两种亚型ADHD儿童在停止信号任务中的反应抑制

采用停止信号任务，操纵其中的反应冲突，探查两种亚型（注意缺陷型和混合型）ADHD儿童在不同抑制功能——反应冲突和反应停止上的表现，以及儿童在内源性和外源性两种注意条件下反应抑制的表现。结果发现，与正常儿童相比，ADHD儿童在两种反应抑制上都有不同程度的缺损，不仅冲突效应量更大，反应停止的错误率也更高；但在控制年龄因素后，未观察到两种亚型ADHD儿童之间在反应冲突和反应停止能力上有明显差异。研究还发现，儿童在内源性和外源性两种注意条件下反应抑制的表现模式相似，说明反应冲突和反应停止可能存在某些共同的神经机制，两种亚型ADHD儿童在这些机制的功能缺损上有类似之处。

RESPONSE INHIBITION IN TWO SUBTYPES OF CHILDREN WITH ADHD

Two stop-signal tasks were used to investigate two types of response inhibition, response conflict and response stopping. Subjects were two subtypes of children with ADHD (18 of predominantly inattentive and 11 of combined in Exp.1, 25 of predominantly inattentive and 31 of combined in Exp.2) and normal controls. Results showed that ADHD children were deficient in both types of response inhibition compared with normal controls. No significant differences were observed between the two subtypes of ADHD children after the effect of age was partialed out. Moreover, children showed the same pattern of effects in response inhibition under condition of either endogenous or exogenous attentional cueing. These findings suggest that the two types of response inhibition employ some common cognitive and brain mechanisms and the two subtypes of ADHD were impaired equivalently on these functions.