Future Directions in the Study of Active Processes and Otoacoustic Emissions

Author(s):  
Geoffrey A. Manley ◽  
William E. Brownell
2004 ◽  
Vol 92 (5) ◽  
pp. 2685-2693 ◽  
Author(s):  
Geoffrey A. Manley ◽  
Ulrike Sienknecht ◽  
Christine Köppl

Active processes in the inner ear of lizards can be monitored using spontaneous otoacoustic emissions (SOAE) measured outside the eardrum. In the Australian bobtail lizard, SOAE are generated by an active motility process in the hair-cell bundle. This mechanism has been shown to be sensitive to the calcium-chelating agent 1,2-bis(o-aminophenoxy)ethane- N,N,N′,N′-tetraacetic acid and is presumed to be related to the calcium-sensitive transduction-channel motor implicated in other nonmammalian hair cell systems. In studies of frog saccular and turtle auditory papillar hair cells in vitro, the frequency and amplitude of bundle oscillations depend on the concentration of calcium in the bathing solutions. In the present study, the calcium concentration in the endolymph was changed in vivo in the Australian bobtail lizard Tiliqua rugosa, and SOAE were monitored. Glass pipettes with large tips and containing different calcium concentrations in their fluids were introduced into scala media, and their contents were allowed to passively flow into the endolymph. Low calcium concentrations resulted in a downward shift in the frequency of SOAE spectral peaks and generally an increase in their amplitudes. Calcium concentrations >2 mM resulted in increases in frequency of SOAE peaks and generally a loss in amplitude. These frequency shifts were consistent with in vitro data on the frequencies and amplitudes of spontaneous oscillation of hair cell bundles and thus also implicate calcium ions in the generation of active motility in nonmammalian hair cells. The data also suggest that in this lizard species, the ionic calcium concentration in the cochlear endolymph is ≥1 mM.


2018 ◽  
Author(s):  
Yuttana Roongthumskul ◽  
Daibhid O Maoileidigh ◽  
Albert Hudspeth

Spontaneous otoacoustic emissions (SOAEs) are weak sounds that emanate from the ears of tetrapods in the absence of acoustic stimulation. These emissions are an epiphenomenon of the active process of the inner ear, which enhances the sensitivity of the auditory system to weak sounds, but their mechanism of production remains a matter of debate. To understand the relationship between SOAEs that we recorded simultaneously from the two ears of the tokay gecko, we developed a mathematical model of the eardrums as noisy nonlinear oscillators coupled by the air within the mouth of a lizard. We found that binaural emissions could be strongly correlated: some emissions occurred at the same frequency in both ears and were highly synchronized. Suppression of the emissions in one ear often changed the amplitude or shifted the frequency of emissions in the other. Decreasing the frequency of emissions from one ear by lowering its temperature usually reduced the frequency of the contralateral emissions. By according with the model, the results indicate that some SOAEs are generated bilaterally through acoustic coupling across the oral cavity. The model predicts that sound localization through the acoustic coupling between ears is influenced by the active processes of both ears.


Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.


2019 ◽  
Vol 28 (4) ◽  
pp. 877-894
Author(s):  
Nur Azyani Amri ◽  
Tian Kar Quar ◽  
Foong Yen Chong

Purpose This study examined the current pediatric amplification practice with an emphasis on hearing aid verification using probe microphone measurement (PMM), among audiologists in Klang Valley, Malaysia. Frequency of practice, access to PMM system, practiced protocols, barriers, and perception toward the benefits of PMM were identified through a survey. Method A questionnaire was distributed to and filled in by the audiologists who provided pediatric amplification service in Klang Valley, Malaysia. One hundred eight ( N = 108) audiologists, composed of 90.3% women and 9.7% men (age range: 23–48 years), participated in the survey. Results PMM was not a clinical routine practiced by a majority of the audiologists, despite its recognition as the best clinical practice that should be incorporated into protocols for fitting hearing aids in children. Variations in practice existed warranting further steps to improve the current practice for children with hearing impairment. The lack of access to PMM equipment was 1 major barrier for the audiologists to practice real-ear verification. Practitioners' characteristics such as time constraints, low confidence, and knowledge levels were also identified as barriers that impede the uptake of the evidence-based practice. Conclusions The implementation of PMM in clinical practice remains a challenge to the audiology profession. A knowledge-transfer approach that takes into consideration the barriers and involves effective collaboration or engagement between the knowledge providers and potential stakeholders is required to promote the clinical application of evidence-based best practice.


