Acoustic reflexes: should we be paying more attention?

OBJECTIVE: The clinical audiology test battery often involves playing physically simple sounds with questionable ecological value to the listener. In this technical report, we revisit how valid this approach is using an automated, involuntary auditory response; the acoustic reflex threshold (ART). DESIGN: The ART was estimated four times in each individual in a quasi-random ordering of task conditions. The baseline condition (referred to as Neutral) measured the ART following a standard clinical practice. Three experimental conditions were then used in which a secondary task was performed whilst the reflex was measured: auditory attention, auditory distraction and visual distraction tasks. STUDY SAMPLE: Thirty-eight participants (27 males) with a mean age of 23 years were tested. All participants were audiometrically healthy. RESULTS: The ART was elevated when a visual task was performed at the same time as the measurements were taken. Performing an auditory task did not affect the ART. CONCLUSIONS: These data indicate that simple audiometric measures widely used in the clinic, can be affected by central, non-auditory processes even in healthy, normal-hearing volunteers. The role of cognition and attention on auditory responses will become ever more important in the coming years.

Magnetic resonance spectroscopy and auditory brain-stem response audiometry as predictors of bilirubin-induced neurologic dysfunction in full-term jaundiced neonates.

The purpose of this research was to define the functions of MRS and ABR as predictors of bilirubin-induced neurologic dysfunction (BIND) in full-term neonates who required intervention (phototherapy and/or exchange transfusion). This prospective cohort study was done at the NICU of Tanta University Hospitals over a 2-year duration. Fifty-six full-term neonates with pathological unconjugated hyperbilirubinemia were divided according to MRS and ABR findings into 2 groups: group (1) included 26 cases with mild acute bilirubin encephalopathy (BIND-M score 1-4). Group (2) included 30 cases with neonatal hyperbilirubinemia only. In addition, 20 healthy neonates with similar ages were employed as the controls. When compared to group 2 and the control group, group 1's peak-area ratios of NAA/Cr and NAA/Cho were found to be significantly reduced (P < 0.05). As compared to group 2 and the control group, group 1's Lac/Cr ratio was significantly greater (P < 0.05), but the differences were not significant for group 2 when compared to the control group. Waves III and V peak latencies, I-III, and I-V interpeak intervals were significantly prolonged in group 1 in comparison to group 2 and controls (P < 0.05) with no significant difference between group 2 and control group.   Conclusion: When the symptoms of ABE are mild and MRI does not show any evident abnormalities, MRS and ABR are helpful in differentiating individuals with ABE from patients with neonatal hyperbilirubinemia.    Trial registration:  ClinicalTrials.gov , Identifier: NCT06018012. What is Known: • MRS can be used as a diagnostic and prognostic tool for the differential diagnosis of patients with acute bilirubin encephalopathy, from patients with neonatal hyperbilirubinemia What is New: • ABR is a useful diagnostic and prognostic tool in the care and management of neonates with significantly raised bilirubin. It can be used as early predictor of acute bilirubin encephalopathy in the earliest stage of auditory damage caused by bilirubin.

Modified T2 Statistics for Improved Detection of Aided Cortical Auditory Evoked Potentials in Hearing-Impaired Infants.

The cortical auditory evoked potential (CAEP) is a change in neural activity in response to sound, and is of interest for audiological assessment of infants, especially those who use hearing aids. Within this population, CAEP waveforms are known to vary substantially across individuals, which makes detecting the CAEP through visual inspection a challenging task. It also means that some of the best automated CAEP detection methods used in adults are probably not suitable for this population. This study therefore evaluates and optimizes the performance of new and existing methods for aided (i.e., the stimuli are presented through subjects' hearing aid(s)) CAEP detection in infants with hearing loss. Methods include the conventional Hotellings T2 test, various modified q-sample statistics, and two novel variants of T2 statistics, which were designed to exploit the correlation structure underlying the data. Various additional methods from the literature were also evaluated, including the previously best-performing methods for adult CAEP detection. Data for the assessment consisted of aided CAEPs recorded from 59 infant hearing aid users with mild to profound bilateral hearing loss, and simulated signals. The highest test sensitivities were observed for the modified T2 statistics, followed by the modified q-sample statistics, and lastly by the conventional Hotelling's T2 test, which showed low detection rates for ensemble sizes <80 epochs. The high test sensitivities at small ensemble sizes observed for the modified T2 and q-sample statistics are especially relevant for infant testing, as the time available for data collection tends to be limited in this population.

