Application of clitoris exposure + episioplasty + dermabrasion + platelet-rich plasma injection + chemexfoliation in vulvar lichen sclerosus.

Introduction: To investigate the therapeutic effect of clitoris exposure + episioplasty + dermabrasion + platelet-rich plasma (PRP) injection + chemexfoliation on vulvar lichen sclerosus (VLS). Methods: Twenty children with VLS (under 14 years old) at our hospital from July 2020 to November 2022 were enrolled and treated with clitoris exposure + episioplasty + dermabrasion + PRP injection + chemexfoliation. Additionally, symptomatic changes and improvements in signs were recorded. Results: Significant therapeutic effects were achieved in all children enrolled in this study. The Cattanco score was 8.02 ± 1.22 points before surgery, 2.21 ± 0.70 points 3 months after surgery, and 2.61 ± 0.59 points 6 months after surgery, demonstrating that the score after surgery was significantly lower than that before surgery (p < 0.05). Mild complications (one case of mild vulvar swelling, one case of minor bleeding, and one case of superficial ulcer) were observed in three children after surgery, with an overall complication incidence of 15%; all complications were improved after the intervention, and no severe adverse reactions were observed. Recurrence was observed in one child (5%) 6 months after surgery. Conclusion: Clitoris exposure + episioplasty + dermabrasion + PRP injection + chemexfoliation is an effective approach for the treatment of VLS. Systematic Review Registration: https://www.chictr.org.cn/searchproj.html, identifier: ChiCTR2100054787.

Novel design constructed In2S3@SnO2 hollow heterojunctions by insufficiently etched MOFs as framework for photoelectrochemical bioanalysis.

Compared to sufficiently etched MOFs materials, insufficiently etched MOFs materials tend to display unsatisfactory performance due to their immature structure and have been eliminated from scientific research. Herein, this work reported a novel In2S3@SnO2 heterojunction (In2S3@SnO2-HSHT) materials, which were stably synthesized in high temperature aqueous environment and equipped extraordinary photoelectrochemical (PEC) properties, fabricated by a succinct hydrothermal synthesis method using insufficiently etched MIL-68 as a self-sacrificing template. Compared with the control groups and In2S3@SnO2 heterojunctions with collapse morphology synthesized by sufficiently etched MIL-68 in high temperature aqueous environment, In2S3@SnO2-HSHT synthesized from insufficiently etched MIL-68 as a template had a massively enhanced light-harvesting capability and generated more photoinduced charge carriers due to its well-preserved hollow structure. Therefore, based on outstanding PEC performance of In2S3@SnO2-HSHT, the established PEC label-free signal-off immunosensor to detect CYFRA 21-1, revealing vivid selectivity, stability, and reproducibility. This novel strategy adopted the insufficient chemical etching method neglected by the mainstream chemical etching approaches, which solved the challenge that the stability of the sufficient etched MOFs with hollow structure cannot be maintained under the subsequent high temperature aqueous reaction conditions, and was further applied to the design of hollow heterojunction materials for photoelectrochemical fields.

Amisulpride augmentation therapy improves cognitive performance and psychopathology in clozapine-resistant treatment-refractory schizophrenia: a 12-week randomized, double-blind, placebo-controlled trial.

BACKGROUND: Although clozapine is an effective option for treatment-resistant schizophrenia (TRS), there are still 1/3 to 1/2 of TRS patients who do not respond to clozapine. The main purpose of this randomized, double-blind, placebo-controlled trial was to explore the amisulpride augmentation efficacy on the psychopathological symptoms and cognitive function of clozapine-resistant treatment-refractory schizophrenia (CTRS) patients. METHODS: A total of 80 patients were recruited and randomly assigned to receive initial clozapine plus amisulpride (amisulpride group) or clozapine plus placebo (placebo group). Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Clinical Global Impression (CGI) scale scores, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Treatment Emergent Symptom Scale (TESS), laboratory measurements, and electrocardiograms (ECG) were performed at baseline, at week 6, and week 12. RESULTS: Compared with the placebo group, amisulpride group had a lower PANSS total score, positive subscore, and general psychopathology subscore at week 6 and week 12 (PBonferroni < 0.01). Furthermore, compared with the placebo group, the amisulpride group showed an improved RBANS language score at week 12 (PBonferroni < 0.001). Amisulpride group had a higher treatment response rate (P = 0.04), lower scores of CGI severity and CGI efficacy at week 6 and week 12 than placebo group (PBonferroni < 0.05). There were no differences between the groups in body mass index (BMI), corrected QT (QTc) intervals, and laboratory measurements. This study demonstrates that amisulpride augmentation therapy can safely improve the psychiatric symptoms and cognitive performance of CTRS patients. CONCLUSION: This study indicates that amisulpride augmentation therapy has important clinical significance for treating CTRS to improve clinical symptoms and cognitive function with tolerability and safety. Trial registration Clinicaltrials.gov identifier- NCT03652974. Registered August 31, 2018, https://clinicaltrials.gov/ct2/show/NCT03652974.

