Audiologic Monitoring for Ototoxicity

Role of Otoacoustic Emission in Early Detection of Cisplatin Induced Ototoxicity

Cisplatin is a chemotherapeutic agent effective against head and neck carcinoma but unfortunately it is cochleotoxic. This study has been designed to investigate the efficacy of OAE in identifying early effects of cisplatin on the cochlea and the importance of protocol for audiological monitoring of cisplatin induced ototoxicity. This is a prospective observational study conducted from October 2012 to September 2014 on 70 patients, receiving Cisplatin for various malignant conditions. Audiological criteria for ototoxicity was considered as a difference of 10 d B or more in pure tone thresholds of two or more adjacent frequencies in conventional audiometry and in DPOAE-Signal noise ratio less than 6 dB or DPOAE amplitude less than 20 dBSPL (irrespective of SNR > 6 dB). According to PTA, 60.7% patients showed ototoxicity after completion of chemotherapy. In DPOAE, according to SNR and amplitude criteria more than 60% patients showed ototoxicity after first cycle of cisplatin at high frequencies (4-8 kHz). DPOAEs is a sensitive tool for early detection of ototoxicity and protocol is necessary for monitoring ototoxicity in patients receiving cisplatin to improve the quality of life.

Adverse Audio-Vestibular Effects of Drugs and Vaccines Used in the Treatment and Prevention of COVID-19: A Review

(1) Background: The purpose of this article is to review pharmacological treatments for COVID-19 (currently approved by the EMA (European Medical Agency) and FDA (Food and Drug Administration)) and highlight their potential audio-vestibular side-effects as an ototoxic adverse reaction. (2) Methods: Review of the available literature in the scientific databases PubMed, ResearchGate, Scopus, and ScienceDirect, and in summaries of product data sheets. (3) Results: In accordance with EBM (evidence-based medicine) the treatment of COVID-19 by using lopinavir/ritonavir, chloroquine and hydroxychloroquine, azithromycin, favipiravir, amantadine, oseltamivir, and ivermectin is no longer recommended for patients suffering from COVID-19 due to a lack of clinical data, publications, and recommendations. There were 39 publications and 15 summaries of product characteristics (as other sources of data) which were also used in this analysis. Adverse events could be permanent or disappear over time. Following treatment for COVID-19, the most frequent adverse audio-vestibular reactions reported in clinical trials and publications in the area of audiology and otorhinolaryngology were: dizziness, blurry vision with dizziness, nasopharyngitis, dysgeusia, and tinnitus. As far as vaccines are concerned, dizziness as an ototoxic effect was uncommon and occurs only in hypersensitive people who experience anaphylactic shock. (4) Conclusions: The ototoxicity of the drugs discussed here does not have as severe symptoms as the drugs used in the treatment of COVID-19 in 2020 (e.g., hydroxychloroquine), and relates mainly to disorders of the vestibulocochlear system. However, there is still a need to monitor ototoxic side-effects because of potential interactions with other ototoxic drugs. Many of the drugs approved by EMA and FDA are new, and not every side-effect is known.

Pharmaco-Audiology Vigilance in the Treatment of Adult Patients with HIV/Aids: Ototoxicity Monitoring Protocol Recommendation

South Africa is considered the epicenter of HIV/AIDS with a high rate of TB infection as well. Links have been established between treatments of these conditions to ototoxicity. However, no standardized and systematic ototoxicity monitoring exists within the clinical sites where these conditions are treated, with very minimal and adhoc involvement of audiologists as part of the treatment team. With 3.4 million HIV-infected South Africans being reported to have been on antiretroviral drugs by the end of March 2016; with universal coverage being the target, it is important that ototoxicity monitoring becomes part of the treatment plan. The objective of the current paper is to propose an ototoxicity monitoring protocol that can be implemented within this population to ensure that systematic data are collated in order for evidence-based protocols to be adopted within the South African context. Such a protocol will also allow for early identification and intervention of ototoxic hearing loss within this population. Enough evidence exists to support implementation of standardized protocols that will allow for proper, accurate, efficient, and reliable comparisons of data within and between patients; as well as between and within treatment sites - both locally and internationally. It is hoped that implementation of such a monitoring protocol will also have significant implications for the expanded role of the audiologist in the drug development process, affording evidence-based benefit-risk assessments of drugs in the market for this population.

