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ABSTRACT: A new method for automatically assessing hearing loss by means of extrapolated DPOAE I/O-functions was applied for the first time in newborns.
DPOAE I/O-functions were recorded in 118 ears of 93 newborns (mean age 3 days) at 12 frequencies between 1 and 8 kHz. L(2) was varied between 20 and 65 dB SPL with L(1)=0.4L(2)+39 and f(2)/f(1)=1.2. Auditory thresholds were constructed using the estimated DPOAE threshold level from extrapolated DPOAE I/O-functions. Follow-up measurements were conducted in 15 ears 4 weeks later.
The first measurement revealed a high-frequency hearing loss. The second measurement showed normal hearing function. This fact and the decrease of DPOAE level in the frequency range of the hearing loss, while keeping the compressive shape of the DPOAE I/O-functions, indicate that transitory sound conduction disturbance may be due to amniotic fluid.
The method fulfils the essential criteria for screening newborn hearing. It is fast and easy to handle, and measurement and data analysis are performed automatically. Preliminary results suggest that the new method is able to differentiate between transitory middle-ear dysfunction and persisting cochlear disorders. Due to its better diagnostic capabilities in comparison to TEOAE, DPOAE, and FAEP, this method may provide a new instrument with which to make a fast evaluation of hearing function in children.
HNO 01/2004; 51(12):971-80. · 0.40 Impact Factor
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ABSTRACT: ZielZur mglichen Erweiterung herkmmlicher Hrscreeningmethoden wurde an Neugeborenen eine an Erwachsenen evaluierte automatisierte Bestimmung der Hrschwelle mittels extrapolierter DPOAE-Wachstumsfunktionen erprobt.MethodeAn 118 Ohren von 93 Neugeborenen (mittleres Alter 3Tage) wurden DPOAE-Wachtumsfunktionen zwischen 20 und 65dB SPL bei 12 Frequenzen zwischen 1 und 8kHz aufgenommen. Zur Schtzung der Hrschwelle wurde mittels linearer Regressionsanalyse der DPOAE-Schwellenpegel aus dem Schnittpunkt der Regressionsgeraden mit der Primrtonpegelachse ermittelt . An 15 Ohren wurden die Messungen nach 4Wochen wiederholt.ErgebnisseBei der Erstmessung ergab sich im Hochtonbereich ein Hrverlust als Folge noch vorhandener Fruchtwasserreste, der bei der Zweitmessung fehlte.FazitNach den vorlufigen Ergebnissen erlaubt die Methode die Differenzierung zwischen passagerer (mittelohrbedingter) und persistierender (kochlerer) Hrstrung. Wegen ihrer im Vergleich zum herkmmlichen Hrscreening hheren diagnostischen Aussagekraft knnte sich die Methode zum erweiterten Hrscreening und zur schnellen Abklrung der Hrfunktion bei Kindern im Vorschul- und Schulalter eignen.Background and aimA new method for automatically assessing hearing loss by means of extrapolated DPOAE I/O-functions was applied for the first time in newborns.MethodsDPOAE I/O-functions were recorded in 118 ears of 93 newborns (mean age 3days) at 12 frequencies between 1 and 8kHz. L2 was varied between 20 and 65dB SPL with L1=0.4L2+39 and f2/f1=1.2. Auditory thresholds were constructed using the estimated DPOAE threshold level from extrapolated DPOAE I/O-functions. Follow-up measurements were conducted in 15 ears 4weeks later.ResultsThe first measurement revealed a high-frequency hearing loss. The second measurement showed normal hearing function. This fact and the decrease of DPOAE level in the frequency range of the hearing loss, while keeping the compressive shape of the DPOAE I/O-functions, indicate that transitory sound conduction disturbance may be due to amniotic fluid.ConclusionsThe method fulfils the essential criteria for screening newborn hearing. It is fast and easy to handle, and measurement and data analysis are performed automatically. Preliminary results suggest that the new method is able to differentiate between transitory middle-ear dysfunction and persisting cochlear disorders. Due to its better diagnostic capabilities in comparison to TEOAE, DPOAE, and FAEP, this method may provide a new instrument with which to make a fast evaluation of hearing function in children.
