To develop quantitative spatiotemporal measures of finger tapping using a novel-frog-in-maze paradigm in idiopathic Parkinson’s disease (PD).

Motor blocks occur in Parkinson’s disease (PD) patients during speech, upper limb movements (such as handwriting and finger tapping) and gait. While freezing of gait has been extensively studied, difficulty with manual dexterity, often precedes gait dysfunction. Quantitative measures of upper limb function could allow earlier detection of freezing of the upper limb.

PD patients with freezing (n=9), without freezing (n=12), and age-matched controls (n=25) were consented after IRB approval. Using finger presses on button boxes, subjects were asked to “walk” a frog through a maze on a computer screen using mazes of different complexity, some of which incorporated turns and a time pressure of a car chase, as these clinically provoke gait freezing. Intertap-intervals were extracted and compared between the groups for different mazes. Stride length was extracted from walks performed on an instrumented gait mat. PD patients performed assessments both OFF and ON-levodopa.