Comparative study of different surgical approaches for treatment of UPJ obstruction according to the degree/severity of hydronephrosis factor.

Objective: To compare the efficacy of two different surgical approaches during and after pyeloplasty according to the degree/severity of hydronephrosis factor. Materials and methods: Sixty child patients with UPJ obstruction admitted to our hospital from August 2019 to October 2021 were collected. Patients who underwent retroperitoneal laparoscopic pyeloplasty (RPLP) were enrolled into Group A (n = 20), while those who received transperitoneal laparoscopic pyeloplasty (TLP) were selected as Group B (n = 40). Clinical parameters, including gender, age, laterality of UPJ obstruction, degree/severity of hydronephrosis, body weight, operation time, drainage tube indwelling time, complete oral feeding time, and length of hospital stay, were compared between the two groups. Results: All 60 child patients were operated upon successfully without conversion to open surgery. There were no statistically significant differences in gender, age, laterality of UPJ obstruction, and body weight between the two groups, while the operation time of TLP was shorter than that of RPLP, indicating a statistically significant difference (P < 0.001). The differences in complete oral feeding time, drainage tube indwelling time, and length of hospital stay were statistically significant between the two groups, and RPLP was superior to TLP in terms of postoperative recovery time (P < 0.001). A stratified comparison showed that there were no statistically significant differences in anteroposterior diameter ≤ 20 mm, while there were statistically significant differences in anteroposterior diameter >20 mm. Hydronephrosis is reviewed after 3 months of the operation, degree/severity of hydronephrosis have been reduced. Conclusion: Both RPLP and TLP are safe and feasible in the treatment of UPJ obstruction, and their overall surgical effects are equivalent. For child patients with anteroposterior diameter ≤ 20 mm, RPLP is available, while patients with anteroposterior diameter >20 mm, TLP is recommended.

Increased Serum Trimethylamine N-Oxide Level in Type 2 Diabetic Patients with Mild Cognitive Impairment.

Purpose: Trimethylamine N-oxide (TMAO) is a metabolite of phosphatidylcholine in red meat and other diets, which is associated with cardiovascular and other diseases. The aim of this study is to evaluate the associations of serum TMAO with mild cognitive impairment (MCI) in the Chinese type 2 diabetes mellitus (T2DM) population. Materials and Methods: A total of 253 hospitalized T2DM patients and 150 healthy controls were included in this cross-sectional study. Montreal Cognitive Assessment (MoCA) assessed the cognition function, and the 253 T2DM patients were divided into 74 subjects with MCI and 179 with non-MCI. Demographic data and biochemical test results were evaluated. Serum TMAO level was measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results: A higher serum TMAO level was observed in T2DM patients compared with the healthy controls (P < 0.001). Among all T2DM patients, the MCI group (n = 74) showed higher serum TMAO levels than the non-MCI group. Spearman correlation test showed that TMAO levels were significantly positively correlated with age (r = 0.147, P = 0.019), body mass index (BMI) (r = 0.153, P = 0.015), diabetes duration (r = 0.160, P = 0.011), HbA1c (r = 0.138, P = 0.029), triglyceride (TG) (r = 0.138, P = 0.029), creatinine (r = 0.184, p = 0.003), hs-CRP (r = 0.243, P < 0.001), and were negatively correlated with HDL-C (r = -0.144, P = 0.022), BDNF (r = -0.165, p = 0.009), and MoCA (r = -0.386, P < 0.001) score (all P < 0.05). Multivariable Logistic regression identified high serum TMAO level as a significant independent factor of MCI in the T2DM patients (OR = 1.404, 95% CI = 1.255-1.571; P < 0.001). Conclusion: Our study showed that T2DM patients with MCI have elevated serum TMAO levels.

