Neonatal hearing screening in a neonatal intensive care unit using distortion-product otoacoustic emissions

OBJECTIVE: To determine pass and refer rates, and identify risk factors relating to refer responses, in neonates screened using distortion-product otoacoustic emissions (DPOAEs). MATERIAL AND METHODS: A total of 435 neonates admitted to the neonatal intensive care unit (NICU) of the Philippine General Hospital between May and October 2000 were screened using DPOAEs within 48 h of admission. RESULTS: The male:female ratio in the sample was 1.05. In total, 56% of neonates were born preterm, the mean birthweight was 2,428.39 +/- 710.39 g and 8.9% weighed < 1,500 g. In total, 47.9% were delivered by Caesarian section and 44.9% were delivered vaginally. Almost 14% of neonates had 1-min Apgar scores of < 6, and 4% had 5-min Apgar scores of < 7. Approximately 95% of neonates had a poor perinatal history. Using pediatric aging it was noted that 46% of these neonates were born preterm. and 30.4% were small for gestational age. At least one neonatal disease was found in 42% of neonates, whilst 95.7% had to be given medication. The bilateral refer rate was 29.1%. Two-by-two analysis of risk factors for hearing loss and DPOAE measurements showed that only male sex seemed to have a significant association with a refer response. Neonates weighing < 1,500 g at birth showed a marginally significant association with a refer response (p = 0.07). All other neonates showed no crude association with DPOAE measurements. CONCLUSION: These preliminary data show that a high proportion of NICU patients may have poor outer hair cell function, and thus poor hearing. In order to develop an effective neonatal hearing screening program, further studies of prevalence and risk factors should be pursued in the same setting.     

Performance of two hearing screening protocols in NICU in Shanghai

Objective

To study the sensitivity and specificity of targeted neonatal hearing screening for the single-session distortion product otoacoustic emissions (DPOAE) technique and the combined DPOAE/automated auditory brain-stem response (AABR) technique.

Methods

3000 high-risk newborns were studied at Children's Hospital of Fudan University. They were required to take two different screening procedures separately. The first procedure consisted of DPOAE alone and the second consisted of DPOAE combined with the AABR. Based upon the etiology in high-risk babies, they were divided into four groups. In group I there were 670 very-low-birth-weight (VLBW) newborns (1340 ears), and in group II there were 890 preterm babies (1780 ears). 850 babies (1700 ears) suffered from hyperbilirubinemia in group III, whereas 790 babies (1580 ears) with asphyxia were in group IV. The babies in groups II, III, and IV came from the neonatal intensive-care unit (NICU) of our hospital. The study protocols consisted of the DPOAE alone and DPOAE combined with AABR hearing screening at an age of less than 1 month, and a diagnostic stage at the age of 2 months.

Results

With single-session DPOAE screening, the referral rate (8% of the NICU babies), the false-positive rate (4.96%) and the false-negative rate (0.8%) were higher. The different etiologies in NICU babies had significantly different referral rates (F-test, p < 0.01). A 4.46% referral rate of hyperbilirubinemi babies was much lower. The combined DPOAE/AABR screening technique revealed a referral rate of 5.03%, a false-positive rate of 2% and a false-negative rate of 0.06%. The false-positive rate was well below the suggested 3% of the American Academy of Pediatric. Comparisons of the referral rate, false-positive rate and false-negative rate of two hearing screening protocols (DPOAE alone and combined DPOAE/AABR) revealed significant differences (t-test, p < 0.05, p < 0.01, p < 0.01). 91 infants (3.03% of the NICU babies) who failed the combined DPOAE/AABR screening were confirmed on hearing impairment. Of 22 babies who passed DPOAE screening but failed the AABR screening had a severe to profound hearing loss based on classic ABR. These patients (24% of the NICU babies with hearing losses) with hyperbilirubinemia and asphyxia problems at newborn stage were diagnosed as auditory neuropathy based on evaluations of DPOAE screening passed, abnormal ABR and absent middle-ear muscle reflexes (MMR).

Conclusion

Our study demonstrates the use of a combination of DPOAE and AABR testing ensures high sensitivity and acceptable specificity, and predict the AN profile in NICU babies. Our efforts identified 22 NICU babies with auditory neuropathy who hopefully will benefit from early remediation of their hearing deficit.     