HNO 01/2003; 51(12):971-980. · 0.40 Impact Factor
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ABSTRACT: Previous studies described a systematic asymmetry of the level of the 2f(1)-f(2) distortion product otoacoustic emission (DP) in the space of the primary tones levels L(1) and L(2) in normal-hearing humans. Optimal primary tone level separations L(1)-L(2), which result in maximum DP levels, were close to L(1)=L(2) at high levels, but continuously increased with decreasing stimulus level towards L(1)>L(2) (Gaskill and Brown, 1990, J. Acoust. Soc. Am. 88, 821-839). At these optimal L(1)-L(2), however, not only DP levels in normal hearing were maximal, but also trauma-induced DP reductions. A linear equation that approximates optimal L(1)-L(2) level separations thus was suggested to be optimum for use in clinical applications (Whitehead et al., 1995, J. Acoust. Soc. Am. 97, 2359-2377). It was the aim of this study to extend the generality of optimal L(1)-L(2) separations to the typical human test frequency range for f(2) frequencies between 1 and 8 kHz. DPs were measured in 22 normal-hearing human ears at 61 primary tone level combinations, with L(2) between 5 and 65 dB SPL and L(1) between 30 and 70 dB SPL (f(2)/f(1)=1.2). It was found that the systematic dependence of the maximum DP level on the L(1)-L(2) separation is independent on frequency. Optimal L(1)-L(2) level separations may well be approximated by a linear equation L(1)=a L(2)+(1-a) b (after Whitehead et al., 1995) with parameters a=0.4 and b=70 dB SPL at f(2) frequencies between 1 and 8 kHz and L(2) levels between 20 and 65 dB SPL. Below L(2)=20 dB SPL, the optimal L(1) was found to be almost constant. Following previous notions (Gaskill and Brown, 1990), an analysis of basilar membrane response data in experimental animals (after Ruggero and Rich, 1991, Hear. Res. 51, 215-230) is further presented that relates optimal L(1)-L(2) separations to frequency-selective compression of the basilar membrane. Based on the assumption that optimal conditions for the DP generation are equal primary tone responses at the f(2) place, a linear increase of the optimal L(1)-L(2) level separation is graphically demonstrated, similar to our results in human ears.
Hearing Research 09/2000; 146(1-2):47-56. · 2.70 Impact Factor
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ABSTRACT: Up to now changes of intracranial pressure can only be objectively assessed by invasive measurement tools e.g. epidural transducers or intraventricular or intraparenchymatous catheters. Changes of intracranial pressure (ICP) are known to influence the inner ear since the subarachnoid space is linked to the perilymphatic space of the inner ear via the cochlear aquaeduct. A new method for assessing cochlear disorders is based on otoacoustic emissions (OAE) which are generated by the outer hair cells (OHCs) of the inner ear. The aim of the present study was to find out whether changes of intracranial pressure can be monitored by spontaneous otoacoustic emissions (SOAEs), transient evoked otoacoustic emissions (TEOAEs) and distortionproduct otoacoustic emissions (DPOAEs). SOAEs, TEOAEs and DPOAEs were measured in 12 young normally hearing subjects (volunteer group) in different body postures (horizontal, -30 degrees and +30 degrees supine position). In 5 patients undergoing continuous intraventricular pressure monitoring for the assessment of normal pressure hydrocephalus (NPH), DPOAEs were measured simultaneously in different body postures as well (patient group). At an increase of ICP the SOAE-level of the volunteer group decreased by -3.3 dB SPL (sound pressure level) and the TEOAE-level by -2.1 dB SPL. The DPOAEs showed a frequency dependent reduction of its level with maximal changes at the lowest frequency tested (f2 = 1 kHz; -7.9 dB SPL). In the patient group the ICP amounted to 19.2 cm H(2)0 and the DPOAE-level also decreased particularly at lower frequencies (-2.0 dB SPL). In conclusion otoacoustic emissions, particularly DPOAEs, may provide a new clinical tool for non-invasive monitoring of ICP.
Zentralblatt für Neurochirurgie 02/2000; 61(4):177-80. · 0.63 Impact Factor
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ABSTRACT: The 2 f1-f2 distortion product otoacoustic emission (DP) was measured in 20 normal hearing subjects and 15 patients with moderate cochlear hearing loss and compared to the pure-tone hearing threshold, measured with the same probe system at the f2 frequencies. DPs were elicited over a wide primary tone level range between L2 = 20 and 65 dB SPL. With decreasing L2, the L1-L2 primary tone level difference was continuously increased according to L1 = 0.4L2 + 39 dB, to account for differences of the primary tone responses at the f2 place. Above 1.5 kHz, DPs were measurable with that paradigm on average within 10 dB of the average hearing threshold in both subject groups. The growth of the DP was compressive in normal hearing subjects, with strong saturation at moderate primary tone levels. In cases of cochlear impairment, reductions of the DP level were greatest at lowest, but smallest at highest stimulus levels, such that the growth of the DP became linearized. The correlation of the DP level to the hearing threshold was found to depend on the stimulus level. Maximal correlations were found in impaired ears at moderate primary tone levels around L2 = 45 dB SPL, but at lowest stimulus levels in normal hearing (L2 = 25 dB SPL). At these levels, 17/20 impaired ears and 14/15 normally hearing ears showed statistically significant correlations. It is concluded that for a clinical application and prediction of the hearing threshold, DPs should be measured not only at high, but also at lower primary tone levels.
