Electroencephalogram findings of children diagnosed with Autism Spectrum Disorder with and without regression

Objective: The aim of this study is to compare electroencephalogram (EEG) findings, laboratory and psychometric test results in children diagnosed with Autism Spectrum Disorder (ASD) according to whether there is regression or not, and to reveal the relationship between regression and EEG disorder. Materials and Methods: This study was designed as a retrospective and cross- sectional study. Between January 2020 and June 2023, patients who applied to Çukurova University Faculty of Medicine Child and Adolescent Psychiatry Polyclinic, were aged 0-6 years old and diagnosed with ASD according to DSM-V, and had an EEG taken. It was conducted on 160 patients. The autism behavior checklist (ABC), Modified Early Childhood Autism Screening Scale (M-CHAT), Ankara Developmental Screening Inventory (AGTE) results, and routine laboratory results of the cases were evaluated.The cases were divided into two groups: those with showing clinical regression and without. Results: The total of 160 cases, 56 (35%) with regression and 104 (65%) without regression, were evaluated within the scope of the study. 81.9% of the children involved in the study were boys and 18.1% were girls. There was no statistically significant difference between the groups with and without regression in terms of gender, seizure history and epilepsy diagnosis. As again, the prevalence of epilepsy and/or epileptiform EEG abnormalities were similar in those with the history of regression compared to those without the history of regression. EEG disturbance was seen in 38.1% of ASD cases, but no significant relationship was found between regression and EEG disturbance. Children with ASD, 52.1% had focal anomalies and 47.8% had generalized anomalies, but no significant relationship was found between these anomaly types and regression. Despite the word and sentence ages were higher in the groups without regression, no statistically significant difference was detected between the groups with and without regression. It was determined that the age of toilet training in the groups with regression was statistically significantly lower than in those without regression. Father's age was found to be lower in the group with regression than in the group without regression, and this difference was statistically significant. No statistically significant difference was found between the groups according to the source of the epileptic waves. The proportion of girls in the ASD group with epilepsy or epileptic activity was found to be statistically significantly higher than in the group without these. Conclusion:This study provides a detailed analysis to understand the complex relationship between regression and EEG in children with ASD. Keywords: Autism Spectrum Disorder, epilepsy, electroencephalogram.