Dopamine transporter availability in motor subtypes of de novo drug-naïve Parkinson’s disease

Abstract

Tremor dominant (TD) and akinetic-rigid type (ART) are two motor subtypes of Parkinson's disease associated with different disease progression and neurochemical/neuropathological features. The role of presynaptic nigrostriatal dopaminergic damage is still controversial, poorly explored, and only assessed in medicated patients. In this study, we investigated with FP-CIT SPECT the striatal dopamine transporter (DAT) availability in drug-naïve PD patients with ART and TD phenotypes. Fifty-one de novo, drug-naïve patients with PD underwent FP-CIT SPECT studies. Patients were evaluated with Unified Parkinson's Disease Rating Scale (UPDRS) part III and Hoehn and Yahr scale (H&Y) and divided into ART (24/51) and TD (27/51) according to UPDRS part III. ART and TD patients were not different with regard to age, gender, and disease duration. However, compared to TD, ART patients presented higher UPDRS part III (p = 0.01) and H&Y (p = 0.02) and lower DAT availability in affected and unaffected putamen (p = 0.008 and p = 0.007, respectively), whereas no differences were found in caudate. Moreover, in the whole group of patients, rigidity and bradykinesia, but not tremor scores of UPDRS part III were significantly related to FP-CIT binding in the putamen. These results suggest that in newly diagnosed drug-naïve PD patients DAT availability might be different between ART and TD in relation to different disease severity.

White matter changes and the development of motor phenotypes in de novo Parkinson's Disease

“…Indeed, axial impairment in PD seems to be only partly explained by dopaminergic dysfunction [22], and, conversely, non-dopaminergic pathways might be involved [4,23]. Similarly, white matter disease might contribute to axial motor features by altering the integrity of cortico-striatal and cortico-cortical connections, rather than through the direct or indirect pathway [11].…”

Motor subtype in Parkinson's disease: Different disorders or different stages of disease?

“…Conversely, Moccia and colleagues described greater loss of DAT binding in the putamen of A/R‐D than T‐D patients, but no differences in the caudate DAT concentration. The UPDRS part III and the H&Y scores were worse in the A/R‐D group . Finally, Song found no difference in striatal [ 123 I]FP‐CIT uptake between the T‐D patients and those without tremor .…”

“…Kaasinen and colleagues found better preservation of [ 123 I]FP‐CIT uptake in the caudate but not in the putamen in T‐D patients . Conversely, Moccia and colleagues described greater loss of DAT binding in the putamen of A/R‐D than T‐D patients, but no differences in the caudate DAT concentration. The UPDRS part III and the H&Y scores were worse in the A/R‐D group .…”

Overview of Dopamine Transporter Imaging in Parkinson’s Disease, Dementia with Lewy Bodies and Other Dementias

“…Even when there were no differences with regard to age, gender, and disease duration between cases with the two different motor phenotypes, dopamine function was relatively preserved in TDPD both in affected (p=0.008) and unaffected putamen (p=0.007) compared to those with the AKR phenotype. This was reflected in the lower Unified Parkinson's disease rating scale (UPDRS) part 3 scores (p=0.01) and H&Y (p=0.02) stages compared to the AKR group [27].…”