High-frequency Pure-tone Thresholds Research Articles

Extended high-frequency pure-tone thresholds predict speech-in-speech recognition even when extended high-frequency speech cues are absent

Recent work has demonstrated that extended high-frequency (EHF; >8 kHz) hearing is valuable for speech-in-noise recognition. These findings contradict the broadly accepted “speech bandwidth” that has historically been limited to below 8 kHz. Several studies also indicate that EHF pure-tone thresholds predict speech-in-noise performance. One question that has arisen is whether the association that has been observed between EHF pure-tone thresholds and speech-in-noise recognition is causal—that loss of audibility of EHF cues in speech degrades speech-in-noise recognition. Indeed, this effect has been demonstrated using low-pass filtering, but whether elevated EHF thresholds would produce a similar effect is not certain. Another possibility is that EHF thresholds are a marker for subclinical dysfunction at lower frequencies that degrades speech recognition. These two possibilities are not mutually exclusive (nor exhaustive) and each could contribute to the observed relationship. Here we present a reanalysis of previous data collected in our lab, the results of which suggest that 16-kHz pure-tone thresholds are consistent predictors of speech-in-speech recognition, regardless of whether EHF cues are present in the speech signal. These findings suggest elevated EHF thresholds may indicate subclinical auditory dysfunction impairing speech-in-speech recognition.

Suprathreshold Differences in Competing Speech Perception in Older Listeners With Normal and Impaired Hearing.

Purpose Age-related declines in auditory temporal processing and cognition make older listeners vulnerable to interference from competing speech. This vulnerability may be increased in older listeners with sensorineural hearing loss due to additional effects of spectral distortion and accelerated cognitive decline. The goal of this study was to uncover differences between older hearing-impaired (OHI) listeners and older normal-hearing (ONH) listeners in the perceptual encoding of competing speech signals. Method Age-matched groups of 10 OHI and 10 ONH listeners performed the coordinate response measure task with a synthetic female target talker and a male competing talker at a target-to-masker ratio of +3 dB. Individualized gain was provided to OHI listeners. Each listener completed 50 baseline and 800 "bubbles" trials in which randomly selected segments of the speech modulation power spectrum (MPS) were retained on each trial while the remainder was filtered out. Average performance was fixed at 50% correct by adapting the number of segments retained. Multinomial regression was used to estimate weights showing the regions of the MPS associated with performance (a "classification image" or CImg). Results The CImg weights were significantly different between the groups in two MPS regions: a region encoding the shared phonetic content of the two talkers and a region encoding the competing (male) talker's voice. The OHI listeners demonstrated poorer encoding of the phonetic content and increased vulnerability to interference from the competing talker. Individual differences in CImg weights explained over 75% of the variance in baseline performance in the OHI listeners, whereas differences in high-frequency pure-tone thresholds explained only 10%. Conclusion Suprathreshold deficits in the encoding of low- to mid-frequency (~5-10 Hz) temporal modulations-which may reflect poorer "dip listening"-and auditory grouping at a perceptual and/or cognitive level are responsible for the relatively poor performance of OHI versus ONH listeners on a different-gender competing speech task. Supplemental Material https://doi.org/10.23641/asha.12568472.

Sensorineural hearing loss and volatile organic compound metabolites in urine.

Oxidative stress in the auditory system contributes to acquired sensorineural hearing loss. Systemic oxidative stress, which may predict auditory oxidative stress, can be assessed by measuring volatile organic compound metabolite concentrations in urine. The purpose of this retrospective study was to determine if hearing decreased in those with higher concentrations of urinary volatile organic compound metabolites. Audiometric, demographic, and metabolite concentration data were downloaded from the 2011-2012 cycle of the U.S. National Health and Nutritional Examination Survey. Participants were first grouped by reported noise exposure. For each metabolite, an analysis of covariance was used to look for differences in age-adjusted hearing loss among urinary volatile organic compound metabolite concentration groups. Participants were grouped into quartiles based on concentration for each metabolite separately because many individuals were at the lower limit of concentration detection for several metabolites, leading to a non-normal distribution. Age-adjusted high-frequency pure-tone thresholds were significantly (FDR < 0.05) increased by about 3 to 4 dB in high concentration quartile groups for five metabolites. All five metabolites were glutathione-dependent mercapturic acids. The parent compounds of these metabolites included acrylonitrile, 1,3 butadiene, styrene, acrylamide, and N,N-dimethylformamide. Significant associations were only found in those with no reported noise exposure. Urinary metabolites may help to explain susceptibility to oxidative stress-induced hearing loss.

