Biomedical subjects

Keli Cao

Publications and source records attributed to Keli Cao.

10 recordsLinked to original sources

PubMed2006

[Multi-channel cochlear implantation in patients with congenital inner ear malformation accompanied middle ear malformation].

OBJECTIVE: To report the multi-channel cochlear implantation in three patients with congenital inner ear malformation accompanied middle ear malformation, including CI surgery and postoperative outcomes of hearing and speech recovery. METHOD: Multi-channel cochlear implantation surgeries have been performed in three cases with congenital inner ear malformation accompanied middle ear malformation in our hospital from May 1995 to May 2002. The transmastoid approach was performed to the cases with congenital inner ear malformation accompanied middle ear malformation. The postoperative sound field hearing tests were taken to the cases three months after the cochlear implantation. RESULT: Multi-channel cochlear implantation was successfully performed in three cases with congenital inner ear malformation accompanied middle ear malformation. The 27, 28, 32 electrodes were inserted respectively in three cases. The intraoperative "Ozze" occurred in three patients. No severe intraoperative and postoperative complications occurred in three cases. All postoperative hearing thresholds were at 35-40 dBHL. CONCLUSION Multi-channel cochlear implantation could be performed in the cases with congenital inner ear malformation accompanied middle ear malformation through the transmastoid approach. The postoperative outcomes were satisfied.

Child↗

PubMed2006

[Use of intraoperative round window electrocochleography for assessment of cochlear implantation safety].

OBJECTIVE: To objectively evaluate whether cochlear implantation surgery made damage to cochlear basal membrane or not through analyzing the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. METHOD: Round window electrocochleography was performed on 40 cases with profound sensorineural deafness under general anesthesia in the standard operating room in order to analyze the change of the threshold of cochlear microphonic (CM) of round window electrocochleography before and after inserting electrode during cochlear implantation surgery. RESULT: Among the 40 cases, thresholds of cochlear microphonic (CM) before and after inserting electrode during cochlear implantation surgery were similar in 39 cases. The thresholds of cochlear microphonic (CM) after inserting electrode decreased about 5 dB at certain frequency. The thresholds of cochlear microphonic (CM) after inserting electrode increased 20-50 dB in only one case. There was a sense of resistance in implanting the electrodes in this patient. CONCLUSION: Use of round window electrocochleography may objectively evaluate whether cochlear implantation surgery make damage to cochlear basal membrane or not.

Adolescent↗

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↗

PubMed2005

[Nucleus 24 contour in patients with sound sensorineural hearing loss].

OBJECTIVE: To report the surgery and the postoperative outcomes with Nucleus 24 Contour electrode array in patients suffered from profound sensorineural hearing loss. METHOD: The surgery and postoperative current level making electrical hearing are compared between the group with Nucleus 24 contour and the group with Nucleus 24 M. RESULT: Among the 82 cases,32 electrodes were inserted in 81 cases, 28 electrodes in 1 case. The intraoperative small CSF flowing occurred in 31 cases and no CSF flowing occurred in 2 cases. The slight postoperative complications of the surgeries occurred in seven patients. The postoperative NRT threshold of the group with Nucleus 24 Contour was lower than the group with Nucleus 24M. There was a statistically significant difference in the 1th channel about the NRT threshold (P < 0.05). CONCLUSION: Using Nucleus 24 Contour makes the surgery esaier than using Nucleus 24 M, minimizes the introcochlear trauma during insertion and reduces the current level producing electrical hearing. The Nucleus 24 Contour is a new, safe and effective implantation to the patients with profound sensorineural hearing loss.

Adolescent↗

PubMed2004

Mandarin tone recognition in cochlear-implant subjects.

This study examined tone recognition in five cochlear-implant subjects who were native speakers of Mandarin and used a Nucleus-22 device. Psychophysical experiments were conduced to measure rate discrimination in individual electrodes from the most apical to the most basal electrodes. The rate range was from 100 to 200 Hz, which corresponded to the range of variation in fundamental frequency for the tonal tokens used in this study. Speech recognition experiments were also conducted to measure tone recognition as function of the number of electrodes from a 1-electrode map to a 20-electrode map. Large individual variability was observed for both rate discrimination and tone recognition result: Average rate discrimination ranged between 0.2 and 1.2 (Weber's fraction) whereas tone recognition ranged between 30% and 70% correct. A highly significant correlation was found between rate discrimination and tone recognition with the 20-electrode map, but a non-significant correlation was observed with the 1-electrode map due to a floor effect in tone recognition. The present result supports the hypothesis that both spectral and temporal cues contribute to tone recognition. In addition, the present result shows that current cochlear-implant subjects produced significantly lower performance than acoustic simulations in normal-hearing subjects, suggesting that neither temporal nor spectral cues have been adequately and appropriately extracted and encoded in current cochlear implants. New designs are discussed to improve tone recognition in cochlear implant subjects.

Adult↗

PubMed2004

[Clinical study of congenital middle ear malformations].

OBJECTIVE: To search into the diagnosis and treatment of congenital malformation of middle ear. METHOD: Nine patients were involved in our study, exploratory tympanotomy was undergone in all patients (eleven ears) and eight ears were reconstructed the ossicular chain. RESULT: Exploratory tympanotomy showed a variety of abnomalities of the middle ear which were difficult to identify preoperatively, despite the modern imaging techniques. Stapedectomy using a wire prosthesis with an oval window tissue graft to prevent a perilymphatic leak was carried out in four ears, fenestration of vestibule with stapes prosthesis in two ears, removing the fibrotic strand around the incudostapedial joint in one ear, TORP (Total replacement prosthesis) were used in one ear, gain in hearing thresholds was obtained without severe complications occurrence. CONCLUSION: Exploratory tympanotomy is essential to identify congenital conductive hearing loss and wire prosthesis may provide a potential way for reconstruction of ossicular chain.

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↗

PubMed2002

[Electrically evoked auditory nerve compound action potentials in Nucleus CI24M cochlear implant users].

OBJECTIVE: To study the feasibility and clinical applicability of electrically evoked auditory nerve compound action potentials (ECAP) in young patients with Nucleus CI24M cochlear implants. METHOD: ECAPs have been recorded from 37 Nucleus CI24M cochlear implant users in response to monopolar electrical stimulation of the cochlea by using the neural response telemetry(NRT) software and the hardware. Behavioral thresholds and maximum comfortable levels were measured in 12 of those patients. RESULT: ECAPs could be recorded in 87.6% of all patients. Good relations were observed between ECAP threshold and behavioral threshold, but poor relations between ECAP threshold and the impedance of different electrodes. We also observed growth functions and threshold variations of ECAP across subjects for a given place as well as across electrodes within a subject. These findings might be that these particular physiological measures are related to the number of living neural fibers and the excitability of the auditory nerve to electrical stimulation. CONCLUSION: ECAPs were proved to be useful in adjusting the stimulation parameters of the cochlear implant speech processor in order to maximize an individual's performance with the device, especially in young children.

Action Potentials↗