BackgroundRadiologically isolated syndrome (RIS) is a condition characterized by asymptomatic, incidentally detected demyelinating plaques in the CNS in a patient without typical clinical findings of multiple sclerosis (MS). This study aimed to compare the mental status and cognitive functions of child and adolescent RIS cases with healthy controls and to investigate the relationship between psychometric test results and the demyelinating lesion characteristics. MethodsThe mental status and cognitive functions of 12 RIS cases and 12 healthy controls were compared. Semi-structured interviews, behavioral evaluations, depression and anxiety scales, neuropsychological test battery, and an intelligence test were applied for the evaluation of mental state and cognitive functions. These results were compared with the number and localization of demyelinating lesions. ResultsSustained attention, visual-motor coordination, short-term memory skills, and ability to use visual-spatial information were found worse in the RIS group. There was no correlation between mental state and cognitive functions, and the number and localization of demyelinating lesions. ConclusionOur study showed that pediatric RIS cases may have worse cognitive performance than healthy controls, but no correlation was found between the number and location of demyelinating lesions and psychiatric findings. Although it is controversial whether psychiatric disorders and cognitive disabilities have predictive value in terms of MS conversion in pediatric RIS cases, these subjects were not included in the scope of this study.