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Objective Thresholds for auditory brain stem responses (ABRs) to tone burst and tone burst in notched noises of two different intensities were tested in adults with sensorineural hearing loss.The relationship between ABR and puretone thresholds was analyzed to identify an acoustic stimuli with better frequency-specificity.Methods Thirty-eight adults with sensorineural hearing loss (totally 45 ears) were included in the study.Tone burst used to elicit ABRs had 2.5 cycles on the rise and fall and no plateau.Notched noises of two different intensities were used to mask tone burst ipsilaterally when recording ABRs.Those two kinds of notched noises were 25 dB (intensity A) and 15 dB (intensity B) lower than tone burst in intensity respectively.Tone burst ABRs without masking were named tb-ABR,while tone burst ABRs in notched noises of intensity A and B named as amtb-ABR and bmtb-ABR.Thresholds for tb ABR,amtb ABR and bmtb-ABR were tested and analyzed.Results The regression coefficients between puretone thresholds and thresholds for tb-ABR,amtb-ABR and bmtb-ABR of all frequencies were greater than 0.8.The mean differences between ABR and puretone thresholds were all less than 10 dB.Tb-ABR thresholds the were the closest to puretone thresholds at 500 Hz,while bmtb ABR thresholds were the closest at the other three frequencies.Bmtb-ABR thresholds were more close to puretone thresholds in patients with steeply sloping hearing loss.Conclusion Thresholds for all those three ABRs could be used to predict puretone thresholds.In most condition,tb-ABR thresholds were able to estimate puretone thresholds.In some condition,different stimuli could be chosen to elicit ABR at different frequencies.It was reasonable to choose bmtb -ABR for puretone thresholds estimation in patients with steeply sloping hearing loss.
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Objective To compare the results of TEOAE and DPOAE in the same population of normal newborns, to provide information on choosing appropriate screening tools.Methods A two-steps protocol was taken with the first screening during the first 48 to 72 hours of birth and rescreened from one to two months old if the newborns failed the first screening.For each step of screening, TEOAE and DPOAE were performed simultaneously using AccuScreen hearing screening instrument (Madsen-GN Otometrics, Taastrup, Denmark).A total of 1 062 normal newborns (F/M=508/554) delivered in Peking Union Medical College Hospital were enrolled in this research for the first screening.Infants who failed either TEOAE or DPOAE screening in the first screening were referred to a second screening.Among them, 135 performed both DPOAE and TEOAE in the second step.The newborns who failed the second screening would receive ABR when they were 3 months old.Results In the first screening,the failure rate for TEOAE was 11.0% (117/1 062) and 13.7% (145/1 062) for DPOAE.In the second screening step, the failure rates were 17.8% (24/135) and 20.7% (28/135) for TEOAE and DPOAE, respectively.Chi-square and Fisher's test showed that the failure rates of DPOAE were significant higher than TEOAE for both steps (P<0.001).The agreements between TEOAE and DPOAE were 96.0% and 95.6% for the first and second steps respectively, and the kappa values were 0.817 and 0.857.As to the average time taken to accomplish the screening for one ear, TEOAE was 24±25 s and DPOAE was 40±34 s during the first screening;in the rescreening, TEOAE was 52±41 s and DPOAE was 73±62 s.Paired-t tests showed that the differences between DPOAE and TEOAE testing time were statistically significant (P=0.000) in both screening steps.Finally, 7 newborns (10 ears) were diagnosed conductive hearing loss(except 1 ear was sensorineural hearing loss).Conclusion As a screening tool, TEOAE got lower refer rates and took less time than DPOAE implicating TEOAE a better screening tool for normal neonates.
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OBJECTIVE@#To investigate the surgical technique of the pericanal electrode insertion technique for ies cochlear implantation.@*METHOD@#Forty cases of sensorineural deafness were subjected to the ies cochlear implants. Cochleostomy was performed through the external auditory canal with a microdrill anterior to the round window. The electrode impedance and electrically auditory brainstem responses(EABR) were tested during the operation. The X-ray photographs were taken after the operation. The cochlear implant was activated in all 40 cases 4 weeks following surgery.@*RESULT@#All of the electrodes were inserted and all of the implants worked well. No electrode extrusions or serious surgical complications happened during postoperative observation for 6 months.@*CONCLUSION@#The pericanal electrode insertion technique is a safe approach for ies cochlear implantation.
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Child, Preschool , Female , Humans , Infant , Male , Cochlear Implantation , Methods , Cochlear Implants , Ear Canal , General Surgery , Hearing Loss, Sensorineural , General Surgery , Otologic Surgical Procedures , Methods , Subcutaneous Tissue , General SurgeryABSTRACT
Objective To compare the accuracy of auditory brain stem response (ABR) thresholds to tone burst and tone burst ipsilaterally masked by notched noise in estimating puretone thresholds of adults with normal hearing.To study characteristics of ABRs evoked by tone burst and tone burst in notched noise of two different intensities.These three kinds of ABRs were named as follows:tb-ABR,amtb-ABR and bmtb-ABR.Methods Puretone audiometry,ABRs to tone burst and tone burst ipsilaterally masked by notched noise of different intensities were tested in 20 adults (totally 40 ears) with normal hearing.Results ①Thresholds for tb-ABR,amtb-ABR and broth-ABR of each frequency all approximated each other,and there were no statistically significant differences between them.②The mean differences between puretone thresholds and thresholds for tb-ABR,amtb -ABR and bmtb-ABR of each frequency were all less than 15 dB.Those mean differences of different ABRs of the same frequency were approximate to each other and had no statistically differences.③No matter what kind of ABR was tested,the latencies of wave V shortened with increase of frequency in each ABR at the same intensity.When the intensity and frequency of the tone burst were the same,the latency of wave V of tb-ABR was always statistically shorter than that of amtb-ABR.The latter was also always statistically shorter than that of bmtb-ABR.Conclusion Thresholds for ABRs to tone burst and tone burst ipsilaterally masked by notched noise were useful in predicting puretone thresholds.