Long-term vancomycin use had low risk of ototoxicity

Background

Vancomycin is a commonly used antibiotic with potent activity against Gram-positive organisms, but prolonged use and high doses can lead to toxicity. While vancomycin-associated nephrotoxicity is widely reported, few cases of ototoxicity have been described. The objective of this study was to determine the prevalence of negative changes in audiograms in patients receiving long-term intravenous (IV) vancomycin and to identify high-risk patients who need audiogram monitoring.

Methods

This was an IRB approved, cross-sectional study performed at an academic medical center from 1/2012-3/2019. Patients who were prescribed IV vancomycin for ≥ 14 days and had baseline and follow-up weekly audiometry were included. All data was extracted from the electronic medical record. The primary endpoint was worsening audiogram while on vancomycin. Descriptive and bivariate statistics were used to describe the patient population.

Results

424 patients were screened for inclusion; 92 received at least two audiograms while on vancomycin. Fifty-three percent of patients were men, the median (IQR) patient age was 44 (34–58) years, and 8% of patients had an estimated Cockcroft-Gault creatinine clearance ≤ 30 mL/min or received hemodialysis. The median (IQR) vancomycin exposure up until the last recorded audiogram was 30 (17–42) days. Vancomycin indications were: 53 (58%) bone and joint infections, 17 (18%) infective endocarditis, 10 (11%) bacteremia, 12 (13%) other infections. Seven (8%) patients experienced a worsening change in hearing from baseline, two (2%) of them suffered mild loss, two (2%) had mild to moderate loss, and three (3%) developed moderate-to-severe hearing loss. In bivariate analyses, no variables were found to be associated with a worsening change in audiogram, including baseline abnormal audiogram, age ≥ 40 years, elevated serum vancomycin levels, or vancomycin doses ≥ 4 grams/day.

Conclusions

The prevalence of negative changes in audiograms among patients receiving long-term intravenous vancomycin was low. The utility of routine audiogram testing in this population remains questionable except in high-risk patients; however, larger prospective studies with controls may be warranted to further explore the risk of ototoxicity.

Drug-Induced Ototoxicity: Diagnosis and Monitoring

Ototoxicity diagnosis and management has historically been approached using a variety of methods. However, in recent years a consensus on useful and practical approaches has been developed through clinical guidelines of the American Speech Language Hearing Association, the American Academy of Audiology, and multiple clinical trials published in peer-reviewed literature. Some of the guidelines and approaches are used to detect and monitor ototoxicity, while others are used to grade adverse events. Some of the audiologic measures are primary, while others are adjunct measures and may be tailored to the specific needs of the patient or clinical trial. For some types of monitoring, such as drug-induced tinnitus or dizziness, validated paper survey instruments can be both sensitive and easy for fragile patients. This review addresses the characteristics of some of the most common clinical ototoxins and the most common methods for detecting and monitoring ototoxicity in clinical practice and clinical trials.

Alteraciones auditivas en artritis reumatoide, lupus eritematoso sistémico y síndrome de Sjögren

