Normal Audiograms Research Articles

Listening difficulties with despite? a clinically normal audiogram

Listening difficulties with despite? a clinically normal audiogram

Hearing Aids Reduce Self-Perceived Difficulties in Noise for Listeners With Normal Audiograms.

This study assessed hearing aid benefits for people with a normal audiogram but hearing-in-noise problems in everyday listening situations. Exploratory double-blinded case-control study whereby participants completed retrospective questionnaires, ecological momentary assessments, speech-in-noise testing, and mental effort testing with and without hearing aids. Twenty-seven adults reporting speech-in-noise problems but normal air conduction pure-tone audiometry took part in the study. They were randomly separated into an experimental group that trialed mild-gain hearing aids with advanced directional processing and a control group fitted with hearing aids with no gain or directionality. Self-reports showed mild-gain hearing aids reduce hearing-in-noise difficulties and provide a better hearing experience (i.e., improved understanding, participation, and mood). Despite the self-reported benefits, the laboratory tests did not reveal a benefit from the mild-gain hearing aids, with no group differences on speech-in-noise tests or mental effort measures. Further, participants found the elevated cost of hearing aids to be a barrier for their adoption. Hearing aids benefit the listening experience in some listening situations for people with normal audiogram who report hearing difficulties in noise. Decreasing the price of hearing aids may lead to greater accessibility to those seeking remediation for their communication needs.

Audiologic Consequences of Gunshot Wounds to the Temporal Bone Show No Relation to Concomitant Neurologic or Vascular Injuries.

To evaluate audiologic consequences of gunshot wounds (GSWs) to the temporal bone (TB), and to correlate hearing outcomes with neurologic and vascular injuries adjacent to the temporal bone. Retrospective case series. University-based level-one trauma center. Retrospective review of 35 patients surviving TB ballistic injury, 2012 to 2021. Main outcomes were audiologic results. Demographics, concomitant injuries, CT, and interventions were reviewed. Mean age was 30.7 years; 80% male. Seventeen patients (48.6%) underwent audiologic testing. Mean pure tone average (PTA) was 75 ± 35 dB, bone line average 41 ± 26 dB, and speech discrimination score (SDS) 60 ± 43%. Nineteen (54.3%) demonstrated facial nerve injury (FNI), who were more likely to show SNHL especially anacusis, though their mean PTA and SDS were not statistically different from those without (P = .30 and .47, respectively). Radiographic review of those with sensorineural loss (SNHL, 6/17) revealed otic capsule-disrupting fracture (n = 2), pneumolabyrinth (n = 2), intracranial hemorrhage (n = 3). Those with mixed loss (6/17) showed otic capsule-sparing fracture (n = 6), EAC injury (n = 5), ossicular discontinuity (n = 2), and intracranial hemorrhage (n = 4). Two with mastoid tip fractures alone had normal audiograms. Audiometric outcomes were not predicted by concomitant CSF leak, spinal injuries, vascular injuries, cranial neuropathies, or traumatic brain injury. All patterns of hearing loss-conductive, sensorineural, mixed and normal-may be seen following TB ballistic injuries. Trauma severe enough to disrupt the facial nerve is more likely to cause anacusis. However, all should be formally evaluated, since ballistic injuries complicated by neurologic or vascular damage do not necessarily correlate with worse audiologic outcomes, while patients with minimal fractures may demonstrate losses.

Hidden Hearing Loss, Cochlear Synaptopathy and Occupational Noise

Introduction: Cochlear synaptopathy after noise exposure (CSNE) is defined as the transient or permanent functional damage to the ribbon synapsis of the inner hair cells of the cochlea. This article has the objective of comment the usefulness of early identification of the hidden hearing loss after CSNE based on audiological markers and in changes in the clinical methodology in clinical groups for its searching. Method: Review of related literature in scientific databases and narrative description of results. Results: CSNE results in a hidden hearing loss in patients with normal pitch audiogram, mainly workers or individuals exposed to high noise levels. The main studies of identification have been performed mainly in groups of students from college or musicians. Conclusions: Is necessary adjustments in hearing health policy for an wide early identification of CSNE in at risk populations for the identification of the hidden hearing loss and fight for its damage regulation.

