Clinical Interpretation of Word-Recognition Scores for Listeners with Sensorineural Hearing Loss: Confidence Intervals, Limits, and Levels.

OBJECTIVES: Confidence levels were established to determine if a word-recognition score is within the expected range for a hearing loss group (based on 3-frequency pure-tone average) or significantly below or above the expected range. DESIGN: Two large clinical databases were mined to produce data-sets composed of word-recognition scores obtained with Q/MASS NU-6 materials and VA NU-6 materials for patients with average hearing losses ranging from 0 to 70 dB HL. Percentiles representing scores that are below (2.5%, 5%, and 10%) and above (90%, 95%, and 97.5%) the expected range (defined as the 80% confidence interval) were established. To estimate the distribution of scores and percentiles for the Auditec NU-6 materials (for which a large database is not available) Q/MASS scores were transformed to Auditec scores based on published psychometric functions. RESULTS: The resulting confidence levels and expected ranges of word-recognition scores should be useful for interpreting the relationship between a score and the distribution of scores for the patient's hearing loss severity. Confidence levels are described as low, moderate, and high corresponding to the statistical level of assurance that a score is lower or higher than the expected score. CONCLUSIONS: The confidence levels and expected ranges may be helpful for interpreting word-recognition scores obtained with three widely used sets of NU-6 test materials.

Non-linguistic auditory speech processing.

OBJECTIVES: A method for testing auditory processing of non-linguistic speech-like stimuli was developed and evaluated. DESIGN: Monosyllabic words were temporally reversed and distorted. Stimuli were matched for spectrum and level. Listeners discriminated between distorted and undistorted stimuli. STUDY SAMPLE: Three groups were tested. The Normal group was comprised of 12 normal-hearing participants. The Senior group was comprised of 12 seniors. The Hearing Loss group was comprised of 12 participants with thresholds of at least 35 dB HL at one or more frequencies. RESULTS: The Senior group scored lower than the Normal group, and the Hearing Loss group scored lower than the Senior group. Scores for forward compressed speech were slightly higher than backward compressed speech but the difference was not statistically significant. Retest scores were slightly higher than scores on the first test, but the difference was not statistically significant. CONCLUSIONS: Large differences in discrimination of distorted speech were observed among the three groups. Age and hearing loss separately affected performance. The depressed performance of the Senior group may be a result of "hidden hearing loss" that is attributed to cochlear synaptopathy. The backward-distorted speech task may be a useful non-linguistic test of speech processing that is language independent.

Evaluation of binomial distribution estimates of confidence intervals of speech-recognition test scores.

Speech-recognition tests are a routine component of the clinical hearing evaluation. The most common type of test uses recorded monosyllabic words presented in quiet. The interpretation of test scores relies on an understanding of the variance of repeated tests. Confidence intervals are useful for determining if two scores are significantly different or if the difference is due to the variability of test scores. Because the response to each test item is binary, either correct or incorrect, the binomial distribution has been used to estimate confidence intervals. This method requires that test scores be independent. If the scores are not independent, the binomial distribution will not accurately estimate the variance of repeated scores. A previously published dataset with repeated scores from normal-hearing and hearing-impaired listeners was used to derive confidence intervals from actual test scores in contrast to the predicted confidence intervals in earlier reports. This analysis indicates that confidence intervals predicted by the binomial distribution substantially overestimate the variance of repeated scores resulting in erroneously broad confidence intervals. High correlations were found for repeated scores, indicating that scores are not independent. The interdependence of repeated scores invalidates confidence intervals predicted by the binomial distribution. Confidence intervals and confidence levels for repeated measures were determined empirically from measured test scores to assist in interpreting differences between repeat scores.

Ambient Noise Monitoring during Pure-Tone Audiometry.

