J Psychiatry Neurosci 2015;40(5):325-335
Huey-Ling Chiang, MD; Yu-Jen Chen, PhD; Yu-Chun Lo, PhD; Wen-Yih Isaac Tseng, MD, PhD; Susan Shur-Fen Gau, MD, PhD
Background: The neural substrate for clinical symptoms and neuropsychological performance in individuals with attention-deficit/hyperactivity disorder (ADHD) has rarely been studied and has yielded inconsistent results. We sought to compare the microstructural property of fibre tracts associated with the prefrontal cortex and its association with ADHD symptoms and a wide range of attention performance in youth with ADHD and healthy controls.
Methods: We assessed youths with ADHD and age-, sex-, handedness-, coil- and intelligence-matched controls using the Conners’ Continuous Performance Test (CCPT) for attention performance and MRI. The 10 target tracts, including the bilateral frontostriatal tracts (caudate to dorsolateral prefrontal cortex, ventrolateral prefrontal cortex and orbitofrontal cortex), superior longitudinal fasciculus (SLF) and cingulum bundle were reconstructed using diffusion spectrum imaging tractography. We computed generalized fractional anisotropy (GFA) values to indicate tract-specific microstructural property.
Results: We included 50 youths with ADHD and 50 healthy controls in our study. Youths with ADHD had lower GFA in the left frontostriatal tracts, bilateral SLF and right cingulum bundle and performed worse in the CCPT than controls. Furthermore, alteration of the right SLF GFA was most significantly associated with the clinical symptom of inattention in youths with ADHD. Finally, youths with ADHD had differential association patterns of the 10 fibre tract GFA values with attention performance compared with controls.
Limitations: Ten of the youths with ADHD were treated with methylphenidate, which may have long-term effects on microstructural property
Conclusion: Our study highlights the importance of the SLF, cingulum bundle and frontostriatal tracts for clinical symptoms and attention performance in youths with ADHD and demonstrates the involvement of different fibre tracts in attention performance in these individuals.
Submitted Apr. 21, 2014; Revised Aug. 29, 2014; Accepted Dec. 25, 2015; Early-released Apr. 14, 2015.
Affiliations: From the Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ( Chiang, Gau); Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (Chiang, Gau); Department of Psychiatry, Far Eastern Memorial Hospital, Taipei, Taiwan (Chiang); Center for Optoelectronic Medicine, National Taiwan University College of Medicine, Taipei, Taiwan (Chen, Tseng, Lo); Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan (Tseng, Gau); Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan (Tseng); Department of Psychology, School of Occupational Therapy, and Graduate Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan (Gau).
Acknowledgements: This work was supported by the National Science Council (NSC99-2627-B-002-015, NSC100-2627-B-002-014, NSC101-2627-B-002-002, NSC101-2321-B-002-079) and the National Taiwan University Hospital (NTUH101-S1910), Taiwan. The manuscript preparation was supported by the National Health Research Institute (NHRI-EX102-0008PI) and Ministry of Economic Affairs (101-EC-17-A-19-S1-175), Taiwan.
Competing interests: None declared.
Contributors: H.-L. Chiang and S.S.-F. Gau designed the study. W.- Y.I. Tseng and S.S.-F. Gau acquired the data, which H.-L. Chiang, Y.-J. Chen, Y.-C. Lo and S.S.-F. Gau analyzed. H.-L. Chiang, Y.- J. Chen and S.S.F. Gau wrote the article, which all authors reviewed and approved for publication.
Clinical trial registration: This work was registered before study implementation (ClinicalTrials.gov number, NCT01677793, NCT00916851). The authors assert that all procedures contributing to this work comply with the ethical standards of relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975 as revised in 2008.
Correspondence to: S.S.-F. Gau, Department of Psychiatry, National Taiwan University Hospital and College of Medicine, No. 7, Chung-Shan South Rd., Taipei, Taiwan; firstname.lastname@example.org or W.-Y.I. Tseng, Center for Optoelectronic Medicine, National Taiwan University College of Medicine, No. 1, Sec. 1, Jen-Ai Rd., Taipei, Taiwan; email@example.com