The value of headphone accommodations in Apple Airpods Pro for managing speech-in-noise hearing difficulties of individuals with normal audiograms

Objective To investigate the extent to which Headphone Accommodations in Apple AirPods Pro attend to the hearing needs of individuals with normal audiograms who experience hearing difficulties in noisy environments. Design Single-arm interventional study using acoustic measures, speech-in-noise laboratory testing, and real-world measures via questionnaires and ecological momentary assessment. Study sample Seventeen normal-hearing individuals (9 female, 21–59 years) with self-reported hearing-in-noise difficulties. Results Acoustic measures showed that, relative to unaided, AirPods Pro provided a SNR advantage of +5.4 dB. Speech intelligibility performance in laboratory testing increased 11.8% with AirPods Pro, relative to unaided. On average, participants trialling AirPods Pro in real-world noisy venues reported that their overall hearing experience was a bit better than without them. Five participants (29%) reported that they would continue using AirPods Pro in the future. The most relevant barriers that would discourage their future use were limited hearing benefit, discomfort, and stigma. Conclusions Occasional use of AirPods Pro may help some individuals with normal audiograms ameliorate their speech-in-noise hearing difficulties. The identified barriers may inspire the development of new technological solutions aimed at providing an optimal management strategy for the hearing difficulties of this segment of the population.

Semantic Context Can Mask Intelligibility Declines at Above-Conversational Speech Levels in Normal-Hearing Listeners.

While speech audibility generally improves with increasing level, declines in intelligibility are inconsistently observed at above-conversational levels, even in listeners with normal audiograms (NAs). The inconsistent findings could be due to different types of speech materials, ranging from monosyllabic words to everyday sentences, used across studies. Here, we hypothesized that semantic context can "mask" intelligibility declines at high levels by constraining plausible response options. Intelligibility was assessed in speech-shaped noise with monosyllabic words, sentences without semantic context, and sentences with semantic context. Two presentation levels were used: 80 and 95 dB SPL broadband. Bandpass filtering was applied to minimize upward spread of masking. Twenty-two young adults with NAs were tested. Poorer performance at the higher level was found with the monosyllabic words and context-free sentences but not with the context-rich sentences. The scores obtained at the higher level with the two context-free materials were strongly correlated. The correlation was independent of the lower-level scores, suggesting that the high-level performance declines reflect "normal" auditory functioning. Young adults with NAs show intelligibility decreases at above-conversational levels when tested with speech materials without semantic context. Top-down processing as facilitated by context information can mask such declines.

Suprathreshold auditory processes in listeners with normal audiograms but extended high-frequency hearing loss

Hearing loss in the extended high-frequency (EHF) range (>8 kHz) is widespread among young normal-hearing adults and could have perceptual consequences such as difficulty understanding speech in noise. However, it is unclear how EHF hearing loss might affect basic psychoacoustic processes. The hypothesis that EHF hearing loss is associated with poorer auditory resolution in the standard frequencies was tested. Temporal resolution was characterized by amplitude modulation detection thresholds (AMDTs), and spectral resolution was characterized by frequency change detection thresholds (FCDTs). AMDTs and FCDTs were measured in adults with or without EHF loss but with normal clinical audiograms. AMDTs were measured with 0.5- and 4-kHz carrier frequencies; similarly, FCDTs were measured for 0.5- and 4-kHz base frequencies. AMDTs were significantly higher with the 4 kHz than the 0.5 kHz carrier, but there was no significant effect of EHF loss. There was no significant effect of EHF loss on FCDTs at 0.5 kHz; however, FCDTs were significantly higher at 4 kHz for listeners with than without EHF loss. This suggests that some aspects of auditory resolution in the standard audiometric frequency range may be compromised in listeners with EHF hearing loss despite having a normal audiogram.

