O.I. Efimov – Neurologist, Head of Children's Neurological Clinic «Prognoz» (Saint-Petersburg)
V.L. Efimova – Ph.D. (Ped.), Speech Therapist, Manager Speech Therapy Center “Logoprognoz” (Saint-Petersburg)
V.P. Rozhkov – Ph.D. (Biol.), Leading Research Scientist, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (Saint-Petersburg)
N.A. Ryabchikova – Dr.Sc. (Biol.), Senior Research Scientist, Department of The Higher Nervous Activity,
Faculty of Biology, Lomonosov Moscow State University
Autistic spectrum diorders (ASD) is a heterogenous group of disorders of psychological development featuring impaired social behavior, communication, verbal abilities. The urgency of studying the problem of ASD is related both to the prevalence of RAS, and the need to address issues of differential diagnosis, refinement of etiology, pathogenesis, which will allow developing adequate approaches to therapy.One of crucial characteristics of ASD is delay or total arrest of speech development. Earlier study of BAEP showed that children with speech disorders have slow rates of signal conduction evoked by acoustic stimuli in sensory tracts of the brainstem. That is disorders of auditory signal processing play an important role in the origin of these impairments in the brainstem. The purpose of the study is to find how often children with ASD have impaired speed of conduction and processing of auditory information in the auditory centres and tracts of the brainstem. 54 boys and 18 girls with ASD aged 2.5–9 were examined in our study. Control group was made up of 38 children aged 2.5-10 without speech delays or neuropathology. Potentials were recorded with the help of Nicolet Viking SelectTM System (USA) with standard (click 0.1 ms 85 dB NHL) and modified (a tone at 4kHz – 1ms, front 0.5 ms 85 dB NHL) methods. Stimuli were presented with the frequency of 10.1 Hz. Under standard stimuli conditions interval between peaks III – V of BAEP among children with ASD was increased in 47% of cases. The use of modified stimulus allowed at peak latency of wave VI (more than 750 ms) to find conduction delay of auditory signals in one or both sides among 76% of children with ASD. Therefore, most children with ASD can be diagnosed with slow conduction of acoustic signals in auditory brainstem tracts. This temporal factor in the work of auditory system significantly limits speech signals segmentation and can hinder speech development, and communicative functions among children with ASD. Taking into account characteristics of speech disorders, disassociation and speech delays, an important focus area of correction for children with ASD is the soonest speech recovery using specific methods which help normalize the speed of conduction and processing of auditory information.
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