Paper—Brain Waves Characteristics in Individuals with Obsessive-Compulsive Disorder: A Preliminary... Brain Waves Characteristics in Individuals with Obsessive-Compulsive Disorder: A Preliminary Study https://doi.org/10.3991/ijoe.v18i01.26805 Tahereh Najafi 1 , Rosmina Jaafar 1() , Kiomars Najafi 2 , Fatemeh Eslamdoust-Siahestalkhi 2 1 Department of Electrical, Electronics & Systems Engineering, Universiti Kebangsaan Malaysia, Bangi, Malaysia 2 Department of Psychiatry, Guilan University of Medical Sciences, Guilan, Iran rosmina@ukm.edu.my Abstract—Obsessive-Compulsive Disorder (OCD) is a mental illness caus- ing patients to suffer from recurring undesirable thoughts (obsessions) conduct- ing to do affairs repetitively (compulsions). Brain signals recorded by Electro- encephalogram (EEG) can be analyzed in order to present a diagnostic proce- dure considering the localization approach. In this study, the signals acquired by EEG have been recorded from three groups; two case groups; patients with se- vere obsessive symptoms and patients with severe compulsive symptoms, and one healthy control group. Brain signal processing techniques have been ap- plied on the signals emitted from frontal and parieto-occipital regions to discov- er the features leading to the best discrimination between case groups and healthy controls. In this regard, after preprocessing, the features of time and frequency domains presenting the significant meaningful relation were nomi- nated for classification by linear discrimination analysis (LDA). Although the parieto-occipital region performed better in the diagnosis for both obsessive and compulsive groups, the features gained from the frontal cortex resulted in better discrimination for only the compulsive group. In addition, time domain features had a more significant influence in diagnosis rather than frequency domain for both case groups. The study presented particular characteristics of brain signals in two dimensions of OCD in specific brain regions leading to more accurate presurgical assessments in the studies between the affected brain regions and behavioral issues. Keywords—obsessive-compulsive disorder, EEG, statistical analysis, linear discrimination analysis, localization 1 Introduction Obsessive compulsive disorder (OCD) is a mental health condition accompanied by the presence of obsessions such as intrusive and unwanted thoughts, and compul- sions such as repetitive and intentional rituals [1]. The disorder is associated with significant disruption in functioning across multiple settings including work, home, and social life [2]. The disorder is ranked by the World Health organization (WHO) as 96 http://www.i-joe.org