Response Inhibition In Children With High Functioning Autism And Attention Deficit Hyperactivity Disorder: A Near-infrared Spectroscopy Study

【Objective】The objectives of this study were to compare the function of response inhibition between children with high functioning autism (HFA), attention deficit hyperactivity disorder(ADHD), and typically developing (TD); to investigate the characteristics of blood flow activity changing in prefrontal cortex during response inhibition task; and to explore the neurophysiology basis of pathogenesis in children with HFA and ADHD.【Method】Go/no-go task and Stroop task were applied to assess the function of response inhibition in 21children with HFA ,28 children with ADHDand 20 normal controls, while all the data of oxygenated hemoglobin (oxy-Hb) concentration levels in prefrontal cortex area were collected by functional near-infrared spectroscopy (NIRS). A multiariable analysis of variance and multiple correction binary comparison were used to analyse the difference on response inhibition among these three groups. Linear regression was used to investigate the relationship between types of disease,age,IQ and response inhibition, then construct a regression equation. 【Results】(1) During no-go task, the children with ADHD made a greater number of reaction errors[(4.11±2.28)vs(2.53±1.43) P=0.025], and they needed more time to make a response comparing with TD group[(534.11±70.47)ms vs (473.63±45.63)ms P=0.012]; children with HFA needed more time to make a response than TD group[(567.15±106.72)ms vs (473.63±45.63)ms P=0.00]. (2) During In incongruent task, ADHD group made a greater number of reaction errors than TD group[(4.19±2.42) vs (2.50±2.25) P=0.022], and they also needed more time to make a response[(1934.93±381.29)ms vs (1691.52±311.35)ms P=0.037]; however there was no significant difference between HFA group and TD group neither in the number of reaction errors nor in reaction time(P>0.05). (3) The number of reaction errors was associated with disease group and the reaction time was associated with disease group and the age of children. (4) During no-go task, the HFA group had lower levels of oxy-Hb concentration in the upper right prefrontal cortex area than TD group[(-0.06±0.18)(10^-2×a.u) vs (0.11±0.24)(10^-2×a.u) P=0.01]; the ADHD group also had lower levels of oxy-Hb concentration in the upper right prefrontal cortex area than TD group[(-0.01±0.14)(10^-2×a.u) vs (0.11±0.24)(10^-2×a.u) P=0.03]; and three groups did not differ significantly on concentration levels of oxy-Hb in neither left prefrontal cortex nor right prefrontal cortex during Stroop task(P>0.05).【Conclusions】(1) The children with ADHD have deficits in response inhibition,and children with HFA have deficits in some but not all aspects of response inhibition. Response inhibition impediment could be a nerve intrapsychic phenotype of HFA and ADHD.(2) NIRS brain imaging studies show that both children with HFA and children with ADHD have lower activation in the upper right prefrontal regions during tasks of inhibition function.