Response Inhibition and Neurological Soft Signs among Children with Attention Deficit Hyperactivity Disorder (ADHD)

Introduction: Children with attention deficit hyperactivity disorder (ADHD) manifest a higher number of motor deviations like neurological soft signs (NSS) than typically developing children. Understanding the relationship of NSS to different subprocesses of response inhibition could clarify the degree to which NSS is connected to the executive inhibitory processes. Method: This study aimed to investigate NSS with response inhibition in a sample of 31 drug naïve children with ADHD and a sample of 30 age and IQ matched typically developing children. The Stroop colour word task, go/no go task and a choice task with stop signal assessed executive inhibitory processes. Physical and Neurological Examination of Soft Signs (PANESS) measured NSS. Results: The results showed that the ADHD group was significantly different from typically developing children in ongoing response inhibition and NSS, i.e. Z = −4.982; P <0.0083), total timed dysrhythmia ( Z = −3.854; P < 0.0083) and speed of timed activities (SFA scores) ( Z = −5.276; P < 0.0083). Discussion: Moderated regression analysis revealed that the slowness in timed activities predicted successful inhibition in the choice task differentially in the ADHD group. The results are discussed in the light of existing literature.