IMR Press / JIN / Volume 21 / Issue 2 / DOI: 10.31083/j.jin2102057
Open Access Review
A systematic review of frontal lobe volume in autism spectrum disorder revealing distinct trajectories
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1 Faculty of Health, School of Psychology, Deakin University, Geelong, 3220 VIC, Australia
*Correspondence: (Mark A. Stokes)
Academic Editor: Woo-Yang Kim
J. Integr. Neurosci. 2022, 21(2), 57;
Submitted: 20 May 2021 | Revised: 3 August 2021 | Accepted: 20 August 2021 | Published: 22 March 2022
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Frontal lobe volume has been extensively researched in individuals with Autism spectrum disorder (ASD), though findings are yet to be summarised to explain the developmental trends of frontal lobe volume. The aim of the present study is to consolidate all existing frontal lobe volume and age data of autistic individuals below 30 years of age, and compare this data to non-autistic (N-ASD) controls. Following a systematic review, frontal lobe volume data were obtained from seven papers. Raw data, or the means and standard deviations of frontal lobe volume, and age, were obtained from the studies giving 372 autistic and 190 N-ASD participants. Data were plotted and analysed. Findings revealed that regression lines of fit for ASD (R2Linear = 0.33; R2Quadratic = 0.52) and N-ASD (R2Linear = 0.14; R2Quadratic = 0.39) were significantly different by diagnosis (linear p = 0.002, quadratic p = 0.02) with quadratic models providing significantly better fit within ASD (p < 0.001) and N-ASD (p < 0.001). Additional analyses revealed that frontal lobe volume was greater in autistic individuals than N-ASD between two and four years (F(1,31) = 12.965, p < 0.005, η2 = 0.291). In the present study, there were distinct developmental trends for frontal lobe volume between ASD and N-ASD.

Autism spectrum disorder
Frontal lobe volume
Systematic review
Fig. 1.
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