Association of Vitamin D Deficiency in Patients with Tinnitus with Normal Audiogram.

In the present study we aim to evaluate serum vitamin D levels in participants having tinnitus with normal audiometric findings. Total 98 participants in the age range 20-70 year were included in the study. Participants underwent detail case history, ear examination, pure tone audiometry and impedance audiometry. 68 participants with subjective tinnitus for more than 3 months and with normal audiometric thresholds and "A" type tympanogram were included in study group and 30 participants without tinnitus in the control group. The participants fullfillng the inclusion criteria underwent thorough tinnitus evaluation which included administration of tinnitus severity index tinnitus handicap inventory, psychophysical evaluation of tinnitus (pitch matching, loudness matching) and assessment of Vitamin D levels. It was seen that the mean Vitamin D levels were significantly lower in study group, and out of 68 participants only 11 had optimal Vitamin D levels, 57 (83%) had Vitamin D levels less that 30mg/dl. In the control group 20 (66%) had vitamin D deficiency. The difference came out to be statistically significant. Our study suggests that there is a link between vitamin D and tinnitus, in view of these findings we recommend evaluating serum Vitamin D levels in patients of chronic idiopathic tinnitus, especially in adults with normal hearing. Our study suggests vitamin D deficiency may be one of the risk factor for tinnitus in people with normal hearing in the absence of other manifestations.

Case Study: COVID-19 Brain Fog or Auditory Processing Disorder?

Case Study: COVID-19 Brain Fog or Auditory Processing Disorder?

Supra-threshold envelope-following responses in the ageing population: An early marker of sensorineural hearing damage

Envelope-following-responses (EFRs) evoked by supra-threshold amplitude-modulated sounds are promising markers of age-related or ototoxic-induced cochlear synaptopathy (CS) in research animals. A direct translation of these findings to EFR-based CS-quantification in humans is complicated by possible combinations of CS, inner-, outer-hair-cell damage or central deficits that can also affect EFR markers. To work towards a sensitive CS-marker for use in humans, we focus on an EFR stimulus that—in computational model simulations—is maximally sensitive to CS and investigate how this marker declines in an ageing population with or without OHC damage. 108 subjects participated in this study and were divided into two groups: (i) an ageing group with normal audiograms (i.e., 4-kHz-thresholds <20 dB HL, n = 89, 18–65 years) and (ii) older adults with impaired audiograms (n = 19, 45–75 years). We collected 120-Hz modulated EFRs, along with extended high-frequency audiograms, distortion-product otoacoustic emissions, and speech-reception thresholds (Flemish Matrix test). We calculated the rate of decline of each metric with age and conclude that the EFR marker predicts sensorineural hearing damage approximately 10 years earlier than the standard clinical audiogram. Additional relationships between audiometric, speech-intelligibility, and EFR markers are discussed. [Work supported by ERC 678120 RobSpear and 899858 CochSyn.]

The Relative Contribution of Cochlear Synaptopathy and Reduced Inhibition to Age-Related Hearing Impairment for People With Normal Audiograms.

