Deep repetitive transcranial magnetic stimulation for autism spectrum disorder

The prevalence of autism spectrum disorder (ASD) is currently estimated at 1 in 88, but there is a distinct lack of validated biomedical treatments that target the core symptoms. Non-invasive brain stimulation techniques, including repetitive transcranial magnetic stimulation (rTMS), have been established as safe and efficacious treatments for a range of psychiatric disorders, particularly depression. We conducted a pilot, placebo-controlled study of deep rTMS (a form of rTMS providing stimulation of brain structures further away from the scalp) among individuals with ASD (n = 28) that involved a conservative two-week course of stimulation, and found evidence of improved social relating among those undergoing active deep rTMS. Following on from our pilot research, this study will examine the underlying mechanism of deep rTMS, and the safety and efficacy of a stronger course of deep rTMS in ASD. There will be two phases to this study. Phase 1 will involve 20 individuals with ASD aged 18 or older. They will undergo positron emission tomography (PET) and clinical assessment before and after receiving 30 minutes of active deep rTMS each weekday for 3 weeks, and for 2 weekdays of the following week. This phase will help to understand the underlying brain mechanism of deep rTMS. Phase 2 will involve 60 individuals with ASD aged 15 or older. They will receive 30 minutes of either active (n = 30) or sham (placebo) (n = 30) deep TMS each weekday for 3 weeks, and for 2 weekdays of the following week. Clinical assessments will be conducted at five points: (1) before the first treatment, (2) immediately after the last treatment, (3) 1 month after the last treatment, (4) 3 months after the last treatment, and (5) 6 months after the last treatment. These assessments will comprise self-report and parent-report (or significant other-report) questionnaires assessing ASD symptomatology and short experimental measures assessing distinct aspects of social relating (e.g., perception of other’s emotions). Individuals must have been assessed to have an IQ of 55 or above (i.e., mild intellectual disability, average intelligence, or above average intelligence). Capacity to provide informed consent will be evaluated and monitored for all adult participants. Child participants will require parental consent to participate. For Phase 1, it is expected that deep rTMS will enhance activity within the brain’s ‘mentalising network’ (i.e., a series of connected regions devoted to understanding others thoughts, beliefs, intentions, and feelings) and result in clinical improvements to social relating symptoms. For Phase 2, it is expected that active deep rTMS will improve social abilities in ASD, and that these will be maintained after 6 months. Should our hypotheses be supported, it will indicate the possibility of deep rTMS as a neurobiological intervention for ASD.