Visual cortex abnormalities in adults with ADHD: A structural MRI study

Abstract

Objectives. Most structural imaging studies in ADHD have focused on prefronto-striatal circuits. However, findings remained inconsistent while recent reports point to the posterior parietal cortex as an additional target for research. Moreover, although adult ADHD clinically differs from the childhood presentation little is known about the structural correlates of ADHD in adults. The aim of this study was to clarify the involvement of prefronto-striatal and posterior parietal areas in adult ADHD. Methods. Voxel-based morphometry of high resolution MRI scans was applied to analyze volumetric brain differences between 31 adult patients with ADHD and 31 control subjects. Results. The volume of prefrontal, striatal and parietal gray matter was normal. ADHD patients displayed a significant reduction of gray matter volume bilaterally in the early visual cortex (P < 0.04). Conclusions. The unexpected finding of visual cortex abnormalities might be related to impairments in early-stage, ‘subexecutive” attentional mechanisms. The results support the notion that executive dysfunction may not be the dominant neurobiological characteristic of ADHD at least in adult patients. The visual cortex deserves more consideration as a potentially important site of dysfunction in adult and possibly childhood ADHD.

Key words::

• Attention
• attention-deficit/hyperactivity disorder
• MRI
• occipital lobe
• voxel-based morphometry

Acknowledgements

This work was supported by grants from the German Federal Ministry of Education and Research (# 01GV0606 to LTVE), and the Ministry of Science, Research and the Arts of Baden-Württemberg, Germany (AZ: 23-7532.22-11/1 to LTVE). NR was supported by a Marie Curie Outgoing International Fellowship of the European Union. MW received funding from the German Research Council (DFG: SFB550, C4). The funding sources had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Statement of interest

None to declare.