Stephen A Fausti

Portland VA Medical Center, Portland, Oregon, United States

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Publications (102)203.09 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite a robust hearing conservation program, military personnel continue to be at high risk for noise induced hearing loss (NIHL). For more than a decade, a number of laboratories have investigated the use of antioxidants as a safe and effective adjunct to hearing conservation programs. Of the antioxidants that have been investigated, N-acetylcysteine (NAC) has consistently reduced permanent NIHL in the laboratory, but its clinical efficacy is still controversial. This study provides a prospective, randomized, double-blinded, placebo-controlled clinical trial investigating the safety profile and the efficacy of NAC to prevent hearing loss in a military population after weapons training.
    No preview · Article · Jan 2015 · Hearing Research
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    ABSTRACT: Background: Previous studies reported that particular types of interferon medications might contribute to hearing loss in some patients. The package insert included in the original Food and Drug Administration application for intramuscular interferon beta-1a (Avonex) stated that some patients in the treatment group reported decreased hearing sensitivity. Objective: The purpose of the present investigation was to assess if individuals with multiple sclerosis (MS) taking intramuscular interferon beta-1a have significantly poorer hearing thresholds than those not currently using any disease-modifying therapies. Methods: This was a secondary analysis of data collected as part of two larger studies evaluating auditory function in patients with MS. The goal of this analysis was to determine if users of interferon beta-1a do not have significantly worse hearing thresholds than nonusers of disease-modifying therapies, after adjusting for potential confounders. A linear mixed model was fit to the audiometric thresholds of our subjects. This model included interferon beta-1a use, MS disease subtype, gender, test frequency, age, disease duration (number of years), and the Expanded Disability Status Scale score. Results and conclusions: With all subjects included, there is insufficient evidence to say that intramuscular interferon-beta 1a is not ototoxic (in relation to nonuse of a disease-modifying therapy) at all frequencies tested except 3000 and 6000 Hz. After removing two influential subjects, the results indicated that there is statistical support for no ototoxic effect of intramuscular interferon beta-1a at test frequencies from 250 to 6000 Hz. There is insufficient evidence, however, to rule out an ototoxic effect at 8000 Hz. Future studies should further evaluate the effect of interferon on auditory function in patients with MS. Neuroscience nurses should monitor their patients' hearing throughout the course of treatment.
    No preview · Article · Dec 2014 · Journal of Neuroscience Nursing
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    ABSTRACT: The electrodes of a cochlear implant are located far from the surviving neurons of the spiral ganglion, which results in decreased precision of neural activation compared to the normal ear. If the neurons could be induced to extend neurites toward the implant, it might be possible to stimulate more discrete subpopulations of neurons, and to increase the resolution of the device. However, a major barrier to neurite growth toward a cochlear implant is the fluid filling the scala tympani, which separates the neurons from the electrodes. The goal of this study was to evaluate the growth of cochlear neurites in three-dimensional extracellular matrix molecule gels, and to increase biocompatibility by using fibroblasts stably transfected to produce neurotrophin-3 and brain-derived neurotrophic factor. Spiral ganglion explants from neonatal rats were evaluated in cultures. They were exposed to soluble neurotrophins, cells transfected to secrete neurotrophins, and/or collagen gels. We found that cochlear neurites grew readily on collagen surfaces and in three-dimensional collagen gels. Co-culture with cells producing neurotrophin-3 resulted in increased numbers of neurites, and neurites that were longer than when explants were cultured with control fibroblasts stably transfected with green fluorescent protein. Brain-derived neurotrophic factor-producing cells resulted in a more dramatic increase in the number of neurites, but there was no significant effect on neurite length. It is suggested that extracellular matrix molecule gels and cells transfected to produce neurotrophins offer an opportunity to attract spiral ganglion neurites toward a cochlear implant.