Introducción. En la actualidad no hay cifras sobre las personas que padecen artritis reumatoide (AR), lupus eritematoso sistémico (LES) o síndrome de Sjögren (SS) ni información sobre las alteraciones auditivas que puede causar el tratamiento farmacológico utilizado para controlar dichas enfermedades.Objetivo. Evidenciar las posibles afectaciones y alteraciones audiológicas y vestibulares producidas por AR, LES y SS o su tratamiento farmacológico.Materiales y métodos. Se analizaron los hallazgos clínicos de herramientas diagnósticas y procedimientos de prevención e intervención de alteraciones auditivas en artículos de investigación publicados en español, inglés, francés y portugués en bases de datos científicas entre los años 2000 y 2016.Resultados. Se extrajeron 62 artículos de investigación (31 de AR, 5 de LES, 12 de SS, 5 de Hipoacusia inmunomediada, 9 de medicamentos ototóxicos), 1 tesis doctoral sobre AR, 1 tesis doctoral sobre AR y LES y 1 guía de práctica clínica para la detección temprana, diagnóstico y tratamiento de AR. Se evidenció que las pérdidas auditivas con mayor reporte son hipoacusia neurosensorial, lesiones en cadena osicular y vestíbulo-coclear.Conclusiones. Se confirmó la relación entre las lesiones audiológicas y AR, LES y SS, pero aun no es claro el desarrollo de los ototóxicos.

An evaluation of hearing in infants administered with colistin in the premature neonatal intensive care unit

AIM

The aim of this study was to investigate the effects of colistin on hearing by evaluating the otoacoustic emission tests and clinical auditory brainstem responses in preterm infants treated with colistin in the neonatal intensive care unit.

METHOD

The study included 30 neonates (male: n = 16, female: n = 14) born before 37 weeks who were admitted to the Neonatal Intensive Care Unit at the Kahramanmaras Sutcu Imam Medical Faculty between January 2014 and January 2015 and who were treated with colistin during their time in intensive care because of infection. A control group was formed consisting of 30 preterm infants (male: n = 18, female: n = 12) with no additional disease born in the hospital during the same period. Following an ear, nose and throat examination the distortion product otoacoustic emission test, transient evoked otoacoustic emission and clinical auditory brainstem response tests were applied to all 60 patients.

RESULTS

The otoacoustic emission responses obtained from the control group were positive and clinical auditory brainstem responses up to 15 dB were obtained. In the colistin group negative otoacoustic emission responses were obtained in two patients unilaterally and in one patient bilaterally and loss was observed at the thresholds in the clinical auditory brainstem response test. Significantly prolonged fifth wave latency was observed in the colistin group compared to the control group for the clinical auditory brainstem response at 15 dB.

CONCLUSIONS

Given that the study results showed unilateral hearing loss in two patients and bilateral hearing loss in one as well as latency at 15 dB, hearing tests to check for ototoxicity are recommended for patients given colistin.

Evaluation and Management of Hearing Loss in Survivors of Childhood and Adolescent Cancers: A Report From the Children's Oncology Group

Hearing loss (HL) is common in childhood cancer survivors exposed to platinum chemotherapy and/or cranial radiation and can severely impact quality of life. Early detection and appropriate management can mitigate academic, speech, language, social, and psychological morbidity resulting from hearing deficits. This review is targeted as a resource for providers involved in aftercare of childhood cancers. The goal is to promote early identification of survivors at-risk for HL, appropriate evaluation and interpretation of diagnostic tests, timely referral to an audiologist when indicated, and to increase knowledge of current therapeutic options.

Concordance between the chang and the International Society of Pediatric Oncology (SIOP) ototoxicity grading scales in patients treated with cisplatin for medulloblastoma

BACKGROUND

Reporting ototoxicity is frequently complicated by use of various ototoxicity criteria. The International Society of Pediatric Oncology (SIOP) ototoxicity grading scale was recently proposed for standardized use in reporting hearing loss outcomes across institutions. The aim of this study was to evaluate the concordance between the Chang and SIOP ototoxicity grading scales. Differences between the two scales were identified and the implications these differences may have in the clinical setting were discussed.

PROCEDURES

Audiological evaluations were reviewed for 379 patients with newly diagnosed medulloblastoma (ages 3-21 years). Each patient was enrolled on one of two St. Jude clinical protocols that included craniospinal radiation therapy and four courses of 75 mg/m(2) cisplatin chemotherapy. The latest audiogram conducted 5.5-24.5 months post-protocol treatment initiation was graded using the Chang and SIOP ototoxicity criteria. Clinically significant hearing loss was defined as Chang grade ≥2a and SIOP ≥2. Hearing loss was considered serious (requiring a hearing aid) at the level of Chang grade ≥2b and SIOP ≥3.

