Influence of obstructive sleep apnea on auditory event-related potentials.

PURPOSE: To evaluate the influence of obstructive sleep apnea (OSA) on the P300 response of auditory event-related potentials (ERPs) and to correlate the electrophysiological findings with OSA severity. METHODS: Patients with no OSA and mild, moderate, and severe OSA according to polysomnography (PSG) with normal hearing and no comorbidities were studied. Individuals with a body mass index (BMI) ≥ 40 kg/m2, hypertension, diabetes, dyslipidemia, the use of chronic medications, and a risk of hearing loss were excluded. All patients underwent full PSG and auditory ERP measurement using the oddball paradigm with tone burst and speech stimuli. For P300 analysis (latencies and amplitudes), normal multiple linear regression models were adjusted with the groups (No OSA, Mild OSA, Moderate OSA, Severe OSA), age, BMI, and Epworth score as explanatory variables. RESULTS: We studied 54 individuals (47 males) aged 35 ± 8 years with a BMI of 28.4 ± 4.3 kg/m2. Patients were divided according to the apnea-hypopnea index (AHI) derived from PSG into no OSA (n = 14), mild (n = 16), moderate (n = 12), and severe OSA (n = 12) groups. Patients with severe OSA presented prolonged P300 latencies with tone burst stimuli compared to patients with no OSA and those with mild and moderate OSA. CONCLUSION: Severe OSA is associated with impairment of the P300 response of auditory ERPs, suggesting a decrease in the processing speed of acoustic information that may be mediated by the level of somnolence.

Relationship Between Distortion Product - Otoacoustic Emissions (DPOAEs) and High-Frequency Acoustic Immittance Measures.

BACKGROUND Pathologies that alter the impedance of the middle ear may consequently modify the DPOAE amplitude. The aim of this study was to correlate information from 2 different clinical procedures assessing middle ear status. Data from DPOAE responses (both DP-Gram and DP I/O functions) were correlated with data from multi-component tympanometry at 1000 Hz. MATERIAL AND METHODS The subjects were divided into a double-peak group (DPG) and a single-peak group (SPG) depending on 1000 Hz tympanogram pattern. Exclusion criteria (described in the Methods section) were applied to both groups and finally only 31 ears were assigned to each group. The subjects were also assessed with traditional tympanometry and behavioral audiometry. RESULTS Compared to the single-peak group, in terms of the 226 Hz tympanometry data, subjects in the DPG group presented: (i) higher values of ear canal volume; (ii) higher peak pressure, and (iii) significantly higher values of acoustic admittance. DPOAE amplitudes were lower in the DPG group only at 6006 Hz, but the difference in amplitude between the DPG and SPG groups decreased as the frequency increased. Statistical differences were observed only at 1001 Hz and a borderline difference at 1501 Hz. In terms of DPOAE I/O functions, significant differences were observed only in 4 of the 50 tested points. CONCLUSIONS The 1000-Hz tympanometric pattern significantly affects the structure of DPOAE responses only at 1001 Hz. In this context, changes in the properties of the middle ear (as detected by the 1000 Hz tympanometry) can be considered as prime candidates for the observed variability in the DP-grams and the DP I/O functions.

Psychoacoustic analyses of cochlear mechanisms in tinnitus patients with normal auditory thresholds.

OBJECTIVE: Tinnitus is often related to auditory dysfunction. We hypothesised that, among individuals with normal auditory thresholds, the mechanism of frequency selectivity might differ between subjects with and without tinnitus. Our objective was to identify any differences between normal-hearing individuals with tinnitus and those without in terms of psychophysical tuning curves (PTCs) and threshold-equalising noise (TEN) test results. DESIGN: We determined PTCs and performed the TEN test. STUDY SAMPLE: We evaluated 57 individuals, 16 with bilateral tinnitus (tinnitus-group) and 41 without tinnitus (control-group). RESULTS: We found significant differences between tinnitus and control groups regarding the following: 2 kHz PTCs obtained in noise at 6 and 8 kHz; 4 kHz PTCs obtained in noise at 2 and 8 kHz; and 6 and 8 kHz PTCs obtained in noise at 2 and 3 kHz. The TEN test revealed differences between groups in terms of auditory thresholds, which were significantly higher in the tinnitus group. In addition, none of the individuals in the tinnitus group were found to have dead regions in the cochlea. CONCLUSIONS: Despite having normal auditory thresholds, individuals with tinnitus have auditory patterns that differ significantly from those seen in individuals without tinnitus, such differences being suggestive of cochlear impairment.