    No preview · Article · Jun 2013 · Neural Regeneration Research
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    Full-text · Dataset · Dec 2012
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    Full-text · Dataset · Nov 2012
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    Full-text · Dataset · Nov 2012
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    ABSTRACT: Thirty-six blast-exposed patients and twenty-nine non-blast-exposed control subjects were tested on a battery of behavioral and electrophysiological tests that have been shown to be sensitive to central auditory processing deficits. Abnormal performance among the blast-exposed patients was assessed with reference to normative values established as the mean performance on each test by the control subjects plus or minus two standard deviations. Blast-exposed patients performed abnormally at rates significantly above that which would occur by chance on three of the behavioral tests of central auditory processing: the Gaps-In-Noise, Masking Level Difference, and Staggered Spondaic Words tests. The proportion of blast-exposed patients performing abnormally on a speech-in-noise test (Quick Speech-In-Noise) was also significantly above that expected by chance. These results suggest that, for some patients, blast exposure may lead to difficulties with hearing in complex auditory environments, even when peripheral hearing sensitivity is near normal limits.
    Full-text · Article · Oct 2012 · The Journal of Rehabilitation Research and Development
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    ABSTRACT: Auditory system functions, from peripheral sensitivity to central processing capacities, are all at risk from a blast event. Accurate encoding of auditory patterns in time, frequency, and space are required for a clear understanding of speech and accurate localization of sound sources in environments with background noise, multiple sound sources, and/or reverberation. Further work is needed to refine the battery of clinical tests sensitive to the sorts of central auditory dysfunction observed in individuals with blast exposure. Treatment options include low-gain hearing aids, remote-microphone technology, and auditory-training regimens, but clinical evidence does not yet exist for recommending one or more of these options. As this population ages, the natural aging process and other potential brain injuries (such as stroke and blunt trauma) may combine with blast-related brain changes to produce a population for which the current clinical diagnostic and treatment tools may prove inadequate. It is important to maintain an updated understanding of the scope of the issues present in this population and to continue to identify those solutions that can provide measurable improvements in the lives of Veterans who have been exposed to high-intensity blasts during the course of their military service.
    Full-text · Article · Oct 2012 · The Journal of Rehabilitation Research and Development
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    ABSTRACT: Research suggests that individuals with multiple sclerosis (MS) may be susceptible to deficits in central auditory processing (CAP). Audiologists need to be able to select appropriate tests to screen for such deficits in this patient population. The purpose of this report is to identify promising CAP tests for screening patients with MS. A comprehensive behavioral CAP test battery was administered to 26 subjects with MS and 27 subjects without MS. Out of six potential tests, selected based on the CAP deficits reported in the scientific literature, results suggest that the Staggered Spondaic Word test and the SCAN-A, followed by the Masking Level Difference test, are the most promising screening tests in this patient population. The Frequency Patterns Test, the Dichotic Digits Test, and the Gaps-in-Noise Test, on the other hand, were less promising. It should be noted, however, that this is a preliminary analysis, and that no clinical recommendations can be made until the reference standards are established in a much larger sample population.
    No preview · Article · Aug 2012 · Seminars in Hearing
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    ABSTRACT: Multiple sclerosis (MS) pathology can cause disruptions in central auditory processing. Here, we applied quantitative magnetic resonance imaging (MRI) techniques to investigate the impact of global neurodegenerative processes on dichotic listening performance in MS. We studied 28 subjects with clinically definite MS and 26 healthy controls using 3T MRI and a dichotic digits task (DDT) performed in the scanner. Subjects with MS displayed increased white matter lesions, prolonged water proton longitudinal relaxation time constants in normal appearing white matter, reduced gray matter volumes, and reduced corpus callosum areas compared with controls. No group differences were found for any of the DDT performance measures. In subjects with MS, corpus callosum area was strongly correlated with DDT performance. This relationship remained present after controlling for other measures of neuropathology, suggesting that callosal atrophy directly impacts dichotic listening performance in MS.
