Can we image premotor Parkinson disease?

Area of Science:

• Neuroscience
• Medical Imaging
• Neurology

Background:

• Parkinson disease (PD) involves neuronal degeneration before motor symptoms manifest, presenting a diagnostic challenge.
• This preclinical phase offers a critical window for early intervention and testing of new therapies.
• Identifying individuals at risk during this premotor period is essential for understanding PD onset and progression.

Purpose of the Study:

• To highlight the importance of imaging biomarkers for detecting premotor Parkinson disease.
• To explore novel strategies for identifying at-risk individuals before the onset of motor symptoms.
• To discuss the potential of various imaging targets in understanding PD etiology and heterogeneity.

Main Methods:

• Review of existing studies utilizing dopaminergic imaging to detect PD at the motor threshold.
• Exploration of novel strategies combining dopaminergic imaging with genetic data, early clinical signs (olfactory loss, REM sleep behavior disorder).
• Discussion of imaging targets beyond dopaminergic systems, including other neurotransmitter systems, inflammation, and alpha-synuclein.

Main Results:

• Dopaminergic imaging can detect PD at the motor symptom threshold.
• Combined imaging strategies and early clinical/genetic markers show promise for identifying at-risk individuals.
• Imaging of nondopaminergic targets may offer insights into PD pathogenesis and heterogeneity.

Conclusions:

• Imaging biomarkers are critical for identifying individuals in the premotor stage of Parkinson disease.
• A multifaceted approach combining various imaging targets and clinical/genetic information is necessary to map PD risk.
• Future research should focus on developing diverse imaging biomarkers to address the heterogeneity of PD.