Extended high-frequency bone conduction audiometry Calibration of bone conductor transducers in the conventional and extended high-frequency range.

OBJECTIVE: To monitor ototoxicity, air conduction (AC) extended high frequency (EHF) thresholds can be measured up to 16 kHz. However, conductive hearing loss might influence these results. This is unfortunate because the EHF thresholds are important to follow the impact of ototoxic medication during therapy. Therefore a suitable bone conduction (BC) transducer and norm values for EHF BC measurements are needed. DESIGN: In this study three different BC transducers were used: the B71 (Radioear), the KH70 (Präcitronic), and the KLH96 (Westra). Hearing thresholds were measured from 0.125 to 16 kHz using AC transducers (Telephonics TDH39, Sennheiser HDA200), and BC thresholds from 0.25 to 8 kHz with the B71, and from 0.25 to 16 kHz with the KLH96 and KH70. STUDY SAMPLE: 60 ears of 30 normal hearing subjects were measured. RESULTS: The KLH96 showed the highest output for the high frequencies, and distortion measurements were similar to the KH70. The results show that EHF measurements are possible using the KLH96 and KH70 bone conductors. CONCLUSION: EHF BC measurements are reliable when using the KLH96 and KH70 bone conductors. The extended force sensitivity of the used artificial mastoid should be determined for a proper EHF BC calibration.

User-operated audiometry - an evaluation of expert vs. non-expert headphone placement.

OBJECTIVE: User-operated audiometry faces multiple barriers. One of these is the concern of audiologists that patients (non-experts) placing headphones by themselves results in invalid hearing thresholds due to greater placement variability. DESIGN: Comparative study. Participants took the AMTAS pure-tone air-conduction audiometry under two different conditions, expert and non-expert circumaural headphone placement for five frequencies within the range 250-8000 Hz. Questionnaires were also used to gain insight into the usability of the user-operated audiometry system - as well as the participants' perceived handling of the audiometry headphones. STUDY SAMPLE: Thirty participants (mean age 67.5 years). RESULTS: No statistically significant mean differences in hearing thresholds between the expert and non-expert conditions were found. The mean system usability scale score was 84.5. Handling the headphones was also rated as being easy (30%) or very easy (60%) by most non-experts. CONCLUSION: The conclusion of the study is that non-experts can be trusted to properly equip a pair of circumaural audiometry headphones for the correct conduction of pure-tone audiometry with only a few digital instructions.

Transcutaneous Electric Nerve Stimulation in Chronic Subjective Tinnitus.

OBJECTIVE: It is aimed to determine the therapeutic role of transcutaneous electrical nerve stimulation (TENS) on chronic subjective tinnitus with a randomized and comparative analysis. METHOD: 46 individuals with normal hearing, chronic subjective tinnitus, aged 20-65; randomly divided into the study (TENS therapy) and tje control groups. The control group (n = 23) was informed only about tinnitus, while the study group (n = 23) received TENS therapy (20 sessions in 4 weeks). Before TENS therapy, tinnitus-related evaluations of all participants [tinnitus frequency, loudness, minimum masking level (MMS), residual inhibition (RI)] were made and Tinnitus Handicap Inventory (THI), Visual Analogue Scale (VAS), Short Form 36 (SF-36), and The Quality of Life Scale were applied to the participants. These evaluations and questionnaires were repeated after 4 weeks of the therapy. RESULTS: There was a significant decrease in the tinnitus severity after TENS therapy in the study group (p = 0.003). Moreover, it was found that VAS (loudness and annoyance), THI (functional, emotional and total score), SF-36 (physical function, physical role, pain, general health, vitality, emotional role and social function) values improved compared to before TENS therapy and the difference was significant (p < 0.05). There was no significant difference between the first and last evaluations of the control group (p > 0.05). CONCLUSION: TENS is an effective, practical and reliable therapy method in reducing severity, loudness, and annoyance of tinnitus, and increasing the quality of life in individuals with chronic subjective tinnitus.

