Phase Stability Analysis of Chirp Evoked Auditory Brainstem Responses by Gabor Frame Operators

Comparison of ASSR and frequency specificity ABR induced by NB CE-Chirp for prediction of behavioral hearing thresholds in children with conductive hearing loss

Background: The electrophysiology of auditory nerve mature is particularly important for unilateral hearing loss.Objectives: To assess the hearing status in young children with congenital monaural malformation and evaluate their potential for practical use in the functional maturation parameters of the auditory pathway.Materials and methods: ABR (auditory brainstem responses) and ASSR (auditory steady-state responses) threshold measurements were performed in 21 young children with congenital monaural atresia.Results: The average electrophysiologic thresholds for the ABR were 65 dB nHL ± 1.20 in malformed ears and 25 dB nHL ± 0.48 in normal ones. All 21 atretic ears presented with typical conductive hearing loss. There was no statistic positive correlation in hearing-impaired ears between the methods of ABR and ASSR responses (r = 0.12, 0.20 and 0.17). The IPL (interpeak latency) of I–III, III–V and I–V of atretic ears in ABR test was decreased relative to normal ears. Furthermore, a shortening of the IPLs I–III, III–V, I–V can be observed with increasing age of the children in malformed ears.Conclusions and significance: The ABR- and ASSR-based hearing evaluation in young children with congenital monaural malformation should be viewed as complementary technologies. Besides, there was no delay of functional maturation at brainstem level although unilateral hearing was deprived during their early years of life.

Physical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-β (TGFβ)-responsive pathway that controls osteoblast differentiation. Deregulated TGFβ or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2+/⁻ mice, inhibition of TGFβ signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue function.

Objective: Hearing loss (HL) with a local prevalence of 5.7%, is the commonest childhood disability, requiring Early Hearing Detection and Intervention (EHDI) programs to reduce the disability burden. Knowing the degree, type and configuration of HL is prerequisite for appropriate amplification, with Automated Auditory Brainstem Responses (ABR) being commonly used for this purpose, however Auditory Steady State Response (ASSR) has been recently introduced in the region. This study was conducted to compare ABR to ASSR, as an early diagnostic tool in children under five years of age.
 Methodology: This cross-sectional comparative study was performed at the Auditory Verbal Institute of Audiology and Speech (AVIAS) clinics in Rawalpindi and Islamabad, from December 2016 to September 2017. It included thirty-two cases (n=32) who visited AVIAS clinics for hearing assessment and conformed to the investigative protocol using non probability convenient sampling technique, and subjected to both ABR and ASSR for comparative purposes. Correlations were calculated between the thresholds obtained by ABR and ASSR.
 Results: N=32 children (64 ears) with male female ratio of 2.2:1 and mean age of 33.50±17.73 months were tested with ABR and ASSR for hearing thresholds and correlation coefficient between 2KHz, 4KHz ASSR and average of both with ABR was calculated to be 0.92 and 0.90 and 0.94 respectively.
 Conclusion: ASSR provides additional frequency specific hearing threshold estimation compared to C-ABR, essentially required for proper setting of amplification devices.

Abnormal sensory processing is core to neuropsychiatric and neurodevelopmental disorders, such as schizophrenia and autism spectrum disorders. Developing efficient therapies requires understanding the basic sensory pathways and identifying circuit abnormalities during early development. Auditory brainstem responses (ABRs) are well-established biomarkers for auditory processing on the brainstem level. Beyond their advantage of being easily applicable in clinics (given their non-invasive nature), ABRs have high reproducibility in rodents and translate well to humans (e.g. wave identity), despite species differences (e.g. wave features). We hypothesized that ABRs would reveal sensory abnormalities in neurodevelopmental models with construct validity, such as Neurexin1α knockout (Nrxn1α KO) rats during their development. In a previous study, adult Nrxn1α KO rats showed altered cortical auditory-evoked potentials and impaired prediction error to auditory stimuli (Janz in Transl Psychiat, 12:455, 2022 ). This study used ABR measurements to assess brainstem physiology during auditory processing in Nrxn1α KO rats and their wild-type littermates. Therefore, we followed the development trajectories of ABRs from the age of 3 weeks to 12 weeks longitudinally. We found that juvenile Nrxn1α KO rats (3 weeks of age) show altered ABRs, which normalized during further development. This alteration was confined to increased latency in waves II, III, and IV of the ABRs, suggesting impaired auditory processing on the level of the superior olivary complex and inferior colliculus. In conclusion, our results suggest that early but transient deficits in the processing of auditory information on the level of the brainstem are present in Nrxn1α KO rats, which may contribute to later cortical auditory processing deficits observed in adulthood. Our study emphasizes the value of ABRs as a functional readout of auditory brainstem circuit function with potential value as a translational biomarker.

