Primary Tones Research Articles

Electrophysiological Measurement of Binaural Beats: Effects of Primary Tone Frequency and Observer Age

Electrophysiological Measurement of Binaural Beats: Effects of Primary Tone Frequency and Observer Age

Distortion-Product Otoacoustic Emissions: Body Position Effects with Simultaneous Presentation of Tone Pairs.

This study examined the effect of three different body positions on distortion-product otoacoustic emission (DPOAE) amplitude and noise levels with multiple primary tone pairs simultaneously-presented to 36 normal-hearing female human adults. Other studies have demonstrated that the simultaneously presented tone pairs method shows clinical promise as a screener, but the sequential method remains in widespread clinical use. Postural changes have been suggested to have an effect not only on DPOAEs, but also transient-evoked OAEs and stimulus-frequency OAEs. DPOAE amplitude and noise levels were recorded in seated, supine, and side-lying positions to the following order of simultaneously-presented tone pairs relative to the f2 frequencies: 1187, 2375, and 4812 Hz; 1500, 3000, and 6062 Hz; and 1875, 3812, and 7625 Hz. No DPOAE could be detected reliably at 7625 Hz as result of poor signal-to-noise ratio. For remaining DPOAEs, statistical analyses revealed that amplitudes were not significantly different among the three body positions. However, at 1500 Hz and below, body position did have a statistically significant effect on noise levels though they are likely clinically negligible. Except at 7625 Hz, results suggest that DPOAEs recorded using a simultaneously presented tone pairs appear to be comparably recorded regardless of an individual’s body position.

Automaticity in attractive face processing

Attractive faces have a special status, possibly because of evolutionary reasons. We assessed the automaticity of facial attractiveness processing in a dual-task paradigm manipulating the availability of cognitive resources to face processing by a primary tone task presented at varying stimulus onset asynchrony (SOA). In event-related brain potentials, attractive relative to neutral faces induced an increased posterior negativity from 260 ms onwards indicating enhanced stimulus encoding at the cortical level. Interestingly, effects of attractive faces on event-related brain potentials were most pronounced at high temporal overlap with the primary task (short stimulus onset asynchrony). This indicates that a shortage of cognitive resources may enhance the processing of attractive faces, revealing hard-wired processing biases of the human information processing system for evolutionarily prepared stimuli.

Measurement of Medial Olivocochlear Efferent Activity in Humans

To assess the suitability of contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) for measurement of activity of the medial olivocochlear (MOC) efferents. The MOC efferent system has been shown to be involved in sound discrimination, selective attention to tones, sound localization, and protection of the cochlea against noise. A great variety of paradigms for measurement of MOC activity by CS of OAE (MOC reflex [MOCR]), has been described. An issue of this approach is the dependence of the CS values on stimulus parameters, especially when DPOAE are used. Four different measurement paradigms, which used different combinations of stimulus frequencies and primary tone levels, were applied in 16 human subjects. Mean absolute values of CS were in the range of 1.2 to 2.6 dB. The use of different stimulus parameters produced not only MOCR values of different size-which was expected-but, in many cases, also different relative classifications of the subjects according to their MOCR strength. The suppression effects on DPOAE demonstrated in this study reflect MOC activity. However, the new conclusion from our data is that CS of DPOAE measurements, as they were used in this study, may not allow for a consistent quantitative classification of human subjects according to their MOCR strength. This finding concerns interpretation of previous studies using CS of DPOAE and analogous future studies. One future approach may lie in the separation of the DPOAE components to distinguish interference phenomena, which complicate interpretation of CS values.

Time-domain analysis and experimental examination of cumulative second-harmonic generation by primary Lamb wave propagation

Within the second-order perturbation approximation, the physical process of cumulative second-harmonic generation by the primary Lamb wave propagation has been investigated in the time domain. Based on the preconditions that the transfer of energy from the primary Lamb wave to the double frequency Lamb wave is not zero and that the phase velocity matching condition is satisfied, we focus on analyzing the influence of mismatching of the group velocities on the generation of the second harmonic by propagation of a primary Lamb wave tone burst with a finite duration. Our analysis indicates that the time-domain envelope of the second harmonic generated is dependent on the propagation distance when both the duration of the primary Lamb wave tone burst and the group velocity mismatch are given. Furthermore, it can be concluded that the integrated amplitude of the time-domain second harmonic, which quantifies the efficiency of the second-harmonic generation, grows with the propagation distance even when the group velocity matching condition is not satisfied. The experimental examination has been performed, and it verifies our theoretical analysis.

