University of Wuerzburg, Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, 97080 Wuerzburg, Germany.
J Psychiatr Res. 2010 Jul;44(10):621-8. doi: 10.1016/j.jpsychires.2009.11.018. Epub 2009 Dec 30.
Deficits in working memory have been repeatedly found on a behavioural level in children with attention-deficit/hyperactivity disorder (ADHD). Functional brain imaging studies have revealed evidence for alterations in the prefrontal cortex associated with working memory. So far it remains unresolved whether object (OWM) and spatial visual working memory (SWM) are distinctly impaired in ADHD. We investigated this issue with the fist multi-channel functional near-infrared spectroscopy study of children with ADHD.
We investigated 19 children with ADHD combined type (DSM-IV) and 19 controls matched for age (8-15years), sex, handedness, and intelligence during a working memory task assessing OWM and SWM separately, and a control condition (CON). Prefrontal brain activity was measured by concentration changes of oxygenated haemoglobin.
Working memory performance showed significant differences for conditions (OWM>SWM>CON), but no differences between groups. Cortical prefrontal activation was significantly higher for OWM and SWM in contrast to CON, again with no differences between groups.
We found no indication for an altered prefrontal processing during OWM and SWM tasks in ADHD children compared to controls. Reviewing the existing imaging literature on working memory in ADHD and considering the present data, we discuss possible confounding factors relevant for brain activity in previous, the current, and future investigations. Thus, it is of high importance to capture developmental trajectories, task specific discrepancies, and effects of permanent medication intake in future studies.
在注意力缺陷多动障碍（ADHD）儿童的行为水平上，已经反复发现工作记忆缺陷。功能脑成像研究揭示了与工作记忆相关的前额叶皮层改变的证据。到目前为止，ADHD 儿童的物体（OWM）和空间视觉工作记忆（SWM）是否明显受损仍未解决。我们使用多通道近红外光谱功能成像技术对 ADHD 儿童进行了首次研究。
我们在一项工作记忆任务中分别评估了 OWM 和 SWM 以及控制条件（CON），对 19 名 ADHD 综合型（DSM-IV）儿童和 19 名年龄（8-15 岁）、性别、利手和智力相匹配的对照组进行了研究。通过含氧血红蛋白浓度变化测量前额叶脑活动。
工作记忆表现因条件（OWM>SWM>CON）而异，但组间无差异。与 CON 相比，OWM 和 SWM 的皮质前额叶激活显著更高，组间也无差异。
与对照组相比，我们未发现 ADHD 儿童在 OWM 和 SWM 任务中前额叶处理异常的迹象。回顾 ADHD 工作记忆的现有影像学文献，并考虑本研究数据，我们讨论了可能影响以前、当前和未来研究中脑活动的混杂因素。因此，在未来的研究中，捕捉发育轨迹、任务特异性差异以及永久性药物摄入的影响非常重要。
