Lack of effects of four-week theta burst stimulation on white matter macro/microstructure in children and adolescents with autism

• Published in: NeuroImage clinical 2023-01, Vol.37, p.103324-103324, Article 103324
• Main Authors: Ni, Hsing-Chang, Chao, Yi-Ping, Tseng, Rung-Yu, Wu, Chen-Te, Cocchi, Luca, Chou, Tai-Li, Chen, Rou-Shayn, Gau, Susan Shur-Fen, Yeh, Chun-Hung, Lin, Hsiang-Yuan
• Format: Article
• Language: English
• Subjects: Adolescent; Autism; Autistic Disorder - diagnostic imaging; Brain - diagnostic imaging; Child; Diffusion MRI; Humans; Posterior superior temporal sulcus; Randomized controlled trial; Regular; Single-Blind Method; Theta burst stimulation; Theta Rhythm - physiology; Transcranial magnetic stimulation; Transcranial Magnetic Stimulation - methods
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2023.103324

•No significant white matter changes following 8-week iTBS over bilateral pSTS in ASD.•Symptom changes do not correlate with white matter metrics following 4-week iTBS.•It is imperative to have more studies on brain markers linked to responses to rTMS. Following the published behavioral and cognitive results of this single-blind parallel sham-controlled randomized clinical trial, the current study aimed to explore the impact of intermittent theta burst stimulation (iTBS), a variant of excitatory transcranial magnetic stimulation, over the bilateral posterior superior temporal sulci (pSTS) on white matter macro/microstructure in intellectually able children and adolescents with autism. Participants were randomized and blindly received active or sham iTBS for 4 weeks (the single-blind sham-controlled phase). Then, all participants continued to receive active iTBS for another 4 weeks (the open-label phase). The clinical results were published elsewhere. Here, we present diffusion magnetic resonance imaging data on potential changes in white matter measures after iTBS. Twenty-two participants in Active-Active group and 27 participants in Sham-Active group underwent multi-shell high angular resolution diffusion imaging (64-direction for b = 2000 & 1000 s/mm2, respectively) at baseline, week 4, and week 8. With longitudinal fixel-based analysis, we found no white matter changes following iTBS from baseline to week 4 (a null treatment by time interaction and a null within-group paired comparison in the Active-Active group), nor from baseline to week 8 (null within-group paired comparisons in both Active-Active and Sham-Active groups). As for the brain-symptoms relationship, we did not find baseline white matter metrics associated with symptom changes at week 4 in either group. Our results raise the question of what the minimal cumulative stimulation dose required to induce the white matter plasticity is.