La surdité brusque résultats thérapeutique et facteurs pronostiques / Sudden sensorineural hearing loss: therapeutic outcome and prognostic factors

Objectifs: évaluer les résultats thérapeutiques et étudier les facteurs pronostiques de la surdité brusque.Patients et méthodes: Il s'agit d'une étude rétrospective à propos de 61 patients (39 hommes et 22 femmes) pris en charge pour surdité brusque dans le service d'Otorhinolaryngologie et de Chirurgie Cervico-Faciale de l'hôpital Bourguiba de Monastir durant une période de 16 ans (2001-2016). Une analyse statistique a été réalisée afin d'identifier les facteurs influençant le pronostic de la surdité brusque. Le seuil de significativité retenu était de 5%. Résultats:L'âge moyen était de 43 ans [16-80 ans]. Le taux global de récupération auditive était de 45%. Les facteurs pronostiques selon l'analyse uni variée étaient: un antécédent d'hypoacousie controlatérale, la présence d'un vertige associé, la sévérité de la perte auditive initiale, une courbe audiométrique de type E, l'absence du réflexe stapédien et le recours à l'oxygénothérapie hyperbare (OHB). En analyse multivariée, les seuls facteurs retenus étaient une perte auditive initiale supérieure ou égale à 70 dB, la présence d'un vertige et l'absence d'un épisode infectieux précédant la survenue de la surdité. Conclusion: Notre étude a permis de retenir comme facteurs de mauvais pronostic indépendants la perte auditive initiale supérieure ou égale à 70 dB, la présence d'un vertige et l'absence d'un épisode infectieux précédant la survenue de la surdité. Ceci nous incite à une réflexion quant au protocole thérapeutique adopté dans notre service et à indiquer l'OHB, qui est normalement prescrite en cas de non réponse, en première intention, afin d'optimiser la récupération auditive.

Distortion Product Otoacoustic Emission (DPOAE) Growth in Aging Ears with Clinically Normal Behavioral Thresholds.

Age-related hearing loss (ARHL) is a devastating public health issue. To successfully address ARHL using existing and future treatments, it is imperative to detect the earliest signs of age-related auditory decline and understand the mechanisms driving it. Here, we explore early signs of age-related auditory decline by characterizing cochlear function in 199 ears aged 10-65 years, all of which had clinically defined normal hearing (i.e., behavioral thresholds ≤ 25 dB HL from .25 to 8 kHz bilaterally) and no history of noise exposure. We characterized cochlear function by measuring behavioral thresholds in two paradigms (traditional audiometric thresholds from .25 to 8 kHz and Békésy tracking thresholds from .125 to 20 kHz) and distortion product otoacoustic emission (DPOAE) growth functions at f2 = 2, 4, and 8 kHz. Behavioral thresholds through a standard clinical frequency range (up to 8 kHz) showed statistically, but not clinically, significant declines across increasing decades of life. In contrast, DPOAE growth measured in the same frequency range showed clear declines as early 30 years of age, particularly across moderate stimulus levels (L2 = 25-45 dB SPL). These substantial declines in DPOAE growth were not fully explained by differences in behavioral thresholds measured in the same frequency region. Additionally, high-frequency Békésy tracking thresholds above ~11.2 kHz showed frank declines with increasing age. Collectively, these results suggest that early age-related cochlear decline (1) begins as early as the third or fourth decade of life, (2) is greatest in the cochlear base but apparent through the length of the cochlear partition, (3) cannot be detected fully by traditional clinical measures, and (4) is likely due to a complex mix of etiologies.

Neuropsychological monitoring of current acoustic therapies as alternative treatment of chronic tinnitus.

At present, the majority of the top tinnitus treatments is based on sound. Sound-based therapies may become highly effective when the right patient at the correct time and the appropriate context is selected. The investigation presented here attempts to compare sound therapies based on music, retraining, neuromodulation, and binaural sounds in line with (1) neuro-audiology assessments and (2) psychological evaluations. Sound-based therapies were applied in 76 volunteers with tinnitus for 60 days. The neuro-audiology assessment was based on the estimation of the approximate entropy of the electrical neural activity. This assessment revealed that the whole frequency structure of the neural networks showed a higher level of activeness in tinnitus sufferers than in control individuals. Then psychological evaluation showed that retraining treatment tended to be the most effective sound-based therapy to reduce tinnitus perception, but it may be not recommended for individuals with anxiety. Binaural sounds and neuromodulation produced very similar effects at reducing tinnitus perception, stress and anxiety. Music treatments can be applied with caution since they may worsen the condition due to their frequency content.

