19995
Repetitive Transcranial Magnetic Stimulation over the Dorsolateral Prefrontal Cortex and Posterior Superior Temporal Sulcus Improves Core Symptoms of Autism
Effective biological interventions for autism have remained elusive and repetitive transcranial magnetic stimulation (rTMS) is considered a promising approach. Previous studies demonstrated that repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex (DLPFC) decreased repetitive behaviors in autism, however, there was no obvious response in improving social impairments in autism. Efficacy of rTMS over other brain areas is unknown in autism.
Objectives:
To test whether rTMS over (1) the bilateral posterior superior temporal sulcus (pSTS) and (2) the bilateral DLPFC could improve core symptoms and neuropsychological functions of autism
Methods:
25 adults with autism (mean age: 21.2 years old, 20 males) participated in a randomized, sham-controlled, cross-over trial of rTMS, and 19 of them completed the study. Every participant randomly accepted the single-session rTMS over the bilateral DLPFC, bilateral pSTS and inion (as Sham control) with one-week interval. A modified rTMS paradigm, intermittent Theta-Burst stimulation, which has been shown to produce a long lasting excitation of the cortex, was applied in our study. The stimulus intensity over the DLPFC and pSTS was 80% active motor threshold (AMT) and over inion was 60% AMT with reverse of the coils. Locations of the DLPFC and pSTS were determined via a three-dimensional brain reconstruction provided by a TMS-dedicated navigation system from individual magnetic resonance imaging data. Behavioral outcomes were measured with Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and Social Responsiveness Scale (SRS), rated by participants themselves and their parents before and after every course of stimulation (8 hours and 2 days later, respectively). Neuropsychological functions were indexed by the Conners’ Continuous Performance Test and Wisconsin Card Sorting Test (WCST) before and after every course of stimulation (practiced within one hour after stimulation).
Results:
In comparison to sham stimulation, total scores of the Y-BOCS rated by parents and total scores of the SRS rated by participants significantly decreased 8 hours after pSTS-stimulation. Besides, total scores of the Y-BOCS and scores of social awareness in the SRS rated by parents also significantly decreased 2 days after pSTS-stimulation. As for neuropsychological outcomes, commission errors in CPT significantly increased but there was no significant difference in performance of WCST after pSTS-stimulation. In comparison to sham stimulation, scores of social communication in the SRS rated by participants significantly decreased 8 hours and 2 days after DLPFC-stimulation, respectively. Scores of autistic mannerism in the SRS rated by parents significantly decreased 2 days after DLPFC-stimulation. As for neuropsychological outcomes, hit reaction time in CPT significantly decreased after DLPFC-stimulation, but there was no significant difference in performance of WCST after DLPFC-stimulation.
Conclusions:
We found that single session rTMS over the bilateral DLPFC and pSTS improved social functions and repetitive behaviors in autism. Beyond consistency in effects of DLPFC-stimulation, the efficacy of rTMS over the pSTS needs to be investigated and replicated by future multiple-sessions rTMS studies.