比较单一的DPOAE和DPOAE/AABR联合技术进行的目标新生儿听力筛查方法研究

目的通过单一的畸变产物耳声发射（DPOAE）和DPOAE／自动听性脑干反应（AABR）联合技术进行目标新生儿的听力筛查，以研究目标新生儿听力筛查的敏感性。方法记录出生3～24天的200名新生儿（400耳）的单一畸变产物耳声发射（DPOAE）和DPOAE／AABR联合技术测试的结果。筛查对象来自复旦大学附属儿科医院和上海儿童医学中心新生儿重症监护室（NICU）的有高危听力损害的新生儿。结果在开始的听力筛查中，共有29名新生儿（14．5％）在单一的DPOAE中未通过，而9名（4．5％）在联合运用DPOAE和AABR检查中未通过。在随访的诊断评估中，包括耳科检查、声阻抗、诊断性的听性脑干反应（DABR），6名新生儿11耳（3％）在出生后2个月时最终被诊断为真正的感音神经性听力损失。运用DPOAE和AABR联合测试，使高危儿童听力筛查的敏感性高达98．5％，并能够大大减少假阳性率。在频率分析中发现在通过AABR（短声刺激）测试的23耳中，高频的DPOAE通过率（％）比较高（2562Hz为93％，3187HZ为88％）。没有通过AABR测试的15耳，低频（500、1000和1593Hz）的DPOAE通过率（％）比高频（2562．3187和4031Hz）略高。结论DPOAE和AABR联合测试技术可以广泛运用于新生儿听力筛查，敏感性较高，可以减少假阳性并提供频率特异性。     

Hearing evaluation with distortion-product otoacoustic emissions in young patients undergoing haemodialysis

Sensorineural hearing loss is frequently reported in young patients with chronic renal failure having haemodialysis. The effect of a single session of haemodialysis on hearing acuity was assessed prospectively in nine children with end-stage renal disease using pure-tone audiometry (PTA) and distortion-product otoacoustic emissions (DPOAEs). Results were compared with those obtained from nine audiologically normal healthy children also tested with PTA and DPOAEs twice during a 4-h interval. Sensorineural hearing loss of unknown aetiology was found in 55.5% of renal patients, mainly in the higher frequencies. Patients on HD had mean PTA thresholds significantly poorer than those of the control group in the frequency range 1000–12 000Hz (P < 0.05). Their mean DPOAE amplitudes were significantly lower in all frequencies > 1184 Hz (P < 0.05). Furthermore, patients' ears with normal PTA thresholds between 250 and 4000 Hz also had decreased DPOAE amplitudes. No significant changes in PTA thresholds or DPOAE amplitudes were encountered in renal patients before and after a HD session (P > 0.05). Changes in PTA thresholds or DPOAE amplitudes were not significantly different than those in the control group (P > 0.05). In conclusion, sensorineural hearing loss of unknown origin, especially in high frequencies, is frequent in young renal patients under HD and single HD sessions do not seem to alter the hearing acuity of these patients. DPOAEs seem to be more sensitive to incipient cochlear damage than behaviour thresholds in monitoring renal patients.     

Recognition of speech in noise and relations with suppression of otoacoustic emissions and the acoustic reflex

Subjects presenting difficulties in understanding speech with competing sounds may have absence of otoacoustic emission suppression and the acoustic reflex.Aim: To study the performance of the efferent auditory system in normal hearing subjects complaining of difficulties to understand speech in noise.Material and methods: A prospective study comprising 50 normal-hearing subjects aged from 19 to 32 years, reporting difficulties with speech recognition in noise (with complaints - WC) or not (with no complaints - WNC). Distortion product evoked otoacoustic emissions (DPOAEs) were tested at frequencies from 1500 to 6000 Hz.The contralateral acoustic reflex (CAR) was investigated from 500 to 4000 Hz.Results: Groups differed statistically as to the occurrence of CAR in the left ear at 4000 Hz. At 1500 Hz, there was a statistically significant effect - absence of DPOAEs in the WC group in the right ear. In left ears, absence of DPOAE suppression was higher in the WC at 1500 Hz and 2000 Hz.Conclusion: An association between self-reported difficulties in discriminating speech in noise and the absence of contralateral acoustic reflex at 4000 Hz in the left ear was observed; there was also absence of the suppression effect of DPOAEs, especially at middle frequencies in both ears.     