Neurophysiological correlates of residual inhibition in tinnitus: Hints for trait-like EEG power spectra.

OBJECTIVE: To investigate oscillatory brain activity changes following acoustic stimulation in tinnitus and whether these changes are associated with behavioral measures of tinnitus loudness. Moreover, differences in ongoing brain activity between individuals with and without residual inhibition (RI) are examined (responders vs. non-responders). METHODS: Three different types of noise stimuli were administered for acoustic stimulation in 45 tinnitus patients. Subjects resting state brain activity was recorded before and after stimulation via EEG alongside with subjective measurements of tinnitus loudness. RESULTS: Delta, theta and gamma band power increased, whereas alpha and beta power decreased from pre to post stimulation. Acoustic stimulation responders exhibited reduced gamma and a trend for enhanced alpha activity with the latter localized in the right inferior temporal gyrus. Post stimulation, individuals experiencing RI showed higher theta, alpha and beta power with a peak power difference in the alpha band localized in the right superior temporal gyrus. Neither correlations with behavioral tinnitus measures nor stimulus-specific changes in EEG activity were present. CONCLUSIONS: Our observations might be indicative of trait-specific forms of oscillatory signatures in different subsets of the tinnitus population related to acoustic tinnitus suppression. SIGNIFICANCE: Results and insights are not only useful to understand basic neural mechanisms behind RI but are also valuable for general neural models of tinnitus.

Auditory evoked potentials: Differences by sex, race, and menstrual cycle and correlations with common psychoacoustical tasks.

Auditory brainstem responses (ABRs) and auditory middle-latency responses (AMLRs) to a click stimulus were measured in about 100 subjects. Of interest were the sex differences in those auditory evoked potentials (AEPs), the correlations between the various AEP measures, and the correlations between the AEP measures and measures of otoacoustic emissions (OAEs) and behavioral performance also measured on the same subjects. Also of interest was how the menstrual cycle affected the various AEP measures. Most ABR measures and several AMLR measures exhibited sex differences, and many of the former were substantial. The sex differences tended to be larger for latency than for amplitude of the waves, and they tended to be larger for a weak click stimulus than for a strong click. The largest sex difference was for Wave-V latency (effect size ~1.2). When subjects were dichotomized into Non-Whites and Whites, the race differences in AEPs were small within sex. However, sex and race interacted so that the sex differences often were larger for the White subjects than for the Non-White subjects, particularly for the latency measures. Contrary to the literature, no AEP measures differed markedly across the menstrual cycle. Correlations between various AEP measures, and between AEP and OAE measures, were small and showed no consistent patterns across sex or race categories. Performance on seven common psychoacoustical tasks was only weakly correlated with individual AEP measures (just as was true for the OAEs also measured on these subjects). AMLR Wave Pa unexpectedly did not show the decrease in latency and increase in amplitude typically observed for AEPs when click level was varied from 40 to 70 dB nHL (normal Hearing Level). For the majority of the measures, the variability of the distribution of scores was greater for the males than for the females.

Clinical features and prognostic factors of pediatric idiopathic sudden hearing loss from moderate to profound degree.

BACKGROUND: The pediatric idiopathic sudden sensorineural hearing loss (PISSNHL) is not rare in the clinics, however, the prognostic factors of PISSNHL are still unclear. OBJECTIVES: To investigate the clinical and audiologic characteristics associated with prognosis in PISSNHL. MATERIAL AND METHODS: Clinical and audiological characteristics and possible prognostic factors were retrospectively evaluated in 76 PISSNHL patients aged less than 19 years. RESULTS: Hearing loss was moderate in nine patients, severe in 21 patients, profound in 46 patients. Among five types of audiogram, 3.9% were classified as ascending, 11.8% as descending, 25.0% as flat, 55.3% as profound, and 3.9% as concave. The recovery rate according to Siegel's criteria was 55.3%. There was no significant difference between the recovery group and the poor recovery group in terms of age, sex, laterality of hearing loss, the onset of treatment, and accompanying symptoms (p > 0.05). The initial hearing levels and the audiogram type were significantly different in the two groups (p < 0.001) according to univariate analysis, while only the initial hearing level was significantly different (p = 0.046) according to multivariate analysis. CONCLUSIONS AND SIGNIFICANCE: Prognosis of PISSNHL was mainly related to initial hearing at onset. An initial hearing level greater than 80 dB was a poor prognostic factor.