Older people often show auditory temporal processing deficits and speech-in-noise intelligibility difficulties even when their audiogram is clinically normal. The causes of such problems remain unclear. Some studies have suggested that for people with normal audiograms, age-related hearing impairments may be due to a cognitive decline, while others have suggested that they may be caused by cochlear synaptopathy. Here, we explore an alternative hypothesis, namely that age-related hearing deficits are associated with decreased inhibition. For human adults (N = 30) selected to cover a reasonably wide age range (25-59 years), with normal audiograms and normal cognitive function, we measured speech reception thresholds in noise (SRTNs) for disyllabic words, gap detection thresholds (GDTs), and frequency modulation detection thresholds (FMDTs). We also measured the rate of growth (slope) of auditory brainstem response wave-I amplitude with increasing level as an indirect indicator of cochlear synaptopathy, and the interference inhibition score in the Stroop color and word test (SCWT) as a proxy for inhibition. As expected, performance in the auditory tasks worsened (SRTNs, GDTs, and FMDTs increased), and wave-I slope and SCWT inhibition scores decreased with ageing. Importantly, SRTNs, GDTs, and FMDTs were not related to wave-I slope but worsened with decreasing SCWT inhibition. Furthermore, after partialling out the effect of SCWT inhibition, age was no longer related to SRTNs or GDTs and became less strongly related to FMDTs. Altogether, results suggest that for people with normal audiograms, age-related deficits in auditory temporal processing and speech-in-noise intelligibility are mediated by decreased inhibition rather than cochlear synaptopathy.

Contralateral inhibition of distortion product otoacoustic emissions in young noise-exposed Veterans.

Although animal models show a clear link between noise exposure and damage to afferent cochlear synapses, the relationship between noise exposure and efferent function appears to be more complex. Animal studies indicate that high intensity noise exposure reduces efferent medial olivocochlear (MOC) reflex strength, whereas chronic moderate noise exposure is associated with a conditioning effect that enhances the MOC reflex. The MOC reflex is predicted to improve speech-in-noise perception and protects against noise-induced auditory damage by reducing cochlear gain. In humans, MOC reflex strength can be estimated by measuring contralateral inhibition of distortion product otoacoustic emissions (DPOAEs). The objective of this study was to determine the impact of military noise exposure on efferent auditory function by measuring DPOAE contralateral inhibition in young Veterans and non-Veterans with normal audiograms. Compared with non-Veteran controls, Veterans with high levels of reported noise exposure demonstrated a trend of reduced contralateral inhibition across a broad frequency range, suggesting efferent damage. Veterans with moderate noise exposure showed trends of reduced inhibition from 3 to 4 kHz but greater inhibition from 1 to 1.5 kHz, consistent with conditioning. These findings suggest that, in humans, the impact of noise exposure on the MOC reflex differs depending on the noise intensity and duration.

Rethinking the Audiogram for Hearing Aid Selection

Rethinking the Audiogram for Hearing Aid Selection

Functional consequences of extended high frequency hearing impairment: Evidence from the speech, spatial, and qualities of hearing scale.

Hearing loss in the extended high frequencies, despite a normal audiogram, could affect speech-in-noise recognition. However, it is not known if extended high frequency (EHF) hearing loss is associated with everyday listening and communication deficits. The present study aimed to determine the functional effects of impaired EHF hearing among adults using the Speech, Spatial, and Qualities of Hearing Scale (SSQ). A secondary objective was to evaluate the relationship between objective (speech-in-noise recognition) and subjective (SSQ) measures of hearing function. Listeners with EHF hearing loss provided lower SSQ ratings compared with their EHF-normal counterparts. The lower ratings could not be attributed to the age or standard audiogram of the listeners. Ratings from more than 50% of EHF-impaired listeners were below the 2 SD cutoff point obtained from EHF-normal listeners. The mean speech recognition threshold was poorer for EHF-impaired listeners, and a poorer speech recognition threshold was associated with lower SSQ ratings, i.e., poorer self-reported hearing ability. For some listeners, EHF hearing loss could be the missing link between self-reported hearing difficulty in the presence of a normal audiogram. These findings provide evidence for the functional deficits associated with EHF hearing loss and invoke the need for future investigations into the management of EHF loss.

A Systematic Review and Meta-Analysis of Extended High-Frequency Hearing Thresholds in Tinnitus With a Normal Audiogram.