Temporal aspects of suppression in distortion-product otoacoustic emissions

This study examined the time course of cochlear suppression using a tone-burst suppressor to measure decrement of distortion-product otoacoustic emissions (DPOAEs). Seven normal-hearing subjects with ages ranging from 19 to 28 yr participated in the study. Each subject had audiometric thresholds ≤ 15 dB HL [re ANSI (2004) Specifications for Audiometers] for standard octave and inter-octave frequencies from 0.25 to 8 kHz. DPOAEs were elicited by primary tones with f(2) = 4.0 kHz and f(1) = 3.333 kHz (f(2)/f(1) = 1.2). For the f(2), L(2) combination, suppression was measured for three suppressor frequencies: One suppressor below f(2) (3.834 kHz) and two above f(2) (4.166 and 4.282 kHz) at three levels (55, 60, and 65 dB SPL). DPOAE decrement as a function of L(3) for the tone-burst suppressor was similar to decrements obtained with longer duration suppressors. Onset- and setoff- latencies were ≤ 4 ms, in agreement with previous physiological findings in auditory-nerve fiber studies that suggest suppression results from a nearly instantaneous compression of the waveform. Persistence of suppression was absent for the below-frequency suppressor (f(3) = 3.834 kHz) and was ≤ 3 ms for the two above-frequency suppressors (f(3) = 4.166 and 4.282 kHz).

Characterizing distortion-product otoacoustic emission components across four species

Distortion-product otoacoustic emissions (DPOAEs) were measured as level/phase (L/P) maps in humans, rabbits, chinchillas, and rats with and without an interference tone (IT) placed either near the 2f(1)-f(2) DPOAE frequency place (f(dp)) or at one-third of an octave above the f(2) primary tone (1/3-oct IT). Vector differences between with and without IT conditions were computed to derive a residual composed of the DPOAE components removed by the IT. In humans, a DPOAE component could be extracted with the expected steep phase gradient indicative of reflection emissions by ITs near f(dp). In the laboratory species, ITs near f(dp) failed to produce any conclusive evidence for reflection components. For all species, 1/3-oct ITs extracted large DPOAE components presumably generated at or basal to the IT-frequency place that exhibited both distortion- and reflection-like phase properties. Together, these findings suggested that basal distortion components could assume reflection-like phase behavior when the assumptions of cochlear-scaling symmetry, the basis for shallow phase gradients for constant f(2)/f(1) ratio sweeps, are violated. The present results contradict the common belief that DPOAE components associated with steep or shallow phase slopes are unique signatures for reflection emissions arising from f(dp) or distortion emissions generated near f(2), respectively.

Recurrent internal waves in a small lake: Potential ecological consequences for metalimnetic phytoplankton populations

Lay AbstractWind mixing is one of the main factors controlling the ecology of lakes. Large, deep lakes, as well as small, shallow ones, can develop a seasonal thermal stratification. Because both light and heat come from above, a warm and illuminated surface layer develops above a colder, darker, and heavier bottom water layer under the influence of gravity. Gravity also controls the tendency for the microscopic plants that make up the floating plankton—the phytoplankton, which are a bit heavier than water—to fall from the top layer to the bottom layer, where they die and decompose, releasing the nutrients contained in their bodies. For this reason, the warmer surface layer, or epilimnion, becomes depleted in plant nutrients and the deep layer becomes enriched with nutrients. Specialized phytoplankton can grow at the interface of these two layers, leading to the development of a deep‐chlorophyll maximum in the intermediate layer known as the metalimnion. Strong winds can stir the waters of the upper layer and increase resource availability to the plankton in the upper layer in two ways. First, the mixing can bring nutrients across the metalimnion and up into the epilimnion. Second, the wind increases turbulence in the epilimnion, thereby keeping the phytoplankton suspended in the lighted layer and resuspending cells from the metalimnion. In this study, a particular consequence of wind mixing known as internal waves, which are waves that occur in the metalimnion, was observed in a small lake. These waves are caused by the wind physically pushing the warm surface layer to the downwind side of the lake, where the warm water accumulates and pushes down on the metalimnion, inducing a lakewide tilt in the metalimnion. When the wind relaxes, the waves on the surface of the lake diminish, but larger waves can be induced in the metalimnion as it tries to reestablish its equilibrium with gravity. In much the same way as plucking a guitar string can produce a primary tone as well as several overtones, the oscillation in the metalimnion has more than one frequency. This study links lake physics and ecology by characterizing the different modes of internal waves and examining the potential ecological consequences of each for phytoplankton productivity. Until now, the exploitation of internal waves by specialized phytoplankton has been thought to be important mainly in large, deep lakes. This study highlights the occurrence and ecological importance of both vertically complex internal waves and the dominance of a deep chlorophyll maximum over the entire summer stratification period in a small shallow lake.

