Swept-sines provide a tool for fast and high-resolution measurement of evoked otoacoustic emissions. During the measurement, a response to swept-sine(s) is recorded by a probe placed in the ear canal. Otoacoustic emissions can then be extracted by various techniques, e.g., Fourier analysis, the heterodyne method, and the least-square-fitting (LSF) technique. This paper employs a technique originally proposed with exponential swept-sines, which allows for direct emission extraction from the measured intermodulation impulse response. It is shown here that the technique can be used to extract distortion-product otoacoustic emissions (DPOAEs) evoked with two simultaneous swept-sines. For proper extraction of the DPOAE phase, the technique employs previously proposed adjusted formulas for exponential swept-sines generating so-called synchronized swept-sines (SSSs). Here, the SSS technique is verified using responses derived from a numerical solution of a cochlear model and responses measured in human subjects. Although computationally much less demanding, the technique yields comparable results to those obtained by the LSF technique, which has been shown in the literature to be the most noise-robust among the emission extraction methods.
- MeSH
- Fourierova analýza MeSH
- kochlea * fyziologie MeSH
- lidé MeSH
- otoakustické emise spontánní * fyziologie MeSH
- zvukovod fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The basilar membrane in the cochlea can be modeled as an array of fluid coupled segments driven by stapes vibration and by the undamping nonlinear force simulating cochlear amplification. If stimulated with two tones, the model generates additional tones due to nonlinear distortion. These distortion products (DPs) can be transmitted into the ear canal and produce distortion-product otoacoustic emissions (DPOAEs) known to be generated in the healthy ear of various vertebrates. This study presents a solution for DPs in a two-dimensional nonlinear cochlear model with cochlear roughness-small irregularities in the impedance along the basilar membrane, which may produce additional DPs due to coherent reflection. The solution allows for decomposition of various sources of DPs in the model. In addition to the already described nonlinear-distortion and coherent-reflection mechanisms of DP generation, this study identifies a long-latency DPOAE component due to perturbation of nonlinear force. DP wavelets that are coherently reflected due to impedance irregularities travel toward the stapes across the primary generation region of DPs and there evoke perturbation of the nonlinear undamping force. The ensuing DP wavelets have opposite phase to the wavelets arising from coherent reflection, which results in partial cancellation of the coherent-reflection DP wavelets.
PURPOSE: The study aims to evaluate the number of examined newborns and the results of screening for twelve years (2008-2019) and to assess the effectiveness of the established system of neonatal hearing screening. DESIGN AND METHODS: The study was designed as a retrospective longitudinal data analysis. The data included all the children (19,043) born in the hospital and also children (74) transferred from other healthcare facilities. A total of 19,117 children were included in the research group. RESULTS: In the first three years, a higher number of children did not pass the hearing screening, which was followed by a declining trend in the following years. After the first year of screening (2008), there was an improvement in diagnosis linked with a decrease in false-positive screening results (from 9.4% to 6.4%; p = 0.002). From 2008 to 2015, the ratio of children with positive screening to those with negative screening had a steady or declining trend. CONCLUSIONS: The results showed a reduction in false-positive results after the first year of the screening program, probably due to improved care management and a gradual increase in the skills of the nurses performing the screening. PRACTICE IMPLICATIONS: The cornerstones of neonatal hearing screening are a sufficient number of trained neonatology nurses, their mutual substitutability and the availability of a hearing screening device in the newborn ward every day. The results imply the importance of periodic evaluation of the obtained data, enabling early detection of possible deficiencies in the hearing screening system.
