Objective: To evaluate substantia nigra hyperechogenicity (SN+) with transcranial sonography (TCS) in different PD motor subtypes.

Background: Parkinson´s disease (PD) patients display a range of motor phenotypes which are classified as PD motor subtypes including tremor dominant (TD), postural instability and gate disorder (PIGD), and mixed phenotypes.

Methods: The motor phenotype of 266 PD patients was evaluated on the MDS-UPDRS motor scale and their SN+ was measured by transcranial sonography on both sides. PD pathology start side was recorded. Patient characteristics and clinical parameters were correlated to SN+ separately in the three PD subtype groups. The interaction between PD initial side SN+ and significantly correlating clinical parameters was demonstrated in linear regression analysis.

Results: We found that the start side SN+ values do not differ significantly between PD motor phenotype groups. We demonstrated a significant negative correlation between PD duration and initial side SN+ in TD (p<0.01) and PIGD groups (p<0.001). Regression analysis revealed that the interaction between PD duration and start side SN+ is 2.5 times greater in the TD group as compared to the PIGD group. In the PIGD group showed a weak association with age. We didn’t detect any significant correlation between clinical parameters and SN+ in the mixed group.

Conclusions: The present study demonstrates that SN+ is not a stable biomarker for different motor subtypes of Parkinson’s disease and that disease duration and age are associated with a change in SN+ are different depending on the PD motor phenotype.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/substantia-nigra-hyperechogenicity-in-parkinsons-disease-motor-phenotypes/