Exploratory Study of rTMS Neuromodulation Effects on Electrocortical Functional Measures of Performance in an Oddball Test and Behavioral Symptoms in Autism

Abstract

There is no accepted pathology to autism spectrum disorders (ASD) but research suggests the presence of an altered excitatory/inhibitory (E/I) bias in the cerebral cortex. Repetitive transcranial magnetic stimulation (rTMS) offers a non-invasive means of modulating the E/I cortical bias with little in terms of side effects. In this study, 124 high functioning ASD children (IQ > 80, <18 years of age) were recruited and assigned using randomization to either a waitlist group or one of three different number of weekly rTMS sessions (i.e., 6, 12, and 18). TMS consisted of trains of 1.0 Hz frequency pulses applied over the dorsolateral prefrontal cortex (DLPFC). The experimental task was a visual oddball with illusory Kanizsa figures. Behavioral response variables included reaction time and error rate along with such neurophysiological indices such as stimulus and response-locked event-related potentials (ERP). One hundred and twelve patients completed the assigned number of TMS sessions. Results showed significant changes from baseline to posttest period in the following measures: motor responses accuracy [lower percentage of committed errors, slower latency of commission errors and restored normative post-error reaction time slowing in both early and later-stage ERP indices, enhanced magnitude of error-related negativity (ERN), improved error monitoring and post-error correction functions]. In addition, screening surveys showed significant reductions in aberrant behavior ratings and in both repetitive and stereotypic behaviors. These differences increased with the total number of treatment sessions. Our results suggest that rTMS, particularly after 18 sessions, facilitates cognitive control, attention and target stimuli recognition by improving discrimination between task-relevant and task-irrelevant illusory figures in an oddball test. The noted improvement in executive functions of behavioral performance monitoring further suggests that TMS has the potential to target core features of ASD.

Effects of Transcranial Magnetic Stimulation Therapy on Evoked and Induced Gamma Oscillations in Children with Autism Spectrum Disorder

“…These improvements have been noted on tests of cognitive flexibility, conceptual tracking, attention and working memory [ 65 , 66 , 67 ]. In ASD, TMS can change some of the core deficits, more specifically, those impairments in self-monitoring that constitute our supervisory attentional system [ 10 , 29 , 40 , 41 , 68 ]. Higher amplitude of early evoked gamma activity has been correlated to faster behavioral responses, which could constitute impulsive behaviors [ 69 ].…”

“…Indeed, results from previous trials suggest that individuals with ASD have a reduced sensitivity for monitoring errors (i.e., a diminished response time after committing an error) and instituting corrective actions. Researchers believe that a deficit in monitoring errors might manifest itself as perseverative behaviors typical of ASD [ 10 , 29 , 40 , 41 , 68 ].…”

“…EEG data was screened for artifacts and all trials that had eye blinks, gross movements and other artifacts were removed using Netstation artifact rejection tools [ 39 ]. Other details of our experimental procedure and EEG data acquisition, pre-processing and analysis can be found in our prior studies using the same methodology [ 26 , 27 , 28 , 29 , 40 , 41 ]. Stimulus-locked dependent EEG variables for the frontal (F3, F4, F7, F8) and parietal (P3, P4, P7, P8) sites-of-interest referenced to vertex (Cz) and nasion as a ground were used for gamma oscillation analysis.…”

The erring brain: Error‐related negativity as an endophenotype for OCD—A review and meta‐analysis

“…A similar result has been reported for repetitive transcranial magnet stimulation over the dorsolateral prefrontal cortex in autism. Besides an increase in ERN, performance was also improved (Sokhadze et al, ). In summary, several interventions have been successfully applied to modify the ERN, albeit not in OCD populations so far, and future research should follow up these promising results.…”

Effects of cTBS on the Frequency-Following Response and Other Auditory Evoked Potentials

“…Notably, a crucial element when considering the effectiveness of any TMS protocol in cortical areas is how deep within the brain the stimulation target is. In addition to fMRI-measured and sensory processing effects observed in the studies described, several studies measuring rTMS effects on event-related potentials, as we do, have targeted areas of superficial cortex [e.g., prefrontal (Lowe et al, 2018;Sokhadze et al, 2018) or somatosensory (Poreisz et al, 2008) areas]. However, our target area of stimulation, the primary auditory cortex, includes a part of cortex buried within the temporal lobe, at the supratemporal plane [i.e., Heschl's gyri (Abdul-Kareem and Sluming, 2008)].…”