The Journal of the Acoustical Society of America 07/1998; 103(6):3431-44. · 1.55 Impact Factor
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ABSTRACT: High-resolution hearing threshold and 2 f1-f2 distortion product otoacoustic emission (DP) were measured with the same in-the-ear sound probe and same calibration at 51 frequencies between 500 and 8000 Hz in 39 sensorineural hearing loss ears associated with tinnitus. Using a primary tone setting L1 = 0.4L2 + 39 that accounts for the nonlinear interaction of the two primary tones at the DP generation site at f2, DPs were elicited in a wide range from L2 = 65 to 20 dB SPL. We failed to find a uniform DP behavior in the 39 tinnitus ears tested. Seventeen of them behaved like impaired ears without tinnitus. In these ears a linearized DP growth was observed where the DP level decreased and the slope of the DP I/O functions steepened with increasing hearing loss and as a result both the DP level and the DP slope strongly correlated with hearing threshold. The other population, 22 tinnitus ears, exhibited a poor or even inverse relationship between DP level and hearing threshold, i.e., displayed an increase of DP level with increasing hearing loss. Despite the severe hearing loss but due to the high level, DPs could be recorded well in the frequency range that corresponded to the appearance of the tinnitus. The DP slope, however, increased with increasing hearing loss and, therefore, did still correlate with hearing threshold revealing pathological alteration. The data suggest that the DP level alone is hardly capable of assessing hearing impairment in tinnitus ears and may even be misleading. Thus just the DP slope seems to be the only reliable indicator of cochlear malfunction around the tinnitus frequency. The observed nonuniform DP behavior suggests different cochlear impairments in tinnitus ears. In those ears where the DP level decreases and the slope of the I/O functions increases with hearing loss, cochlear sensitivity and tuning are supposed to be diminished. In those ears where the DP level increases with increasing hearing loss, a reinforced mechanical distortion is hypothetized to be generated by cochlear hyperactivity that can be the source of both the abnormally high DP level and the tinnitus.
The Journal of the Acoustical Society of America 07/1998; 103(6):3418-30. · 1.55 Impact Factor
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ABSTRACT: The suppression tuning properties of the 2 f1-f2 distortion-product otoacoustic emission (DPOAE) were measured in 16 ears of normally hearing human subjects. DPOAE were elicited by fixed, low-level primary tones in four frequency regions with the second primary tone frequency f2 at 1, 2, 4, and 6 kHz. For various suppressor frequencies, suppression of the DPOAE was measured as a function of the suppressor tone level, enabling the assessment of the threshold and the growth of suppression. Depending on the distance of the suppressor tone to f2, there were marked differences in the suppression behavior of different suppressor frequencies. The threshold of suppression was minimal slightly above f2 and hardly increased with increasing frequency, but increased continuously with decreasing suppressor frequency. The growth of suppression, however, did not systematically change below f2, but decreased rapidly above f2. Both changes resulted in asymmetrical, V-shaped suppression tuning curves. They were sharply tuned to a frequency slightly above f2, with Q10 dB values up to 7.87. This is consistent with the assumption that the main source of the DPOAE is at the f2 site. In some cases, the DPOAE was particularly sensitive to suppressor tones near the DPOAE frequency. In one individual case, facilitation was found for corresponding frequency-level ranges of the suppressor tone. This may suggest a secondary emission source at the distortion product place.
The Journal of the Acoustical Society of America 08/1995; 98(1):197-210. · 1.55 Impact Factor
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ABSTRACT: The "Duplizitätstheorie" of Meyer zum Gottesberge (1948) states that signal processing takes place at low sound intensities on the nerve fibers of the outer hair cells, whereas at high sound intensities on the nerve fibers of the inner hair cells. The discovery of oto-acoustic emissions by Kemp (1978) makes a modification of the "Duplizitätstheorie" necessary. The outer hair cells are supposed to be motor-drives final control elements to enhance the sensitivity of inner hair cells. Thus outer hair cells do not serve for the direct transmission of information in the sense of neural coding. Signal processing takes place at all intensities exclusively on the nerve fibers of the inner hair cells.
Laryngo-Rhino-Otologie 12/1991; 70(11):613-5. · 0.97 Impact Factor
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ABSTRACT: Frequency-specific information on high tone loss in the inner ear can, and if so only indirectly, be obtained from changes in latency of the click-evoked brain stem potential (ABR). The relationship between latency increases of the Jewett-wave-V in basocochlear hearing loss and the time course of the travelling wave on the basilar membrane will be presented. The latency increases of basocochlear hearing loss at 2 kHz, 1 kHz and 500 Hz correspond to both the computer-simulated time course of the travelling wave and to those of the derived responses. From a pathophysiological standpoint, receptor cells in basocochlear hearing loss are not functional, beginning at the oval window, so that, dependent on the degree of inactivity, a delay corresponding to that of the time course of the travelling wave passes until active hair cells are reached and action potentials released that produce, when summed up a potential of delayed latency.