- Klíčová slova
- Hearing impairment, Newborn hearing screening, Otoacoustic emissions, Permanent hearing loss, TEOAE,
- MeSH
- dítě MeSH
- lidé MeSH
- novorozenec MeSH
- novorozenecký screening MeSH
- otoakustické emise spontánní * MeSH
- retrospektivní studie MeSH
- sluch MeSH
- sluchové testy * MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Stimulus-frequency otoacoustic emissions (SFOAEs) are generated by coherent reflection of forward traveling waves by perturbations along the basilar membrane. The strongest wavelets are backscattered near the place where the traveling wave reaches its maximal amplitude (tonotopic place). Therefore, the SFOAE group delay might be expected to be twice the group delay estimated in the cochlear filters. However, experimental data have yielded steady-state SFOAE components with near-zero latency. A cochlear model is used to show that short-latency SFOAE components can be generated due to nonlinear reflection of the compressor or suppressor tones used in SFOAE measurements. The simulations indicate that suppressors produce more pronounced short-latency components than compressors. The existence of nonlinear reflection components due to suppressors can also explain why SFOAEs can still be detected when suppressors are presented more than half an octave above the probe-tone frequency. Simulations of the SFOAE suppression tuning curves showed that phase changes in the SFOAE residual as the suppressor frequency increases are mostly determined by phase changes of the nonlinear reflection component.
The amplitudes of distortion-product otoacoustic emissions (DPOAEs) may abruptly decrease even though the stimulus level is relatively high. These notches observed in the DPOAE input/output functions or distortion-product grams have been hypothesized to be due to destructive interference between wavelets generated by distributed sources of the nonlinear-distortion component of DPOAEs. In this paper, simulations with a smooth cochlear model and its analytical solution support the hypothesis that destructive interference between individual wavelets may lead to the amplitude notches and explain the cause for onset and offset amplitude overshoots in the DPOAE signal measured for intensity pairs in the notches.
- MeSH
- akustická stimulace MeSH
- kochlea fyziologie MeSH
- lidé MeSH
- otoakustické emise spontánní * MeSH
- teoretické modely * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Screening programs examining neonatal hearing serve to detect hearing defects, as a prerequisite for hearing rehabilitation, communication skills, and the enhancement of speech development. There are two methods through which neonatal hearing screening is carried out - the transiently evoked otoacoustic emissions (TEOAE) or the automatic BERA (AABR, automated auditory brainstem response). Positive screening means the discovery of a hearing defect (permanent hearing loss), and negative screening (normal TEOAE or the AABR results) means the absence of a hearing defect. The procedural aim is to update and adjust the neonatal hearing screening, which is determined by the Bulletin of the Ministry of Health of the Czech Republic No. 7/2012. Neonatal screening is performed at three levels: at neonatological site, at the ENT (phoniatric) rescreening site and at the ENT regional centre. The activities at each level are accurately and concretely identified including the issue of billing the performance to health insurance companies and informed consent to personal data protection (GDPR). The correct functioning of screening for hearing loss is based on the simple organization of the screening, patient examination comfort, medical recovery from it, and its economic viability. The schedule for neonatal hearing screening and rehabilitation recommends the following steps: 1. screening of a newborns hearing on the second or third day after delivery by a neonatological nurse using otoacoustic emissions, alternatively AABR for newborns at risk; 2. hearing rescreening in the third to sixth week of child`s age at the ENT rescreening site; 3. completion of hearing impairment diagnostics within three to sixth months of age at the ENT regional centre. The failure to follow the procedure above is a threat to the hearing and speech development of the child with severe permanent hearing impairment. The collaboration of ENT doctors with neonatologists and paediatricians allows for creating conditions under which the functional nationwide hearing screening of newborns can be established throughout the Czech Republic.