2019 ◽  
Vol 4 (5) ◽  
pp. 936-946
Author(s):  
Dawn Konrad-Martin ◽  
Neela Swanson ◽  
Angela Garinis

Purpose Improved medical care leading to increased survivorship among patients with cancer and infectious diseases has created a need for ototoxicity monitoring programs nationwide. The goal of this report is to promote effective and standardized coding and 3rd-party payer billing practices for the audiological management of symptomatic ototoxicity. Method The approach was to compile the relevant International Classification of Diseases, 10th Revision (ICD-10-CM) codes and Current Procedural Terminology (CPT; American Medical Association) codes and explain their use for obtaining reimbursement from Medicare, Medicaid, and private insurance. Results Each claim submitted to a payer for reimbursement of ototoxicity monitoring must include both ICD-10-CM codes to report the patient's diagnosis and CPT codes to report the services provided by the audiologist. Results address the general 3rd-party payer guidelines for ototoxicity monitoring and ICD-10-CM and CPT coding principles and provide illustrative examples. There is no “stand-alone” CPT code for high-frequency audiometry, an important test for ototoxicity monitoring. The current method of adding a –22 modifier to a standard audiometry code and then submitting a letter rationalizing why the test was done has inconsistent outcomes and is time intensive for the clinician. Similarly, some clinicians report difficulty getting reimbursed for detailed otoacoustic emissions testing in the context of ototoxicity monitoring. Conclusions Ethical practice, not reimbursement, must guide clinical practice. However, appropriate billing and coding resulting in 3rd-party reimbursement for audiology services rendered is critical for maintaining an effective ototoxicity monitoring program. Many 3rd-party payers reimburse for these services. For any CPT code, payment patterns vary widely within and across 3rd-party payers. Standardizing coding and billing practices as well as advocacy including letters from audiology national organizations may be necessary to help resolve these issues of coding and coverage in order to support best practice recommendations for ototoxicity monitoring.


Author(s):  
Nuriye Yıldırım Gökay ◽  
Bülent Gündüz ◽  
Fatih Söke ◽  
Recep Karamert

Purpose The effects of neurological diseases on the auditory system have been a notable issue for investigators because the auditory pathway is closely associated with neural systems. The purposes of this study are to evaluate the efferent auditory system function and hearing quality in Parkinson's disease (PD) and to compare the findings with age-matched individuals without PD to present a perspective on aging. Method The study included 35 individuals with PD (mean age of 48.50 ± 8.00 years) and 35 normal-hearing peers (mean age of 49 ± 10 years). The following tests were administered for all participants: the first section of the Speech, Spatial and Qualities of Hearing Scale; pure-tone audiometry, speech audiometry, tympanometry, and acoustic reflexes; and distortion product otoacoustic emissions (DPOAEs) and contralateral suppression of DPOAEs. SPSS Version 25 was used for statistical analyses, and values of p < .05 were considered statistically significant. Results There were no statistically significant differences in the pure-tone audiometry thresholds and DPOAE responses between the individuals with PD and their normal-hearing peers ( p = .732). However, statistically significant differences were found between the groups in suppression levels of DPOAEs and hearing quality ( p < .05). In addition, a statistically significant and positive correlation was found between the amount of suppression at some frequencies and the Speech, Spatial and Qualities of Hearing Scale scores. Conclusions This study indicates that medial olivocochlear efferent system function and the hearing quality of individuals with PD were affected adversely due to the results of PD pathophysiology on the hearing system. For optimal intervention and follow-up, tasks related to hearing quality in daily life can also be added to therapies for PD.


Sign in / Sign up

Export Citation Format

Share Document