    Full-text · Article · Aug 2012 · Seminars in Hearing
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    ABSTRACT: Cancer treatment often requires patients to be exposed to drugs that can damage hearing. Drugs such as cisplatin can cause permanent damage to hearing if not detected early. Damage typically occurs first in the more basal regions of the cochlea which are specific for high-frequency (HF) hearing and progresses to more apical regions that are relevant to speech understanding. Monitoring of HF hearing loss can be an effective means for early detection of ototoxicity caused by chemotherapy. Once ototoxicity is detected, the oncology medical team could adjust the drug dosage or switch to medications that are less ototoxic. Telehealth technology may improve access to ototoxicity monitoring. Patients could monitor their own hearing using a device that alerts healthcare professionals in the event of a change in hearing. A portable audiometer is currently not available that is 1) capable of automatic or manual (by an audiologist) operation; 2) designed with precision pure-tone functionality up to 20 kHz; and 3) able to remotely transfer health status information to a healthcare professional. This paper describes the design of a technology, the ototoxicity identification (OtoID), that includes a portable audiometer with HF test functionality that meets ANSI/ASA S3.6-2010 standards and is capable of reliably detecting a person's drug-related hearing changes relative to a baseline period (i.e., before ototoxic drugs) using an automated test. The system includes a wireless cellular modem capable of notifying a remote healthcare professional in the event that a significant change in hearing has occurred in the patient. The system was evaluated on test subjects within a sound-proof booth, a noisy hospital ward, and within their homes. Results indicate that the OtoID system can be used by patients to effectively monitor hearing changes remotely within their home or in a hospital ward, ultimately enabling early detection of ototoxicity and potentially avoiding hearing loss.
    Full-text · Article · Jul 2012 · IEEE transactions on bio-medical engineering
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    ABSTRACT: Cisplatin is effective in the treatment of several cancers but is a known ototoxin resulting in shifts to hearing sensitivity in up to 50-60% of patients. Cisplatin-induced hearing shifts tend to occur first within an octave of a patient's high frequency hearing limit, termed the sensitive range for ototoxicity (SRO), and progress to lower frequencies. While it is currently not possible to know which patients will experience ototoxicity without testing their hearing directly, monitoring the SRO provides an early indication of damage. A tool to help forecast susceptibility to ototoxic-induced changes in the SRO in advance of each chemotherapy treatment visit may prove useful for ototoxicity monitoring efforts, patient counseling, and therapeutic planning. This project was designed to (1) establish pretreatment risk curves that quantify the probability that a new patient will suffer hearing loss within the SRO during treatment with cisplatin and (2) evaluate the accuracy of these predictions in an independent sample of Veterans receiving cisplatin for the treatment of cancer. Two study samples were used. The Developmental sample contained 23 subjects while the Validation sample consisted of 12 subjects. DATA COLLECTION and Risk curve predictions for SRO threshold shifts following cisplatin exposure were developed using a Developmental sample comprised of data from a total of 155 treatment visits obtained in 45 ears of 23 Veterans. Pure-tone thresholds were obtained within each subject's SRO at each treatment visit and compared with baseline measures. The risk of incurring an SRO shift was statistically modeled as a function of factors related to chemotherapy treatment (cisplatin dose, radiation treatment, doublet medication) and patient status (age, pre-exposure hearing, cancer location and stage). The model was reduced so that only statistically significant variables were included. Receiver-operating characteristic (ROC) curve analyses were then used to determine the accuracy of the risk curve predictions in an independent Validation sample of observations from over 62 treatment visits obtained in 24 ears of 12 Veterans. Only cumulative cisplatin dose and pre-exposure hearing were found to be significantly related to the risk for hearing shift. The dose-ototoxicity risk curve predictions developed from the Developmental sample yielded area under the ROC curve accuracy estimates of 0.85 when applied to an independent Validation sample. Cumulative cisplatin dose in combination with pre-exposure hearing provides an indication of whether hearing will shift in the SRO in advance of cisplatin administration. The validated dose-ototoxicity risk curves described herein can be used before and during treatment to anticipate hearing loss. While having such a tool would not replace serial hearing testing, it would be of great benefit to an ototoxicity monitoring program. It would promote relevant pretreatment counseling. Furthermore, for those found to be at risk of SRO shifts within the speech frequencies, the oncology treatment plan could incorporate anticipated dosing adjustments that could stave off the impact that ototoxicity might bring.
