Poster #22 - Neurological soft signs and response inhibition among children with Attention Deficit Hyperactivity Disorder (ADHD): An Empirical Investigation

• In Event: Poster Session 18

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by core symptoms of inattention, hyperactivity and impulsivity. Children with ADHD manifest a higher number of motor deviations like neurological soft signs (NSS) than typically developing children. Understanding the relationship of NSS to different sub-processes of response inhibition could clarify the degree to which NSS is connected to the executive inhibitory processes. 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, Go/No-Go, and a choice task with stop-signal assessed executive inhibitory processes. Physical and Neurological Examination of Soft Signs (PANESS) measured NSS. Results revealed significant differences between the ADHD and control groups in the choice stop signal inhibition (Z=-5.025; p <0.0083). The ADHD group and the control group did not differ in performance of the Stroop signal task (Z=-1.135; p=0.25) and Go/No-Go task inhibition (Z=-2.206; p=0.027). There were significant differences between the ADHD group and the control group in all the PANESS measures: total overflow movements (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) Results showed that the ADHD group was significantly different from typically developing children in ongoing response inhibition and NSS. In regression analysis, executive inhibitory control measures were regressed on measures of NSS. Significant predictor-outcome relationship existed between total overflow and stroop interference (β= -.575, t = -2.064, p=.043), total overflow and choice stopping inhibition (β= -2.00, t = -2.80, p=.007), dysrhythmia and Go/No-Go inhibition (β= -.578, t = -2.303, p=.025), SFA score and and choice stopping inhibition (β= -.841, t = -2.055, p=.044). Moderated regression analysis was used to determine whether ADHD moderates the relationship between executive inhibitory control measures and neurological soft signs. The model with PANESS SFA (Standard deviation from average time taken to do patterned movements, with higher SFA indicating slower than expected movements) and Choice stop inhibition (Percentage of responses correctly inhibited in a choice response stop task) had a significant interaction effect by the diagnosis status. When the child has ADHD, there is a significant positive relationship between the time taken for movements (SFA score) and correctly inhibiting an ongoing response, b = 1.700, t = 2.952, p =.005 (Figure 1). Thus the time taken for patterned motor movements could predict the ability to inhibit ongoing response in children with ADHD but not in the control group. The results suggest that children with ADHD had deficient ongoing response inhibition. All neurological soft signs measured by Physical and Neurological Examination of Soft Signs (PANESS) were significantly higher in children with ADHD than typically developing children. An increased amount of overflow movements and dysrhythmia during patterned movements were evident in the ADHD group, pointing to a deficient or lagging motor development compared to control group children belonging to the same age group. The results are discussed in the light of existing literature.

Group Authors

Nanditha K

Author

• Azizuddin Khan, Indian Institute of Technology Bombay, India
  Presenting Author