GM in PDAR. Conclusions: We demonstrated that cerebellar GM is affected in PDT patients only; they showed atrophy particularly in the anterior lobe and motor-related lobules and these changes seemed to parallel disease severity.