Slow motion videography in Parkinson's disease: unraveling masked phenomenology.

Slow motion (SM) videography provides a novel approach to documenting and understanding movement disorders by revealing subtle phenomenological features not easily captured at normal speed. While widely used in sports and wildlife analysis, its application in clinical neurology remains limited. We present a case series of four patients with Parkinson’s disease in whom SM videography uncovered unique motor signatures. Case 1 revealed the “Scoop Sign” of hand tremor, highlighting wrist and forearm rotational components. Case 2 demonstrated incessant progressive micrographia, a distinctive writing pattern of gradual diminution and incessant continuation, atypical for PD. Case 3 illustrated the “Fulcrum Sign” in freezing of gait, where one foot acted as a pivot. Case 4 depicted the “Octopus Sign” in levodopa-induced dyskinesia. These cases highlight the utility of smartphone-based SM videography as an accessible, cost-effective clinical tool to unravel masked PD phenomenology, enhance bedside observation, and improve recognition of subtle motor patterns.