The Effect of the Nonlinear Frequency Compression Methods on the Recognition of Monosyllabic Words in Persian Language

• Main Authors: Noushin Zarza, Nariman Rahbar, Hassan Haddadzadeh Niri
• Format: Article
• Language: English
• Published: Iran University of Medical Sciences 2019-02-01
• Series: Function and Disability Journal
• Subjects: nonlinear frequency compression; hearing loss; hearing aids; speech perception
• Online Access: http://fdj.iums.ac.ir/article-1-65-en.html
• ISSN: 2588-6304; 2588-6304

Background and objective: The aim of all Frequency Lowering methods is access to high frequencies (HFs) for people with hearing loss. The advantage of these methods has been approved for improving speech perception and limitations reduction of affected people. One of these method is Nonlinear Frequency Compression that reduces the bandwidth of frequency band. This study was carried out to compare the Adaptive Nonlinear Frequency Compression (ANFC) with original algorithm of Nonlinear Frequency Compression (NFC) and Conventional Processing (CP). Material and Methods: Thirty people in the range of 18-40 years old with ski-sloping hearing loss were evaluated. The presence of cochlear dead region at least in one of the frequencies of 1500, 2000, 3000 and 4000 Hz was proved in all cases by performing the Threshold Equalizing Noise test (TEN (HL)). The evaluation was carried out using monosyllabic balanced-word lists in Persian language. Each of Lists used for recognition in one of the three processing modes such as ANFC, NFC and CP which it has been performed in the free field at 90 centimeters distance of the speaker and 0° azimuth.  Results: The scores of frequency compression algorithms are better than CP and it leads to improve recognition whereas the scores of NFC and ANFC were similar. In addition, it is not dependent to gender, the obtained scores in three processing modes.  Conclusion: It is more useful for a person with ski-sloping hearing loss to use hearing aids with frequency compression technology rather than CP. In fact, frequency compression gives them a better speech perception, but the effect of the two different algorithms is similar.