Current evidence supports the growing application of extended high-frequency (EHF: 9 to 20 kHz) audiometry in hearing research, which likely results from the high vulnerability of this frequency region to damage induced by known auditory risk factors. The present systematic review and meta-analysis were performed to investigate whether adults with a normal audiogram and tinnitus show increased EHF hearing thresholds relative to control peers. A comprehensive search was undertaken on electronic databases consisting of PubMed, ScienceDirect, Wiley, and Google Scholar using combined keywords: "tinnitus," "extended high frequency," "normal audiogram," and "hidden hearing loss." From 261 articles found by searching databases, nine studies met the inclusion criteria for the meta-analysis. A significant difference was observed between tinnitus and control groups in the effect size analysis of hearing thresholds at 10, 12.5, 14, 16, and 18 kHz ( p ≤ 0.001), and the I-square heterogeneity analysis was below 50% in all studies ( p ≥ 0.131). Visual inspection by the Funnel plot and Egger's regression test ( p ≥ 0.211) also exhibited no publication bias in the meta-analyses. Our findings are in support of the idea that in most cases, tinnitus is associated with some degree of cochlear mechanical dysfunction, which may not be detected by conventional audiometry alone. This finding underscores the significance of EHF audiometry in clinical practice, which may help both early identification of individuals susceptible to developing tinnitus and reduce the number of new cases through preventive counseling programs.

The hunt for hidden hearing loss in humans: From preclinical studies to effective interventions.

Many individuals experience hearing problems that are hidden under a normal audiogram. This not only impacts on individual sufferers, but also on clinicians who can offer little in the way of support. Animal studies using invasive methodologies have developed solid evidence for a range of pathologies underlying this hidden hearing loss (HHL), including cochlear synaptopathy, auditory nerve demyelination, elevated central gain, and neural mal-adaptation. Despite progress in pre-clinical models, evidence supporting the existence of HHL in humans remains inconclusive, and clinicians lack any non-invasive biomarkers sensitive to HHL, as well as a standardized protocol to manage hearing problems in the absence of elevated hearing thresholds. Here, we review animal models of HHL as well as the ongoing research for tools with which to diagnose and manage hearing difficulties associated with HHL. We also discuss new research opportunities facilitated by recent methodological tools that may overcome a series of barriers that have hampered meaningful progress in diagnosing and treating of HHL.

Subclinical Hearing Deficits in Noise-Exposed Firefighters.

Noise-induced hearing loss (NIHL) is the most prevalent occupational disease in the world and firefighters are at increased risk of NIHL due to their frequent exposure to hazardous levels of noise during service. Adverse effects of NIHL include acceleration of age-related hearing loss and an increased risk of cognitive decline. A critical challenge in addressing NIHL is the delayed clinical presentation of symptoms and lack of sensitive tools for early detection. To study the early clinical symptoms of NIHL in this high-risk group, we collected hearing function data including behavioral audiometric thresholds and distortion product otoacoustic emissions (DPOAEs) in 176 firefighters during annual physical assessments. Results revealed significant deficits in cochlear outer hair cell function in the presence of normal audiograms. Additionally, 55% of firefighters self-reported changes in hearing, while 20% self-reported concerns about their balance. This study is the first to characterize DPOAEs in firefighters who display decreased DPOAE amplitudes with increasing years in the fire service. These effects were observed even when controlling for hearing loss and age and are suggestive of a link between hearing loss and occupational exposure to hazardous noise.

Estimated cochlear neural degeneration is associated with loudness hypersensitivity in individuals with normal audiograms.

In animal models, cochlear neural degeneration (CND) is associated with excess central gain and hyperacusis, but a compelling link between reduced cochlear neural inputs and heightened loudness perception in humans remains elusive. The present study examined whether greater estimated cochlear neural degeneration (eCND) in human participants with normal hearing thresholds is associated with heightened loudness perception and sound aversion. Results demonstrated that loudness perception was heightened in ears with greater eCND and in subjects who self-report loudness aversion via a hyperacusis questionnaire. These findings suggest that CND may be a potential trigger for loudness hypersensitivity.

Relating Suprathreshold Auditory Processing Abilities to Speech Understanding in Competition.