Pure-tone thresholds and the binaural masking level difference

Although several studies have examined the relationship between high-frequency pure-tone thresholds and the 500-Hz binaural masking level difference (BMLD), the results have not always been consistent. In this study, a retrospective analysis was conducted on an existing dataset from over 3000 military service members that included both pure-tone thresholds measured as part of their annual hearing conservation testing and a 33-trial clinical test of the BMLD. There was only a slight dependence of the 500-Hz BMLD on high-frequency pure-tone thresholds. For listeners with elevated pure-tone thresholds, this dependence was in good agreement with the findings of Jerger et al. [Arch. Otolaryngol. 110, 290–296 (1984)] and slightly larger than that reported by Wilson and Weakley [J. Am. Acad. Audiol. 16, 367–382 (2005)]. For listeners with near-normal hearing, the dependence of the 500-Hz BMLD on the 4-kHz pure-tone threshold was substantially less than that reported by Bernstein and Trahiotis [J. Acoust. Soc. Am. 140, 3540–3548 (2016)]. A possible explanation might be the degree of training offered to the subjects and procedural differences between clinical and laboratory techniques. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]

Age-Related Hearing Loss Associations With Changes in Brain Morphology.

Age-related hearing loss has been associated with varied auditory cortex morphology in human neuroimaging studies. These findings have suggested that peripheral auditory system declines cause changes in brain morphology but could also be due to latent variables that affect the auditory periphery and brain. The current longitudinal study was designed to evaluate these explanations for pure-tone threshold and brain morphology associations. Thirty adults (mean age at Time 1 = 64.12 ± 10.32 years) were studied at two time points (average duration between visits = 2.62 ± 0.81 years). Small- to medium-effect size associations were observed between high-frequency pure-tone thresholds and auditory cortex gray matter volume at each time point. Although there were significant longitudinal changes in low- and high-frequency hearing measures and brain morphology, those longitudinal changes were not significantly correlated across participants. High-frequency hearing measures at Time 1 were significantly related to more lateral ventricle expansion, such that participants with higher measures exhibited larger increases in ventricle size. This ventricle effect was statistically independent of high-frequency hearing associations with auditory cortex morphology. Together, these results indicate that there are at least two mechanisms for associations between age-related hearing loss and brain morphology. Potential explanations for a direct hearing loss effect on brain morphology, as well as latent variables that likely affect both the inner ear and brain, are discussed.

Discrimination of Gain Increments in Speech.

During a hearing-aid fitting, the gain applied across frequencies is often adjusted from an initial prescription in order to meet individual needs and preferences. These gain adjustments in one or more frequency bands are commonly verified using speech in quiet (e.g., the clinician’s own voice). Such adjustments may be unreliable and inefficient if they are not discriminable. To examine what adjustments are discriminable when made to speech, this study measured the just-noticeable differences (JNDs) for gain increments in male, single-talker sentences. Sentences were presented with prescribed gains to the better ears of 41 hearing-impaired listeners. JNDs were measured at d’ of 1 for octave-band, dual-octave-band, and broadband increments using a fixed-level, same-different task. The JNDs and interquartile ranges for 0.25, 1, and 4 kHz octave-band increments were 6.3 [4.0–7.8], 6.7 [4.6–9.1], and 9.6 [7.3–12.4] dB, respectively. The JNDs and interquartile ranges for low-, mid-, and high-frequency dual-octave-band increments were 3.7 [2.5–4.6], 3.8 [2.9–4.7], and 6.8 [4.7–9.1] dB, respectively. The JND for broadband increments was 2.0 [1.5–2.7] dB. High-frequency dual-octave-band JNDs were positively correlated with high-frequency pure-tone thresholds and sensation levels, suggesting an effect of audibility for this condition. All other JNDs were independent of pure-tone threshold and sensation level. JNDs were independent of age and hearing-aid experience. These results suggest using large initial adjustments when using short sentences in a hearing-aid fitting to ensure patient focus, followed by smaller subsequent adjustments, if necessary, to ensure audibility, comfort, and stability.

Concurrent effect of noise exposure and smoking on extended high-frequency pure-tone thresholds

Objective: Concurrent effect of noise and smoking on hearing loss is a recent concern. In this study, the concurrent effect of noise and smoking on hearing loss in conventional frequencies and frequencies higher than 8 kHz was assessed. Design: This was a cross-sectional study on workers exposed to noise who were divided into two groups: smokers and non-smokers. Hearing thresholds were assessed by conventional audiometry, and HFA. Data were analysed using non-parametric tests and Student's t-test. Study sample: There were 212 workers. Results: Ninety-seven subjects were smokers and 115 individuals were non-smokers. All subjects were exposed to 92.1 ± 2.4 dBA (Leq8h). The highest threshold in conventional and high-frequency audiometry was observed at 6 kHz and 16 kHz, respectively. Hearing threshold at frequencies above 1 kHz was significantly higher in the smokers than non-smokers. There was no correlation between hearing thresholds and pack-years of smoking. Conclusions: Concurrent exposure to noise and smoking may be associated with more hearing loss than exposure to noise alone in the conventional and high frequencies. However, other differences between smokers and non-smokers may explain these differences as well.