The Relationship between Psychoacoustic and Electrophysiological Assessments of Temporal Resolution.

BACKGROUND: Temporal resolution is essential to speech acoustic perception. However, it may alter in individuals with auditory disorders, impairing the development of spoken and written language. The envelope of speech signals contains amplitude modulation (AM) that has critical information. Any problem reducing the listener's sensitivity to these amplitude variations (auditory temporal acuity) is likely to cause speech comprehension problems. The modulation detection threshold (MDT) test is a measure for evaluating temporal resolution. However, this test cannot be used for patients with poor cooperation; therefore, objective evaluation of MDT is essential. PURPOSE: The main aim of this study is to find the association between the auditory steady-state response (ASSR) and psychoacoustic measurement of MDT at different intensity levels and to assess the amplitude and phase of ASSR as a function of modulation depth. DESIGN: This was a correlational research. STUDY SAMPLE: Eighteen individuals (nine males and nine females) with normal hearing sensitivity, aged between 18 and 23 years, participated in this study. DATA COLLECTION AND ANALYSIS: ASSR was recorded at fixed AM rates and variable AM depths for carrier frequencies of 1,000 and 2,000 Hz with varying intensities. The least AM depth, efficient to evoke an ASSR response, was interpreted as the physiological detection threshold of AM. The ASSR amplitude and phase, as a function of AM depth, were also evaluated at an intensity level of 60 dB hearing level (HL) with modulation rates of 40 and 100 Hz. Moreover, the Natus instrument (Biologic Systems) was used for the electrophysiological measurements. An AC40 clinical audiometer (Intra-acoustic, Denmark) was also used for the psychoacoustic measurement of MDT in a similar setting to ASSR, using the two-alternative forced choice method. Pearson's correlation test and linear regression model and paired t-test were used for statistical analyses. RESULTS: A significant positive correlation was found between psychoacoustic and electrophysiological measurements at a carrier frequency of 1000 Hz, with a modulation rate of 40 Hz at intensity levels of 60 dB HL (r = 0.63, p = 0.004), 50 dB HL (r = 0.52, p = 0.02). A significant positive correlation was also found at a carrier frequency of 2000 Hz, with a modulation rate of 47 Hz at 60 dB HL (r = 0.55, p = 0.01) and 50 dB HL (r = 0.67, p = 0.002) and a modulation rate of 97 Hz at 60 dB HL (r = 0.65, p = 0.003). Moreover, a significant association was found between the modulation depth and ASSR amplitude and phase increment at carrier frequencies of 1,000 and 2000 Hz, with modulation rates of 40 and 100 Hz. CONCLUSION: There was a significant correlation between ASSR and behavioral measurement of MDT, even at low intensities with low modulation rates of 40 and 47 Hz. The ASSR amplitude and phase increment was a function of modulation depth increase. The findings of this study can be used as a basis for evaluating the relationship between two approaches in the clinical population.

Envelope following responses predict speech-in-noise performance in normal-hearing listeners.