Laryngo-Rhino-Otologie 08/1989; 68(7):379-82. · 0.97 Impact Factor
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ABSTRACT: Polarity of the stimulus influences latency, amplitude and waveform of the human auditory brainstem response (ABR). One clear feature is the splitting of the wave complex JIV and JV in separate peaks following rarefaction stimulation. ABR was recorded using high-pass filtering to mask the basilar membrane partially to establish whether and to what extent basal hair cells contribute to waves IV and V. Wave IV disappeared in response to rarefaction stimuli with masking of the basal region. In contrast, wave V appeared with reduced amplitude and delayed latency in response to condensation stimuli. A model was developed to determine the motion of the basilar membrane and the distribution over time of the action potential on the auditory nerve fibers following rarefaction and condensation stimuli. The rarefaction stimulus produces a bifid and the condensation stimulus only a single-peaked contribution. It is suggested that the splitting of the wave complex IV and V may be traced to mechanical processing in the cochlea.
HNO 01/1989; 36(12):511-5. · 0.40 Impact Factor
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ABSTRACT: A schematic description of the correlation between the various types of hearing disorders and the behaviour of auditory brain stem responses (ABR) is presented. Conductive pathology and high-frequency cochlear hearing loss prolong wave component latency due to energy loss and hair cell dysfunction. Latency is not affected in flat cochlear hearing loss. Prolonged interwave latencies between wave I and wave V indicate eighth nerve and brain stem disorders. An algorithm in the form of a flow chart was developed for location of the malfunction. Families of characteristics of wave V intensity-latency functions were designed for faster detection and more precise evaluation of conductive and cochlear hearing losses.
HNO 09/1988; 36(8):318-23. · 0.40 Impact Factor
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ABSTRACT: A schematic description of the correlation between various pathologies of hearing impairments and the behavior of auditory brainstem responses (ABR) is presented. Conductive pathology and high-frequency cochlear hearing losses prolong wave component latency due to energy loss and hair cell dysfunction. In cases of flat cochlear hearing loss latency is not affected. Prolonged interwave latencies between wave I and wave V indicate eight nerve and brainstem disorders. An algorithm was developed in the form of a flow chart for locating various malfunctions. Fields of wave V intensity-latency functions were designed for the faster detection and more precise evaluation of conductive and cochlear hearing losses.
Archives of Oto-Rhino-Laryngology 02/1988; 245(5):259-65.
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ABSTRACT: A mathematical model of the cochlea was implemented on a computer. The basilar membrane motion was computed for single, two, and multi-tone stimuli as well as for musical sounds and vowels. The pattern of the travelling waves were presented in three-dimensional color computer graphics. The high performance 3D graphics system performs local hidden surface removal, 3D geometric transformations and supports local lighting models to generate truly realistic shading for complex 3D objects. An addressable 1280 by 1024 pixel matrix assures crisp, precise resolution of the finest detail in the graphic images. The spatial pattern of basilar membrane motion conveys an impression of the image of acoustic stimuli on the basilar membrane. Firstly, the motion pattern of the travelling wave to a single tone is presented. The superposition of several tones (two-tone, multi-tone) causes a superposition of the travelling waves along the basilar membrane whereby the place principle in the cochlear partition becomes more clearly recognizable. Sounds (flute and violin) and vowels (German "u" and "i") evoke a complex motion pattern on the basilar membrane. The realization of the chronological order of movements on the basilar membrane can be made by computer animation. This enables the analysis of the space-time patterns of complex acoustic stimuli.
HNO 08/1987; 35(7):302-9. · 0.40 Impact Factor
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ABSTRACT: In order to investigate the propagation time of the traveling wave in the cochlea after bone-conduction stimulation of the inner ear, bone-conducted auditory brainstem responses (ABRs) were recorded in 6 normally hearing subjects after masking the basal cochlear region using high-pass filtered noise. As in air-conducted ABRs, Jewett V wave latency is delayed corresponding to the propagation time of the traveling wave front traversing the desynchronized hair cell region. These results support the theory of paradoxical wave propagation proposed by von Békésy in 1952, who postulated that wave motion always starts from the stiffest part of the basilar membrane, independent of the location of the vibrating force. In addition, we also found a latency delay of the Jewett V wave of bone-conducted ABRs in 8 patients with high-frequency hearing loss which corresponded to the severity of their hearing impairment.
ORL 62(1):1-8. · 0.91 Impact Factor