- Klíčová slova
- neonatal hearing screening, otoacoustic emissions, permanent hearing loss,
- MeSH
- lidé MeSH
- novorozenec MeSH
- novorozenecký screening MeSH
- otoakustické emise spontánní MeSH
- sluchové kmenové evokované potenciály MeSH
- sluchové testy * MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Obstructive sleep apnea (OSA) is characterized by recurrent episodes of upper airway obstruction during sleep, which is manifested by apnea or hypopnea. Decreased blood oxygen saturation, changes in heart rate, fluctuations in brain perfusion, changes in intracranial pressure, snoring and vibration are factors that may potentially affect hearing in patients with OSA. The aim of the present study was to test the hypothesis that hearing is affected in OSA. 43 males aged 34-74 years (mean 48.2) with suspected sleep-disordered breathing without other comorbidity or medication that may affect sleep or hearing were included. Nocturnal polysomnography, pure tone audiometry (PTA), transient evoked otoacoustic emissions (TEOAE) and brainstem auditory evoked potentials (BAEP) were evaluated. The severity of OSA was indicated by the number of apneas and hypopneas per hour of sleep (apnoe/hypopnoe index - AHI). OSA (AHI>/=5) was detected in 28 patients by polysomnography. Mild OSA (AHI 5-15) was confirmed in 11 patients, severe OSA (AHI>/=30) in 17 patients. Simple snoring (AHI<5) was diagnosed in 15 males. In patients suffering from severe OSA, tone audiometry demonstrated higher auditory threshold at frequencies of 4000 and 8000 Hz than in patients with AHI<15 (p<0.005). Auditory threshold values correlated with age in all groups. At a frequency of 8000 Hz, auditory threshold additionally correlated with BMI, AHI, oxygen desaturation index and decreased oxygen saturation. No differences were detected in TEOAE and BAEP between subjects with OSA and snoring. PTA and TEOAE decreased with increasing age. The present results show decreased perception of high frequency sound in severe OSA.
- MeSH
- akustická stimulace MeSH
- audiometrie čistými tóny MeSH
- Cortiho orgán patofyziologie MeSH
- dospělí MeSH
- index tělesné hmotnosti MeSH
- kyslík krev MeSH
- lidé středního věku MeSH
- lidé MeSH
- obstrukční spánková apnoe patofyziologie psychologie MeSH
- otoakustické emise spontánní MeSH
- polysomnografie MeSH
- senioři MeSH
- sluchová percepce * MeSH
- sluchové kmenové evokované potenciály MeSH
- vláskové buňky MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- kyslík MeSH
The development, maturation, and maintenance of the inner ear are governed by temporal and spatial expression cascades of transcription factors that form a gene regulatory network. ISLET1 (ISL1) may be one of the major players in this cascade, and in order to study its role in the regulation of inner ear development, we produced a transgenic mouse overexpressing Isl1 under the Pax2 promoter. Pax2-regulated ISL1 overexpression increases the embryonic ISL1(+) domain and induces accelerated nerve fiber extension and branching in E12.5 embryos. Despite these gains in early development, the overexpression of ISL1 impairs the maintenance and function of hair cells of the organ of Corti. Mutant mice exhibit hyperactivity, circling behavior, and progressive age-related decline in hearing functions, which is reflected in reduced otoacoustic emissions (DPOAEs) followed by elevated hearing thresholds. The reduction of the amplitude of DPOAEs in transgenic mice was first detected at 1 month of age. By 6-9 months of age, DPOAEs completely disappeared, suggesting a functional inefficiency of outer hair cells (OHCs). The timing of DPOAE reduction coincides with the onset of the deterioration of cochlear efferent terminals. In contrast to these effects on efferents, we only found a moderate loss of OHCs and spiral ganglion neurons. For the first time, our results show that the genetic alteration of the medial olivocochlear (MOC) efferent system induces an early onset of age-related hearing loss. Thus, the neurodegeneration of the MOC system could be a contributing factor to the pathology of age-related hearing loss.
