Multiple step pattern as a biomarker in Parkinson disease.

Area of Science:

• Neuroscience
• Ophthalmology
• Genetics

Background:

• Parkinson disease (PD) diagnosis relies on clinical assessment, often detecting symptoms late.
• Biomarkers for early detection in PD patients and at-risk populations are crucial.

Purpose of the Study:

• To assess quantitative saccade measures as potential biomarkers for early Parkinson disease (PD).
• To evaluate these measures in individuals at risk for PD.

Main Methods:

• A study included 68 participants: PD patients, unaffected siblings, and controls.
• Eye tracking recorded saccade measures (latency, velocity, gain, error rate, multiple step pattern) during visually guided, anti-saccadic, and memory-guided tasks.
• Genotyping for LRRK2 G2019S mutation was performed in PD patients and siblings.

Main Results:

• PD patients and some siblings showed increased multiple step patterns (MSP) and reduced saccade gain compared to controls.
• MSP demonstrated high sensitivity (87%) and specificity (96%) in distinguishing PD patients.
• Abnormalities were more pronounced in a challenging memory-guided saccade task.

Conclusions:

• Abnormalities in saccadic eye movements are sensitive and specific indicators in PD patients and at-risk individuals.
• Quantitative saccade testing may enhance the neurological exam for identifying individuals at higher risk for PD.