Contralateral suppression of otoacoustic emissions: input-output functions in neonates.

BACKGROUND: The literature suggests that contralateral acoustic stimulation (CAS) alters the amplitude of the distortion product otoacoustic emissions (DPOAEs), but it is still unknown whether the DPOAE Input/Output (I/O) functions are also affected. To elucidate this aspect of the DPOAEs, the present study assessed the effects of CAS on DPOAE I/O functions at the frequencies of 2 kHz and 4 kHz, in a sample of term neonatal subjects. MATERIAL/METHODS: Sixty randomly selected neonates were included in the study. The DPOAE I/O functions were obtained at 2 kHz and 4 kHz, in the presence of a 60 dB SPL broad band-contralateral white noise, using the TDH39 headphones contralaterally. DPOAEs were recorded up to a stimulus level of L2 = 35 dB peSPL. RESULTS: Significant DPOAE amplitude suppression effects were observed at various L2 stimulus levels for both tested frequencies at 2 and 4 kHz. In contrast, the corresponding DPOAE slopes showed various alterations that were not statistically significant. CONCLUSIONS: The data from the present study show that contralateral acoustic stimulation significantly affects only the amplitude of the DPOAE I/O functions; the slope is affected, but not significantly. This observation can shed light on the nature of CAS, suggesting that the latter is primarily a linear phenomenon without the cochlear compression and non-linear components seen in the healthy cochlea. From the available data it is not possible to infer whether the sample size has influenced the obtained results and the study should be repeated with a larger sample size and assessing more frequencies.

Influence of cochlear function on auditory temporal resolution in tinnitus patients.

Our aim was to analyze the influence of subtle cochlear damage on temporal auditory resolution in tinnitus patients. Forty-eight subjects (hearing threshold

Development of auditory perception in preschool children.

OBJECTIVE: The aim of this study was to determine whether the auditory skills presented by five-year-old children can predict their performance in auditory processing (AP) tests at seven years old. DESIGN: Thirty-five children were evaluated for AP at two different times. At evaluation 1, the children were between 5 years 2 months and 6 years 1 month of age, and at evaluation 2, they were between 7 years 1 month and 7 years 8 months of age. The interval between the evaluations ranged from 18 to 23 months. After evaluation 2, the 7-year-olds were classified according to their performance on central AP tests. The children were divided into three groups: GI included nine children with at least two AP tests that scored two standard deviations below the mean and the presence of a speech complaint; GII included 18 children with at least two AP tests that scored two standard deviations below the mean and no speech complaints; and GIII included eight children with no more than one test scored two standard deviations below the mean and no speech disorders complaint. The analysis was performed considering each test individually and as a battery of applied tests. From the results obtained, a discriminant analysis was performed to assess the differences in test performance between the groups when the children were 5 years old. RESULTS: The discriminant analysis showed that with the results obtained during evaluation 1, it was possible to predict which group 74.3% of the children would be classified into after evaluation 2. The percentage of correct classifications for each group was 77.8% for GI, 66.7% for GII and 87.5% for GIII. That is, 87.5% of the children who were classified as GIII after evaluation 2 had already demonstrated good auditory performance in the tests applied at 5 years of age. CONCLUSIONS: Children who exhibited lower scores on AP tests at 7 years of age had demonstrated poor auditory perception at 5 years of age. This finding is relevant because it offers the possibility of stimulating or training these auditory skills in preschoolers to foster their development.

The effect external and middle ears have in otoacoustic emissions.

UNLABELLED: Characteristics of how external and middle ear resonance frequency can impact the capture of otoacoustic emissions. AIM: to study the impact of external and middle ear resonance frequency in otoacoustic emissions. STUDY DESIGN: Prospective, clinical, series study. MATERIALS AND METHODS: Microphone-probe measurements were made in the external ear, together with multifrequency timpanometry distortion product transient otoacoustic emissions in 19 right and 20 left ears from male individuals and 23 right and 23 left ears from female individuals with 17 to 30 years of age. The 85 ears were audiologically normal. RESULTS: We did not observe statistically significant associations between the best otoacoustic emission best frequencies and the occluded external and middle ear resonance frequencies. CONCLUSION: Response levels for both transient and distortion product otoacoustic emissions are not influenced by the external and middle ear resonances alone.