Permanent threshold elevation after noise exposure or aging is caused by loss of sensory cells; however, animal studies show that hair cell loss is often preceded by degeneration of the synapses between sensory cells and auditory nerve fibers. Silencing these neurons is likely to degrade auditory processing and may contribute to difficulties understanding speech in noisy backgrounds. Reduction of suprathreshold ABR amplitudes can be used to quantify synaptopathy in inbred mice. However, ABR amplitudes are highly variable in humans, and thus more challenging to use. Since noise-induced neuropathy preferentially targets fibers with high thresholds and low spontaneous rate and because phase locking to temporal envelopes is particularly strong in these fibers, measuring envelope following responses (EFRs) might be a more robust measure of cochlear synaptopathy. A recent auditory model further suggests that modulation of carrier tones with rectangular envelopes should be less sensitive to cochlear amplifier dysfunction and, therefore, a better metric of cochlear neural damage than sinusoidal amplitude modulation. In this study, we measure performance scores on a variety of difficult word-recognition tasks among listeners with normal audiograms and assess correlations with EFR magnitudes to rectangular versus sinusoidal modulation. Higher harmonics of EFR magnitudes evoked by a rectangular-envelope stimulus were significantly correlated with word scores, whereas those evoked by sinusoidally modulated tones did not. These results support previous reports that individual differences in synaptopathy may be a source of speech recognition variability despite the presence of normal thresholds at standard audiometric frequencies.NEW & NOTEWORTHY Recent studies suggest that millions of people may be at risk of permanent impairment from cochlear synaptopathy, the age-related and noise-induced degeneration of neural connections in the inner ear. This study examines electrophysiological responses to stimuli designed to improve detection of neural damage in subjects with normal hearing sensitivity. The resultant correlations with word recognition performance are consistent with a contribution of cochlear neural damage to deficits in hearing in noise abilities.

Acceptance and Benefits of Electro-Acoustic Stimulation for Conventional-Length Electrode Arrays.

BACKGROUND: Prior studies have shown an advantage for electro-acoustic stimulation (EAS) in cochlear implant (CI) patients with residual hearing, but the degree of benefit can vary. The objective was to explore which factors relate to performance with and acceptance of EAS for CI users with conventional-length electrodes. METHODS: A retrospective chart review was conducted for adults with an average threshold of 75 dB hearing loss or better across 250 and 500 Hz preoperatively (n = 83). All patients underwent cochlear implantation with a conventional-length electrode. Low-frequency audiometric thresholds were measured at initial activation as well as 3 and 12 months postoperatively to determine who met the criteria for EAS. Speech perception for CNC words and AzBio sentences in quiet and +10 dB SNR noise was evaluated 3 and 12 months after activation. RESULTS: Speech perception in quiet and noise was similar regardless of whether or not the patient was eligible for EAS. Less than half of the patients who met the EAS criteria chose to use it, citing reasons such as physical discomfort or lack of perceived benefit. EAS users performed better on CNC words but not sentence recognition than EAS nonusers. CONCLUSIONS: EAS use is dependent on audiologic and nonaudiologic issues. Hearing preservation is possible with conventional electrodes, but hearing preservation alone does not guarantee superior speech perception.

Stapes surgery for otosclerosis under local anaesthesia with sedation.

The stapes surgery surgical technique has now been clearly standardized, ensuring a reliable and reproducible procedure with a satisfactory success rate. The possibility of performing this surgery under local anaesthesia with sedation requires very good collaboration between surgeons and anaesthetists. The patient is informed about the various steps of the operation to ensure that he or she is reassured both before and during the procedure. Local anaesthesia with sedation constitutes an alternative in patients afraid of general anaesthesia. Sudden onset of dizziness reported by the patient during the operation after piston placement may be due to an excessively long piston, which may need to be adjusted. We describe the technique used in our centre. In the literature, there is no difference in terms of audiometric performance and dizziness between patients operated under local anaesthesia with sedation or general anaesthesia.

Prevalence of Sensorineural Hearing Loss in Pediatric Patients with Sickle Cell Disease: A Meta-analysis.

OBJECTIVES: To determine the prevalence of Sensorineural Hearing Loss (SNHL) attributable to Sickle Cell Disease (SCD) in the global pediatric population and to identify factors contributing to its severity. STUDY DESIGN: Meta-analysis. METHODS: We performed a comprehensive literature search for scientific articles in PubMed, Scopus, CINAHL, Web of Science, and the Cochrane Library that reported the incidence of hearing loss in populations under 18 years of age with excluding studies analyzing patients on iron chelation therapy, adults, or those without objective audiological analysis. RESULTS: We identified 138 initial studies with 17 selected for analysis after applying the exclusion criteria. A total of 1,282 SCD patients and 553 controls were included in the meta-analysis. There was a statistically significant increase in the prevalence of SNHL in children with SCD compared to the general population with a cumulative risk ratio of 3.33. CONCLUSION: This is the first systematic investigation of the relationship between SCD and SNHL in pediatric patients across the globe. The increased prevalence of SNHL in the pediatric SCD population warrants future research into the predictors of SNHL severity and merits routine audiometric monitoring of SCD patients to reduce the social and developmental morbidity of hearing loss at a young age. PROSPERO Registration #: CRD42019132601. Laryngoscope, 131:1147-1156, 2021.