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

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). 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=80/70dB SPL). The DPOAE amplitude was measured at the 11 frequencies of 2f1-f2 with f2 varying from 593 to 6031Hz. 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. 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 4812Hz (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 4812Hz, but not with that at the other f2 frequencies tested. The correlation coefficients were 0.528 and 0.522 for 3031 and 4812Hz, 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 4812Hz, respectively. 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.

Hearing threshold estimation using concurrent measurement of distortion product otoacoustic emissions and auditory steady-state responses

Both distortion product otoacoustic emissions (DPOAEs) and auditory steady-state responses (ASSRs) provide frequency-specific assessment of hearing. However, each method suffers from some restrictions. Hearing losses above 50 dB HL are not quantifiable using DPOAEs and their performance at frequencies below 1 kHz is limited, but their recording time is short. In contrast, ASSRs are a time-consuming method but have the ability to determine hearing thresholds in a wider range of frequencies and hearing losses. Thus, recording DPOAEs and ASSRs simultaneously at their adequate frequencies and levels could decrease the overall test time considerably. The goal of the present study was to develop a parameter-setting and test-protocol to measure DPOAEs and ASSRs binaurally and simultaneously at multiple frequencies. Ten normal-hearing and 23 hearing-impaired subjects participated in the study. The interaction of both responses when stimulated simultaneously at frequencies between 0.25 and 6 kHz was examined. Two limiting factors need to be kept. Frequency distance between ASSR carrier frequency f(c) and DPOAE primary tone f(2) needs to be at least 1.5 octaves, and DPOAEs may not be measured if the ASSR stimulus level is 70 dB SPL or above. There was a significant correlation between pure-tone and DPOAE/ASSR-thresholds in sensorineural hearing loss ears.

Calibration Color Patch Reduction for Electrophotography

This paper presents results of reducing color patches printed during a calibration using a variable selection approach for color electrophotography (EP). During a calibration, primary color patches at different halftone levels are printed on a belt and measured using on-board sensors. Regression models are used to predict primary color tone values on output media from these onboard sensor measurements. Then necessary adjustments using tone correction or other control variables can be applied to compensate tone deviation. Laying down and measuring color patches consumes time and toner. It is desired to determine a minimal set of color patches for the regression models while ensuring their prediction accuracy. This work proposes a procedure that reduces color patches in regression model development. The procedure applies variable selection algorithms to identify the appropriate number of color patches and their associated halftone levels. Results demonstrate that the proposed method can use 45% fewer color patches for the regression models while maintaining prediction accuracy effectively the same as that of models using all the available color patches.

Tracing Distortion Product (DP) Waves in a Cochlear Model.

In many cases a cochlear model suffices to explain (by simulation) the properties of waves in the cochlea. This is not so in the case of a distortion product (DP) set up by presenting two primary tones to the cochlea. A three-dimensional model predicts, apart from a DP wave traveling in the apical direction, a DP wave that travels from the region of overlap of the two tone patterns towards the stapes-setting the stapes in motion so as to produce an otoacoustic emission at the DP frequency. Experimental research has shown, however, that the actual DP wave in the cochlea appears to travel in the opposite direction, from near the stapes to the overlap region. This feature has been termed "inverted direction of wave propagation" (IDWP). The forward wave could result from an unknown process such as a "hidden source" near the stapes. In the present study we have disproved this notion, by using a one-dimensional model of the cochlea. It is found that both reverse and forward waves are set up by the source of nonlinearity, in the same way as has been published in an earlier work. The present results reveal that IDWP in the data corresponds to the region where the DP wave, originally created as a reverse wave but reflected from the stapes, has received so much amplification that it starts to dominate over the reverse wave. Hence we conclude that IDWP in a one-dimensional model is a direct manifestation of cochlear amplification.

Against Abstraction: Zoe Leonard's Analogue

In the late 1990s, Zoe Leonard began photographing the storefronts and sidewalks of her Lower East Side neighborhood. For the next ten years, she assembled an archive of quirky and forlorn scenes. In one image, two tattered chairs stand awkwardly outside a grimy laundromat, while in another image, pink and white foam pillows press up against a glass facade, and in a third, threadbare suits and dresses hang in a dimly lit window display. Comprising over four hundred chromogenic and gelatin silver photographs, Analogue offers vignettes of marginalized discards as well as mass-produced kitsch. In one of the first sustained responses to the work, Mark Godfrey remarks that such objects seem above all to belong to the category of the outmoded, to “a passing era of material and retail culture.”1 Echoing Godfrey's observation, Helen Molesworth describes Analogue as staging the “tension between disappearance and tenacity” of an older mode of exchange—the mom-and-pop store, the corner bodega, the artisan tailor—as it keeps at bay, if only temporarily, the multinational corporation lurking somewhere off-camera.2 This sentiment of loss is the primary tone in which critics have received—and consistently praised—Analogue.

