Normalized jerk as an indicator of discrete kinematic disfluency in parkinson disease: a preliminary report

Normalized jerk is an established metric for the assessment of kinematic fluency across a range of human movements (e.g. writing, manual aiming, balance, and gait) [1-3]. While normalized jerk has been employed to evaluate manual disfluencies in Parkinson disease (PD) patients over extended trials, the measure has not been applied for the identification of discrete ‘freezing,’ or akinetic, events. A preliminary assessment of normalized jerk for the identification of discrete akinetic events (DAE) during a continuous manual task demonstrates the potential for automated/assisted detection. In particular, the identification and isolation of DAEs is important for the obviation of associated jerk values that may substantially skew trial-wide measures. Identification of such events would also facilitate analyses of kinematic fluency both preceding and following a DAE.