“…The d2 test (Brickenkamp, 1972(Brickenkamp, , 2002 measures processing speed, rule compliance and quality of performance, allowing for a neuropsychological estimation of individual attention and concentration performance. The reliability has proven to be very high, and the validity of the technique has been documented by a number of research studies (Brickenkamp, 2002;Flett, Madorsky, Hewitt, & Heisel, 2002). Norms are available based on representative German samples (Brickenkamp, 2002).…”