G.Khaydarova

Tashkent Medical Academy, Republic of Uzbekistan

Features of auditory analyzer disorders in children with

central nervous system diseases

Summary

The study involved 105 children with hearing impairment, of whom 28 showed lesion of the central nervous system syndromes expressed muscular dystonia and hyper excitability. Based on the results shown efficacy of methods of OAE and ABR diagnostic for the diagnosis of hearing loss in children with diseases of the central nervous system.

Keywords: sensorineural hearing loss, diseases of the central nervous system, otoacoustic emissions, brainstem auditory evoked potentials

According to the World Health Organization hearing loss affects about 6% of the world population, which is about 120 million people. In particular, in Russia number of such patients approaches to 13 million., including children and adolescents – more than 1 million [2]. The problem of lesion of the auditory analyzer is important for children, as hearing loss results in a delay not only vocal, but also the mental development of the child. It was found that 82% of children with hearing loss pathology occurs in the first year of life, i.e., to the development of speech, or the period of its formation, of which 38.5% of children violations occur in the perinatal life. It is estimated that nearly half of all hearing impairment in children is congenital in nature and, according to statistics on thousands of normal deliveries, there is one child with a severe degree of hearing loss, information on the prevalence of mild and moderate hearing loss need to be clarified. According to foreign authors, the average age of the child when detected congenital (early) hearing loss, if ineffectiveness of screening programs is 18-30 months, and it is only in the presence of deep bilateral hearing loss, excluding the weak and the average loss [1]. So 33% of children are registered at ages 3 to 7 years, i.e., after a critical age (1-2 years), children, who were registered from 1 to 3 years 21%, and the detection of children with hearing disabilities under one year of age is 4%. This is largely due to the numerous amount of etiologic factors and insufficient knowledge of the pathogenesis of the sensorineural hearing loss [4].

As you know, development and formation of the person’s hearing organ starts with the first weeks of fetal development and continues throughout pregnancy. To defeat the auditory analyzer can cause unfavorable factors affecting at this moment on the mother and her unborn child. Adverse influences on the child's body leads to disruption of blood flow and oxygen supply of the metabolism in organs and tissues, including the inner ear, resulting in the development of hypoxia and, ultimately, death of auditory receptors [5], as well as central nervous system disorders. According to N.L.Kunelskaya et al. [3], the hypoxic condition of the inner ear is caused by changes in the rheological properties of blood and homostasis: patients with acute sensorineural hearing loss on the background of vascular changes are determined by varying degrees of severity factor intravascular microcirculation disorders due to the effect of «bonding» of blood. Thus, in children with signs of pre-perinatal lesion of CNS there are all preconditions to the defeat of the auditory analyzer.

The criteria for the risk of hearing disorders in the literature are: the pathology during the pregnancy of the mother, revealing signs of hypoxic-ischemic, hypoxic-hemorrhagic, toxic or metabolic lesions of CNS (cerebral ischemia, expansion of the ventricular system and the subarachnoid space of the brain during neurosonography), as well as the presence of excitation syndromes or depression of the central nervous system.

Thus, the study of the auditory analyzer in children with diseases of the central nervous system is the objective of this study.

Material and methods: We examined 105 children who addressed to the 2^nd clinic of Tashkent Medical Academy. Parents of children observed in children hearing loss, speech underdevelopment, inattention and distraction. Investigation of the auditory function in children was carried out using the following techniques: acoustic impedometry, registration of transient evoked acoustic emission (TEAE); registering latent auditory evoked potentials (LAEP).

Results and discussion: among examined sensorineural hearing loss caused by central nervous system was found in 28 children (26.7%). This group of patients had evidence of hypoxic-ischemic lesions of the CNS, which were expressed in muscle dystonia syndromes and hyperexcitability.

Register of acoustic emission was observed in 2 patients, whereas others failed to register it, which indicated that the defeat of the organ of Kortiev in this category of patients. The next stage of the study to confirm these results, we performed ABR standard registration of various intensities of stimulation signal (from 10 to 70 dB). This assessment of the results was performed by the following parameters: latency of ABR wave peaks (I, III, V); evaluated interpeak intervals (IIP) ABR (I-III, III-V, IV); curve of intensity / latency and interaural difference above indicators.

All patients latencies of ABR peaks were statistically significant (P <0.05) greater when the intensity of the stimulation signal 40 dB or more (at lower levels of stimulation, we did not compare these figures, because it was not reliable recording peaks. The same picture was observed when comparing the average interpeak intervals. Interaural difference of ABR parameters in children of these groups did not differ significantly and should not exceed 0.2 ms. Curve function intensity / latency in children c signs pre-perinatal lesion of the was moved up the y-axis.

Thus, indicators of auditory function in children with hearing loss in the background of the CNS indicated they have evidence of lesions audio analyzer. Patients were followed for ENT and neurologist. All children were prescribed medication, aimed at improving the microcirculation and the conduction of nerve tissue.

Drug therapy was carried out under dynamic audiological control. Also, according to the results of the examination patients underwent correction of electroacoustic hearing.

Conclusion. Based on these results we can conclude about the effectiveness of the method TEOAE and ABR to determine the acoustic analyzer in infants with lesions of the CNS disease. Improving the efficiency of timely diagnosis of the pathology of hearing in young children requires the use of reliable methods during audiological research. Register of short latent auditory evoked potentials using standard techniques incremental time acoustic stimulation can detect early hearing disorders in children with lesions of the CNS.

BIBLIOGRAPHY

1. J.Zokirhonova Early diagnosis and correction of hearing impairment in infants and young children. // PhD dissertation author's abstract. M. N. - Tashkent, 2011

2. M .Kulagin Characteristics of auditory function in infants with pre-perinatal lesions of the central nervous system. // PhD dissertation author's abstract. - Moscow, 2009

3. N. Kunelskaya, T.Polyakov. Pathogenetic aspects of sensorineural hearing loss and their correction // Mater. XVII Congress of otolaryngologists of Russia. – Niginiy Novgorod., 2006. - p. 33.

4. L. Lazareva. Assessment of regulatory-adaptive systems in patients with acute sensorineural hearing loss during treatment // Mater. XVII Congress of otolaryngologists of Russia. - Niginiy Novgorod., - 2006. - S. 33.

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