Date Presented 04/05/19
Neuroanatomical differences in ADHD is one of the most investigated topics. Therefore, we aimed to identify these differences through the first published Systematic Overview of Systematic Reviews, using Cochrane guidelines and PRISMA to criteria. We propose a hypothesis of an unbalanced multinetwork neurofunctioning and the scientific evidence that OT must be integrated in primary-care teams to assess how a multiskill involvement impacts functional and occupational performance.
Primary Author and Speaker: Bruno Vieira de Melo
Contributing Authors: Maria João Trigueiro, Pedro Rodrigues
PURPOSE: Neuroanatomical differences in ADHD is one of the most investigated topics for several decades, with over 100 reviews and yet inconclusive large-scale brain network implications and models. Given this volume of scientific information, this paper seeks to identify neuroanatomical differences in ADHD through a systematic overview of systematic reviews that report encephalic differences compared to a control group in volume, area, activation likelihood or chemical composition. This paper seeks to create conclusive evidence about this differences providing further support for functional and occupational performance analysis.
DESIGN: We conducted an Overview with a systematic search in PubMed, Scopus, Web of Science, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects. This review was conducted following the guidelines from the Cochrane Handbook for Systematic Reviews of Interventions and quality criteria by PRISMA Statement. Discrepancies were resolved by consensus among two investigators. No protocol or overview was identified to be similar to the methods applied in this overview. We included systematic reviews that used an imaging diagnostic technique to report functional or structural neuroanatomical differences between ADHD without comorbidity and normal controls, were included. English, Spanish, Italian, French, and Portuguese languages were included. No date restriction was applied.
METHOD: Search results were imported to Mendeley, duplicates were excluded and were subjected to two levels of screening: title/abstract and full text. Additional reviews identified in full text analysis were included. The PRISMA 27-item criteria checklist was applied and the data extracted to four main tables and eight supplemental tables.
The divergence in the type of results between systematic reviews did not allow for a quantitative analysis. A qualitative synthesis of neuroanatomical functional and structural differences in ADHD vs normal controls is provided.
RESULTS: A total of 8,253 articles were initially retrieved. 103 systematic reviews were identified by reviewing title/abstract. A full-text analysis yielded 17 systematic reviews that aimed to identify the structural or functional neuroanatomical differences between ADHD and normal controls. Trials used were pooled so that the overlap could be analyzed and the PRISMA 27-item checklist was applied. 6 systematic reviews were included in this review covering 145 individual trials (out of the total 191 pooled trials) using MRI; MRI-VBM; fMRI; MRS and MRI-DTI-TBSS, from 1990 to 2015, with over 4144 participants.
Neuroanatomical results revealed broad encephalic involvement that tend to a functional frontal and cingulate hypoactivation and structural differences in corpus callosum, cerebellum and basal nuclei.
CONCLUSIONS: ADHD is clearly suggested to go beyond the frontoparietal network and dopaminergic system and we propose that it might be due to a multi-network unbalanced functioning hypothesis.
This hypothesis is consistent with its translation to multiple implications in cognitive, emotional regulation, motor, sensory-perceptual, and social skills.
IMPLICATIONS FOR PRACTICE: This study highlights the importance of an assessment of non-core symptoms and functional/occupational performance.
IMPLICATIONS FOR RESEARCH: This study highlights the urgent need for highly homogeneous trials and supports ADHD models that conceptualize a systemic implication of the nervous system.
IMPACT STATEMENT: This study creates the scientific evidence that Occupational Therapy should be integrated in primary care teams for its training and expertise in the assessment of functional/occupational performance and its multi-skill relationship.
References
Aoki, Y., Inokuchi, R., Suwa, H., & Aoki, A. (2013). Age-related change of neurochemical abnormality in attention- deficit hyperactivity disorder: A meta-analysis. Neuroscience & Biobehavioral Reviews, 37(8), 1692–1701. doi:10.1016/j.neubiorev.2013.04.019
Chen, L., Hu, X., Ouyang, L., He, N., Liao, Y., Liu, Q., . . . Gong, Q. (2016). A systematic review and meta-analysis of tract-based spatial statistics studies regarding attention-deficit/hyperactivity disorder. Neuroscience and Biobehavioral Reviews, 68, 838–847. doi:10.1016/j.neubiorev.2016.07.022
Cortese, S., Kelly, C., Chabernaud, C., Proal, E., Di Martino, A., Milham, M. P., & Castellanos, F. X. (2012). Toward systems neuroscience of ADHD: A meta-analysis of 55 fMRI sudies. American Journal of Psychiatry, 169(10), 1038– 1055. doi:10.1176/appi.ajp.2012.11101521
Durston, S., De Zeeuw, P., & Staal, W. G. (2009). Imaging genetics in ADHD: A focus on cognitive control. Neuroscience and Biobehavioral Reviews, 33(5), 674–689. doi:10.1016/j.neubiorev.2008.08.009