RESULTS

A strong concordance was observed between the Chang and SIOP ototoxicity scales (Stuart's tau-c statistic = 0.89, 95% CI: 0.86, 0.91). Among those patients diagnosed with serious hearing loss, the two scales were in good agreement. However, the scales deviated from one another in classifying patients with less serious or no hearing loss.

CONCLUSIONS

Although discrepancies between the Chang and SIOP ototoxicity scales exist primarily for patients with no or minimal hearing loss, the scales share a strong concordance overall.

Speech recognition and frequency of hearing loss in patients treated for cancer in childhood

BACKGROUND

The aim of this study was to characterize the audiological profile accompanying oncological treatment in patients who had cancer in childhood and had been free of oncological treatment for at least 8 years. Our main interest lay in identifying the affected frequencies that interfered with speech intelligibility (SI) in those who had acquired hearing loss after treatment.

PROCEDURE

Two hundred patients who had cancer in childhood were evaluated. Diagnosis was made at the mean age of 6 years old, and hearing evaluation was performed at a mean age of 21 years. Fifty-one of these patients received chemotherapy without cisplatin, carboplatin or head and neck radiotherapy; 64 received cisplatin without head and neck radiotherapy; 75 received head and neck radiotherapy without cisplatin; and 10 received both head and neck radiotherapy and cisplatin chemotherapy. All patients underwent pure tone audiometry and speech audiometry.

RESULTS

Patients who had hearing loss primarily had bilateral symmetric sensorineural hearing loss. Although the average SI for ears with hearing loss in the frequency range from 4 to 8 kHz was normal, the Kruskall-Wallis test showed a significant difference between ears without hearing loss and those with hearing loss between 4 and 8 kHz. The average SI score in ears with hearing loss between 1 and 8 kHz was significantly different from all other ears.

CONCLUSIONS

Hearing loss involving frequencies at and above 4 kHz determines a decline in SI.

Hearing and cochlear function of patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disorder that primarily affects the spine and sacroiliac joints. Recent studies described audiovestibular impairment in AS patients. The aim of this study was to evaluate the hearing and function of the cochlear system in patients with AS. Thirty-seven AS patients and 20 healthy controls were evaluated prospectively. Otorhinolaryngologic examinations were performed in all patients together with pure tone audiometry, speech discrimination test, tympanometry, and distortion product otoacoustic emission (DPOE). Disease duration, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores, and hematologic findings (CRP and ESR) were also collected. Pure tone audiometry findings of the patients and controls were significantly different in all frequencies (p < 0.01). Speech discrimination scores were also significantly different (p < 0.01). No significant difference was found between DPOE responses of the patients and controls (p > 0.05). There was no correlation between disease duration, BASDAI scores, hematological findings, and audiometry findings (p > 0.05). This study demonstrated that there is an association between AS and hearing loss, but the cochlea is not the main source of hearing loss.

Distortion-product otoacoustic emission test performance for ototoxicity monitoring

INTRODUCTION

A nonbehavioral method for monitoring ototoxicity in patients treated with cisplatin is needed because patients enduring chemotherapy may not be well or cooperative enough to undergo repeated hearing tests. Distortion-product otoacoustic emissions (DPOAEs) provide a nonbehavioral measure of auditory function that is sensitive to cisplatin exposure. However, interpreting DPOAE findings in the context of ototoxicity monitoring requires that their accuracy be determined in relation to a clinically accepted gold standard test.

OBJECTIVES

Among patients receiving cisplatin for the treatment of cancer, we sought to (1) identify the combination of DPOAE metrics and ototoxicity risk factors that best classified ears with and without ototoxic-induced hearing changes; and (2) evaluate the test performance achieved by the composite measure as well as by DPOAEs alone.