Media coverage of off-label promotion: A content analysis of US newspapers

Background Promotion of drugs for off-label use is newsworthy, because it is an illegal but all too common strategy used by pharmaceutical companies. The print media are an important source of information about coverage of off-label promotion of drugs and devices and can influence public perceptions of the practice. Objectives Print media coverage of off-label promotion during the years 1990-2008 were described and quantified. The primary themes and general tones relating to off-label promotion articles were evaluated. General concerns associated with off-label promotion and complaints about specific brand name drugs were also identified. Methods Content analyses of the top 6 US newspapers were conducted over the period of 1990-2008 to analyze the media coverage given to off-label promotion of drugs and devices. Headlines and full text of articles were analyzed for primary themes and tones of the coverage. Intercoder reliability tests were performed on all the study variables. Results One hundred and one articles were identified meeting the study inclusion criteria. Coverage varied by newspaper. The Wall Street Journal had the most coverage on the topic (45%), and USA Today and Chicago Tribune had the least coverage (5%). Overall, most of the stories sampled were deemed to have a negative tone in coverage (77%), focusing mainly on lawsuits against drug companies for promoting their drugs for off-label uses. Pfizer’s Neurontin ® (Pfizer Inc., New York, NY 10017, USA) and Johnson & Johnson’s Retin-A ® (Orthoneutrogena, Los Angeles, CA 90045, USA) received the most media attention. Conclusion The news media helps shape public understanding of promotional practices of pharmaceutical companies and their potential benefits and harms. This study suggests that print media coverage is generally negative about off-label promotion, focusing on legal actions taken against drug companies and the negative consequences of such promotional practices.

Impact of three hours of discotheque music on pure-tone thresholds and distortion product otoacoustic emissions

The aim of this study was to investigate whether distortion product otoacoustic emissions (DPOAEs) are a suitable means for detecting changes in outer hair cell (OHC) functionality due to exposure to three hours of discotheque music and whether efferent reflex strength of the medial olivocochlear bundle is able to predict the ear's susceptibility to high-level noise. High-resolution DPOAEs (Δf(2)=47 Hz) were recorded between 3.5 and 4.5 kHz at close-to-threshold primary tone levels. For comparison, high-resolution pure-tone audiometry was conducted in the same frequency range. Efferent reflex strength was measured by means of DPOAEs at a specific frequency with and without contralateral acoustic stimulation. A significant deterioration of more than 10 dB was found for pure-tone thresholds and DPOAE levels indicating that three hours of high-level noise exert a considerable influence on hearing capability and OHC functionality. A significant correlation between shifts in pure-tone threshold and shifts in DPOAE level occurred when removing data with differing calibration across measurements. There was no clear correlation between efferent reflex strength and shifts in pure-tone threshold or shifts in DPOAE level suggesting that the applied measures of efferent reflex strength may not be suitable for quantifying individual vulnerability to noise.

Relationship between medial‐olivocochlear reflex strength and masked thresholds.

Otoacoustic emission amplitude is reduced by contralateral acoustic stimulation (CAS). This effect is produced by the medial‐olivocochlear (MOC) reflex. Past studies have shown that the MOC reflex is related to listening in noise and selective attention. The present study examined the relationship between the MOC reflex and masked thresholds in 14 normally hearing adults. Detection thresholds were determined for a 1000‐Hz, 300‐ms tone presented simultaneously with a 300‐ms masker. Three masking conditions in which energetic or informational masking predominate were investigated. DPOAEs were evoked from 500–4000 Hz with primary tones swept in frequency at 8 s/oct, using a fixed f2/f1 ratio of 1.22 at 65/55 dB sound pressure level. The MOC reflex and MOC‐shift were measured at DPOAE fine structure maxima at 948 and 1091 Hz with and without CAS. An inverse fast‐Fourier transform was performed to evaluate MOC effects on individual DPOAE components. Preliminary data analyzes showed MOC activity to be correlated with masked thresholds for both indices of medial efferent function. Most notably, higher masked thresholds for the random and broadband conditions were associated with a stronger MOC reflex for DPOAE maxima around 948 Hz. These results suggest that MOC activation plays a role in selective listening.

