Abstract
Individuals with Attention Deficit Hyperactivity Disorder (ADHD) typically perform cognitive tasks with greater response time variability than matched peers. This is thought to be due to the greater occurrence of occasional extremely slow responses associated with lowered arousal levels. To test this we designed a new, less arousing task to measure sustained attention, named the Disappearance Detection Task (DDT). This study aimed to investigate the relationship between response time variability and levels of ADHD symptoms both in this new, low-arousal sustained attention task and in the Sustained Attention to Response Task (SART). Twenty-eight children and 49 adolescents participated. On both tasks, ADHD symptom levels were associated with response time variability measures of SDRT and tau, but not with sigma. On the DDT, children with higher ADHD symptoms made more commission errors and were less accurate in detecting the target (d'), whereas adolescents made a similar number of commission errors and d' irrespective of their ADHD symptom levels. This pattern was not present in the SART. The adolescents found the DDT more challenging than the SART as their target sensitivity was lower during the DDT. The children were less confident in nominating the target (criterion) during the DDT than the SART. The results indicate that RTV measures are more consistently associated with ADHD symptoms than other RT measures and that the DDT is a sensitive task of sustained attention and response inhibition performance, particularly in children, and in children with higher symptoms of ADHD.