Contralateral suppression of linear and nonlinear transient evoked otoacoustic emissions in neonates at risk for hearing loss.

UNLABELLED: To investigate the transient evoked otoacoustic emissions (TEOAE) contralateral suppression in neonates at risk for hearing loss, 55 neonates at risk for hearing loss (risk group) and 72 full-term neonates not at such risk (control group) were bilaterally tested. In all neonates, the TEOAE were recorded in two stimulation modes (linear and nonlinear clicks), with and without contralateral acoustic stimulation. Findings revealed significant contralateral suppression of otoacoustic emissions in both groups, but the amount of TEOAE contralateral suppression was reduced for at risk group (p=0.001), supporting the hypothesis that medial olivocochlear bundle function is reduced in neonates at risk for hearing loss. The combination of contralateral acoustic stimulation and TEOAE enables easy and noninvasive study of auditory efferent function. However it should be emphasized that the reduction in TEOAE contralateral suppression in the risk group, statistically identified as a group effect, might not be detectable in individual cases. Further studies are needed in order to determine whether the lower amount of TEOAE contralateral suppression in neonates at risk for hearing loss represents a risk for developing auditory processing disorders. LEARNING OUTCOMES: The reader will be introduced to the study using auditory efferent pathway activation by contralateral acoustic stimulation (CAS), resulting in the TEOAE suppression effect. The characteristics of TEOAE suppression in the neonatal population, in which it provides evidence of the reduced medial olivocochlear system function in those at risk for hearing loss, will also be addressed.

Acoustic immittance in children without otoacoustic emissions.

UNLABELLED: Considering the hypothesis that middle ear changes can impair the recording of otoacoustic emissions, it is possible that absent otoacoustic emissions in infants could be associated with a light tympanometric change. AIM: To study the association between transient otoacoustic emissions and changes in acoustic immittance measurements with 226 Hz probe tone in neonates. METHODS: Cross-sectional contemporary cohort study. 20 infants with no transient otoacoustic emissions (study group) and 101 infants with transient otoacoustic emissions (control group), with ages ranged from birth to eight months, were assessed. Infants were submitted to: admittance tympanometry; contralateral acoustic reflex threshold with stimulus of 0.5, 1, 2, 4 kHz and broad band noise; transient and distortion product otoacoustic emissions. The auditory brain response was used to study the threshold in neonates without transient otoacoustic emissions. RESULTS: Significant statistical differences were observed between the groups (p < 0.005), characterized by reduction in tympanometric configuration and increase acoustic reflex thresholds in the study group. These data suggest the occurrence of middle ear mild impairment in infants without transient otoacoustic emissions associated with normal auditory brain response. CONCLUSION: tympanometry associated with acoustic reflex adds accuracy to the diagnosis of middle ear abnormalities.

Efferent auditory system: its effect on auditory processing.

UNLABELLED: Auditory processing depends on afferent and efferent auditory pathways integrity. The efferent auditory system may be assessed in humans by two non-invasive and objective methods: acoustic reflex and otoacoustic emissions suppression. AIM: Analyze the efferent auditory system activity by otoacoustic emission suppression and acoustic reflex sensitization in human subjects with auditory processing disorders. METHOD: Prospective study: fifty children with auditory processing disorders (study group) and thirty-eight children without auditory processing disorders (control group) were evaluated using otoacoustic emission with and without contralateral noise; and acoustic reflex with and without contralateral facilitating stimuli. RESULTS: OAE suppression mean value was equal to or less than 1.50 dB for the control group, and equal to or less than 1.26 dB for the study group. The mean sensitization reflex value was equal to or less than 14.60 dB for the study group and equal to or less than 15.21 dB for the control group. There was no statistically significant difference between the responses from the control group and the study group in both procedures. CONCLUSION: The study group had lower OAE suppression values and higher acoustic reflex sensitization values when compared to the control group.

Tympanometry in neonates with normal otoacoustic emissions: measurements and interpretation.