Differences in the suppression of distortion product otoacoustic emissions by contralateral white noise between patients with acute or chronic tinnitus

Objective: The mechanisms underlying the shift from acute tinnitus to chronic remain obscure. An association between tinnitus and medial olivocochlear bundle (MOCB) reflex dysfunction has been hypothesised by several studies. The differences between participants with acute and chronic tinnitus have not yet been investigated. Design: Participants were examined with distortion product otoacoustic emissions (DPOAEs) suppression elicited by contralateral white noise. They were compared in terms of frequency regions with non-recordable DPOAEs, suppression amplitudes and the presence of DPOAE enhancement. Study sample: Eighteen participants with acute tinnitus, 40 age-matched adults with chronic tinnitus and 17 controls were included. All participants (aged 34.7?±?9.6years; mean?±?Standard deviation) had normal hearing. Tinnitus was bilateral in 22 participants and unilateral in 36. Results: Ears with chronic tinnitus presented significantly lower DPOAE suppression amplitudes than ears with acute tinnitus (p?p?p?=?0.0002, respectively). Non-recordable DPOAEs were significantly more frequent in the chronic than in the acute tinnitus and control groups (p?Conclusions: The differences between study groups indicate that when tinnitus becomes chronic, DPOAEs suppression presents changes that might reveal corresponding steps in tinnitus pathophysiology. Treatment implications are discussed.     

新生儿监护病房儿童听力筛查及诊断结果分析

目的对在耳鼻喉科听力诊断中心进行听力诊断评估,并且有新生儿监护病房住院史婴幼儿的听力筛查及诊断结果进行比较分析,旨在评价目前所用听力筛查方法的有效性。方法选取有新生儿监护病房住院史并于耳鼻咽喉科进行听力诊断评估的婴幼儿,分析其自动听性脑干反应(AABR)及畸变产物耳声发射(DPOAE)筛查资料,并与诊断型听性脑干反应(ABR)的结果进行对比分析。结果本组同时完成DPOAE、AABR筛查及诊断型ABR测试,并且资料完整保存者共89例177耳。DPOAE筛查未通过率为45.8%,AABR筛查的未通过率为46.3%。两种筛查方法的一致率为64.4%。AABR的假阴性率为27.9%,DPOAE为16.3%,联合使用两种筛查方法时其假阴性率为4.7%。诊断型ABR测试异常共26例43耳(24.3%),其中轻度听力损失22耳,中度7耳,重度3耳,极重度11耳,听力损失为双侧者17例,单侧者9例,双侧听力损失患者中双耳听力损失程度对称者12例,不对称者5例。本组确诊听力损失婴幼儿中存在的高危因素包括:新生儿重症监护病房(NICU)住院超过5天;早产儿呼吸窘迫综合征;机械通气48h以上;出生体重低于1500g;新生儿窒息(Apgar评分1分钟0~4分或5分钟时0~6分);高胆红素血症胆红素水平达到换血要求;颌面部畸形(小耳、外耳道闭锁或畸形、腭裂);细菌性脑膜炎。结论使用AABR或AABR与DPOAE联合筛查可用于NICU新生儿的听力筛查,有新生儿听力损失高危因素的婴幼儿有转诊进行听力诊断评估的指证。     

Distortion-product otoacoustic emissions in humans with high frequency sensorineural hearing loss

Distortion-product otoacoustic emissions (DPOAEs) and pure-tone behavioral thresholds were compared in 20 ears with normal hearing and in 20 ears with high-frequency sensorineural hearing loss. The purpose was to determine if DPOAE amplitude is associated with pure-tone behavioral threshold. Comparison of results from the two groups of ears indicated that DPOAEs were reduced in amplitude or were absent in ears with high-frequency hearing loss. The differences occurred at frequencies above 1,500 Hz. Comparing results from 750 to 8,000 Hz within the same ear revealed a frequency-related correspondence of elevated behavioral threshold to reduced DPOAE amplitude. When behavioral thresholds were better than 20 dB HL, DPOAE amplitude was within the range (+/- 2 SDs) determined for the ears with normal hearing. When pure-tone threshold was greater than 50 dB HL, DPOAEs were absent or were significantly attenuated in 16/17 subjects (94%). The association of emission level with behavioral threshold level was variable when threshold was between these two extremes. Results imply that the measurement of DPOAEs has clinical potential as a means of detecting hearing loss by frequency.     

