Distinct finger-tapping feature in progressive supranuclear palsy correlates with motor function and brain atrophy

Area of Science:

• Neuroscience
• Biomarkers
• Movement Disorders

Background:

• Progressive Supranuclear Palsy (PSP) is a rare tauopathy with overlapping symptoms with Parkinson's Disease (PD).
• Accurate differentiation between PSP and PD is challenging due to symptom overlap.
• Objective biomarkers are needed for reliable diagnosis and assessment.

Purpose of the Study:

• To evaluate video-based kinematic analysis of finger tapping as a potential biomarker for differentiating PSP from PD.
• To assess the correlation between finger-tapping parameters and clinical motor/balance function in PSP.
• To explore associations between finger-tapping kinematics and brain structure volumes in PSP.

Main Methods:

• Video-based kinematic analysis of finger-tapping performance was conducted in 31 PSP patients, 31 PD patients, and 30 healthy controls (HC).
• Key kinematic parameters including angle, velocity, and cycle duration were measured.
• Statistical analyses were performed to compare groups and assess correlations.

Main Results:

• PSP patients demonstrated significantly smaller finger-tapping angles, slower velocities, and shorter cycle durations compared to PD patients and HCs.
• A notable absence of the sequence effect was observed in PSP patients.
• The average finger-tapping angle showed good discriminative ability between PSP and PD (AUC = 0.83).
• In PSP, reduced finger-tapping angles and velocities correlated with poorer motor and balance function.
• Finger-tapping parameters were associated with the volumes of specific brain regions, including the nucleus accumbens, superior temporal gyrus, cerebellum, and brainstem.

Conclusions:

• Video-based kinematic analysis of finger tapping is a promising non-invasive biomarker for distinguishing PSP from PD.
• This method can aid in PSP diagnosis and provide insights into motor and balance deficits.
• Finger-tapping kinematics may reflect underlying neurodegenerative changes in specific brain structures relevant to PSP.