If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Brief Summary:
In the current project, investigators have two main goals: i) Testing whether an excessive plasticity, i.e. hyperplasticity in the motor cortex underlies motor function difficulties in autistic adults, and ii) Using repetitive Transcranial Magnetic Stimulation (rTMS) with autistic adults to examine whether resulting reduced hyperplasticity in the motor cortex will be associated with clinical improvements in the motor function.
Detailed Description:
Autism spectrum disorder (ASD) is a very common developmental condition, yet the cause remains unknown and effective treatment options to improve outcomes remain limited. Most autistic adults experience significant motor function difficulties involving balance, posture, coordination, and strength that negatively affect their quality of life, social interaction, confidence and daily functioning. Therefore, such difficulties remain an important treatment target. However, there are no known effective clinical interventions for such difficulties. Investigators previously showed that the part of the brain that controls motor movements, i.e. motor cortex, showed hyperplasticity, as assessed by theta-burst magnetic brain stimulation (TBS), in autistic adults. Hyperplasticity may adversely affect brain health and behavior. Investigators also previously found that rTMS may reduce such hyperplasticity in the motor cortex in autistic adults.
In this project, 100 autistic adults with significant motor function difficulties and 50 neurotypical (NT) controls matched 2:1 based on age, sex, and IQ will be recruited. At the Centre for Addiction and Mental Health, Toronto, each autistic adult's participation will consist of eight visits, while each NT adult's participation will include two visits.
All participants, both autistic and NT, will undergo clinical, adaptive, and motor function assessments during their first visit (lasting approximately 3 hours) and a pre- and post-intermittent-TBS (iTBS) session, paired with electroencephalography (EEG), to induce and assess plasticity in the left or right motor cortex (depending on handedness) during their second visit (lasting approximately 3 hours). Based on the preliminary evidence that rTMS reduces hyperplasticity in the motor cortex in autistic adults, the investigators will then use a randomized, double-blind, sham-controlled design for bilateral 3-session rTMS on the motor cortex. Autistic participants will be randomized (1:1, sex-stratified) to receive either active or sham rTMS (150 trains of 40 pulses with an inter-train interval of 25 seconds, delivered at 90% of the resting motor threshold for both conditions) three days a week (approximately 1.5 hours each), from their third to fifth visits (total of 3 sessions). Assessment of motor and adaptive function, and plasticity in the motor cortex will be repeated the next day, one week (seventh visit), and four weeks (eighth visit) after the last rTMS session (i.e. 3rd rTMS session).