Hearing sensitivity affects survival and reproduction in animals that communicate vocally. The Chinese tiger frog exhibits sexual dimorphism in body size, reflecting the evolution of mating behaviour and life-history strategies. In this study, we recorded auditory brainstem responses (ABRs) to determine hearing sensitivity in both female and male frogs. We also compared male and female hearing characteristics with the shape of the tympanic membrane in light of previous studies showing that smaller middle ear cavities improve hearing sensitivity. We found that ABR thresholds differ significantly between males and females, with the greatest sensitivities in both sexes at frequencies close to the dominant frequency of male calls. ABR thresholds were significantly lower in females compared to males for frequencies in the 0.9–1.3 kHz range and at 1.6 kHz. The tympanic membrane diameter was significantly smaller in females (5.94 ± 0.87 mm) than in males (6.71 ± 0.49 mm). Our results indicate that sexual selection has in all likelihood differentially affected male and female hearing sensitivity as well as the shape of the tympanic membrane in frogs.

Auditory sensation can be elicited by applying a bone conduction vibrator to skin sites on the head, neck, and thorax over soft tissues. This is called soft tissue conduction (STC). We hypothesized that introducing substances with acoustic impedances that sharply deviate from those of soft tissues, such as air pockets, into the soft tissues beneath soft tissue stimulation sites would have an effect on the auditory threshold to stimulation at skin sites over soft tissue. In human subjects, we assessed the auditory threshold with a bone vibrator applied to several STC sites, especially the cheek, and to several bone conduction sites on the skull. The subjects were equipped with bilateral earplugs. The subject then filled his or her cheek with either air or water, and the auditory threshold was again determined. We also recorded the auditory brain stem response to STC stimulation under the chin in fat sand rats in the absence and presence of subcutaneous air or saline solution pockets (0.4 mL) under the chin. In humans, the threshold to stimulation on the cheek was elevated (13 to 18 dB) in the presence of an air-inflated cheek, but not with a water-filled cheek. In animals, in the presence of an air pocket, the auditory brain stem response threshold was elevated by 10 to 20 dB; no threshold change occurred with a saline solution pocket. The introduction of air (but not water) into the soft tissues beneath the soft tissue stimulation sites led to a threshold elevation in both humans and animals. This was not the case when an identical volume of water was introduced, which would also have interrupted a possible parallel bone conduction pathway. These results provide evidence that soft tissue stimulation at low intensities induces tissue vibrations that are transmitted to the cochlea along a series of soft tissues with similar acoustic impedances.

Comparison of ABR and ASSR using NB-chirp-stimuli in children with severe and profound hearing loss

The Nottingham Paediatric Cochlear Implant Programme (NPCIP) specializes in the cochlear implantation of children under the age of 5 years. The initial stage in the pre-implant evaluation process is audiological assessment. In complex paediatric cases, behavioural audiological assessment may be difficult. In such cases, an objective measure to verify the aided hearing threshold is desirable. This study compares unaided and aided hearing thresholds, by both objective and behavioural techniques, in 20 children (aged <1-10 years). Objective data were collected from auditory brainstem responses (ABR) and behavioural thresholds were measured by use of developmental age-appropriate tests. When comparing the unaided ABR click threshold to the behavioural threshold (obtained from the average of 1-4 kHz warble tones) the ABR threshold was, on average, 9 dB lower (more sensitive). Using the same comparison for aided responses a difference of <5 dB was observed. Unaided ABR thresholds resulted in 35% of subjects responding to the click stimulation (when using a maximum stimulation level of 105 dB nHL), whereas introducing aided ABR measurement elicited positive results in 75% of subjects. The effect of the hearing aid on the stimulus was measured by use of a 2 cc coupler which was connected to a precision sound level meter, whose AC output was recorded onto digital audiotape. Analysis of the resultant output spectra in the frequency domain highlighted signal non-linearity and distortion when using high-intensity stimuli with moderate to high aid gains. In conclusion, aided ABR thresholds are valuable in the management of young children. However, when performing either ABR or behavioural aided hearing threshold measurements it is essential to be aware of the limitations of the hearing aid and the stimulus.