    Full-text · Article · Jul 2012 · Journal of the American Academy of Audiology
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    Full-text · Article · Jun 2012 · The Journal of Rehabilitation Research and Development
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    ABSTRACT: Stimulus-frequency (SF) otoacoustic emission (OAE) amplitude and the amplitude of medial olivocochlear (MOC) inhibition of SF OAEs for ipsilateral, contralateral and bilateral MOC reflex elicitors were recorded in six subjects with type 2 diabetes during a glucose tolerance test (GTT). Five of the six subjects were tested twice for a total of 11 trials and three subjects were tested in a control experiment. During the GTT experiment, the subjects' blood glucose was elevated from a euglycemic level below 150 mg/dL to a hyperglycemic level above 160 mg/dL following the consumption of a bolus of 80 g of sugar. A subset of three subjects were tested in a control experiment during which SF OAE and MOC reflex measurements were made while blood sugar levels remained constant within the euglycemic region. Mean SF OAE amplitudes were elevated following glucose consumption. A statistically significant increase in MOC inhibition amplitude was observed during elevated sugar levels for the 11 GTT trials. Maximum inhibition occurred about an hour after glucose consumption when blood glucose levels peaked. Results indicate that acute hyperglycemia influences efferent control of the cochlea in people with type 2 diabetes.
    Full-text · Article · Feb 2012 · The Journal of the Acoustical Society of America
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    ABSTRACT: This cross-sectional study had two goals: (1) Identify and quantify the effects of aging on the auditory brainstem response (ABR); (2) Describe how click rate and hearing impairment modify effects of aging. RESEARCH DESIGN AND ANALYSIS: ABR measures were obtained from 131 predominately male Veteran participants aged 26 to 71 yr. Metrics analyzed include amplitude and latency for waves I, III, and V, and the I-V interpeak latency interval (IPI) at three repetition rates (11, 51, and 71 clicks/sec) using both polarities. In order to avoid confounding from missing data due to hearing impairment, participants had hearing thresholds <40 dB HL at 2 kHz and 70 dB HL at 4 kHz in at least one ear. Additionally, the median 2, 3, and 4 kHz pure tone threshold average (PTA2,3,4) for the sample, ∼17 dB HL, was used to delineate subgroups of better and worse hearing ears, and only the better hearing sample was modeled statistically. We modeled ABR responses using age, repetition rate, and PTA2,3,4 as covariates. Random effects were used to model correlation between the two ears of a subject and across repetition rates. Inferences regarding effects of aging on ABR measures at each rate were derived from the fitted model. Results were compared to data from subjects with poorer hearing. Aging substantially diminished amplitudes of all of the principal ABR peaks, largely independent of any threshold differences within the group. For waves I and III, age-related amplitude decrements were greatest at a low (11/sec) click rate. At the 11/sec rate, the model-based mean wave III amplitude was significantly smaller in older compared with younger subjects even after adjusting for wave I amplitude. Aging also increased ABR peak latencies, with significant shifts limited to early waves. The I-V IPI did not change with age. For both younger and older subjects, increasing click presentation rate significantly decreased amplitudes of early peaks and prolonged latencies of later peaks, resulting in increased IPIs. Advanced age did not enhance effects of rate. Instead, the rate effect on wave I and III amplitudes was attenuated for the older subjects due to reduced peak amplitudes at lower click rates. Compared with model predictions from the sample of better hearing subjects, mean ABR amplitudes were diminished in the group with poorer hearing, and wave V latencies were prolonged. In a sample of veterans, aging substantially reduced amplitudes of all principal ABR peaks, with significant latency shifts limited to waves I and III. Aging did not influence the I-V IPI even at high click rates, suggesting that the observed absolute latency changes associated with aging can be attributed to changes in auditory nerve input. In contrast, ABR amplitude changes with age are not adequately explained by changes in wave I. Results suggest that aging reduces the numbers and/or synchrony of contributing auditory nerve units. Results also support the concept that aging reduces the numbers, though perhaps not the synchrony, of central ABR generators.
