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Updated: Jan 24, 2026

Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
Published on: September 12, 2011
Differences in Cognition and Behaviour in Multiplex and Simplex Autism: Does Prior Experience Raising a Child with
Daniel Berends1, Cheryl Dissanayake1, Lauren P Lawson2,3
1Olga Tennison Autism Research Centre, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Plenty Road & Kingsbury Drive, Melbourne, VIC, 3086, Australia.
Abstract:
Previous research has found multiplex (MPX) children have an advantage in cognition compared to simplex (SPX) children. However, MPX parent's previous experience with older diagnosed siblings has not been considered. We used a large database sample to investigate the MPX advantage and contribution of birth order. Children from the Autism Genetic Resource Exchange (AGRE) were stratified into first- (MPX1, n = 152) and second-affected MPX (MPX2, n = 143), SPX (n = 111), and only-child SPX (SPXOC, n = 23) groups. Both MPX groups had higher cognitive scores compared to SPX groups, with no differences between MPX1 and MPX2 groups. No differences were found for autism symptoms or adaptive behaviour. These results suggest parent experience due to birth order is an unlikely contributor to the MPX cognitive advantage.
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