Outer hair cell functioning in infants with iron deficiency anemia.

BACKGROUND: Distortion product otoacoustic emissions (DPOAE) in infants with Iron Deficiency Anemia (IDA) helps in understanding the cochlear status especially the functioning of outer hair cells. OBJECTIVES: To analyze the presence of DPOAE across frequencies and DP amplitude in infants with and without IDA. METHOD: DPOAE were recorded on 40 infants with IDA and 40 infants without IDA in the age range of 6-24 months. Cubic DPOAEs (2f1-f2) were measured at six f2 frequencies (1500 Hz, 2000 Hz, 3000 Hz, 4500 Hz, 6000 Hz & 8000 Hz) with primary tone stimulus of intensity L1 equal to 65 dBSPL and L2 equal to 55 dBSPL. Immittance audiometry was performed using 226 Hz probe tone prior to DPOAE recording to ascertain normal middle ear functioning. RESULTS: DPOAEs were present in all infants with and without IDA across frequencies tested. DP amplitude across the frequencies did not show any statistically significant difference (p < 0.05) between anemic and non-anemic groups. There was no statistically significant difference observed when both the groups were compared in terms of gender and age. CONCLUSION: The study indicated that reduced iron levels does not have any influence on outer hair cell functioning as there were no changes observed in the DPOAE amplitude levels between infants with IDA and infants without IDA. Iron status does not seem to have a direct effect on outer hair cell functioning in infants. However, fine structure DPOAEs can reveal even more precise changes (if any) that are caused due to iron deficiency.

Detection of Age-Related Hearing Losses (ARHL) via Transient-Evoked Otoacoustic Emissions.

PURPOSE: The objective of the study was to identify subjects presenting hearing deficits, specifically age-related hearing losses (ARHL), via objective assessment methodologies. MATERIALS AND METHODS: Initially, 259 subjects (165 men, 94 women) were enrolled in the study. After the application of inclusion criteria, the final number was reduced to 88 subjects (49.8 ± 19.1 ys) subdivided into 64 normal and 83 ARHL cases. The subjects were assessed with traditional audiometry tests and with transiently evoked otoacoustic emissions (TEOAEs). Since each ear has its own acoustic signature, the TEOAE analyses were conducted in terms of ears and not subjects. The TEOAE data were processed by traditional and recurrence quantification analyses, leading to the estimation of the WWR (whole waveform reproducibility) and the new RAD2D (2-dimensional radius) parameters. A plot of WWR vs RAD2D was used to optimize the classification of the cases presenting ARHL. RESULTS: By using a WWR value of 70% as a classifier, the sensitivity of TEOAEs was estimated as 75.9% and the specificity as 89.1%. By using the RAD2D parameter (with a cut-off value of 1.78), a sensitivity value of 80.7% and a specificity value of 71.9% were obtained. When both parameters were used, a sensitivity value of 85.5% and a specificity value of 92.2% were estimated. In the latter classification paradigm, the number of false negatives decreased from 20 to 12 out of 83 ears (14%). CONCLUSION: In adult hearing screening assessments, the proposed method optimizes the identification of subjects with a hearing impairment correlated to the presence of age-related hearing loss.

Japanese quail (Coturnix japonica) audiogram from 16 Hz to 8 kHz.

The purpose of this study was to determine if the Japanese quail, a domesticated, gallinaceous bird, could detect infrasound. Behavioral thresholds were determined for three birds, two males and one female, ranging from 16 Hz to 8 kHz. The animals' hearing range, at a cutoff of 60 dB SPL (re 20 µN/m2), covers 6.88 octaves, ranging from 59.5 Hz to 7 kHz. All animals had the greatest sensitivity to 2 kHz, with an average threshold of 4.4 dB SPL. Although the birds' threshold at 16 Hz was equivalent to that of humans, at no frequency did the birds' sensitivity ever exceed that of humans. Therefore, the Japanese quail does not hear infrasound.