- Klíčová slova
- Age-related hearing loss, Islet1 transcription factor, Medial olivocochlear efferent system, Outer hair cells, Transgenic mouse,
- MeSH
- analýza přežití MeSH
- embryo savčí metabolismus patologie MeSH
- ganglion spirale patologie MeSH
- kochlea inervace patologie patofyziologie MeSH
- messenger RNA genetika metabolismus MeSH
- molekulární motory metabolismus MeSH
- myši transgenní MeSH
- nedoslýchavost patologie patofyziologie MeSH
- neurony eferentní MeSH
- otoakustické emise spontánní MeSH
- počet buněk MeSH
- proteiny s homeodoménou LIM metabolismus MeSH
- sluchový práh MeSH
- stárnutí patologie MeSH
- transkripční faktor PAX2 metabolismus MeSH
- transkripční faktory metabolismus MeSH
- vnější vláskové buňky patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- insulin gene enhancer binding protein Isl-1 MeSH Prohlížeč
- messenger RNA MeSH
- molekulární motory MeSH
- Pax2 protein, mouse MeSH Prohlížeč
- Pres protein, mouse MeSH Prohlížeč
- proteiny s homeodoménou LIM MeSH
- transkripční faktor PAX2 MeSH
- transkripční faktory MeSH
OBJECTIVES: Arterial hypertension negatively influences the peripheral auditory system, causing sensorineural hearing loss. Much less is known about the detrimental effects of hypertension on the central auditory functions. METHODS: We tested 32 arterial hypertension patients and 32 age and sex-matched healthy volunteers with the expanded tonal audiometry (0.125-12.5 kHz), distortion product otoacoustic emissions (0.75-8 kHz), horizontal minimum audible angle test for eight azimuths with binaural stimulation and the random gap detection test. RESULTS: Peripheral hearing of the hypertensive patients was impaired in comparison with the controls within all audiometric frequencies (0.125-12.5 kHz) and within specific groups of frequencies. Distortion product otoacoustic emission results were significantly lower for frequencies 4 (P = 0.04) and 6 kHz (P < 0.001). The sound localization ability in the horizontal minimum audible angle test was significantly worse in the hypertensive patients in the 0°, 45°, 90°, 135°, and 270° azimuth when the interaural pure tone average (0.5-1-2 kHz) was set less than 20 dB hearing level (P < 0.05), and in the 0°, 90°, 225°, and 270°azimuth when the binaural pure tone average (0.5-1-2 kHz) was set 20 dB or less hearing level (P < 0.05). Gap detection thresholds in the random gap detection test did not differ between the two groups. CONCLUSION: Arterial hypertension is independently related to the damage of the peripheral part of the auditory system resulting in high-frequency hearing loss. Hypertensive disturbances of central auditory processing are more discrete and concern the spatial hearing resolution.
- MeSH
- audiometrie čistými tóny MeSH
- dospělí MeSH
- hypertenze komplikace epidemiologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- otoakustické emise spontánní MeSH
- percepční nedoslýchavost epidemiologie etiologie MeSH
- studie případů a kontrol MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
There is a long-lasting question of how distortion products (DPs) arising from nonlinear amplification processes in the cochlea are transmitted from their generation sites to the stapes. Two hypotheses have been proposed: (1) the slow-wave hypothesis whereby transmission is via the transverse pressure difference across the cochlear partition and (2) the fast-wave hypothesis proposing transmission via longitudinal compression waves. Ren with co-workers have addressed this topic experimentally by measuring the spatial vibration pattern of the basilar membrane (BM) in response to two tones of frequency f(1) and f(2). They interpreted the observed negative phase slopes of the stationary BM vibrations at the cubic distortion frequency f(DP) = 2f(1) - f(2) as evidence for the fast-wave hypothesis. Here, using a physically based model, it is shown that their phase data is actually in accordance with the slow-wave hypothesis. The analysis is based on a frequency-domain formulation of the two-dimensional motion equation of a nonlinear hydrodynamic cochlea model. Application of the analysis to their experimental data suggests that the measurement sites of negative phase slope were located at or apical to the DP generation sites. Therefore, current experimental and theoretical evidence supports the slow-wave hypothesis. Nevertheless, the analysis does not allow rejection of the fast-wave hypothesis.
- MeSH
- biologické modely MeSH
- deformace percepce fyziologie MeSH
- Fourierova analýza MeSH
- interferometrie metody MeSH
- kochlea fyziologie MeSH
- lasery MeSH
- lidé MeSH
- otoakustické emise spontánní fyziologie MeSH
- vibrace MeSH
- vnímání výšky zvuku fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
