249 Slow motion analysis of repetitive tapping (SMART) test: a new measurement of bradykinesia

Abstract

ObjectivesTo develop a quantitative and objective tool to track repetitive tapping movements (RTM) using a slow motion capture and and compare patients with Parkinson’s disease (PD), REM-sleep behaviour disorder (RBD) and healthy controls (HC).MethodsWe assessed 48 participants (PD=20, RBD=5, HC=23). For each participant, RTM was recorded during 20s by a smartphone at 240 frames/s and then analysed using novel Python scripts. Two kinetic parameters were extracted: amplitude between fingers and frequency (number of taps/s). Linear regres- sion was used to determine the trend of movement over time.ResultsAlthough HC and RBD group (64.8±8.7yo and 68.4±8.2yo respectively) were older than PD group (58.1±12.8yo), the PD group performed the task significantly slower (p=0.0003) and with greater, but not significant, amplitude decrement than HC (p=0.5). RBD group was similar to PD group with significant slower RTM (p<0.0001) and non-significant amplitude decrement (p=0.3). SMART test was able to differentiate between all three groups, with a positive goodness of fit between PD and HC. The frequency parameter displayed 92.8% and 100% of sensibility (for 60.8% and 13% specificity with respective AUC=0.84 and 0.92) when comparing PD vs HC and RBD vs HC respectively.ConclusionsWe present an accurate way to quantify motor dysfunction in PD. Despite the small number of subjects, the fact that RBD group presented objective motor impairment could help with the early diagnosis at the prodromal phase of PD.15c6.simonet@qmul.ac.uk