UNLABELLED: Tympanometry is used in evaluating middle ear functional conditions. Before six months of age its results may be misleading. High frequency studies aim to provide more valid procedures. AIM: To describe and discuss tympanometric measurements and the interpretation in normal hearing neonates at 226, 678 and 1000Hz. METHOD: 110 neonates that were analyzed had normal otoacoustic emissions and no risk for hearing impairment. The age range was 6 to 30 days. Curves were obtained using the GSI-33-II, at the Divisão de Educação e Reabilitação dos Distúrbios da Comunicação, São Paulo, in 2004. STUDY DESIGN: Clinical prospective. RESULTS: There was a balance between single and double peak curves at 226Hz. Most of the curves were asymmetric at 678Hz, and single-peaked at 1000Hz. quantitative measurements showed a significant gender difference in the Equivalent Ear Canal Volume at 226Hz and on the Peak Compensated Static Acoustic Admittance at 1000Hz. The English protocol showed that almost 100% of ears were normal at 678 and 1000Hz. CONCLUSION: 1000Hz yielded superior results for characterizing normality. The English protocol was efficient to reduce the variability of tympanometric measurements. Data from this study may be used as a guide for diagnosis using tympanometry in neonates.

[Changes in transient evoked otoacoustic emissions contralateral suppression in infants]. / Mudanças das emissões otoacústicas por transientes na supressão contralateral em lactentes.

BACKGROUND: It has been suggested that the function of the medial olivocochlear system (MOCS) can be evaluated by the suppression effect of the transient evoked otoacoustic emission (TEOAE). The competitive noise has an inhibitory effect on the functioning of the outer hair-cell, reducing the level of otoacoustic emissions. Despite the fact that there is no postnatal growth of the cochlea, middle ear growth and auditory processing development continue after birth. AIM: To analyze age-related changes of MOCS using the TEOAE suppression in healthy infants. METHOD: 25 full-term infants with no risk factors for hearing loss were evaluated in two moments: at birth and at the age of six months. At both ages TEOAE were recorded in the "Quickscreen" mode, nonlinear stimulation at 78dB peSPL, for both ears, with and without contralateral noise presented at 60dB SPL. RESULTS: The data analyses, using ANOVA, revealed significant contralateral suppression of otoacoustic emissions in both groups, but the TEOAE levels and the amount of TEOAE contralateral suppression were smaller at six-month of age when compared to the neonatal period (p < 0.01). The TEOAE suppression effect for neonatals was 2.81dB (+/- 0.19dB) and at the age of six months was 1.41dB (+/- 0.29dB). CONCLUSION: The amount of TEOAE suppression decreased from birth to six months of age. The association between contralateral acoustic stimulation and a commercially available rapid TEOAE measurement system enables a non-invasive monitoring of the auditory efferent mechanism and seems to be clinically feasible to evaluate cochlear status and auditory efferent function development in infants at risk.

The influence of (central) auditory processing disorder in speech sound disorders.

INTRODUCTION: Considering the importance of auditory information for the acquisition and organization of phonological rules, the assessment of (central) auditory processing contributes to both the diagnosis and targeting of speech therapy in children with speech sound disorders. OBJECTIVE: To study phonological measures and (central) auditory processing of children with speech sound disorder. METHODS: Clinical and experimental study, with 21 subjects with speech sound disorder aged between 7.0 and 9.11 years, divided into two groups according to their (central) auditory processing disorder. The assessment comprised tests of phonology, speech inconsistency, and metalinguistic abilities. RESULTS: The group with (central) auditory processing disorder demonstrated greater severity of speech sound disorder. The cutoff value obtained for the process density index was the one that best characterized the occurrence of phonological processes for children above 7 years of age. CONCLUSION: The comparison among the tests evaluated between the two groups showed differences in some phonological and metalinguistic abilities. Children with an index value above 0.54 demonstrated strong tendencies towards presenting a (central) auditory processing disorder, and this measure was effective to indicate the need for evaluation in children with speech sound disorder.

The influence of (central) auditory processing disorder on the severity of speech-sound disorders in children.

OBJECTIVE: To identify a cutoff value based on the Percentage of Consonants Correct-Revised index that could indicate the likelihood of a child with a speech-sound disorder also having a (central) auditory processing disorder . METHODS: Language, audiological and (central) auditory processing evaluations were administered. The participants were 27 subjects with speech-sound disorders aged 7 to 10 years and 11 months who were divided into two different groups according to their (central) auditory processing evaluation results. RESULTS: When a (central) auditory processing disorder was present in association with a speech disorder, the children tended to have lower scores on phonological assessments. A greater severity of speech disorder was related to a greater probability of the child having a (central) auditory processing disorder. The use of a cutoff value for the Percentage of Consonants Correct-Revised index successfully distinguished between children with and without a (central) auditory processing disorder. CONCLUSIONS: The severity of speech-sound disorder in children was influenced by the presence of (central) auditory processing disorder. The attempt to identify a cutoff value based on a severity index was successful.