Effect of calibration method on distortion-product otoacoustic emission measurements at and around 4 kHz.

OBJECTIVES: Distortion-product otoacoustic emissions (DPOAEs) collected after sound pressure level (SPL) calibration are susceptible to standing waves that affect measurements at the plane of the probe microphone due to overlap of incident and reflected waves. These standing-wave effects can be as large as 20 dB, and may affect frequencies both above and below 4 kHz. It has been shown that forward pressure level (FPL) calibration minimizes standing-wave effects by isolating the forward-propagating component of the stimulus. Yet, previous work has failed to demonstrate more than a small difference in test performance and behavioral-threshold prediction with DPOAEs after SPL and FPL calibration. One potential limitation in prior studies is that measurements were restricted to octave and interoctave frequencies; as a consequence, data were not necessarily collected at the standing-wave null frequency. In the present study, DPOAE responses were measured with f2 set to each participant's standing-wave frequency in an effort to increase the possibility that differences in test performance and threshold prediction would be observed for SPL and FPL calibration methods. DESIGN: Data were collected from 42 normal-hearing participants and 93 participants with hearing loss. DPOAEs were measured with f2 set to 4 kHz and at each participant's notch frequency after SPL and FPL calibration. DPOAE input/output functions were obtained from -10 to 80 dB in 5 dB steps for each calibration/stimulus condition. Test performance was evaluated using clinical decision theory. Both area under receiver operating characteristic curves for all stimulus levels and cumulative distributions when L2 = 50 dB (a level at which the best performance was observed regardless of calibration method) were used to evaluate the accuracy with which auditory status was determined. A bootstrap procedure was used to evaluate the significance of the differences in test performance between SPL and FPL calibrations. DPOAE predictions of behavioral threshold were evaluated by correlating actual behavioral thresholds and predicted thresholds using a multiple linear regression model. RESULTS: First, larger DPOAE levels were measured after SPL calibration than after FPL calibration, which demonstrated the expected impact of standing waves. Second, for both FPL and SPL calibration, test performance was best for moderate stimulus levels. Third, differences in test performance between calibration methods were evident at low- and high-stimulus levels. Fourth, there were small but statistically significant improvements in test performance after FPL calibration for clinically relevant conditions. Fifth, calibration method had no effect on threshold prediction. CONCLUSIONS: Standing waves after SPL calibration have an impact on DPOAE levels. Although the effect of calibration method on test performance was small, test performance was better after FPL calibration than after SPL calibration. There was no effect of calibration method on predictions of behavioral threshold.

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans.

Distortion-product otoacoustic emission (DPOAE) suppression tuning curves (STCs) were measured in 65 hearing-impaired (HI) subjects at f(2) frequencies of 2.0, 2.8, 4.0, and 5.6 kHz and L(2) levels relative to sensation level (SL) from 10 dB to as much as 50 dB. Best frequency, cochlear-amplifier gain (tip-to-tail difference, T-T), and tuning (Q(ERB)) were estimated from STCs. As with normal-hearing (NH) subjects, T-T differences and Q(ERB) decreased as L(2) increased. T-T differences and Q(ERB) were reduced in HI ears (compared to normal) for conditions in which L(2) was fixed relative to behavioral threshold (dB SL). When STCs were compared with L(2) at constant sound pressure levels (dB SPL), differences between NH and HI subjects were reduced. The large effect of level and small effect of hearing loss were both confirmed by statistical analyses. Therefore, the magnitude of the differences in DPOAE STCs between NH and HI subjects is mainly dependent on the manner in which level (L(2)) is specified. Although this conclusion may appear to be at odds with previous, invasive measures of cochlear-response gain and tuning, the apparent inconsistency may be resolved when the manner of specifying stimulus level is taken into account.

Growth of suppression using distortion-product otoacoustic emission measurements in hearing-impaired humans.