Distortion product otoacoustic emissions in term infants with a low Apgar score

Conclusion. Term infants with a low Apgar score have cochlear impairment, mainly at the frequencies 1–3 kHz. Compared with infants with both a low Apgar score and hypoxic-ischaemic encephalopathy we reported before, the impairment is less severe. Objective. To detect any peripheral impairment of cochlear origin in infants with a low Apgar score. Subjects and methods. Fifty-four term infants with a low Apgar score at 1 and/or 5 min but without clinical signs of hypoxic-ischaemic encephalopathy were recruited. Distortion product otoacoustic emissions (DPOAEs) were recorded with the f₂ primary tone at 10 frequencies (0.5–10 kHz) on days 3–5 and 1 month after birth. Results. On days 3–5 DPOAE pass rates at most frequencies tended to be decreased, and were significant lower than those in normal term controls at 1, 2, 3, 5, 6 and 10 kHz (χ²=4.49–40.31, p<0.05–0.005). The greatest difference occurred at 1 kHz; 18.5% failed the DPOAE test and this was significantly higher than in the controls (4.3%, χ²=7.65, p<0.01). At 1 month the DPOAE pass rate at most frequencies did not show any significant improvement. The overall failure rate (14.8%) did not differ significantly from that on days 3–5.     

Increased prevalence of early cochlear damage in young patients with type 1 diabetes detected by distortion product otoacoustic emissions

Abstract

Objective: To evaluate the hearing of adolescents with diabetes mellitus type 1(DM1) by otoacoustic emissions (OAEs), and by comparing different tests with pure-tone audiometry to identify potential early cochlear impairments. Design: Pure-tone audiometry, transient evoked otoacoustic emissions (TEOAEs), and distortion product otoacoustic emissions (DPOAEs) were performed in a group of adolescents with and without DM1. Clinical characteristics, disease duration, and glycated haemoglobin levels were studied. Study sample: Participants were 40 adolescents with DM1 and 40 healthy subjects. Results: Sensorineural hearing loss, affecting frequencies of 6000 and 8000 Hz, was found only in DM1 subjects when compared to the controls (7.7% vs. 0%, p < 0.05). A higher prevalence of cochlear damage was detected by DPOAE responses, 32% belonging from the diabetic group, vs. 3.7% in the control group. Absent TEOAE responses were observed in only three individuals, all from the diabetic group (5.1% of the tests performed in the diabetic group). Additionally, hearing thresholds were better in diabetic subjects with good control when compared to ones with regular or poor control (p = 0.00). Hearing thresholds were higher in poorly controlled diabetics when compared to subjects with good (p = 0.000) or regular control (p = 0.006). Conclusion: Early evidence of cochlear damage was detected in adolescents with DM1 leading to hearing loss at high frequencies. Abnormal DPOAEs responses were found more frequently than the alterations in TEOAEs and pure-tone audiometry, suggesting that DPOAEs evaluation is the most sensitive and it could be used for monitoring the progression of cochlear damage during the early stages of hearing impairment.     

High-frequency hearing influences lower-frequency distortion-product otoacoustic emissions

OBJECTIVES: The primary goal of this study was to test the ability of 2f1-f2 distortion-product otoacoustic emissions (DPOAEs) to detect reduced cochlear function in the presence of normal behavioral sensitivity. DESIGN: A prospective study was performed in normal-hearing young adults using simple and complex regression analyses to clarify the relationship between ultra-high frequency (UHF) hearing and DPOAE levels at lower frequencies, as well as the influence of hearing levels for frequencies within the conventional test range and subject age on this association. METHODS: Average DPOAE levels between 4 to 8 kHz, which were elicited by equilevel primary tones of low to moderate levels, were measured as level-frequency functions, or distortion-product (DP) grams, and related to the mean UHF hearing levels from 11.2 to 20 kHz. The median hearing level for the UHF hearing was used to separate subjects into good and poor UHF hearers. This distinction was then used to compare DPOAE levels from 4 to 8 kHz for the 2 groups to determine if UHF hearing status influenced DPOAE levels at lower frequencies. RESULTS: Simple regression analysis revealed that the 4-to 8-kHz DPOAE levels were significantly correlated with the pure-tone average (PTA) from 11.2 to 20 kHz. However, the PTA for 4 and 8 kHz was also significantly correlated with the PTA for UHF hearing. Further multiple regression analyses revealed that UHF hearing significantly and uniquely accounted for approximately 14% of the variance in DPOAE levels from 4 to 8 kHz for most of the primary-tone level combinations. In contrast, neither the PTA for the conventional hearing range nor subject age contributed significantly to the DPOAE variance. CONCLUSIONS: The findings suggest that UHF hearing influences DPOAEs at significantly lower frequencies because emissions are sensitive to subtle changes in outer hair cells not yet detected by pure-tone thresholds in this region or because alterations in the basal cochlea affect the generation of lower-frequency DPOAEs originating from more apical cochlear regions.     

