“…However, there are also studies that did not find Pe differences between persons with and without ADHD (Albrecht et al, 2008;Burgio-Murphy et al, 2007;McLoughlin et al, 2009;Wild-Wall et al, 2009). With respect to the Ne, results have been far less consistent: the Ne amplitude has been found to be normal (Jonkman, van Melis, Kemner, & Markus, 2007;O'Connell et al, 2009;Wiersema et al, 2005;Wiersema, van der Meere, & Roeyers, 2009;Wild-Wall, Oades, Schmidt-Wessels, Christiansen, & Falkenstein, 2009;Zhang et al, 2009), reduced (Albrecht et al, 2008;Groen et al, 2008;Liotti, Pliszka, Perez, Kothmann, & Woldorff, 2005;McLoughlin et al, 2009;van Meel, Heslenfeld, Oosterlaan, & Sergeant, 2007), or even enhanced (Burgio-Murphy et al, 2007) in patients with ADHD. Thus, the ERP results generally suggest that children and adults with ADHD have problems with error monitoring with the most consistent finding of a 7 reduced Pe amplitude, implying aberrant conscious evaluation of errors.…”