Growth of distortion-product otoacoustic emission suppression was measured in 65 subjects with mild-to-moderate sensorineural hearing loss (HI). Measurements were made at four probe frequencies (f(2)) and up to five L(2) levels. Eleven suppressor frequencies (f(3)) were used for each f(2), L(2) combination. These data were compared to data from normal-hearing (NH) subjects (Gorga et al., 2011a). In both NH and HI subjects, growth of suppression depended on the relation between f(2) and f(3), such that the slope was close to one when f(3) ≈ f(2), steeper than one when f(3) < f(2), and shallower than one when f(3) > f(2). Differences in growth of suppression between NH and HI subjects were not observed for fixed f(2), L(2) combinations, however large differences were observed in suppressor "threshold" when compared at the same probe sensation level (dB SL). Smaller group differences were observed when compared at the same probe sound-pressure level (dB SPL). Therefore, the extent of these differences depended on how probe level (L(2)) was specified. When the results from NH and HI subjects are compared with each other and with psychophysical studies of masking, differences are observed that have implications for the remediation of mild-to-moderate hearing loss.

Reliability of distortion-product otoacoustic emissions and their relation to loudness.

The reliability of distortion-product otoacoustic emission (DPOAE) measurements and their relation to loudness measurements was examined in 16 normal-hearing subjects and 58 subjects with hearing loss. The level of the distortion product (L(d)) was compared across two sessions and resulted in correlations that exceeded 0.90. The reliability of DPOAEs was less when parameters from nonlinear fits to the input/output (I/O) functions were compared across visits. Next, the relationship between DPOAE I/O parameters and the slope of the low-level portion of the categorical loudness scaling (CLS) function (soft slope) was assessed. Correlations of 0.65, 0.74, and 0.81 at 1, 2, and 4 kHz were observed between CLS soft slope and combined DPOAE parameters. Behavioral threshold had correlations of 0.82, 0.83, and 0.88 at 1, 2, and 4 kHz with CLS soft slope. Combining DPOAEs and behavioral threshold provided little additional information. Lastly, a multivariate approach utilizing the entire DPOAE I/O function was used to predict the CLS rating for each input level (dB SPL). Standard error of the estimate when using this method ranged from 2.4 to 3.0 categorical units (CU), suggesting that DPOAE I/O functions can predict CLS measures within the CU step size used in this study (5).

Distribution of standing-wave errors in real-ear sound-level measurements.

Standing waves can cause measurement errors when sound-pressure level (SPL) measurements are performed in a closed ear canal, e.g., during probe-microphone system calibration for distortion-product otoacoustic emission (DPOAE) testing. Alternative calibration methods, such as forward-pressure level (FPL), minimize the influence of standing waves by calculating the forward-going sound waves separate from the reflections that cause errors. Previous research compared test performance (Burke et al., 2010) and threshold prediction (Rogers et al., 2010) using SPL and multiple FPL calibration conditions, and surprisingly found no significant improvements when using FPL relative to SPL, except at 8 kHz. The present study examined the calibration data collected by Burke et al. and Rogers et al. from 155 human subjects in order to describe the frequency location and magnitude of standing-wave pressure minima to see if these errors might explain trends in test performance. Results indicate that while individual results varied widely, pressure variability was larger around 4 kHz and smaller at 8 kHz, consistent with the dimensions of the adult ear canal. The present data suggest that standing-wave errors are not responsible for the historically poor (8 kHz) or good (4 kHz) performance of DPOAE measures at specific test frequencies.

Distortion-product otoacoustic emission suppression tuning curves in humans.

Distortion-product otoacoustic emission (DPOAE) suppression data as a function of suppressor level (L(3)) for f(2) frequencies from 0.5 to 8 kHz and L(2) levels from 10 to 60 dB sensation level were used to construct suppression tuning curves (STCs). DPOAE levels in the presence of suppressors were converted into decrement versus L(3) functions, and the L(3) levels resulting in 3 dB decrements were derived by transformed linear regression. These L(3) levels were plotted as a function of f(3) to construct STCs. When f(3) is represented on an octave scale, STCs were similar in shape across f(2) frequency. These STCs were analyzed to provide estimates of gain (tip-to-tail difference) and tuning (Q(ERB)). Both gain and tuning decreased as L(2) increased, regardless of f(2), but the trend with f(2) was not monotonic. A roughly linear relation was observed between gain and tuning at each frequency, such that gain increased by 4-16 dB (mean ≈ 5 dB) for every unit increase in Q(ERB), although the pattern varied with frequency. These findings suggest consistent nonlinear processing across a wide frequency range in humans, although the nonlinear operation range is frequency dependent.

