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he majority of cochlear implant (CI) recipients have achieved improved open-set speech understanding in quiet; however, speech perception in noisy environment remains a challenge. CI recipients have variable outcome, especially for speech perception in noise regardless of their performance in quiet, despite enormous improvements in the technology. Several factors contribute to variable CI outcome such as age at CI surgery, time in hearing and language development.
Various tests have been developed to estimate the perception of speech in presence of noise, such as connected sentence test (CST), hearing in noise test (HINT), quick speech-in-noise test (QuickSIN), Bamford-Kowal-Bench speech-in-noise test (BKBSIN), and listening in spatialized noise-sentences (LiSN-S). In addition to various tests developed in Arabic to evaluate speech perception in noise, such as the Arabic version of BKB SIN for children with multitalker babble, the SPIN test, the PSI and the HINT. All these tests are different in terms of target age, measure, procedure, speech material, noise type and level.
Studying CI children’s susceptibility to noise remains a major challenge for researchers and is an important step toward improving CI users’ performance in the adverse noisy conditions.
Therefore, this study is conducted to evaluate and compare speech in noise abilities in a group of CI and normal hearing children aged from 6- 10 years. In addition to exploring and studying different variables that would affect speech perception in noise in CI children in these conditions. This was done using the newly developed Arabic Low Verbal Sentences in Noise test (LV-SIN) with different types of noises presented at different signal-to-noise ratios (SNRs) to simulate as much as possible the natural noisy environment.
The LV-SIN test sentences were taken from Arabic PSI test developed by the Audiology unit, Ain Shams University and an experienced phoniatrician selected only 90 sentences using a phonetic balancing technique where all lists had similar representation of Arabic phonemes.
Then the sentences were divided into nine lists with three levels of difficulty which were matched with the normal hearing child’s age and intelligence. The easiest lists were chosen to assess CI children in this study. The selected lists were digitally manipulated using Audacity software program by adding 3 types of noise (white noise, story noise and multitalker babble) to each track at different SNRs.
Results of the present study were demonstrated in five sections:
First: Comparison between LV-SIN SNR 50% test scores using the 3 types of noise achieved by the CI children and their NH peers. Second: Comparison between LV-SIN SNR 50% test scores using the 3 types of noise (multi-talker babble, story and white noise).Third: Correlation between LV-SIN SNR 50% using different types of noise and different variables. Fourth: Comparison between LV-SIN SNR 50% and the two subgroups of CI children based on age at CI surgery. Fifth: Correlation between LV-SIN 50% scores and language development.
We concluded that:
The newly developed Arabic LV-SIN test proved to be a suitable test in assessment of speech perception in different background noise for toddlers, pre-school, hearing impaired and CI children with language age not less than 2 years and 6 months.
CI children need much better SNR to match speech perception in noise abilities of their NH peers. In addition, several variables proved to have significant affection of their performance and perhaps the most important of them is the age at CI surgery.
Multi-talker babble and story noise proved to be more difficult and challenging rather than white noise which resembled the easiest and least challenging situation.
Using informational masking in the form of: Multitalker babble and\ or story noise provides realistic assessment of speech perception in noise abilities in CI and other hearing impaired children.
Speech in noise assessment using energetic masking in the form of white noise underestimate the difficulties and challenges that CI and hearing impaired children meet in their daily life situations.