The Effect of Noise Exposure on the Cervical Vestibular Evoked Myogenic Potential

The purpose of this study was to investigate the effects of noise exposure on the cervical vestibular evoked myogenic potential (cVEMP) in individuals with asymmetric noise-induced sensorineural hearing loss (NIHL). A cross-sectional observational study was used to compare cVEMP characteristics in 43 individuals with a history of noise exposure greater in one ear (e.g., the left ear of a right-handed rifle shooter) and asymmetric sensorineural hearing loss consistent with the history of noise exposure and in 14 age-matched controls. The characteristics of hearing loss were examined further for the noise-exposed participants with abnormal cVEMPs and the noise-exposed participants with normal cVEMPs. Thirty-three percent of the noise-exposed participants had abnormal cVEMPs, whereas cVEMPs were present and symmetrical in 100% of the age-matched controls, and cVEMP threshold was greater in the noise-exposed group than in the control group. Abnormal cVEMPs occurred most often in the ears with poorer hearing (or greater NIHL), and the noise-exposed participants who had abnormal cVEMPs had poorer high-frequency pure-tone thresholds (greater NIHL) and greater interaural high-frequency pure-tone threshold differences than the noise-exposed participants with normal cVEMPs. These findings are consistent with previous studies that suggest that the sacculocollic pathway may be susceptible to noise-related damage. There is emerging evidence that the severity of NIHL is associated with the presence or absence of cVEMPs.

Age-Related Difference in Melodic Pitch Perception Is Probably Mediated by Temporal Processing

This study was designed to examine whether age-related differences in melodic pitch perception may be mediated by temporal processing. Temporal models of pitch suggest that performance will decline as the lowest component of a complex tone increases in frequency, regardless of age. In addition, if there are age-related deficits in temporal processing in older adults, this group may have reduced performance relative to younger adults even in the most favorable conditions. Six younger adults and 10 older adults with clinically normal audiograms up to 8 kHz were tested in a melodic pitch perception task. In each trial, two consecutive four-note melodies were presented to the listener. Melodies were identical with the exception of one note in the second melody that was shifted in pitch. The listener was required to identify which note was shifted. All notes consisted of eight successive harmonic components, with the average lowest component manipulated to be the 4th, 8th, or 12th component of the harmonic series, with lower components being absent. Age-related differences in melodic pitch perception were only apparent when stimulus parameters favored temporal processing of pitch. Furthermore, modeling a loss of periodicity coding yielded an outcome consistent with the observed behavioral results. Although younger adults generally outperformed older adults, about one-quarter of the older adults performed at levels that were equivalent to those of younger adults. The only follow-up tests that were able to differentiate these exceptional older adults were tests that would be sensitive to temporal processing: fundamental frequency difference limens and 500 Hz pure-tone difference limens. In contrast, otoacoustic emissions and high-frequency pure-tone thresholds, which are more commonly associated with spectral processing deficits, were not able to differentiate older exceptional adults from older typical adults. Age-related declines in temporal processing contribute to deficits in melodic pitch perception. However, some exceptional older adults with normal audiograms preserve excellent temporal processing and continue to perform at levels that are typical of younger adults.

Speech Recognition and Temporal Processing in Middle-Aged Women

This study was designed to examine speech understanding ability and temporal processing in middle-aged women with normal or near-normal pure-tone thresholds. Speech understanding, temporal processing ability, and self-assessed hearing were measured in groups of younger and middle-aged females. Participants were younger and middle-aged females (n = 12 per group) with normal hearing through 4000 Hz bilaterally. Subjects were drawn from nonclinical populations. Speech understanding was measured in the presence of steady-state noise and competing speech, with and without perceived spatial separation of the target speech and masker. The Gaps-In-Noise (GIN) test (Musiek et al, 2005) was used to assess temporal resolution ability. In addition, subjects completed a questionnaire with several items from the Speech, Spatial, and Qualities of Hearing Scale (Gatehouse and Noble, 2004) to gauge their subjective ability to understand speech in complex listening situations. Data were analyzed via repeated-measures ANOVA and Pearson r correlations. Results showed that the performance of the middle-aged subjects was significantly poorer than that of the younger participants in the presence of a spatially coincident speech masker. Although performance in this listening condition was unrelated to pure-tone thresholds, it was strongly correlated with scores on the GIN test. Speech understanding performance in the presence of a steady-state masker was related to high-frequency pure-tone thresholds. These results suggest that some middle-aged women with little or no pure-tone hearing loss experience listening difficulty in complex environments. Results also suggest a strong relationship between temporal processing and speech understanding in certain competing speech situations.