Growth of suppression in humans based on distortion-product otoacoustic emission measurements.

Distortion-product otoacoustic emissions (DPOAEs) were used to describe suppression growth in normal-hearing humans. Data were collected at eight f(2) frequencies ranging from 0.5 to 8 kHz for L(2) levels ranging from 10 to 60 dB sensation level. For each f(2) and L(2) combination, suppression was measured for nine or eleven suppressor frequencies (f(3)) whose levels varied from -20 to 85 dB sound pressure level (SPL). Suppression grew nearly linearly when f(3) ≈ f(2), grew more rapidly for f(3) < f(2), and grew more slowly for f(3) > f(2). These results are consistent with physiological and mechanical data from lower animals, as well as previous DPOAE data from humans, although no previous DPOAE study has described suppression growth for as wide a range of frequencies and levels. These trends were evident for all f(2) and L(2) combinations; however, some exceptions were noted. Specifically, suppression growth rate was less steep as a function of f(3) for f(2) frequencies ≤ 1 kHz. Thus, despite the qualitative similarities across frequency, there were quantitative differences related to f(2), suggesting that there may be subtle differences in suppression for frequencies above 1 kHz compared to frequencies below 1 kHz.

Comparison of distortion-product otoacoustic emission growth rates and slopes of forward-masked psychometric functions.

Slopes of forward-masked psychometric functions (FM PFs) were compared with distortion-product otoacoustic emission (DPOAE) input/output (I/O) parameters at 1 and 6 kHz to test the hypothesis that these measures provide similar estimates of cochlear compression. Implicit in this hypothesis is the assumption that both DPOAE I/O and FM PF slopes are functionally related to basilar-membrane (BM) response growth. FM PF-slope decreased with signal level, but this effect was reduced or reversed with increasing hearing loss; there was a trend of decreasing psychometric function (PF) slope with increasing frequency, consistent with greater compression at higher frequencies. DPOAE I/O functions at 6 kHz exhibited an increase in the breakpoint of a two-segment slope as a function of hearing loss with a concomitant decrease in the level of the distortion product (L(d)). Results of the comparison between FM PF and DPOAE I/O parameters revealed only a weak correlation, suggesting that one or both of these measures may provide unreliable information about BM compression.

Do "optimal" conditions improve distortion product otoacoustic emission test performance?

OBJECTIVES: To determine whether an "optimal" distortion product otoacoustic emission (DPOAE) protocol that (1) used optimal stimulus levels and primary-frequency ratios for each f2, (2) simultaneously measured 2f2 - f1 and 2f1 - f2 distortion products, (3) controlled source contribution, (4) implemented improved calibration techniques, (5) accounted for the influence of middle ear reflectance, and (6) applied multivariate analyses to DPOAE data results in improved accuracy in differentiating between normal-hearing and hearing-impaired ears, compared with a standard clinical protocol. DESIGN: Data were collected for f2 frequencies ranging from 0.75 to 8 kHz in 28 normal-hearing and 78 hearing-impaired subjects. The protocol included a control condition incorporating standard stimulus levels and primary-frequency ratios calibrated with a standard SPL method and three experimental conditions using optimized stimuli calibrated with an alternative forward pressure level method. The experimental conditions differed with respect to the level of the reflection-source suppressor tone and included conditions referred to as the null suppressor (i.e., no suppressor tone presented), low-level suppressor (i.e., suppressor tone presented at 58 dB SPL), and high-level suppressor (i.e., suppressor tone presented at 68 dB SPL) conditions. The area under receiver operating characteristic (A(ROC)) curves and sensitivities for fixed specificities (and vice versa) were estimated to evaluate test performance in each condition. RESULTS: A(ROC) analyses indicated (1) improved test performance in all conditions using multivariate analyses, (2) improved performance in the null suppressor and low suppressor experimental conditions compared with the control condition, and (3) poorer performance below 4 kHz with the high-level suppressor. As expected from A(ROC), sensitivities for fixed specificities and specificities for fixed sensitivities were highest for the null suppressor and low suppressor conditions and lowest for standard clinical procedures. The influence of 2f2 - f1 and reflectance on test performance were negligible. CONCLUSIONS: Predictions of auditory status based on DPOAE measurements in clinical protocols may be improved by the inclusion of (1) optimized stimuli, (2) alternative calibration techniques, (3) low-level suppressors, and (4) multivariate analyses.

