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Abstract Introduction Cochlear implants (CIs) enable objective measures of the neural function in implanted patients through the measurements of the neural response telemetry (NRT) and of the Auditory nerve Recovery Function (REC). These measurements help in programming the speech processor and understanding the auditory system. Objective To compare the NRT and the REC in prelingual and postlingual implanted patients. Methods An observational, descriptive and prospective study was carried out. The NRT and the REC (through the T0, A, and tau parameters) were evaluated in individuals submitted to CI surgery, who were divided into two groups: prelingual and postlingual patients. Results In total, 46 patients were evaluated. Data analysis showed no statistically significant difference between the NRT measurements and the T0, A, and Tau of the REC in the comparison between the two groups, except for the NRT in the basal cochlear region. Conclusion There was no statistically significant difference in the REC in pre- and postlingual patients.
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Objective The aim of this study is to explore the significance of fitting hearing aids before cochle_ar implantation by studying the postoperative impact on neural response telemetry (NRT ) threshold ,the subjective threshold(T -level) and maximal comfort level(C-level) values .Methods A total of 45 patients with cochlear im_plants were divided into 3 groups:patients in group HA1(n=17)had worn hearing aids preoperatively more than 6 months and the age of starting wearing hearing aids was yonger than 3 .5 years old ,patients in group HA2(n=8) had worn hearing aids preoperatively more than 6 months and the starting age was older than 3 .5 years old ,patients in group NHA(n=20 )never wore hearing aids before ACI .The postoperative electrode impedance ,NRT value and T -level and C -level were evaluated at 3rd ,6th ,and 12th months ,respectively .ResuIts Electrode impedances were 10 .9 ± 2 .1 kΩ in NHA group ,10 .5 ± 2 .3 kΩ in HA1 group ,10 .7 ± 2 .7 kΩ in HA2 group ,respectively ,and there were no statistically significant differences .Significant differences were found between group HA1 and group NHA ,group HA1 and group HA2 in terms of NRT threshold value ,T -level or C-level(P0 .05) .ConcIusion The results of this study showed that wearing hearing aids for a longer time before CI was beneficial for hearing rehabilitation postoperatively .
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Introduction Currently the cochlear implant allows access to sounds in individuals with profound hearing loss. The objective methods used to verify the integrity of the cochlear device and the electrophysiologic response of users have noted these improvements. Objective To establish whether the evoked compound action potential of the auditory nerve can appear after electrical stimulation when it is absent intraoperatively. Methods The clinical records of children implanted with the Nucleus Freedom (Cochlear Ltd., Australia) (CI24RE) cochlear implant between January 2009 and January 2010 with at least 6 months of use were evaluated. The neural response telemetry (NRT) thresholds of electrodes 1, 6, 11, 16, and 22 during surgery and after at least 3 months of implant use were analyzed and correlated with etiology, length of auditory deprivation, and chronological age. These data were compared between a group of children exhibiting responses in all of the tested electrodes and a group of children who had at least one absent response. Results The sample was composed of clinical records of 51 children. From these, 21% (11) showed no NRT in at least one of the tested electrodes. After an average of 4.9 months of stimulation, the number of individuals exhibiting absent responses decreased from 21 to 11% (n = 6). Conclusion It is feasible that absent responses present after a period of electrical stimulation. In our sample, 45% (n = 5) of the patients with intraoperative absence exhibited a positive response after an average of 4.9 months of continued electrical stimulation...
Subject(s)
Humans , Child , Cochlear Implantation , Electric Stimulation , Hearing LossABSTRACT
Objective Using maestro software to analyze the application of electrically elicited stapedius reflex and auditory nerve response in assessing acoustic function intraoperatively .Methods 20 SONATATI100cochlear im-plant patients participated in this study .Both ESRT and ECAP were recorded intraoperatively by using MED -EL Maestro software and analyzed .Results 96 .67% typical ESR and 95 .0% typical ECAP were recorded .Certain properties of ECAP recordings varied depending on the stimulation sites in the cochlea .There was strong relation-ship between ESRT and ECAP thresholds .Conclusion ESR and ART were proved to be most beneficial in assessing the functions of the implanted as well as proving that the auditory pathway is stimulated during the cochlear implan-tation surgery .