Analysis of audiological results of patients referred from newborn hearing screening program

Conclusion: As tools of confirmation of sensorineural hearing loss in neonates who are ‘referred’ from a newborn hearing screening program, both ASSR and DPOAE have high sensitivity and specificity. In addition, ASSR can be used as a substitute for ABR. Objectives: To analyze the confirmative audiological results of patients referred from a newborn hearing screening program. Patients and method: From January 2007 to December 2013, hearing tests were performed on 474 babies (804 ears) who were ‘referred’ from the hospital or other maternity centers. Auditory brainstem response (ABR), auditory steady-state response (ASSR), and distortion product otoacoustic emissions (DPOAE) were used for hearing evaluation. Results: Of 474 babies (804 ears), 232 had normal hearing, while 242 babies (358 ears) had over 30 dB nHL threshold from ABR. Among the 156 babies (312 ears) who underwent both ABR and ASSR, the mean ASSR threshold had a strong correlation with ABR threshold (r = 0.942, p < 0.001). Assuming that ABR results were the yardstick of abnormal hearing, sensitivity and specificity of ASSR to ABR were 90.6% and 95%. DPOAE tests were performed on 180 babies (360 ears), with sensitivity of 85.9% and specificity of 84.4%.     

Similarities and differences in distortion-product otoacoustic emissions among four FDA-approved devices

Similarities and differences in distortion-product otoacoustic emissions (DPOAEs) among four Food and Drug Administration (FDA) approved devices were assessed quantitatively. DPOAEs were recorded from 42 adult subjects (84 ears) ranging in age from 19 to 40 years. All subjects had hearing thresholds of 20 dB HL or better for the test frequencies from 0.25 to 8.0 kHz and normal acoustic immittance findings. DPOAEs were collected in a quiet non-sound-treated room. DPOAE measurement parameters included an f2/f1 ratio of approximately 1.2, with f1 at 65 dB SPL (L1) and f2 at 55 dB SPL (L2). There were no significant differences in the mean emissions levels among the four devices. This investigation showed that validity criteria, pass criteria, and strategies for DPOAE measurements interact to produce varying pass and refer results. However, when DPOAEs are obtained with consistent validity criteria, pass criteria, and strategies for measurement, the results are remarkably consistent.     

Hearing evaluation with distortion-product otoacoustic emissions in young patients undergoing haemodialysis.

Sensorineural hearing loss is frequently reported in young patients with chronic renal failure having haemodialysis. The effect of a single session of haemodialysis on hearing acuity was assessed prospectively in nine children with end-stage renal disease using pure-tone audiometry (PTA) and distortion-product otoacoustic emissions (DPOAEs). Results were compared with those obtained from nine audiologically normal healthy children also tested with PTA and DPOAEs twice during a 4-h interval. Sensorineural hearing loss of unknown aetiology was found in 55.5% of renal patients, mainly in the higher frequencies. Patients on HD had mean PTA thresholds significantly poorer than those of the control group in the frequency range 1000-12 000Hz (P < 0.05). Their mean DPOAE amplitudes were significantly lower in all frequencies > 1184 Hz (P < 0.05). Furthermore, patients' ears with normal PTA thresholds between 250 and 4000 Hz also had decreased DPOAE amplitudes. No significant changes in PTA thresholds or DPOAE amplitudes were encountered in renal patients before and after a HD session (P > 0.05). Changes in PTA thresholds or DPOAE amplitudes were not significantly different than those in the control group (P > 0.05). In conclusion, sensorineural hearing loss of unknown origin, especially in high frequencies, is frequent in young renal patients under HD and single HD sessions do not seem to alter the hearing acuity of these patients. DPOAEs seem to be more sensitive to incipient cochlear damage than behaviour thresholds in monitoring renal patients.     