Output sound pressure levels of personal music systems and their effect on hearing

This study looked at output levels produced by new generation personal music systems (PMS), at the level of eardrum by placing the probe microphone in the ear canal. Further, the effect of these PMS on hearing was evaluated by comparing the distortion product otoacoustic emissions and high frequency pure tone thresholds (from 3 kHz to 12 kHz) of individuals who use PMS to that of age matched controls who did not use PMS. The relationship between output sound pressure levels and hearing measures was also evaluated. In Phase I output SPLs produced by the PMS were measured in three different conditions - a) at volume control setting that was preferred by the subjects in quiet b) at volume control setting that was preferred by the subject in presence of 65 dB SPL bus noise c) at maximum volume control settings of the instrument. In Phase II pure tone hearing thresholds and DPOAEs were measured. About 30% of individuals in a group of 70 young adults listened to music above the safety limits (80 dBA for 8 hours) prescribed by Ministry of Environment and Forests, India. Addition of bus noise did not increase the preferred volume control settings of the subjects significantly. There were no significant differences between the experimental and control groups for mean pure tone threshold and for mean DPOAE amplitude comparisons. However, a positive correlation between hearing thresholds and music levels and a negative correlation between DPOAE measures and music levels were found.

Functional outcome of retrosigmoid approach in vestibular schwannoma surgery

Conclusion. The retrosigmoid approach for small vestibular schwannomas (VS) yields a high rate of facial function preservation. Hearing preservation rates depend on tumor size and preoperative hearing. Objectives. To report the results and to investigate the prognostic factors for hearing preservation after removal of small VS by a retrosigmoid approach. Patients and methods. From October 1994 to July 2005, 110 VS removed through a retrosigmoid approach were included in this retrospective study. Preoperative and postoperative clinical, audiometric, videonystagmographic, and imaging data were collected. The mean follow-up period was 23±20.7 months (range 1–110). Results. The preservation of a good facial function (House and Brackmann grade 1–2) was achieved in 91% of patients at 1–2 years after surgery. Among patients with a preoperative class A or B (n=99), a postoperative serviceable hearing (AAO-HNS classes A and B) was preserved in 36% and a useful hearing (classes A, B, and C) in 44%. Hearing preservation appeared to be influenced by tumor size and preoperative hearing. Multiple regression analysis of the preoperative factors influencing the hearing outcome showed that preoperative high frequency pure tone thresholds associated with tumor size were better correlated to postoperative pure tone average (PTA) than preoperative low frequencies.

Effects of standing waves on high-frequency thresholds

The effects of standing waves in the ear canal on high-frequency pure-tone thresholds were investigated. Sound was transmitted from a transducer to a high-impedance source by a long plastic tube 0.64 cm in diameter. The high-impedance source was coupled to the ear canal by a shorter plastic tube 7 cm in length. Thus a standing wave field was created between the high-impedance source and the eardrum. Using a broadband stimulus, standing wave patterns were recorded by a small microphone placed near the high-impedance source. Several maxima and minima of the standing wave pattern were located in the frequency range from 6000–12 500 Hz. Thresholds were measured at two successive minima, the maximum between them and two intermediate values. Thresholds were also obtained with the high-impedance source removed from the system, resulting in a source impedance approximately equal to the characteristic impedance of air. Thresholds with and without the high-impedance source were compared and standing wave ratios (the difference between thresholds at the standing wave maximum and minimum) of 5–10 dB were observed. [Research supported by NIH.]

AUDITORY CHANGES ASSOCIATED WITH MODERATE BLOOD SALICYLATE LEVELS

Thirty patients with rheumatoid arthritis were randomly assigned to two groups: aspirin and placebo. Aspirin group subjects received five grain ASA capsules and placebo group subjects received lactose placebo for seven days. Blood salicylate level (BSL) and audiological evaluations were performed on Days 0, 3 and 7. BSLs never exceeded 21 mg/100 ml. BSLs during the seven days varied only slightly among aspirin group subjects but dropped consistently in the placebo group. Intra-subject comparison of scores on low versus high BSL days indicated significant differences between mean speech reception thresholds (SRT) scores and pure-tone air-conduction thresholds at all test frequencies for both groups, except at 2000 Hz for the aspirin group. Inter-group differences occurred on SRT and high-frequency pure-tone thresholds. The results indicate that moderate BSLs adversely affect hearing ability. These adverse effects appear to be temporary.