DESIGN

Odds of experiencing hearing changes at a given patient visit were determined using data collected prospectively from 24 Veterans receiving cisplatin. Pure-tone thresholds were examined within an octave of each subject's high-frequency hearing limit. DPOAE were collected as a set of four response growth (input/output) functions near the highest f2 frequency that yielded a robust response at L2 = L1 = 65 dB SPL. Logistic regression modeled the risk of hearing change using several DPOAE metrics, drug treatment factors, and other patient factors as independent variables. An optimal discriminant function was derived by reducing the model so that only statistically significant variables were included. Receiver operating characteristic curve analyses were used to evaluate test performance.

RESULTS

At higher cisplatin doses, ears with better hearing at baseline were more likely to exhibit ototoxic hearing changes than those with poorer hearing. Measures of pre-exposure hearing, cumulative drug dose, and DPOAEs generated a highly accurate discriminant function with a cross-validated area under the receiver operating characteristic curve of 0.9. DPOAEs alone also provided an indication of ototoxic hearing change when measured at the highest DPOAE test frequency that yielded a robust response.

CONCLUSIONS

DPOAEs alone and especially in combination with pre-exposure hearing and cisplatin dose provide an indication of whether or not hearing has changed as a result of cisplatin administration. These promising results need to be validated in a separate sample.

Longitudinal assessment of air conduction audiograms in a phase III clinical trial of difluoromethylornithine and sulindac for prevention of sporadic colorectal adenomas

A phase III clinical trial assessed the recurrence of adenomatous polyps after treatment for 36 months with difluoromethylornithine (DFMO) plus sulindac or matched placebos. Temporary hearing loss is a known toxicity of treatment with DFMO, thus a comprehensive approach was developed to analyze serial air conduction audiograms. The generalized estimating equation method estimated the mean difference between treatment arms with regard to change in air conduction pure tone thresholds while accounting for within-subject correlation due to repeated measurements at frequencies. Based on 290 subjects, there was an average difference of 0.50 dB between subjects treated with DFMO plus sulindac compared with those treated with placebo (95% confidence interval, -0.64 to 1.63 dB; P = 0.39), adjusted for baseline values, age, and frequencies. In the normal speech range of 500 to 3,000 Hz, an estimated difference of 0.99 dB (-0.17 to 2.14 dB; P = 0.09) was detected. Dose intensity did not add information to models. There were 14 of 151 (9.3%) in the DFMO plus sulindac group and 4 of 139 (2.9%) in the placebo group who experienced at least 15 dB hearing reduction from baseline in 2 or more consecutive frequencies across the entire range tested (P = 0.02). Follow-up air conduction done at least 6 months after end of treatment showed an adjusted mean difference in hearing thresholds of 1.08 dB (-0.81 to 2.96 dB; P = 0.26) between treatment arms. There was no significant difference in the proportion of subjects in the DFMO plus sulindac group who experienced clinically significant hearing loss compared with the placebo group. The estimated attributable risk of ototoxicity from exposure to the drug is 8.4% (95% confidence interval, -2.0% to 18.8%; P = 0.12). There is a <2 dB difference in mean threshold for patients treated with DFMO plus sulindac compared with those treated with placebo.

Test-Retest Reliability of Pure-Tone Thresholds from 0.5 to 16 kHz using Sennheiser HDA 200 and Etymotic Research ER-2 Earphones

OBJECTIVE

The purposes of the study were: (1) To evaluate the intrasession test-retest reliability of pure-tone thresholds measured in the 0.5-16 kHz frequency range for a group of otologically healthy subjects using Sennheiser HDA 200 circumaural and Etymotic Research ER-2 insert earphones and (2) to compare the data with existing criteria of significant threshold shifts related to ototoxicity and noise-induced hearing loss.