Influence of calibration method on distortion-product otoacoustic emission measurements: II. threshold prediction.

OBJECTIVES: Distortion-product otoacoustic emission (DPOAE) stimulus calibrations are typically performed in sound pressure level (SPL) before DPOAE measurements. These calibrations may yield unpredictable DPOAE response levels, presumably because of the presence of standing waves in the ear canal. Forward pressure level (FPL) has been proposed as an alternative method for stimulus calibration because it avoids complications due to standing waves. DPOAE thresholds after four FPL calibrations and one SPL calibration were compared with behavioral thresholds to determine which calibration results in data that yield the highest correlations between the two threshold estimates. DESIGN: Fifty-two subjects with normal hearing and 103 subjects with hearing loss participated in this study, with ages ranging from 11 to 75 yr. These were the same individuals whose data were used to address the influence of calibration method on test performance in an accompanying article. DPOAE input/output (I/O) functions were obtained at f2 frequencies of 2, 3, 4, 6, and 8 kHz with the primary frequency ratio fixed at f2/f1 approximately 1.22. L(1) was set according to the equation L(1) = 0.4 L(2) + 39 with L(2) levels ranging from -20 to 70 dB SPL and FPL in 5-dB steps. I/O functions were obtained at each frequency for each of the five stimulus calibrations: SPL, daily FPL at room temperature, daily FPL at body temperature, reference FPL at room temperature, and reference FPL at body temperature. DPOAE thresholds were estimated using two methods. In the first method, DPOAE threshold was taken as the lowest L(2) for which DPOAE level is 3 dB or greater than the noise floor (signal- to-noise ratio > or =3 dB). In a second method, a linear regression method first described by Boege & Janssen (2002) and later adapted by Gorga et al. (2003), all DPOAE levels in each I/O function are converted to linear pressure and extrapolated to 0 microPa, at which the L(2) is taken as threshold. Correlations of DPOAE thresholds with behavioral thresholds were obtained for each frequency, calibration method, and threshold-prediction method. RESULTS: Correlations were greatest for frequencies of 3 to 6 kHz and lowest for 8 kHz, consistent with previous frequency effects. Calibration method made little difference in correlations between DPOAE and behavioral thresholds at any frequency. A small difference was noted in correlations for the two threshold prediction methods, with the linear regression method yielding slightly higher correlations at all frequencies. CONCLUSIONS: Little difference in threshold correlations was observed among the five calibration methods used to calibrate the stimuli before DPOAE measurements. These results were not anticipated, given the known effects of standing waves on ear-canal estimates of SPL at the plane of the probe. In addition, there was no effect of temperature (body versus room) or timing (daily versus reference) for FPL calibrations. It may be important to note that differences between SPL and FPL calibrations should not be seen if a standing wave does not occur at the plane of the probe at or near the frequency being tested. The frequencies (2 to 8 kHz) were chosen because it was expected that effects from standing waves would occur between these frequencies because of the typical lengths of ear canals for the age group tested. Because measurements were taken at only five discrete frequencies in the interval, it is possible that standing waves were present but did not affect the specific test frequencies. In total, these results suggest that SPL calibrations may be adequate when attempting to predict pure-tone thresholds from DPOAEs, despite the fact that they are known to be susceptible to errors associated with standing waves.

Influence of calibration method on distortion-product otoacoustic emission measurements: I. test performance.

