Transcranial magnetic stimulation in autism spectrum disorder: a narrative review of neurobiological mechanisms, clinical efficacy, and future directions

Abstract

Autism Spectrum Disorder (ASD) is a complicated neuropsychological disorder associated with social communicational problems, stereotypical interests, and behavior patterns. Though ASD has many causes, there are no treatment modalities today that have an overall impact on the condition itself, leaving room for improvement in existing approaches. Transcranial Magnetic Stimulation (TMS) is one of the innovative approaches to treat such disorders by means of a noninvasive method of neuron activation using a strong magnetic field. The TMS could have an influence on the interconnection of the brain networks, synaptic plasticity, and the brain cortex excitability, which are associated with the alleviation of the symptoms of ASD. Although some randomized and open-label studies have reported improvement, the evidence is weakened by small samples, inconsistent protocols, and the large proportion of uncontrolled studies. This would mean that the process of selecting patients as well as administering TMS would need careful attention. There are no documented long-term impacts of TMS. For future studies, there should be incorporation of the principles from neuroimaging and electrophysiology. TMS is performed using different techniques depending on its objectives, which include single-pulse TMS that assesses brain topography; paired-pulse TMS in evaluating the inhibitory or facilitating nature of the brain cortex; repetitive TMS (rTMS). It can be concluded from all the information presented above that TMS might have immense potential as an add-on treatment for ASDs based on the data we have accumulated. However, more studies are needed to assess the efficacy of this treatment method in addressing ASDs.To summarize, TMS is a relatively novel neuromodulation therapy that can benefit individuals with ASDs based on the neurobiological aspects of their disorders.