DESIGN

Auditory thresholds in the frequency range from 0.5 to 6 kHz and in the extended high-frequency range from 8 to 16 kHz were measured in one ear of 138 otologically healthy subjects (77 women, 61 men; mean age, 24.4 yr; range, 12-51 yr) using HDA 200 and ER-2 earphones. For each subject, measurements of thresholds were obtained twice for both transducers during the same test session. For analysis, the extended high-frequency range from 8 to 16 kHz was subdivided into 8 to 12.5 and 14 to 16 kHz ranges. Data for each frequency and frequency range were analyzed separately.

RESULTS

There were no significant differences in repeatability for the two transducer types for all frequency ranges. The intrasession variability increased slightly, but significantly, as frequency increased with the greatest amount of variability in the 14 to 16 kHz range. Analyzing each individual frequency, variability was increased particularly at 16 kHz. At each individual frequency and for both transducer types, intrasession test-retest repeatability from 0.5 to 6 kHz and 8 to 16 kHz was within 10 dB for >99% and >94% of measurements, respectively. The results indicated a false-positive rate of <3% in reference to the criteria for cochleotoxicity for both transducer types. In reference to the Occupational Safety and Health Administration Standard Threshold Shift criteria for noise-induced hazards, the results showed a minor false-positive rate of <1% for the HDA 200.

CONCLUSION

Repeatability was similar for both transducer types. Intrasession test-retest repeatability from 0.5 to 12.5 kHz at each individual frequency including the frequency range susceptible to noise-induced hearing loss was excellent for both transducers. Repeatability was slightly, but significantly poorer in the frequency range from 14 to 16 kHz compared with the frequency ranges from 0.5 to 6 or 8 to 12.5 kHz. Measurements in the extended high-frequency range from 8 to 14 kHz, but not up to 16 kHz, may be recommended for monitoring purposes.

A Proposed Protocol for Monitoring Ototoxicity in Patients who Take Cochleo- or Vestibulotoxic Drugs

No widely accepted protocol or guideline exists for monitoring ototoxicity in patients who take powerful and potentially cochleotoxic and/or vestibulotoxic agents. Many physicians in other specialties who prescribe these drugs do not understand the important role of otolaryngologists and audiologists in pretreatment counseling and evaluation and the need for follow-up assessments of their patients’ auditory function. Based on our combined experience of more than 50 years, we have developed a uniform yet flexible approach to monitoring cochlear and vestibular function in these patients. We discuss the mechanisms of ototoxic agents, risk factors for ototoxicity, the need for ongoing communication among the various disciplines, and the methods and timing of monitoring.

Detecção precoce de ototoxicidade usando emissões otoacústicas produtivas de distorção

Introdução: Os aminoglicosídeos são potencialmente ototóxicos, sendo que a monitorização tradicional detecta ototoxicidade quando a lesão já aconteceu. Objetivo: Estudamos prospectivamente a audição de pacientes que recebiam amicacina, usando audiometria tonal liminar (ATL) e emissões otoacústicas, produtos de distorção (EOA-PD), visando a suspeita precoce de ototoxicidade e sua prevenção. Forma de estudo: Prospectivo randomizado. Material e método: Avaliamos, com ATL, 29 pacientes em tratamento com amicacina, para detectar alterações audiométricas. Desses 29 pacientes, três tiveram alteração na ATL em 6 e/ou 8 kHz (10,34 %) - um com alteração bilateral; os outros dois, unilateral (quatro ouvidos), todos assintomáticos. Realizamos EOA-PD, para estudar a função coclear. Dos 29 pacientes (58 ouvidos), nove (18 ouvidos) foram afastados do estudo por não completarem as testagens das EOA-PD, ficando 20 pacientes (40 ouvidos) para análise. Resultados: Não encontramos alterações significativas nas respostas das EOA-PD durante o vale e o pico sérico da amicacina, como esperado. Quando comparados os ouvidos com e sem alterações audiométricas, as variações das respostas não foram significativas em 1, 2 e 4 kHz; no entanto, em 6 e 8 kHz mostraram diferenças significativas (p<0,05). As respostas das EOA-PD nos ouvidos com ATL normal apresentaram incrementos mais do que quedas; e o contrário aconteceu nos ouvidos que apresentaram ATL alterada, ou seja: houve mais quedas do que incrementos. Conclusões: a ototoxicidade pode ser monitorada eficazmente com EOA-PD durante a administração da droga, independentemente do horário da sua administração; os incrementos nas respostas poderiam ser um sinal precoce de ototoxicidade por aminoglicosídeos.

