Chinese Recognition In Cochlear Implant By Using Low Frequency Zerocrossing Stimulating-high Frequency Sideband Encoding Strategy

Cochlear implant is the only medical device which can restore partial auditoryperception of a totally deafened person, it effectively shortens the developing cycles ofneurons regenerative technique or gene-therapy methods to cure sensorineural deafness.Pulse stimulations are used in cochlear implant to stimulate the residual auditory nerve forrestoring the partial hearing of the deaf. Recent research shows that: based on the currentuniversal coding strategies, cochlear implantees can even make the telephonecommunication in quiet environments, but in noisy environments, the speech perceptionperformance of cochlear implants drops dramatically, especially in Chinese perception.A cochlear implant coding strategy meeting the Chinese acoustic characteristics isdesigned to solve the shortage of the Chinese perception in this paper. Based on theprevious researches of Chinese coding strategies,by exploring the auditory stimuli modelof normal persons and the threshold of frequency perception of cochlear implantees, wepresent the coding strategy by using the low frequency zerocrossing stimulating-highfrequency sideband encoding strategy-(LFZS-HFSE) and elaborate on the theoretical basis,in addition to the related problems. An auditory simulation experiment is used to validatethe superiority of the presented strategy. We adopt subjective and objective methods tocompare the advantages and disadvantages of different cochlear implant coding strategiesfor Chinese recognition. The main work is as follows:(1) We analyze the effects of acoustic parameters on Chinese recognition intime-domain and frequency-domain, mainly introduce the current universal codingstrategies including CIS (Continuous Interleaved Sampling) and ACE (Advanced Combination Encoding) and use auditory simulation experiments to assess the effects ofthe two coding strategies on Chinese recognitions.(2) We elaborate the principle of the PLS (Phase Locking Stimulating) strategy onexploring the electrical stimulating patterns of the human auditory perception and presentFSZC (Fine Structure Zero-Crossing) strategy which encode the fine structure throughzero-crossing time and transfer speech information in the pulse intervals. The results showthat in lower SNRs, higher recognition rates in comparison to CIS、ACE、PLS strategies as90%for tone,45%for sentence.(3) We present LFZS-HFSE (Low Frequency Zerocrossing Stimulating-HighFrequency Sideband Encoding) strategy ultimately based on theoretical and experimentalresults of FSZC (Fine Structure Zero-Crossing) strategy and SSE (Single SidebandEncoding) strategy. Experiments on and Chinese tone, consonant, word, sentencerecognition are implemented. The results show that in lower SNRs, higher recognitionrates in comparison to other strategies as95%for tone, above40%for consonant and word,and above75%for sentence respectively.In summary, this paper designs a coding strategy for Chinese in cochlear implantswhich accords with the actual auditory perception mode of cochlear implants. Auditorysimulation experiments show the feasibility and superiority of the proposed strategy.