Mathematical cognitive function in children with attention deficit hyperactivity disorder: a behavior and event-related potential study

Abstract

To explore the mathematics cognitive function of children with attention deficit hyperactivity disorder and explore neural mechanisms with event-related potential(ERP) and behaviors. Behavior data and ERP elicited by performing mental calculation tasks were recorded in 27 children with ADHD and 29 normal controls from July to October 2012 at Third Affiliated Hospital of Soochow University.The differences of behaviors and N2 component of ERP were compared and analyzed. The reaction time of the children with ADHD were longer than the control group in addition, subtraction and multiplication ((949 ± 144) vs (829 ± 166) ms, (981 ± 129) vs (856 ± 170) ms, (944 ± 136) vs (825 ± 172) ms, all P < 0.05). While the correct rate were less than normal control in all three arithmetic operations (0.80% (0.72%, 0.88%) vs 0.90% (0.85%,0.96%), 0.78% (0.64%,0.85%) vs 0.90% (0.84%,0.93%), 0.86% (0.74%,0.92%) vs 0.93%(0.90%,0.98%), all P < 0.05). N2 component could be elicited by all subjects in forehead. The amplitude of N2 of children with ADHD were significantly lower than control group in all three arithmetic operations at left frontal (F3: (-3.5 ± 5.2) vs (-6.7 ± 3.5)µV, (-3.8 ± 4.0) vs (-7.4 ± 4.5)µV, -5.8 (-7.6,1.6) vs -6.4(-10.3, -4.9) µV, all P < 0.05) and Fz ((-4.3 ± 6.4) vs ( -7.4 ± 4.2) µV, (-5.0 ± 5.4) vs (-7.9 ± 4.6)µV, -5.2(-9.7, -0.6) vs -7.9 (-10.5, -5.1)µV, all P < 0.05), the latency of ADHD group were prolonger than controls in subtraction operations at right and left frontal ((328 ± 36) vs (307 ± 27)ms, 325 (307,354)vs 309 (280, 330)ms) and frontal electrodes ((331 ± 35) vs (311 ± 30) ms, all P < 0.05). In addition and multiplication operations, there was no significant difference in latency (all P > 0.05). The children with ADHD have weak capacities of inhibition irrelevant information and paying attention to control. Their deficits in mental arithmetics may be due to the difficulties of selecting the best strategy during cognitive tasks.