Biomedical subjects

Chaogang Wei

Publications and source records attributed to Chaogang Wei.

4 recordsLinked to original sources

PubMed2005

Speech recognition with amplitude and frequency modulations.

Amplitude modulation (AM) and frequency modulation (FM) are commonly used in communication, but their relative contributions to speech recognition have not been fully explored. To bridge this gap, we derived slowly varying AM and FM from speech sounds and conducted listening tests using stimuli with different modulations in normal-hearing and cochlear-implant subjects. We found that although AM from a limited number of spectral bands may be sufficient for speech recognition in quiet, FM significantly enhances speech recognition in noise, as well as speaker and tone recognition. Additional speech reception threshold measures revealed that FM is particularly critical for speech recognition with a competing voice and is independent of spectral resolution and similarity. These results suggest that AM and FM provide independent yet complementary contributions to support robust speech recognition under realistic listening situations. Encoding FM may improve auditory scene analysis, cochlear-implant, and audiocoding performance.

Cochlear Implants↗

PubMed2005

[The changes of fundamental frequency and formants of vowel in cochlear implant pre-lingual children of different age].

OBJECTIVE: To observe the changes of fundamental frequency and formants of vowel in cochlear implant pre-lingual children of different age and to provide the basis and direction for post-operative rehabilitation. To find the key period of language development from the aspect of phonetics and to illustrate the necessity of early implantation. METHOD: Nineteen pre-lingual cochlear implant children age from 3-13 who use 24 M or 24 Contour implant and Esprint speech processor participate the experiment. Voice analysis software was Vs99 which was explored by Beijing yangchen electronic technology corporation. Fundamental frequency and formants were abstracted from the sustained segment of vowel[a:]. RESULT: No significant difference of fundamental frequency was found between the age 4 group and normative group. Significant difference of fundamental frequency was found between the age 10 group and normative group (P < 0.05). No significant difference of formant 1 was found between the age 4 group and normative group. Significant difference of formant 1 was found between the age 10 group and normative group (P < 0.01). Formant 2 of the age 4 group was higher than the normative group, significantly. No significant difference of formant 2 was found between the age 10 group and normative group. No significant difference of the ratio of formant 1 to 2 was found between the age 4 group and normative group. Significant difference of the ratio of formant 1 to 2 was found between the age 10 group and normative group (P < 0.01). CONCLUSION: The phonation of the children from the age 4 to age 10 was obviously affected by age. This stage was the key stage for language development.

Adolescent↗

PubMed2003

[Multi-channel cochlear implantation in patients with common cavity malformation].

OBJECTIVE: To report the multi-channel cochlear implantation in patients with Common cavity malformation, including surgeries, pre and postoperative hearing assessments as well as outcomes of speech recognition. METHOD: Multi-channel cochlear implantation surgeries have been performed in 6 cases with common cavity malformation in our hospital from May 1995 to May 2002. The transmastoid lateral semicircular canal approach was used in these cases. The postoperative outcomes of these cases are compared with 6 cases of non-malformed cochlea as a control group. RESULT: Among the 6 cases, All 32 electrodes were inserted in 3 cases, 28 electrodes in 1 cases, 26 electrodes in 1 cases, 22 electrodes in 1 cases. The intra and postoperative complications of the surgeries have no significant difference compared with the surgeries of normal cochlea. The intraoperative "Ozze" occurred in 2 cases, the small CSF flowing occurred in 3 cases and no CSF flowing occurred in 1 case. Postoperative threshold in sound field were 30-40 dB recovery for all cases, and similar to the normal cochlea cases. Most of them received the similar hearing and speech recovery, compared with the result of non-malformed group. Only a few had a higher hearing threshold. The remote effect will be evaluated by long-term follow-up. CONCLUSION: Multi-channel cochlear implantation could be performed in the cases with common cavity malformation, but preoperative hearing assessments and proper images should be done.

Child↗

PubMed2003

[Bilateral total deafness due to mumps and the outcome of cochlear implantation].

OBJECTIVE: Bilateral deafness due to mumps is rare. Here report three cases of bilateral total deafness due to mumps and their outcome of cochlear implantation. METHOD: Three cases of bilateral total deafness due to mumps were reviewed. RESULT: All patients had sudden bilateral total deafness in 3 to 7 days after mumps. 2 had vestibular symptoms. Cochlear implantation has been successful in all 3 patients. Three month after the initial mapping, Case 2 who has been wearing bilateral hearing aids and received one-year language training has the best outcome of hearing and speech than the other two. Case 1 who has been wearing one-side hearing aid and received language training of 6 months has the better outcome than case 3 who has never worn hearing aid and never received language training. CONCLUSION: Hearing loss caused by Mumps is often sudden in onset, conservative therapy have no help. Hearing aid and language training are very important to the outcome of speech perception and speech production after cochlear implantation.

Adolescent↗