OBJECTIVE: Calibration errors in distortion-product otoacoustic emission (DPOAE) measurements because of standing waves cause unpredictable changes in stimulus and DPOAE response level. The purpose of this study was to assess the extent to which these errors affect DPOAE test performance. Standard calibration procedures use sound pressure level (SPL) to determine specified levels. Forward pressure level (FPL) is an alternate calibration method that is less susceptible to standing waves. However, FPL derivation requires prior cavity measurements, which have associated variability. In an attempt to address this variability, four FPL methods were compared with SPL: a reference calibration derived from 25 measurements before all data collection and a daily calibration measurement, both of which were made at body and room temperature. DESIGN: Data were collected from 52 normal-hearing and 103 hearing-impaired subjects. DPOAEs were measured for f2 frequencies ranging from 2 to 8 kHz in half-octave steps, with L2 ranging from -20 to 70 dB SPL (5-dB steps). At each f2, DPOAEs were measured in five calibration conditions: SPL, daily FPL at body temperature (daily body), daily FPL at room temperature (daily room), reference FPL at body temperature (ref body), and reference FPL at room temperature (ref room). Data were used to construct receiver operating characteristic (ROC) curves for each f2, calibration method, and L2. From these curves, areas under the ROC curve (AROC) were estimated. RESULTS: The results of this study are summarized by the following observations: (1) DPOAE test performance was sensitive to stimulus level, regardless of calibration method, with the best test performance observed for moderate stimulus level conditions. (2) An effect of frequency was observed for all calibration methods, with the best test performance at 6 kHz and the worst performance at 8 kHz. (3) At clinically applicable stimulus levels, little difference in test performance among calibration methods was noted across frequencies, except at 8 kHz. At 8 kHz, FPL-based calibration methods provided superior performance compared with the standard SPL calibration. (4) A difference between FPL calibration methods was observed at 8 kHz, with the best test performance occurring for daily calibrations at body temperature. CONCLUSIONS: With the exception of 8 kHz, there was little difference in test performance across calibration methods. At 8 kHz, AROCs and specificities for fixed sensitivities indicate that FPL-based calibration methods provide superior performance compared with the standard SPL calibration for clinically relevant levels. Temperature may have an impact on FPL calculations relative to DPOAE test performance. Although the differences in AROC among calibration procedures were not statistically significant, the present results indicate that standing wave errors may impact DPOAE test performance and can be reduced by using FPL, although the largest effects were restricted to 8 kHz.

The role of suppression in psychophysical tone-on-tone masking.

This study tested the hypothesis that suppression contributes to the difference between simultaneous masking (SM) and forward masking (FM). To obtain an alternative estimate of suppression, distortion-product otoacoustic emissions (DPOAEs) were measured in the presence of a suppressor tone. Psychophysical-masking and DPOAE-suppression measurements were made in 22 normal-hearing subjects for a 4000-Hz signal/f(2) and two masker/suppressor frequencies: 2141 and 4281 Hz. Differences between SM and FM at the same masker level were used to provide a psychophysical estimate of suppression. The increase in L(2) to maintain a constant output (L(d)) provided a DPOAE estimate of suppression for a range of suppressor levels. The similarity of the psychophysical and DPOAE estimates for the two masker/suppressor frequencies suggests that the difference in amount of masking between SM and FM is at least partially due to suppression.

Clinical test performance of distortion-product otoacoustic emissions using new stimulus conditions.

