Evidence for a pure time perception deficit in children with ADHD

Abstract

Background: Deficits have been found previously in children with ADHD on tasks of time reproduction, time production and motor timing, implicating a deficit in temporal processing abilities, which has been interpreted as either secondary or primary to core executive dysfunctions. The aim of this study was to explore further the abilities of hyperactive children in skills of time estimation, using a range of time perception tasks in different temporal domains. Method: Time estimation was tested in a verbal estimation task of 10 seconds. Time reproduction was also acquired for two time intervals of 5 and 12 seconds. A temporal discrimination task aimed to determine the idiosyncratic threshold of minimum time interval (in milliseconds) necessary to distinguish two intervals differing by approximately 300 milliseconds. Twenty-two children diagnosed with ADHD were compared to 22 healthy children, matched for age, handedness and working memory skills. Results: Children with ADHD were significantly impaired in their time discrimination threshold: on average, time intervals had to be 50 ms longer for the hyperactive children in order to be discriminated when compared with controls. Children with ADHD also responded earlier on a 12-second reproduction task, which however only approached significance after controlling for IQ and short-term memory. No group differences were found for the 5-second time reproduction or verbal time estimation tasks. Conclusions: The findings suggest that children with ADHD perform poorly on time reproduction tasks which load heavily on impulsiveness and attentional processes and they also suggest that these children may have a perceptual deficit of time discrimination, which may only be detectable in brief durations which differ by several hundred milliseconds. A temporal perception deficit in the range of milliseconds in ADHD may impact upon other functions such as perceptual language skills and motor timing.

Association of the dopamine transporter (DAT1) 10/10-repeat genotype with ADHD symptoms and response inhibition in a general population sample

“…Inhibitory control problems could be a secondary consequence of altered motivational processes and aversion to delay, 48,83 an insufficient ability to regulate the state of activation, 84,85 or as a consequence of more fundamental, simpler problems such as a more generalized deficit of processing speed, time processing, and motor response organization. 83,86,87 These alternative explanations require further investigation.…”

European clinical guidelines for hyperkinetic disorder ? first upgrade

“…Neuropsychological and electrophysiological studies have found various alterations in higher-order cognitive functions [9,114,142], motivational processes [129], and more basic information processing stages [13,83,135,149,174,188]. The tests used are summarised in the Appendix.…”

Beyond the Dual Pathway Model: Evidence for the Dissociation of Timing, Inhibitory, and Delay-Related Impairments in Attention-Deficit/Hyperactivity Disorder

“…It is clinically plausible as ADHD children have shown TPD across a range of timing tasks. [25][26][27][28][29][30][31] Results on motor timing are less consistent. 29,[32][33][34] fMRI confirms alterations within key components of temporal processing circuits in ADHD.…”