Impulsiveness as a timing disturbance: neurocognitive abnormalities in attention-deficit hyperactivity disorder during temporal processes and normalization with methylphenidate

Abstract

We argue that impulsiveness is characterized by compromised timing functions such as premature motor timing, decreased tolerance to delays, poor temporal foresight and steeper temporal discounting. A model illustration for the association between impulsiveness and timing deficits is the impulsiveness disorder of attention-deficit hyperactivity disorder (ADHD). Children with ADHD have deficits in timing processes of several temporal domains and the neural substrates of these compromised timing functions are strikingly similar to the neuropathology of ADHD. We review our published and present novel functional magnetic resonance imaging data to demonstrate that ADHD children show dysfunctions in key timing regions of prefrontal, cingulate, striatal and cerebellar location during temporal processes of several time domains including time discrimination of milliseconds, motor timing to seconds and temporal discounting of longer time intervals. Given that impulsiveness, timing abnormalities and more specifically ADHD have been related to dopamine dysregulation, we tested for and demonstrated a normalization effect of all brain dysfunctions in ADHD children during time discrimination with the dopamine agonist and treatment of choice, methylphenidate. This review together with the new empirical findings demonstrates that neurocognitive dysfunctions in temporal processes are crucial to the impulsiveness disorder of ADHD and provides first evidence for normalization with a dopamine reuptake inhibitor.

Hyperfocusing as a dimension of adult attention deficit hyperactivity disorder

“…Some authors also argue that abnormalities in timing functions are fundamental to impulsiveness (Rubia, Halari, Christakou, & Taylor, 2009). The passage of time appears to be subjectively longer/more intolerable for these patients suggestive of an abnormal time sense.…”

Real‐time fMRI neurofeedback in adolescents with attention deficit hyperactivity disorder

“…Performance on tasks of inhibition, sustained attention, time estimation and temporal discounting were measured using the Maudsley Attention and Response Suppression task battery (MARS) [Rubia et al, 2007a] (see Supporting Information), including a Go/No‐Go Task (main dependent variable: probability of inhibition), a Continuous Performance Task (CPT; omission and commission errors), a Time Discrimination Task (TD; errors), and an individually adjusted Delay Discounting Task (DD) (impulsiveness factor k) [Kekic et al, 2014; Rubia et al, 2009a]. …”

The experience of time: neural mechanisms and the interplay of emotion, cognition and embodiment

“…In the context of psychiatry research, Rubia et al (2009) postulate that altered time perception and timing functions underlie complex dysfunctional behaviour as seen in individuals with increased impulsivity. For one, their neuroimaging studies in children with attention deficit hyperactivity disorder point to a dysfunctional network of brain areas involved in the processing of time on different time scales and tasks.…”