Heldman DA, Urrea-Mendoza E, Lovera LC, Schmerler DA, Garcia X, Mohammad ME, McFarlane MCU, Giuffrida JP, Espay AJ, Fernandez HH. App-Based Bradykinesia Tasks for Clinic and Home Assessment in Parkinson's Disease: Reliability and Responsiveness. J Parkinsons Dis. 2017; 7(4):741-747.