The role of functional MRI in understanding the origin of speech delay in autism spectrum disorders

Abstract

Autism spectrum disorders (ASD) are disorders of psychic development characterized by the difficulties of social interaction and stereotyped and repetitive patterns of behavior. Rather often they are accompanied by disturbances of speech, intelligence, and adaptive behavior. Pathogenesis of ASD is still poorly studied. MRI with its latest modalities is a modern diagnostic method enabling medical providers to evaluate structural, metabolic, and functional features of brain development in this pathology. The aim of the study was to assess the capabilities of functional MRI (fMRI) in determining pathophysiological mechanisms of delay in speech development in ASD. Materials and Methods. A brief review of international studies is given in the article. Our own results of examining 6 preschool children with one of the ASD forms — early childhood autism and speech disorders, and 6 children of the comparison group without autism and language disturbances are also presented using fMRI and a block design paradigm to analyze speech perception patterns. Results. In all children with normal speech development, bilateral symmetric spread of activation along the cortex of the entire superior temporal gyri was revealed whereas children with autism showed lateralized and limited involvement of the auditory cortex. Sevoflurane anesthesia did not influence the character of auditory zone activation. Conclusion. The possibility of using fMRI with application of the paradigm for speech understanding to study the individual features of brain functioning in children with autism has been demonstrated. The revealed objective instrumental signs of brain activity differences in the children with autism compared to the healthy children allow the fMRI data to be considered as a potential biomarker of this disease. It has also been shown that the possibility to carry out this examination under general anesthesia makes it more acceptable and convenient for patients with childhood autism.