Evaluation of peripheral auditory pathways and brainstem in obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea causes changes in normal sleep architecture, fragmenting it chronically with intermittent hypoxia, leading to serious health consequences in the long term. It is believed that the occurrence of respiratory events during sleep, such as apnea and hypopnea, can impair the transmission of nerve impulses along the auditory pathway that are highly dependent on the supply of oxygen. However, this association is not well established in the literature. OBJECTIVE: To compare the evaluation of peripheral auditory pathway and brainstem among individuals with and without obstructive sleep apnea. METHODS: The sample consisted of 38 adult males, mean age of 35.8 (±7.2), divided into four groups matched for age and Body Mass Index. The groups were classified based on polysomnography in: control (n=10), mild obstructive sleep apnea (n=11) moderate obstructive sleep apnea (n=8) and severe obstructive sleep apnea (n=9). All study subjects denied a history of risk for hearing loss and underwent audiometry, tympanometry, acoustic reflex and Brainstem Auditory Evoked Response. Statistical analyses were performed using three-factor ANOVA, 2-factor ANOVA, chi-square test, and Fisher's exact test. The significance level for all tests was 5%. RESULTS: There was no difference between the groups for hearing thresholds, tympanometry and evaluated Brainstem Auditory Evoked Response parameters. An association was observed between the presence of obstructive sleep apnea and changes in absolute latency of wave V (p=0.03). There was an association between moderate obstructive sleep apnea and change of the latency of wave V (p=0.01). CONCLUSION: The presence of obstructive sleep apnea is associated with changes in nerve conduction of acoustic stimuli in the auditory pathway in the brainstem. The increase in obstructive sleep apnea severity does not promote worsening of responses assessed by audiometry, tympanometry and Brainstem Auditory Evoked Response.

Wideband reflectance in Down syndrome.

OBJECTIVE: Children with Down syndrome (DS) have a high incidence of middle ear disorders and congenital abnormalities of the external, middle and inner ear. Energy reflectance (ER), a wideband acoustic immittance (WAI) measurement parameter, can measure the sound energy reflected or absorbed in the ear canal over a wider range of frequencies more efficiently and faster than conventional single-tone 226 Hz tympanometry. The aim of the present study was to compare the WAI measurements of children with DS with those of typically developing, normal-hearing children according to their tympanometric findings. METHODS: Four groups of children with Down syndrome (age range: 2 years and 4 months to 16 years and 3 months; mean age: 8.5 yr) with normal tympanograms (19 ears), flat tympanograms (13 ears), mild negative pressure tympanograms (6 ears between -100 and -199 daPa at the admittance peak) and severe negative pressure tympanograms (4 ears at -200 daPa or lower at the admittance peak) were assessed. All findings were compared with data obtained from 21 ears of a healthy control group (age range: 3 years and 1 month to 13 years and 11 months; mean age: 7.9 yr). The subjects underwent tympanometry with a 226-Hz probe tone frequency and ER measurements along the 200-6,000 Hz range with a chirp stimulus using the Middle-Ear Power Analyzer (MEPA3 - HearID) by Mimosa Acoustics (Champaign, IL), software, version 3.3 [38]. RESULTS: Statistically significant differences were observed in the ER curves for some comparisons between the studied groups. There was also a negative correlation between the static acoustic admittance at the tympanic membrane level and ER measured with a chirp stimulus at 500 and 1,000 Hz. The discriminant analysis technique, which used a chirp stimulus at 1,000 and 1,600 Hz to classify the participants' data based on ER values, achieved a correct classification rate of 59.52% for participants with DS. CONCLUSION: While groups with abnormal middle ear status, as indicated by tympanometry, showed higher ER values compared to the DS tymp A group and the control group, similar reflectance curves were observed between control group and the DS tymp A group. WAI shows promise as a clinical diagnostic tool in investigating the impact of middle ear disorders in DS group. However, further research is required to investigate this issue in narrower age range group and a larger sample size.