BACKGROUND: There is an increasing need to administer hearing tests outside of sound-attenuating rooms. Maximum permissible ambient noise levels (MPANLs) from published in standards (Occupational Health and Safety Administration [OSHA] 1983; American National Standards Institute [ANSI] S3.1-1999 (R2018)) can be modified to account for the additional attenuation provided by circumaural earphones (relative to supra-aural earphones) that are used for pure-tone audiometry. Ambient noise can influence the results of pure-tone audiometry by elevating thresholds by direct masking and by producing distractions that affect the accuracy of the test. The effects of these distractions have not been studied in relation to pure-tone audiometry in adult listeners. PURPOSE: In Part I MPANLs provided by ANSI and OSHA standards are extended to account for the greater attenuation provided by circumaural earphones. Rules ("alerts") were developed taking into account the listeners' thresholds. In Part II effects of distracting noise on pure-tone thresholds are reported. METHODS AND RESULTS: In Part I MPANLs two standards were modified for circumaural earphones by adding the additional attenuation provided by three circumaural earphones (relative to supra-aural earphones). A set of rules ("alerts") is provided for identifying masking effects from ambient noise in a variety of conditions (earphone type, threshold elevation, uncovered ear). In Part II the distracting effects of an industrial noise sample on thresholds obtained from five listeners with normal hearing are described. Pure-tone thresholds were measured in quiet and in distracting noise presented at various levels. The effects of the distracting noise on the following variables were measured: time per trial, number of trials required to measure threshold, threshold shift, and perceived distractibility of the noise. Time per trial was unaffected by distracting noise. Number of trials required for threshold, threshold shift, and perceived distractibility increased with distracting noise level. CONCLUSION: Part I: The modified MPANLs provide more relevant determinations of the potential effects of ambient noise on pure-tone thresholds than the values in the standards. Part II: Distracting noise affects pure-tone threshold measurements in a manner that is different from direct masking. The potential contaminating effect of distracting noise can be measured and reported.

AMBAND Bone-Conduction Headband.

PURPOSE: As bone-conduction thresholds vary with the coupling force between the vibrator and the head, it is important that the coupling force be within the range specified by audiometer standards. The development and validation of AMBAND, an elastic headband for coupling an audiometric bone vibrator to the head, in either the mastoid or forehead position, is described. METHODS: The headband was constructed from woven, fold-over elastic with Velcro attachment points to produce the proper force on the head for various head sizes. Force measurements were made with a digital force gauge on five artificial heads, representing adult females, adult males, children (age 6 years), infants (age 6 months), and newborns with the bone vibrator in the mastoid and forehead positions. Additional measurements were made with the Radioear P-3333 spring band that is in common use. RESULTS: Force measurements were highly repeatable within a given headband and across headbands. Force measurements for AMBAND were within the range specified by the ANSI S3.6-2018. The Radioear P-3333 spring band produced force levels that exceeded the specified range and had higher variability compared with AMBAND. CONCLUSION: AMBAND can be used to couple audiometric bone vibrators to the head in the forehead and mastoid positions during bone-conduction testing to provide accurate threshold measurements.

Hearing Health Care Utilization Following Automated Hearing Screening.

BACKGROUND: The study examined follow-up rates for pursuing hearing health care (HHC) 6 to 8 months after participants self-administered one of three hearing screening methods: an automated method for testing of auditory sensitivity (AMTAS), a four-frequency pure-tone screener (FFS), or a digits-in-noise test (DIN), with and without the presentation of a 2-minute educational video about hearing. PURPOSE: The study aims to determine if the type of self-administered hearing screening method (with or without an educational video) affects HHC follow-up rates. RESEARCH DESIGN: The study is a randomized controlled trial of three automated hearing screening methods, plus control group, with and without an educational video. The control group completed questionnaires and provided follow-up data but did not undergo a hearing screening test. STUDY SAMPLE: The study sample includes 1,665 participants (mean age 50.8 years; 935 males) at two VA Medical Centers and at university and community centers in Portland, OR; Bay Pines, FL; Minneapolis, MN; Mauston, WI; and Columbus, OH. DATA COLLECTION AND ANALYSIS: HHC follow-up data at 6 to 8 months were obtained by contacting participants by phone or mail. Screening methods and participant characteristics were compared in relation to the probability of participants pursuing HHC during the follow-up period. RESULTS: The 2-minute educational video did not have a significant effect on HHC follow-up rates. When all participants who provided follow-up data are considered (n = 1012), the FFS was the only test that resulted in a significantly greater percentage of HHC follow-up (24.6%) compared with the control group (16.8%); p = 0.03. However, for participants who failed a hearing screening (n = 467), follow-up results for all screening methods were significantly greater than for controls. The FFS resulted in a greater probability for HHC follow-up overall than the other two screening methods. Moreover, veterans had higher follow-up rates for all screening methods than non-veterans. CONCLUSION: The FFS resulted in a greater HHC follow-up rate compared with the other screening methods. This self-administered test may be more motivational for HHC follow-up because participants who fail the screening are aware of sounds they could not hear which does not occur with adaptive assessments like AMTAS or the DIN test. It is likely that access to and reduced personal cost of audiological services for veterans contributed to higher HHC follow-up rates in this group compared with non-veteran participants.