Recommendations for cancer prevention trials using potentially ototoxic test agents

PURPOSE

Preventive oncology applies pharmacologic agents to reverse, retard, or halt progression of neoplastic cells to invasive malignancy, a process that may require administration of agents over long periods of time. Although ototoxicity may be a tolerable side effect of anticancer or antimicrobial therapy, even modest ototoxicity may not be acceptable in agents developed for preventive oncology that are routinely administered to subjects who neither are, nor necessarily will become, clinically ill.

MATERIALS AND METHODS

Age-related shifts in hearing may occur over the course of longterm or open-ended therapy; consequently, age-adjusted norms enable researchers to better distinguish hearing loss caused by drugs from that caused by aging. Norms for hearing sensitivity are derived from the Baltimore Longitudinal Study of Aging and are the basis for the proposed audiologic monitoring recommendations.

RESULTS

Audiologic monitoring recommendations are presented that standardize patient selection, adverse event reporting, posttreatment follow-up, and audiologic testing for potentially ototoxic investigational agents.

CONCLUSION

These recommendations are applicable to trials of investigational agents as well as various classes of drugs used in routine clinical care.

Ototoxicity: an argument for evaluation of the cochlea in safety testing in animals

The cochlea is one of the more common targets for toxic effects, yet current toxicologic screening in animals does not routinely evaluate the cochlea as a potential target organ. Although histopathologic sections are routinely taken from the eye and the optic nerve and tract and most studies include at least 1 section through the nasal cavity and olfactory mucosa, the cochlea is not histopathologically examined in routine toxicity studies. Unfortunately, routine clinical examinations frequently miss ototoxicity because rodents and other species can lose most of their high-frequency hearing and still respond to most ambient noises. Ototoxicity as a deficiency in toxicologic screening can be remedied by using well-established histopathologic and behavioral methods or electrophysiologic methods, such as brain stem auditory evoked responses (BAERs). Once the equipment is in place, BAERs can be obtained quickly and easily for ototoxicity screening (approximately 15 minutes for paired testing of 2 rats and 30 minutes each for dogs). BAERs also can be used in virtually all mammalian species. Three or 4 probe frequencies (eg, 4, 8, 16, and 32 kHz), representing different areas of the cochlea, can be tested in a few minutes with subcutaneous electrodes under short-acting chemorestraint. Given the availability of several approaches to screening for ototoxicity and the importance of the auditory function in human health, safety tests of chemicals and drugs should include an effective screening test for ototoxicity.

Effects of cis-platinum chemotherapy on otoacoustic emissions: the development of an objective screening protocol. Third place--Resident Clinical Science Award 1998

To develop an objective, fast, and simply performed screening protocol for cis -platinum (CP) ototoxicity, we compared the efficacy of screening with distortion-product otoacoustic emissions (DPOAEs) with the outcome of both conventional and ultra-high-frequency (UHF) audiometry. Baseline audiometric and DPOAE testing was performed in 66 patients, 33 of whom met criteria for inclusion in the final database. Comparisons were made between baseline measurements and those recorded before subsequent CP infusions. Outcomes were analyzed clinically and with paired repeated-measures analysis of variance. Results indicated that DPOAEs and UHF were better measures than conventional audiometry. Further, DPOAEs may be better suited for screening older patients receiving CP chemotherapy because DPOAEs are as sensitive as UHF and are present in a greater number of these patients. Screening with DPOAEs may be enhanced by testing only in the 3- to 5.2-kHz range, thus decreasing testing time. Higher time averages to increase the signal-to-noise ratio and use of this narrower bandwidth might also allow for accurate bedside testing.