Latency of DPOAE in milliseconds and waves.

UNLABELLED: The latency of Distortion Product Otoacoustic Emissions is defined as the time interval between the wave onset from initial stimulation and the return to the ear canal. AIM: The aim of this research was to verify the latency of the distortion product otoacoustic emissions in normal hearing adults, analyzing the influence of the gender, ear, frequencies and measurements. STUDY DESIGN: clinical prospective. MATERIAL AND METHOD: The measurements had been taken in milliseconds and waves. It was an experimental study, conducted at São Paulo City in 2003. The sample consisted of 38 adults, 18 men and 20 women. Significant Differences for interactions between frequency, ear, gender and measurements were not observed in relation to the latency in milliseconds and waves. A high correlation between the latency measurements in milliseconds and waves was observed. It was concluded that the latency of distortion product otoacoustic emission diminishes as increases the frequency in milliseconds and the opposite occurs in waves. Statistical differences in latencies of distortion product otoacoustic emission were not observed between gender, ears and measurements.

[Characteristics of transient evoked otoacoustic emissions in newborn hearing screening program]. / Características das emissões otoacústicas por transientes em programa de triagem auditiva neonatal.

BACKGROUND: Otoacoustic emissions (OAE) are considered the main instrument of the Newborn Hearing Screening Program (NHSP). AIM: To analyze the OAE of newborns evaluated in the NHSP. METHOD: Transient evoked OAE recordings were captured in 1000 infants. The data were analyzed using the analysis of multivaried variance (Manova). RESULTS: Reference tables were calculated for the over all OAE levels and for frequency bands, according to gender and ear. The duration of the exam in the nursery was shorter than in the clinic. CONCLUSION: The level of the OAE was influenced by gender and ear, except for 0,7kHz. However, there were no observed differences between neonates without and with auditory risk.

Effect of contralateral stimulation on acoustic reflectance measurements.

INTRODUCTION: Acoustic reflectance is an important tool in the assessment of middle ear afflictions, and the method is considered advantageous in relation to tympanometry. There has been a growing interest in the study of contralateral acoustic stimulation and its effect on the activation of the efferent auditory pathway. Studies have shown that the introduction of simultaneous stimulation in the contralateral ear generates alterations in auditory response patterns. OBJECTIVE: To investigate the influence of contralateral stimulation on acoustic reflectance measurements. METHODS: Case study of 30 subjects with normal hearing, of both genders, aged 18-30 years. The test and retest acoustic reflectance was conducted in the frequency range 200-6000Hz. The procedure was repeated with the simultaneous presence of contralateral white noise at 30dBNS. RESULTS: The analysis of the conditions of test, retest, and test with contralateral noise showed statistical difference at the frequency of 2kHz (p=0.011 and p=0.002 in test and retest, respectively) in the right ear. CONCLUSION: The activation of the auditory efferent pathways through contralateral acoustic stimulation produces alterations in response patterns of acoustic reflectance, increasing sound reflection and modifying middle ear acoustical energy transfer.

Middle ear muscle reflex measurement in neonates: comparison between 1000Hz and 226Hz probe tones.

INTRODUCTION: Middle ear muscle reflex (MEMR) evaluation assists in diagnosing hearing problems because normal responses depend on preconditions of a healthy auditory system. Studies in neonates recording the acoustic reflex with 226Hz probes have described high rates of absence. Other studies using a high frequency probe have found higher rates of presence in normal neonates. However, few studies have compared results between low and high frequency probes in the same newborns. OBJECTIVE: To comparatively assess the ipsilateral acoustic reflex recorded by 226Hz and 1000Hz probes in newborns. METHOD: A total of 77 newborns, with the presence of transient otoacoustic emissions, underwent tympanometry, wideband acoustic immittance, and ipsilateral reflex investigations with 226Hz and 1000Hz tone probes. RESULTS: The acoustic reflex was activated at a much lower intensity with all activating stimuli using the 1000Hz probe compared with the values of the 226Hz probe. There was a higher incidence of ipsilateral acoustic reflexes recorded by the 1000Hz tone probe compared to the 226Hz tone probe. There was no correlation between the acoustic reflex thresholds and otoacoustic emissions. CONCLUSION: In newborns, the acoustic reflex measurements obtained with the 1000Hz probe showed advantages over the 226Hz probe.