OBJECTIVES: To determine whether new stimulus parameters, which have been shown to produce large distortion-product otoacoustic emission (DPOAE) levels in a group of normal-hearing listeners (Neely et al. 2005; Johnson et al. 2006), result in more accurate identification of auditory status and more accurate predictions of behavioral threshold than traditional stimulus conditions. DESIGN: DPOAE input/output (I/O) functions for eight f2 frequencies ranging from 0.7 to 8 kHz were recorded from 96 ears with normal hearing and 226 ears with sensorineural hearing losses ranging from mild to profound. The primary-level differences and primary-frequency ratios were set according to the stimulus relations developed by Johnson et al. (2006). The accuracy of the dichotomous decision task (area under the relative operating characteristic curve [AROC]) for these new stimulus conditions was evaluated as a function of L2 and was compared with previous reports in the literature where traditional stimuli were used (Stover et al. 1996). Here, traditional stimuli are defined as L1 = L2 + 10 and f2/f1 = 1.22 for all L2 and f2 values. In addition to I/O functions, DPgrams with L2 = 55-dB sound pressure level (SPL) and f2 ranging from 0.7 to 8 kHz were recorded for each subject using the traditional stimuli. This provided a direct within-subject comparison of AROC for moderate-level stimuli when the new and traditional stimuli were used. Finally, the accuracy with which DPOAE thresholds predicted behavioral thresholds was evaluated in relation to previous reports in the literature for two definitions of DPOAE threshold, one where the entire I/O function was used to make the prediction and a second where the lowest L2 producing a signal to noise ratio > or =3 dB was used. RESULTS: There was no evidence that the new stimuli improved the accuracy with which auditory status was identified from DPOAE responses. With both the new and traditional stimuli, moderate stimulus levels (L2 = 40- to 55-dB SPL) resulted in the most accurate identification of auditory status. When L2 = 55-dB SPL, the new stimuli produced AROC values that were equivalent to those observed with traditional stimuli. The new stimuli resulted in more accurate prediction of behavioral threshold for several f2 values when using the entire I/O function, although the effect was small. Furthermore, using the entire I/O function to predict behavioral threshold results in more accurate predictions of behavioral threshold than using the signal to noise ratio definition, although this approach can be applied to a smaller percentage of ears. CONCLUSIONS: The new stimuli that had been shown previously to produce large DPOAE levels in normal-hearing listeners (Neely et al. 2005; Johnson et al. 2006) do not result in more accurate identification of auditory status and have only a small positive effect on the prediction of behavioral threshold.

Spectral weights for sample discrimination as a function of overall level.

Doherty and Lutfi [(1996). "Spectral weights for overall level discrimination in listeners with sensorineural hearing loss," J. Acoust. Soc. Am. 99, 1053-1058] examined the weights assigned to individual components of a six-tone complex during a sample discrimination task and reported that hearing-impaired subjects gave the most weight to components in the region of their high-frequency hearing loss. In contrast, weighting patterns varied for normal-hearing subjects. In the current study, the same six-tone complex, comprised of the octave frequencies from 0.25 to 8 kHz, was presented to three subjects with normal hearing in high-pass noise, in low-pass noise, and in quiet at two overall levels. Consistent with Doherty and Lutfi, subjects assigned more weight to the 4-kHz component in the high-pass noise condition, but roughly equal weight to all components in the lower-level quiet condition. Weights in the low-pass noise and higher-level quiet conditions, however, were similar to those in the high-pass noise condition. A second experiment compared weights for seven subjects in quiet at four different mean levels. Weights for the highest-frequency components increased as the overall level of the complexes was increased. These results suggest that overall level, rather than degree of hearing loss or sensation level, was the primary cause of the effect that Doherty and Lutfi observed.

Low-frequency and high-frequency distortion product otoacoustic emission suppression in humans.

Distortion product otoacoustic emission suppression (quantified as decrements) was measured for f(2)=500 and 4000 Hz, for a range of primary levels (L(2)), suppressor frequencies (f(3)), and suppressor levels (L(3)) in 19 normal-hearing subjects. Slopes of decrement-versus-L(3) functions were similar at both f(2) frequencies, and decreased as f(3) increased. Suppression tuning curves, constructed from decrement functions, were used to estimate (1) suppression for on- and low-frequency suppressors, (2) tip-to-tail differences, (3) Q(ERB), and (4) best frequency. Compression, estimated from the slope of functions relating suppression "threshold" to L(2) for off-frequency suppressors, was similar for 500 and 4000 Hz. Tip-to-tail differences, Q(ERB), and best frequency decreased as L(2) increased for both frequencies. However, tip-to-tail difference (an estimate of cochlear-amplifier gain) was 20 dB greater at 4000 Hz, compared to 500 Hz. Q(ERB) decreased to a greater extent with L(2) when f(2)=4000 Hz, but, on an octave scale, best frequency shifted more with level when f(2)=500 Hz. These data indicate that, at both frequencies, cochlear processing is nonlinear. Response growth and compression are similar at the two frequencies, but gain is greater at 4000 Hz and spread of excitation is greater at 500 Hz.