Automated Forced-Choice Tests of Speech Recognition.

PURPOSE: This project was undertaken to develop automated tests of speech recognition, including speech-recognition threshold (SRT) and word-recognition test, using forced-choice responses and computerized scoring of responses. Specific aims were (1) to develop an automated method for measuring SRT for spondaic words that produces scores that are in close agreement with average pure-tone thresholds and (2) to develop an automated test of word recognition that distinguishes listeners with normal hearing from those with sensorineural hearing loss and which informs the hearing aid evaluation process. METHOD: An automated SRT protocol was designed to converge on the lowest level at which the listener responds correctly to two out of two spondees presented monaurally. A word-recognition test was conducted with monosyllabic words (female speaker) presented monaurally at a fixed level. For each word, there were three rhyming foils, displayed on a touchscreen with the test word. The listeners touched the word they thought they heard. Participants were young listeners with normal hearing and listeners with sensorineural hearing loss. Words were also presented with nonrhyming foils and in an open-set paradigm. The open-set responses were scored by a graduate student research assistant. RESULTS: The SRT results agreed closely with the pure-tone average (PTA) obtained by automated audiometry. The agreement was similar to results obtained with the conventional SRT scoring method. Word-recognition scores were highest for the closed-set, nonrhyming lists and lowest for open-set responses. For the hearing loss participants, the scores varied widely. There was a moderate correlation between word-recognition scores and pure-tone thresholds which increased as more high frequencies were brought into the PTA. Based on the findings of this study, a clinical protocol was designed that determines if a listener's performance was in the normal range and if the listener benefited from increasing the level of the stimuli. CONCLUSION: SRTs obtained using the automated procedure are comparable to the results obtained by the conventional clinical method that is in common use. The automated closed-set word-recognition test results show clear differentiation between scores for the normal and hearing loss groups. These procedures provide clinical test results that are not dependent on the availability of an audiologist to perform the tests.

Comparison of Thresholds Obtained With the Radioear B-71 and B-81 Bone-Conduction Transducers.

OBJECTIVES: A new bone conduction transducer, the Radioear B-81, has been designed to be an improvement over the commonly used transducer, the Radioear B-71. Reference Equivalent Threshold Force Levels (RETFLs) were obtained with the new Radioear B-81. DESIGN: Thresholds were obtained in accordance with ANSI-S3.6-2018 (Annex D) and participants were selected as prescribed in ISO 389.9-2009. Thresholds were obtained with automatic audiometry using circumaural earphones (Radioear DD450) and forehead placement of the bone vibrators. RESULTS: Mean bone conduction thresholds obtained using the B-81 and B-71 bone oscillators for frequencies from 250 to 4000 Hz were not statistically different. RETFLs for the B-81 are identical to the values in ANSI S3.6-2018 for the B-71 bone vibrator. Air-bone gaps were observed for both transducers at low frequencies (250 and 500 Hz) due to occlusion effects produced by the circumaural earphone and at high frequencies (3000 and 4000 Hz), previously reported in several studies that used standard RETFLs. Test-retest differences for air conduction thresholds were analyzed and the results are presented in the Appendix A (Supplemental Digital Content 1, http://links.lww.com/EANDH/A639). CONCLUSIONS: RETFLs in ANSI S3.6-2018 and ISO 389.3-2016 are appropriate for use with the B-81 bone vibrator.

Techniques for Obtaining High-quality Recordings in Electrocochleography.

There are several technical challenges to obtaining high-quality recordings of cochlear potentials in human electrocochleography (ECochG). These challenges include electrical artifacts from devices such as acoustic transducers, biological artifacts from excessive myogenic and electroencephalographic potentials, and issues associated with the placement of a tympanic membrane (TM) electrode on the eardrum. This article presents approaches for dealing with these challenges for ECochG measurement using a TM electrode. Emphasis is placed on eliminating stimulus artifact, optimizing the placement of the electrode, and comparing a custom-made electrode with a commercially-available electrode. This comparison revealed that the custom-made electrode results in greater subject comfort, superior ease of placing the electrode on the eardrum, and larger compound action potential (CAP) amplitudes.

Sunny with a Chance of Curtailment: Operating the US Grid with Very High Levels of Solar Photovoltaics.