    Full-text · Article · Jan 2012 · Journal of the American Academy of Audiology
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    ABSTRACT: Thirty-six blast-exposed patients and twenty-nine non-blast-exposed control subjects were tested on a battery of behavioral and electrophysiological tests that have been shown to be sensitive to central auditory processing deficits. Abnormal performance among the blast-exposed patients was assessed with reference to normative values established as the mean performance on each test by the control subjects plus or minus two standard deviations. Blast-exposed patients per-formed abnormally at rates significantly above that which would occur by chance on three of the behavioral tests of central auditory processing: the Gaps-In-Noise, Masking Level Difference, and Staggered Spondaic Words tests. The proportion of blast-exposed patients performing abnormally on a speech-in-noise test (Quick Speech-In-Noise) was also significantly above that expected by chance. These results suggest that, for some patients, blast exposure may lead to difficulties with hearing in complex auditory environments, even when peripheral hearing sensitivity is near normal limits.
    Full-text · Article · Jan 2012 · The Journal of Rehabilitation Research and Development
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Auditory system functions, from peripheral sensitivity to central processing capacities, are all at risk from a blast event. Accurate encoding of auditory patterns in time, frequency, and space are required for a clear understanding of speech and accurate localization of sound sources in environments with background noise, multiple sound sources, and/or reverberation. Further work is needed to refine the battery of clinical tests sensitive to the sorts of central auditory dysfunction observed in individuals with blast exposure. Treatment options include low-gain hearing aids, remote-microphone technology, and auditory-training regimens, but clinical evidence does not yet exist for recommending one or more of these options. As this population ages, the natural aging process and other potential brain injuries (such as stroke and blunt trauma) may combine with blast-related brain changes to produce a population for which the current clinical diagnostic and treatment tools may prove inadequate. It is important to maintain an updated understanding of the scope of the issues present in this population and to continue to identify those solutions that can provide measurable improvements in the lives of Veterans who have been exposed to high-intensity blasts during the course of their military service.
    Full-text · Article · Jan 2012 · The Journal of Rehabilitation Research and Development

  • No preview · Article · Aug 2011 · Seminars in Hearing
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    ABSTRACT: 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. 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. 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. 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. 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.
    No preview · Article · Feb 2011 · Ear and hearing
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    ABSTRACT: This paper presents an overview of key software applications implemented for our mobile, full-frequency-range, auditory testing system which is designed to detect changes in hearing sensitivity due to treatment with ototoxic medications. The system can be used efficiently in remote locations such as hospital wards, out-patient clinics, and industrial settings, as well as in patient homes to monitor for hearing change and also to perform general audiometric hearing threshold testing at frequencies out to 20kHz. We believe the system is the world's first instrument specifically designed to support the Sensitive Range for Ototoxicity (SRO), a shortened serial hearing monitoring protocol which has been shown sensitive and reliable in detecting early hearing change. The primary focus of this paper is to present a functional overview of the main mobile software application designed to support the SRO hearing monitoring protocol. Serial monitoring information for an actual patient is used to illustrate how the main software application is used to monitor and detect hearing change. Analysis of the patient's SRO monitoring data demonstrates the system's efficacy in detecting hearing threshold change. Overviews of two other support applications, one used for system calibration in the acoustics laboratory, and one used for acoustic performance verification in the field are also included.
    No preview · Conference Paper · Jan 2011

Publication Stats

2k Citations
203.09 Total Impact Points

Institutions

  • 1980-2015
    • Portland VA Medical Center
      Portland, Oregon, United States
  • 2014
    • University of Iowa
      Iowa City, Iowa, United States
  • 1999-2012
    • Oregon Health and Science University
      • Department of Otolaryngology, Head & Neck Surgery
      Portland, Oregon, United States
  • 1990-2012
    • U.S. Department of Veterans Affairs
      • National Center for Rehabilitative Auditory Research
      Washington, Washington, D.C., United States
  • 2005
    • University of Connecticut
      Storrs, Connecticut, United States
  • 1994
    • University of California, Los Angeles
      • Department of Head and Neck Surgery
      Los Ángeles, California, United States
  • 1993
    • United States Department of Veterans Affairs
      Бедфорд, Massachusetts, United States