Efficiency of the cochlear implantation in children with severe sensorineural hearing loss and deafness according to the data of speech audiometry in the free sound field and in the noise background

Abstract

Relevance: Any kind of the hearing loss, especially in the childhood, affects the mental and intellectual development negatively as well as behavior and social position of a deaf patient in the hearing world. Cochlear implantation is the most effective and reliable method of medical and educational auditory-speech rehabilitation for both adults and children with severe hearing loss and deafness. One of the key performance indicators of the cochlear implantation is a result of speech audiometry, especially on the noise background. The aim is to study the state of auditory function according to the subjective audiometry in the noise background and the influence of various factors on the effectiveness of rehabilitation of the children after cochlear implantation. Materials and methods: The study involved 150 children with severe sensorineural hearing loss and deafness after cochlear implantation. In age, they ranged from 3 to 18 years old. Evaluation of the efficiency of cochlear implantation was carried out in several stages. All studies were done in the free-field with the cochlear implant on. At first, we performed the pure tone audiometry. Then we defined the 50% intelligibility threshold of numeral test. After that, we defined a word recognition percentage. And finally we defined the impact of masker on speech intelligibility at SPL of useful signal 50, 60 and 80 dB. Results: Based on the analysis of the received data, all children with severe sensorineural hearing loss and deafness after cochlear implantation were divided into 3 groups depending on the speech intelligibility. The first group (high efficiency of cochlear implantation) included 68 children (45,3%). This group was divided into two subgroups depending on the difference between the values of the speech intelligibility in the free sound field and in the noise background. The second group (average efficiency) consisted of 45 children (30%). The third group (low efficiency) were 37 children (24,7%). The influence of various factors on the efficiency of cochlear implantation was analyzed. Conclusion: Speech intelligibility in the noise background must be examinated in all children after cochlear implantation. The main factors affecting the effectiveness of cochlear implantation according to test of speech intelligibility in the noise background are the ethiology of hearing loss and duration of post-operation period. Results of speech intelligibility in the noise background test will help specialists who practice the rehabilitation of children after cochlear implantation (teachers for deaf, speech therapists) to pay attention to the decrease of speech intelligibility in children in the real conditions of communication and to focus their efforts on its improving with the appropriate methods.