Clinical Manifestations.

Background: Mild parkinsonian signs (MPS) are prevalent in older adults and linked to an increased risk of dementia. However, their association with Motoric Cognitive Risk syndrome (MCR), a pre-dementia syndrome characterized by slow gait speed and cognitive complaints, is unclear. This study aims to examine the association of MPS with incident MCR.

Method: Non-demented older adults without Parkinson's disease were monitored annually (average follow-up 30 months). We excluded participants with MCR at baseline and dementia incidence without previous MCR, as non-cases. MPS were defined at baseline by the presence of bradykinesia, rigidity, or rest tremor rated by a study clinician using the Unified Parkinson's Disease Rating Scale (UPDRS). MCR was diagnosed using established criteria at baseline and follow-up. The association of baseline MPS and incident MCR was examined using survival analysis and reported as hazard ratio and 95% confidence intervals (CI).

Result: Of the 580 participants, 227 (39.1%) had MPS and 44 (7.5%) had MCR at baseline. Of the 513 initially MCR-free participants, 46 (8.9%) developed incident MCR. Incident MCR cases had a higher prevalence of MPS at baseline compared to participants who did not develop MCR (OR adjusted for age, geriatric depression scale (GDS) score, and stroke history = 3.8, 95% CI 1.8-8.2), particularly bradykinesia (52.3% vs. 19.0%; p<0.001) and rigidity (54.5% vs. 28.1%; p<0.001). They were older (p<0.001), more disabled (p<0.001), and had more strokes (p = 0.005), and depressive symptoms (p<0.001) compared to individuals who did not develop MCR. Participants with MPS at baseline had a greater risk of developing incident MCR (HR adjusted for age, GDS score, and stroke history = 3.7, 95% CI 1.8-7.7).

Conclusion: MPS predicted the onset of MCR, suggesting a significant role in the pathogenesis and in improving early assessment of risk for MCR.