Non-Invasive Brain Stimulation (NIBS) is a relatively new therapeutic approach that has shown beneficial effects in Autism Spectrum Disorder (ASD). One question to be answered is how enduring its neuromodulatory effect could be. Twenty-four patients with ASD (mean age: 12.2 years) received 20 sessions of NIBS over the left dorsolateral prefrontal cortex (L-DLPFC). They were randomized into two groups with two (G1) or three (G2) clinical evaluations before NIBS. Both groups had a complete follow-up at six months after the intervention, with the aim of determining the short-term outcome using the total score on the Autism Behavior Checklist, Autism Treatment Evaluation Checklist, and the Autism Diagnostic Interview. Transcranial Direct Current Stimulation (tDCS) was used in ASD patients aged <11 years, and repetitive Transcranial Magnetic Stimulation (rTMS) for 11–13-year-olds. Observation points were at one, three, and six months after completing all the sessions of NIBS. A significant reduction in the total score on the three clinical scales was observed and maintained during the first six months after treatment, with a slight and non-significant tendency to increase the scores in the last evaluation. Twenty sessions of NIBS over the L-DLPFC improves autistic symptoms in ASD children, with a lasting effect of six months.

Introduction. Autism Spectrum Disorder(ASD) still being a therapeutic challenge for neurosciences. Different pharmachological and non-pharmachological treatments have been developed inducing benefits in ASD patients in some degree, with cumulative effect; but more research is needed to improve clinical results. There are evidences about the potential positive effects of Non-Invasive Brain Stimulation(NIBS) in ASD patients. Objective. To evaluate the safety and effectiveness of NIBS in patients with ASD. Methods. We carried out a proof of concept study including 15 children with ASD according to DSM-5 diagnostic criteria. They proceeded from the ambulatory services of the International Center for Neurological Restoration and Borras-Marfan Hospital(Havana, Cuba). Inclusion criteria established that children should had no change in their therapeutic approach one month before the intervention; and an equivalent period of stabilization of their symptoms. Repetitive Transcranial Magnetic Stimulation(rTMS) and Transcranial Direct Current Stimulation(tDCS) were used as stimulation methods; tDCS(cathode F3, anode right arm) was used in children under 10 years and 11 month; and 1 Hz rTMS for children over 11 years. Stimulation was focalized over the left dorsolateral prefrontal cortex, and a total of 20 session were applied. Patients were evaluated before and one week after the intervention applying the Autism Treatment Evaluation Checklist(ATEC), the Autism Diagnostic Interview(ADI-R) and the Autism Behavior Checklist(ABC). Results. Only in one patient it was not possible to start the treatment because of poor collaboration. The other 14 completed the 20 sessions with a few adverse effects, basically local pain at the stimulation site. A significant change in clinical scales was observed, with lower scores in the second evaluation, (ADI-R: initial = 52 +/- 9, final = 44.4 +/- 7; ATEC: 58 +/- 19.4 and 41 +/- 14.7; ABC: 108.4 +/- 23.7 and 89 +/- 17; p<0.05); indicating a clinical improvement in the group of patients. Conclusions. NIBS was well tolerated and induced behavioral changes in our sample of patients in key aspects of autistic behavior.