Assessing Cognition, Executive Functions, and Functional Brain Asymmetry in Children with Rett Syndrome

Abstract

Background/Purpose: Rett syndrome is a heterogenous neurodevelopmental disorder and is characterized by a regression of language and psychomotor development, autism and epilepsy. In most cases, Rett syndrome is caused by mutations in the MECP2 (MIM*300005) and the FOXG1 (*164874) gene. Due to the abnormal brain development fundamental neurophysiological principles of the brain like functional asymmetry may be altered. Additionally, executive functions like inhibition, which are imminent for the adaption of behavior to the environment, may also be impaired. We chose a functional neurophysiological approach to address these questions. Methods: Children ( > 10 years) with Rett Syndrome (R1) and healthy, age-matched controls (C1) conducted two computer-based neuropsychological tests while recording a 61-channel EEG. A passive dichotic listening task (DLT) was used to assess speech processing and functional cerebral asymmetries. Response capabilities were assessed using a Go–NoGo inhibition task. Results: Using the DLT we found deviances for early perceptual-attentive event-related potentials (ERPs) in R1. For response inhibition the Go–NoGo task revealed impairments in behavior und electrophysiology (R1). Conclusion: Children with Rett syndrome exhibited altered speech perception and altered functional asymmetry of language processing. We also found impaired response inhibition in Rett patients. The tests are a first step to shed light on the cognitive effects of the developmental abnormalities specific for the Rett syndrome. Our findings may help to improve compensatory and occupational therapies and enable the development of (bio-)markers for future putative therapies. The applied ERP tests are applicable for further neurodevelopmental disorders with a low cognitive functional level and compliance.