(1) Background: Difficulty hearing in noise is exacerbated in older adults. Older adults are more likely to have audiometric hearing loss, although some individuals with normal pure-tone audiograms also have difficulty perceiving speech in noise. Additional variables also likely account for speech understanding in noise. It has been suggested that one important class of variables is the ability to process auditory information once it has been detected. Here, we tested a set of these “suprathreshold” auditory processing abilities and related them to performance on a two-part test of speech understanding in competition with and without spatial separation of the target and masking speech. Testing was administered in the Portable Automated Rapid Testing (PART) application developed by our team; PART facilitates psychoacoustic assessments of auditory processing. (2) Methods: Forty-one individuals (average age 51 years), completed assessments of sensitivity to temporal fine structure (TFS) and spectrotemporal modulation (STM) detection via an iPad running the PART application. Statistical models were used to evaluate the strength of associations between performance on the auditory processing tasks and speech understanding in competition. Age and pure-tone-average (PTA) were also included as potential predictors. (3) Results: The model providing the best fit also included age and a measure of diotic frequency modulation (FM) detection but none of the other potential predictors. However, even the best fitting models accounted for 31% or less of the variance, supporting work suggesting that other variables (e.g., cognitive processing abilities) also contribute significantly to speech understanding in noise. (4) Conclusions: The results of the current study do not provide strong support for previous suggestions that suprathreshold processing abilities alone can be used to explain difficulties in speech understanding in competition among older adults. This discrepancy could be due to the speech tests used, the listeners tested, or the suprathreshold tests chosen. Future work with larger numbers of participants is warranted, including a range of cognitive tests and additional assessments of suprathreshold auditory processing abilities.

Hearing Impairment in the Extended High Frequencies in Children Despite Clinically Normal Hearing.

Pediatric hearing impairment, regardless of degree and type, has a detrimental effect on speech perception, cognition, oral language development, academic outcomes, and literacy. Hearing assessment in the clinic is limited to 8 kHz although humans can hear up to 20 kHz. Hearing impairment in the extended high frequencies (EHFs > 8 kHz) can occur despite clinically normal hearing. However, to date, the nature and effects of EHF hearing impairment in children remain unknown. The goals of the present study were to determine the effects of EHF hearing impairment on speech-in-noise recognition in children and to examine whether hearing impairment in the EHFs is associated with altered cochlear functioning in the standard frequencies. A volunteer sample of 542 participants (4 to 19 years) with clinically normal audiograms were tested. Participants identified with EHF impairment were assigned as cases in a subsequent case-control study. EHF loss was defined as hearing thresholds greater than 20 dB in at least one EHFs (10, 12.5, or 16 kHz). Speech recognition thresholds in multi-talker babble were measured using the digit triplet test. Distortion product otoacoustic emissions ( f2 = 2, 3, 4, and 5 kHz) were measured to assess cochlear functioning. Thresholds in the EHFs were as reliable as those in the standard frequency range. Thirty-eight children had EHF hearing impairment regardless of a clinically normal audiogram. A linear mixed-effects model revealed that children with EHF hearing impairment had higher (poorer) mean speech recognition threshold than children with normal EHF sensitivity ( estimate = 2.14 dB, 95% CI: 1.36 to 3.92; effect size = small). The overall magnitude of distortion product otoacoustic emissions was lower for children with EHF impairment ( estimate = -2.47 dB, 95% CI: -4.60 to -0.73; effect size = medium). In addition, the pure-tone average for standard audiometric frequencies was relatively higher for EHF-impaired children ( estimate = 3.68 dB, 95% CI: 2.56 to 4.80; effect size = small). Hearing impairment in the EHFs is common in children despite clinically normal hearing and can occur without a history of otitis media. EHF impairment is associated with poorer speech-in-noise recognition and preclinical cochlear deficits in the lower frequencies where hearing thresholds are normal. This study highlights the clinical need to identify EHF impairments in children.