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BACKGROUND AND OBJECTIVES: Electrically evoked compound action potential thresholds recorded using neural response telemetry can be used to set MAP thresholds (T-levels) and maximum comfort levels (C-levels) especially in children implanted with the Nucleus 24 device. However, the thresholds and C-levels change over time and the relationship between neural response telemetry (NRT) measurements and behavioral levels in children may also change. The purpose of this study was to apply the neural response threshold to the behavioral levels at the beginning (up to first 6 months). SUBJECTS AND METHOD: The neural response telemetry test was administered in 23 patients (mean age was 16.8) with Nucleus 24 device. Four intra-cochlear electrodes (electrodes 5, 10, 15, and 20) were tested. The behavioral threshold and the maximum comfort level at immediate, 1, 2, 3 and 6 months post-implantation were compared with the neural response threshold. RESULTS: Among 23 patients, 15 had their NRT thresholds within their dynamic range in the 6 months post-mapping period. Although the time when NRT thresholds comes within the dynamic range may differ from patient to patient, it was common finding that this occurred after 2 months of post-mapping in most of the patients. CONCLUSION: During the first few months of post-implantation, care must be exercised when interpreting NRT measurements.
Subject(s)
Child , Humans , Action Potentials , Cochlear Implantation , Cochlear Implants , Electrodes , TelemetryABSTRACT
BACKGROUND AND OBJECTIVES: Neural response telemetry (NRT) has been used as one of the most useful tools to measure neural responses ranging from spiral ganglion cells to electrical stimulation via the Nucleus 24 cochlear implant. The purpose of this study was to assess and analyze the result of NRT measured intraopertively and apply the result in postoperative mapping. SUBJECTS AND METHOD: The NRT test was administered to 72 patients (49 children and 23 adults) with the Nucleus 24 cochlear implant. After inserting of the electrode array into the scala tympani, an impedance test was administered to check the integrity of each inserted electrode. In cases of partial insertion, the electrodes outside the cochlear were excluded along with those proven to be short circuited. The electrically evoked action potential (EAP) was recorded using version 3.0 of NRT software. One intra-cochlear electrode (electrode 2, 4, 6, 8, 10, 12, 14, 16) with MP1 as reference was chosen for the stimulating pair. The recording electrode was located 3 electrodes away apically from the stimulating intracochlear electrode and referenced to MP2. The amplifier gain and sampling delay were optimized for each subject using electrode 4 and these same parameters were used throughout the test. RESULTS: Out of 72 implantees, 56 patients (78%) were observed to produce reliable responses: 16 (70%) of 23 adults and 40 (82%) of 49 children responded. The patients who failed to produce NRT response had higher T levels than patients who had NRT response. CONCLUSION: Eighty percent of the implantees without any inner ear anomaly showed reliable response to intraopertive NRT measurement. The intra-operarative NRT data may be used to predict electrical stimulation levels in programming.
Subject(s)
Adult , Child , Humans , Action Potentials , Cochlear Implantation , Cochlear Implants , Ear, Inner , Electric Impedance , Electric Stimulation , Electrodes , Scala Tympani , Spiral Ganglion , TelemetryABSTRACT
Objective To explore the advantages of intraoperative NRT measurement(neural response telemetry)during cochlea implant surgery.Methods Intraoperative and postoperative NRT measurements were tested in ten SNHL children with CI24M-Nucleus and four SNHL children with CI24R(CS)-Nucleus, the ECAP threshold of intraoperative and postoperative measurements were compared, and the first maps were set up according to the intraoperative ECAP threshold.Results The average intraoperative ECAP threshold of 22 electrodes was higher than postoperative ECAP threshold, the average intraoperative ECAP threshold of CI24M-Nucleus' 22 electrodes was 11CL greater than postoperative ECAP threshold. It was just five minutes to record ECAP of 10 electrodes, and the beginning of fitting was finished in one hour.Conclusion It is confirmed that intraoperative NRT measurement could test the integrity of implants, and could estimate the first map. It is convenient to use and should be popularized.
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Objective To inevestigate the changes of the responses by changing the parameters in the neural response tetemety(NRT).Methods In this project,twenty patients who were implanted in Nucleus C124M were measured the electrically evoked compound action potential(ECAP)using the NRT system.It was expected to observe the changes of the responses by changing the parameters in the NRT 2.04 software.Results It was found that the parameters that made great influences to the responses were current level,stimulate pulse width,gain,delay and masker advance.Conclusion The parameters that made great influences to the record time were stimulate rate and number of sweeps.
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Objective To explore the threshold and latency of patients receiving cochlear implantation using electrically evoked auditory brainstem responses (EABR), and to evaluate the significance of EABR applied to those patients.Methods The EABR and ECAP were recorded in 14 subjects who were operated for Nucleus24 cochlear implant.They were assigned to Group A and Group B according to the results of ECAP. The threshholds of EABR, the wave latency of III and V and inter-wave latency of III-V of EABR were compared and analyzed between Group A and Group B.Results The threshholds of EABR were higher in Group B than in Group A on electrode No 22 when the pulse width was 25,50,75,100,125 ?s,respectively. There were significant differences between Group A and Group B(P0.05).Conclusion The threshholds of EABR were lower in patients whose ECAP findings were positive. The latencies of III and V,and inter-wave latency of III–V of EABR had no significant difference according to the positive findings of ECAP.