Effects of methylphenidate in children with attention deficit hyperactivity disorder: a near-infrared spectroscopy study with CANTAB®

Naomi Matsuura,Tohru Fujioka,Michio Hiratani,Hirotaka Kosaka,Makoto Ishitobi,Yuji Wada,Mizuki Asano,Kaori Kawamura,Sumiyoshi Arai,Keisuke Inohara,Tadamasa Narimoto

doi:10.1186/s13034-014-0032-5

Abstract

BackgroundA wide range of evidence supports the methylphenidate (MPH)-induced enhancement of prefrontal cortex (PFC) functioning and improvements in behavioral symptoms in patients with attention deficit hyperactivity disorder (ADHD). Although working memory (WM) has been hypothesized to be impaired in patients with ADHD, no pharmacological studies have examined visuospatial WM (VSWM) with near-infrared spectroscopy (NIRS).Study aimThe present study was designed to investigate the acute effects of MPH on neuropsychological performance and hemodynamic activation in children with ADHD during VSWM tasks.MethodsThe subject group included 10 boys and 1 girl previously diagnosed with ADHD. Two VSWM tasks of differing degrees of difficulty were conducted. This is the first study on the pharmacological effects of MPH in children with ADHD to evaluate hemodynamic responses in the PFC with simultaneous NIRS.ResultsNo significant differences were found in the scores for both spatial working memory (SWM) and score of spatial span (SSP) tasks between the MPH-off and MPH–on conditions. However, a significant MPH-effect on changes in oxy-hemoglobin levels in the PFC was found only in the SWM task.ConclusionThese findings suggest that PFC activation might be affected by MPH, depending on the degree of difficulty of the particular task. Although the MPH-induced change on behavior may or may not be obvious, NIRS measurements might be useful for assessing the psychological effects of MPH even when performance changes were not observed in the cognitive tasks.

Highlights

Attention-deficit hyperactivity disorder (ADHD) is a common developmental disorder that affects 3% to 7% of school–age children [1]
These findings suggest that prefrontal cortex (PFC) activation might be affected by MPH, depending on the degree of difficulty of the particular task
The MPH-induced change on behavior may or may not be obvious, near-infrared spectroscopy (NIRS) measurements might be useful for assessing the psychological effects of MPH even when performance changes were not observed in the cognitive tasks

Summary

Introduction

Attention-deficit hyperactivity disorder (ADHD) is a common developmental disorder that affects 3% to 7% of school–age children [1]. The current conceptual models of ADHD are centered on neuropsychological theories of impaired functioning of the frontal lobes, especially the prefrontal cortex (PFC). It has been suggested that the cognitive difficulties that are experienced by children with ADHD are accounted for by deficits in executive functions (EFs) [2]. Kofler et al suggested that WM is the core and causal cognitive process that is responsible for ADHD in “The Working Memory Model of ADHD” [6]. A wide range of evidence supports the methylphenidate (MPH)-induced enhancement of prefrontal cortex (PFC) functioning and improvements in behavioral symptoms in patients with attention deficit hyperactivity disorder (ADHD). Working memory (WM) has been hypothesized to be impaired in patients with ADHD, no pharmacological studies have examined visuospatial WM (VSWM) with near-infrared spectroscopy (NIRS).

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