“…Moreover, some studies demonstrated that PD patients have greater difficulty performing PM tasks in which executive functions are particularly stressed, such as time-based versus event-based tasks Katai, Maruyama, Hashimoto, & Ikeda, 2003;Raskin et al, 2011; report divergent results) and non-focal versus focal tasks (Foster, McDaniel, Repovs, & Hershey, 2009). A significant correlation between performance on PM tasks and tests tapping shifting and planning abilities was also reported Costa, Peppe, Brusa, et al, 2008;Kliegel, Phillips, Lemke, & Kopp, 2005;Raskin et al, 2011).…”