三组新生儿的诱发性耳声发射的检测分析

目的　研究新生儿的畸变产物耳声发射 (DPOAE)和瞬态诱发耳声发射 (TEOAE)的特点 ,评价其在新生儿听力筛选中的作用。方法　应用Capella耳声发射分析仪对正常新生儿组、剖腹产儿组、新生儿监护病房组三组新生儿进行DPOAE、TEOAE检测。结果　得出正常新生儿的诱发性耳声发射 (EOAE)的正常参考值和正常新生儿的DPOAE图 ;三组新生儿EOAE筛查的通过率分别为 96.1% (12 3 / 12 8)、90 .8% (10 9/ 12 0 )、81.6% (93 /114 ) ,其中新生儿监护病房组的通过率与前两组比较有统计学意义 (P <0 .0 1) ;各组间DPOAE与TEOAE的筛查通过率差异均有统计学意义 (P <0 .0 1) ;正常新生儿与剖腹产儿的DPOAE的幅值和信噪比差异无统计学意义(P >0 .0 5)。结论　在病房内 (非隔音 )进行听力筛选时 ,可明显降低假阳性率 ;剖腹产因素对新生儿耳声发射未见影响 ;对高危新生儿进行听力筛选更有意义     

Prediction of hearing outcomes by distortion product otoacoustic emissions in patients with idiopathic sudden sensorineural hearing loss

Objective

To investigate whether distortion product otoacoustic emissions (DPOAEs) can be a prognostic indicator of hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).

Methods

Seventy-eight consecutive patients with ISSNHL were enrolled. DPOAEs were measured at the first hospital visit. Two primary pure tones with a frequency ratio (f2/f1) of 1.2 were used at non-equal sound pressure levels (L1/L2 = 80/70 dB SPL). The DPOAE amplitude was measured at the 11 frequencies of 2f1-f2 with f2 varying from 593 to 6031 Hz. All the patients received steroid administration in combination with hyperbaric oxygen (HBO) therapy. Hearing recovery was evaluated by the improvement in hearing compared to the unaffected contralateral ear. Correlations between the hearing improvement rate and five potential prognostic factors (the DPOAE amplitude, patient's age, days from onset to the start of treatment, initial hearing level, and presence of vertigo) were examined by simple and multiple regression analyses.

Results

The net DPOAE amplitude in patients with hearing improvement rate ≥50% was significantly larger than that with hearing improvement rate <50% at f2 frequencies of 3031 and 4812 Hz (unpaired Student's t-test, p < 0.05). A simple regression analysis showed that the hearing improvement rate significantly correlated with the net DPOAE amplitude at f2 frequencies of 3031 and 4812 Hz, but not with that at the other f2 frequencies tested. The correlation coefficients were 0.528 and 0.522 for 3031 and 4812 Hz, respectively, with p values <1 × 10⁻⁶. In a multiple regression analysis, the partial correlation coefficients of the net DPOAE amplitude were 0.308 and 0.246 with p values of 0.008 and 0.036 for 3031 and 4812 Hz, respectively.

Conclusion

The significant correlation between hearing recovery and DPOAEs measured before treatment indicates that DPOAEs are a potentially useful means of predicting hearing prognosis in ISSNHL.     

Detailed f 1, f 2 Area Study of Distortion Product Otoacoustic Emissions in the Frog