Monitoring carboplatin ototoxicity with distortion-product otoacoustic emissions in children with retinoblastoma

Objective Carboplatin is a common chemotherapy agent with potential ototoxic side effects that is used to treat a variety of pediatric cancers, including retinoblastoma. Retinoblastoma is a malignant tumor of the retina that is usually diagnosed in young children. Distortion-product otoacoustic emission tests offer an effective method of monitoring for ototoxicity in young children. This study was designed to compare measurements of distortion-product otoacoustic emissions obtained before and after several courses of carboplatin chemotherapy in order to examine if (a) mean distortion-product otoacoustic emission levels were significantly different; and (b) if criterion reductions in distortion-product otoacoustic emission levels were observed in individual children. Methods A prospective repeated measures study. Ten children with a median age of 7.6 months (range, 3–72 months) diagnosed with unilateral or bilateral retinoblastoma were examined. Distortion-product otoacoustic emissions were acquired from both ears of the children with 65/55 dB SPL primary tones ( f 2 = 793–7996 Hz) and a frequency resolution of 3 points/octave. Distortion-product otoacoustic emission levels in dB SPL were measured before chemotherapy treatment (baseline measurement) and after 3–4 courses of chemotherapy (interim measurement). Comparisons were made between baseline and interim distortion-product otoacoustic emission levels (collapsed across ears). Evidence of ototoxicity was based on criterion reductions (≥6 dB) in distortion-product otoacoustic emission levels. Results Significant differences between baseline and interim mean distortion-product otoacoustic emission levels were only observed at f 2 = 7996 Hz. Four children exhibited criterion reductions in distortion-product otoacoustic emission levels. Conclusions Mean distortion-product otoacoustic emission levels at most frequencies were not changed following 3–4 courses of carboplatin chemotherapy in children with retinoblastoma. However, on an individual basis, children receiving higher doses of carboplatin exhibited criterion reductions in distortion-product otoacoustic emission level at several frequencies. These findings suggest that higher doses of carboplatin affect outer hair cell function, and distortion-product otoacoustic emission tests can provide useful information when monitoring children at risk of developing carboplatin ototoxicity.

Differences in distortion product otoacoustic emission phase recorded from human neonates using two popular probes

DPOAE (2f(1)-f(2)) phase was measured across a 3-octave frequency range from two groups of newborns using ER10B+ and ER10C probe microphones. A marked phase shift was noted in the mid-to-high frequency range for newborn data recorded with the ER10C only. In contrast, the ER10B+ produced phase that was approximately invariant as a function of frequency for most of the range. Probe-related phase shifts can be effectively eliminated by correcting for variations in the phases of the primary tones. Results highlight the importance of detecting and correcting for system-related phase shifts so they are not misinterpreted as cochlear in origin.

Fan and compressor noise attenuation

The present invention is a noise attenuation system (40) and related method for suppressing noise having a primary tone generated by a jet engine (20). An exciting sound wave generator (40) is positioned within the nacelle (22) of the jet engine at its inlet (26) to generate an exciting sound wave having a primary frequency generally different from a frequency of the primary tone of the noise. The exciting sound wave is used to modulate the primary tone of the noise and, therefore, distribute sound energy of the noise from the primary tone to a broad range of side bands so that the amplitude of the primary tone of the noise is reduced. The exciting sound wave generator according to the preferred embodiments is a fence member exposed to the air flow entering the inlet of the nacelle, or an aperture (see fig. 2) defined in the inner wall (30) of the nacelle to jet an air flow into the nacelle. The noise attenuation system avoids complicated noise attenuation devices used in an active noise control system for sensing the noise frequency and phase, and controlling the frequency and phase of the generated sound wave for a match.

Improving Tone Prediction in Calibration of Electrophotographic Printers by Linear Regression: Using Principal Components to Account for Co-Linearity of Sensor Measurements

This work employs principal component regression (PCR) to improve tone prediction accuracy for color electrophotography (EP). During calibration, primary color patches at different half-tone levels are printed on a belt and measured using on-board sensors. Regression models are developed to predict primary color tone values on output media from these on-board sensor measurements. The prediction accuracy of the regression models directly impacts the quality and consistency of color reproduction. Analyses have revealed a high degree of correlation among the on-board sensor measurements of the calibration patches from the same primary color. This indicates that multiple on-board sensor measurements are linearly correlated and using multiple on-board sensor measurements to predict the tone value may improve prediction accuracy if the collinearity of the measurements is taken into consideration. In this study, a PCR-based approach is applied to handle the multicollinear measurements in estimating the regression model coefficients. Experimental results show the proposed PCR models reduce root-mean-squared error by 24.7% over ordinary least-squares regression models.