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Objective To observe whether the animal model of optic nerve injury in rats can be set up by fluid percussion brain injury device (FPI) or not.Methods Seventy-one healthy female Wister rats were randomly divided into 2 groups,inlcuding model group with 66 rats and control group with 5 rats.The rats in model group were randomly divided into 3 groups.Eight rats in group 1 were examined by flash-visual evoked potential (F-VEP) and magnetic resonance imaging (MRI) examines before and 1,3 days,1,2,4,6,and 8 weeks after injury;56 rats in group 2 were randomly divided into 7 subgroups with 8 rats in each subgroup,and were detected by histopathologieal and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) apoptosis examines 1,3 days,1,2,4,6,8 weeks after injury;2 rats in group 3 were examined by electron microscopy 4 and 8 weeks aher injury.According to the degree of injury,the injured eyes were divided into 2 groups including severe injury group with the beat pressure of (699.14±60.79) kPa and mild injury group with the beat pressure of (243.18±20.26) kPa.The right and left eyes in rats in each group were in severe and mild injury group,respectively.Results One day after injury,the latency duration of F-VEP prolonged in severe injury group,wich differed much form which in the normal control group (P<0.05);the amplitude was gradually reduced during the first 2 weeks after injury and kept steady after that (P>0.05).The latency duration prolonged in mild injury group,and its difference with the normal control group was statistically significant (P<0.05);the amplitude was gradually reduced during the first 4 weeks after injury and kept steady after that (P>0.05).The abnormal high signal could be seen on optic nerve 1 day after injury,and was still obvious 8 weeks later.The results of histopathological examination showed ruptured capillary in ganglion cell layer 1 day after injury;retinal ganglion ceils without nucleus could be seen 4 weeks after injury.The apoptosis of positive cells was found in each layer of the retina 3 days after injury.TUNEL results indicated that the number of apoptotic positive cells increased significantly 1-2 weeks after injury.Conclusion An animal model of optic nerve injury can be successfully set up using FPI in rats.
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Objective To study the characteristic of acoustically short latency negative response (ASNR) in auditory brainstem response (ABR) evoked by tone burst in children with hearing loss. Methods ABRs to click and tone burst were recorded from 0～6 years old children with hearing loss using SmartEP auditory evoked potential system. The threshold and latency was analyzed if ASNR was recorded. Results Among all the 80 ears tested, ASNR were recorded in 7 ears (8.75%) when using click, and in 40 ears (50%) when using tone burst. ASNR was most frequently evoked by 1 kHz tone burst (in 37 ears), and 2 kHz (in 25 ears) was the second. Among the ears with ASNR, the lowest threshold of ABR wave V was 65 dB nHL. The lowest threshold of ASNR was 80dB nHL. The latencies of ASNR for 0.5,1,2 and 4 kHz tone burst was 6～8, 5～7,3～5 and 3～4 ms, respectively. The latency decreased along with the increase of intensity. Conclusion ASNR can be recorded while recording tone-burst ABR, but it has no effect in predicting hearing level using the wave V threshold of tone-burst ABR.
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OBJECTIVE To study the characteristic of auditory brain stem responses (ABRs) to air-and bone-conducted tone pip recorded in adults with normal hearing, to access the feasibility of estimating pure tone behavioral thresholds using tone-pip evoked ABR and to examine the effects of bone-conducted ABR to tone pips on differentiating the type of hearing loss. METHODS Air-and bone-conducted ABR to tone pips were recorded from otologically normal persons (n=20, male/female 10/10) using Smart EP auditory evoked potential system. RESULTS ABR thresholds to air-conducted tone pips were (24.8?7.3) , (16.1?6.5) , (13.5?5.5) , (11.9?5.8) dB nHL for 0.5, 1, 2 and 4 kHz, and were (9.5?9.3) , (13.4? 6.6) , (12.2?6.0) , (12.2?7.2) dB higher than the pure tone behavior thresholds respectively; The ABR thresholds to bone-conducted tone pips were (28.4?9.2) , (19.0?7.4) , (15.1?7.7) , (13.6?6.4) dB nHL for 0.5, 1, 2 and 4 kHz, and were (32.0?10.3) , (19.4?10.0) , (14.2?8.2) , (16.1 ?6.9) dB higher than the pure tone behavioral thresholds respectively. There were no statistically significant differences between the ABR thresholds to AC and BC tone pips. The wave forms of tone-evoked ABR were similar to those of click-evoked ABR. The detectability of Wave Ⅰ and Wave Ⅲ decreased with the decrease of tone pip frequency. The wave latencies of tone-pipevoked ABR were longer than those of click-evoked ABR, and they prolonged with the decrease of tone pip frequency. The Wave Ⅴ latency of ABR to BC 0.5 and 1 kHz tone pips at thresholds were longer compared that to AC. CONCLUSION The thresholds of tone-pip evokedABR were useful in estimating the pure tone behavioral threshold and bone-conducted tone-evoked ABR might be helpful in differentiating the type of hearing loss.