Distortion product otoacoustic emissions (DPOAEs) are weak sounds emitted from the ear when it is stimulated with two tones. They are a manifestation of the nonlinear mechanics of the inner ear. As such, they provide a noninvasive tool for the study of the inner ear mechanics involved in the transduction of sound into nerve fiber activity. Based on the DPOAE phase behavior as a function of frequency, it is currently believed that mammalian DPOAEs are the combination of two components, each generated by a different mechanism located at a different location in the cochlea. In frogs, instead of a cochlea, two separate hearing papillae are present. Of these, the basilar papilla (BP) is a relatively simple structure that essentially functions as a single auditory filter. A two-mechanism model of DPOAE generation is not expected to apply to the BP. In contrast, the other hearing organ, the amphibian papilla (AP), exhibits a tonotopic organization. In the past it has been suggested that this papilla supports a traveling wave in its tectorial membrane. Therefore, a two-mechanism model of DPOAE generation may be applicable for DPOAEs from the AP. In the present study we report on the amplitude and phase of DPOAEs in the frog ear in a detailed f₁, f₂ area study. The result is markedly different from that in the mammalian cochlea. It indicates that DPOAEs generated by neither papilla agree with the two-mechanism traveling wave model. This confirms our expectation for the BP and does not support the hypothesized presence of a mechanical traveling wave in the AP.     

ABR和DPOAE在高胆红素血症新生儿听力筛查中的应用

目的探讨听性脑干反应(ABR)及畸变产物耳声发射(DPOAE)对高胆红素血症新生儿听力筛查的临床意义,为早期干预治疗提供依据.方法对170例高胆红素血症新生儿进行ABR和DPOAE检查,对其中部分异常者6个月后复查.结果 170例患儿中,ABR和DPOAE的总异常率分别为54.12%和32.65%;血清胆红素水平越高,ABR和DPOAE异常率越高(P<0.01),ABR异常越严重(P<0.01);胆红素浓度恢复正常后6个月复查ABR和DPOAE,恢复率分别为77.12%和77.01%,其中ABR异常DPOAE正常耳较两者均异常耳容易恢复(P<0.01).结论 ABR和DPOAE联合应用对高胆红素血症新生儿听力的早期定量定位评估比单独应用更准确和全面.     

畸变产物耳声发射在唇腭裂婴幼儿听力检查中的应用

目的探讨唇腭裂婴幼儿畸变产物耳声发射（distortion product otoacoustic emission,DPOAE）的特点,并将其与听性脑干反应（auditory brainstem response,ABR）阂值检查的结果加以对照,以探讨DPOAE在这类患儿听力检查中的应用价值。方法DPOAE检查63例（126耳）,年龄2个月-42个月,平均11.83个月。其中单纯腭裂组（以下简称腭裂组）23例（46耳）,腭裂并发唇裂及牙槽裂组（以下简称唇腭裂组）30例（60耳）,单纯唇裂组（以下简称唇裂组）10例（20耳）,每耳均检查8个频率,若2-5kHz4个频点有≥3个频点通过即为该耳通过。在上述患儿中,ABR阈值检查腭裂组17例（34耳）,唇腭裂组10例（20耳）,唇裂组6例（12耳）,以能重复引出V波的最小刺激强度为ABR阈值。结果DPOAE检查：腭裂组通过7耳,未通过39耳,通过率为15.22％;唇腭裂组通过6耳,未通过54耳,通过率为10.00％;唇裂组通过18耳,未通过2耳,通过率为90％。统计分析腭裂组与唇腭裂组无显著差异,而腭裂组与唇裂组,唇腭裂组与唇裂组均有显著差异。ABR阈值检查统计分析结果与DPOAE一致。将各组DPOAE通过率与ABR正常率进行比较,腭裂组及唇腭裂组中二者无差异（P〉0.05）,虽然唇裂组中二者有差异（P〈0.05）,但唇裂组ABR阈值反应的听力下降较轻（均≤50dB nHL）。从总体趋势上说,DPOAE与ABR阈值检查在检测的结果上是一致的。结论唇腭裂患儿DPOAE和ABR检测结果一致,与ABR相比,DPOAE具有快速、简便、易实施等特点,因此DPOAE可以作为唇腭裂婴幼儿听力检查的手段,但仍需进一步结合ABR及其他相关的听力检查,以明确听力损害的程度和类型。     

畸变产物耳声发射与声阻抗在高危新生儿听力筛查中的应用

目的探讨高危新生儿未通过初次筛查是否与外耳道栓塞,中耳病变有关。方法对166例高危新生儿在出生后进行畸变产物耳声发射(DPOAE)检查,未通过的新生儿立即行声阻抗测试。结果初查时有38例新生儿未通过。声阻抗测得鼓室曲线均为A型。结论本研究显示新生儿未通过初次筛查与外耳道栓塞,中耳病变无明显联系。