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Hearing impairment is a common disability in children. This study is to evaluate the common high risk factors for hearing loss in our locality and to estimate hearing threshold by brain stem evoked response audiometry.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; 100 children under five years were subjected to brainstem evoked response audiometry. Wave V morphology was studied and hearing threshold estimated. The high risk factor(s) were analysed and degree of hearing impairment assessed. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; 38 children were found to have hearing impairment. Most of the children had bilateral hearing impairment. Of them 30 children (79%) had profound hearing loss. Consanguineous marriage was the most common risk factor.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Since consanguinity is the most common risk factor, health education and genetic counselling will help to decrease the incidence of autosomal recessive nonsyndromic deafness. Improvement in immunization for rubella can decrease the hearing impairment due to these infections. Due to availability of medical facilities hearing impairment due to perinatal factors have decreased.&lt;/p&gt;

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The effect of electrolyte imbalance on hearing thresholds and its objective manifestation, as delayed latencies or inter-peak intervals in evoked response audiometry is studied.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; The present prospective study was undertaken in a period of one and a half years, to analyze the audiological profile in patients of chronic renal failure and renal allograft recipients. 60 patients were randomly selected from the out- patient and indoor services of nephrology, urology and oto-rhino-laryngology, Dayanand Medical College and Hospital, Ludhiana. Brain stem evoked response audiometry was performed and the latencies were tabulated. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; A significant delay in the absolute latency of wave V was noted in hyponatremic patients of CRF on comparison with patients of CRF having a normal serum Na&lt;sup&gt;+&lt;/sup&gt; levels. The I-V interpeak interval was also seen to be significantly delayed on comparison. A statistically significant delayed I-III inter-peak latency was also observed in hypernatremic patients in comparison to patients having a serum Na&lt;sup&gt;+&lt;/sup&gt; level in the normal range. No significance of serum creatinine levels and wave latencies was noted on comparison between the three categories of patients of CRF as categorized by their serum creatinine levels.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; There is a definite deterioration of the audiological function in patients of chronic kidney disease, and some reversal of these abnormalities following a successful renal transplantation; indirectly pointing towards uremic milieu being the culprit.&lt;/p&gt;

Audiological Characteristics of Vestibular Schwannoma Patients With Normal Pure-Tone Audiometry.

Supra-threshold disorders in the form of auditory neuropathy (AN)/auditory dys-synchrony (AD) or central auditory processing disorders (CAPD), a special type of retrocochlear hearing loss; and also children with mild permanent hearing loss (PHL), may be missed on current hearing protocols. Otoacoustic emissions (OAE) and Brain stem evoked response audiometry (BERA), are tests, when used in combination, can indirectly help diagnose the different types of hearing loss. To correlate the parental awareness and the pattern of hearing loss (HL) in children with/without auditory and/or speech problems, using both OAE and BERA as hearing tests for indirect identification of suprathreshold disorders and mild PHL. An Observational Prospective study carried out on 100 children in the age group of 0-5years, for detection of type of HL by both OAE and BERA and correlating it with parental awareness of HL and speech defects. In 72.22% of children with speech problem only and without any complaints of HL, some form of HL (confirmed HL-OAE refer/BERA fail or auditory neuropathy/auditory dys-synchrony-OAE pass/BERA fail) was diagnosed, whereas 24.07% had no detectable HL on both OAE and BERA pass, and were considered as indirect evidence of CAPD. 3.7% with OAE refer and BERA pass were considered indicative of mild PHL. AN/AD/CAPD/Mild PHL are important cause of speech delay without parental awareness of HL. OAE and BERA together can be used as an indirect evidence of their presence.

Introduction and Aim: Aging of the auditory pathway is a complex phenomenon consisting of changes in the auditory processing along with a significant elevation of the hearing threshold. The aim of our study was to see the variation in interpeak latencies (IPLs) of Auditory Brainstem Responses (ABRs) with advancing age in males.&#x0D; &#x0D; Materials and Methods: It was an observational study conducted on 60 Indian male subjects aged between 20 and 80 years divided into three groups on the basis of age: Group 1: 20-40 years, Group 2: 41-60 years and Group 3: 61-80 years. Auditory threshold and ABRs were recorded and analysed for interpeak latencies (IPLs) – I-III,I-V and III-V in msec.The comparison of data between the groups was done using one – way ANOVA and Tukey Kramer multiple comparison test. The results were considered significantly different between the groups when ‘P value’ was ? 0.05.&#x0D; &#x0D; Results: It was found that there was no significant difference in the auditory threshold and interpeak latencies (IPLs) when comparison was made between the three groups.&#x0D; &#x0D; Conclusion: Hence we conclude thatage does not have any significant influence on neural conduction time of the auditory pathway which is represented by the IPLs in ABRs.&#x0D;

Effects of pentylenetetrazole and 4-aminopyridine on the auditory brainstem response (ABR) and on the hearing sensitivity in the guinea pig in vivo