Parkinson subtypes progress differently in clinical course and imaging pattern

Abstract

Objective: To elucidate whether Parkinson's disease (PD) subtypes show a differential pattern of FP-CIT-SPECT binding during the disease course.

Methods: We examined 27 patients (10 female, 17 male, mean age 61.68±11.24 years, 14 tremordominant, 13 akinetic-rigid) with [(123)I]FP-CIT-SPECT and clinical ratings including UPDRS III after at baseline and after a mean period of 2.47 years. Patients had been classified at baseline as tremordominant or akinetic-rigid according to a "tremor score" and "non-tremor score". These subgroups were compared for differences in disease progression. Means of clinical ratings and the quantitative analyses of FP-CIT-SPECT for ipsi- and contralateral putamen and caudate nucleus were calculated and compared between baseline and follow-up.

Results: There were no statistical differences concerning age, disease duration, L-Dopa equivalent dose, disease severity (UPDRS III) or dopaminergic uptake in FP-CIT-SPECT at baseline between both subgroups. At follow-up, akinetic-rigid patients showed a distinct and statistically significant reduction of the dopaminergic uptake associated with significant progression of the clinical symptoms (UPDRS III). In contrast, in tremor patients the aggravation of clinical symptoms and dopaminergic deficit was less pronounced without statistical significance among assessments.

Conclusions: This study shows for the first time a considerable progression of clinical symptoms and in-vivo dopaminergic deficit of akinetic-rigid compared to tremordominant PD patients over time. Our data may help to improve strategic planning of further therapeutic trials and to provide a clearer prognosis for patients regarding the perspective of their disease.

Figure 1. Longitudinal differences in subgroups of PD.

a) Mean differences between baseline and follow-up of UPDRS-III-OFF scores for tremordominant and akinetic-rigid PD patients. Significant differences (p<0.05) between the two time points are indicated with *. b) Mean differences between baseline and follow-up of FP-CIT-uptake in the contralateral putamen for tremordominant and akinetic-rigid PD patients c) Mean differences between baseline and follow-up of FP-CIT-uptake in the contralateral caudate for tremordominant and akinetic-rigid PD patients. Significant differences (p<0.05) between the two time points are indicated with *.

Figure 2. SPM results for akinetic-rigid PD patients.

Results of the SPM-analysis superimposed on a standard MRI-scan for akinetic-rigid patients show a significant reduction of the dopaminergic uptake between baseline and follow-up.