With rapid declines in solar photovoltaic (PV) and energy storage costs, futures with PV penetrations approaching or exceeding 50% of total annual US generation are becoming conceivable. The operational merits of such a national-scale system have not been evaluated sufficiently. Here, we analyze in detail the operational impacts of a future US power system with very high annual levels of PV (>50%) with storage. We show that load and operating reserve requirements can be met for all hours while considering key generator operational constraints. Storage plays an active role in maintaining the balance of supply and demand during sunset hours. Under the highest PV penetration scenario, hours with >90% PV penetration are relatively common, which require rapid transitions between predominately conventional synchronous generation and mostly inverter-based generation. We observe hours with almost 400 GW (over 40%) of economic curtailment and frequent (up to 36%) hours with very low energy prices.

Evaluation of Two Circumaural Earphones for Audiometry.

OBJECTIVE: The Sennheiser HDA 200 earphone, a standard circumaural earphone used in audiometry for many years, is out of production and is replaced by the RadioEar DD450. The Sennheiser HD 280 Pro earphone is a consumer product that has characteristics that may be suitable for audiometry and may be a low-cost alternative to the DD450. The DD450 and HD 280 Pro earphones were compared with the HDA 200 for use in audiometry. DESIGN: RadioEar DD450 and Sennheiser HD 280 Pro earphones were evaluated for reference equivalent threshold sound pressure levels (RETSPLs), ambient-noise attenuation, and occlusion effects. Audiometric thresholds measured on a group of normal-hearing adults were used to determine RETSPLs. Ambient-noise attenuation was determined by measuring the sound pressure in the ear canal produced by a broadband signal from a loudspeaker with and without occlusion by the earphone. Acoustic occlusion effects were determined by measuring the ear-canal sound pressure produced by a bone-conducted source with and without occlusion by the earphone. The results were compared with measurements obtained from the HDA 200 earphone. RESULTS: Audiometric thresholds obtained using the DD450 earphone did not differ from those obtained with the HDA 200 earphones, indicating that the HDA 200 RETSPLs provided in the audiometer standards (ANSI S3.6-2010; ISO 389-8-2004) are transferable to the DD450. New RETSPLs for the HD 280 Pro earphone were determined from the threshold measurements. Ambient-noise attenuation provided by the DD450 was equivalent to the attenuation provided by the HDA 200. The HD 280 Pro provided less ambient-noise attenuation than the other circumaural earphones, but more than the supra-aural earphones commonly used in audiometry. The DD450 produced an occlusion effect 5 dB larger than that of the HDA 200 at 0.25 and 0.5 kHz; both earphones produced negligible occlusion effects at higher frequencies. The HD 280 Pro produced larger occlusion effects in the low frequencies than the other two earphones, with negligible occlusion effects at 1.0 kHz and above. CONCLUSIONS: The HDA 200 RETSPLs are transferable to the DD450. Ambient-noise attenuation and occlusion effects are similar for these two earphones. RETSPLs for the HD 280 Pro are provided. The HD 280 Pro has less ambient-noise attenuation and larger occlusion effects than the DD450 but is a viable low-cost alternative.

p27Kip1 regulates the microtubule bundling activity of PRC1.

Cytokinesis begins in anaphase with the formation of the central spindle. PRC1 is a microtubule associated protein that plays an essential role in central spindle formation by crosslinking antiparallel microtubules. We have identified PRC1 as a novel binding partner for p27Kip1 (p27). p27 is a cyclin-CDK inhibitor that causes cell cycle arrest in G1. However, p27 has also been involved in the regulation of G2/M progression and cytokinesis, as well as of other cellular processes, including actin and microtubule cytoskeleton dynamics. We found that p27 interferes with the ability of PRC1 to bind to microtubules, without affecting PRC1 dimerization or its capacity to interact with other partners such as KIF4. In this way, p27 inhibited microtubule bundling by PRC1 in vitro and prevented the extensive microtubule bundling phenotype caused by PRC1 overexpression in cells in culture. Finally, co-expression of p27 or a p27 mutant that does not bind cyclin-CDKs inhibited multinucleation induced by PRC1 overexpression. Together, our results suggest that p27 may participate in the regulation of mitotic progression in a CDK-independent manner by modulating PRC1 activity.

Home Hearing Test: Within-Subjects Threshold Variability.

BACKGROUND: The Home Hearing Test (HHT) is an automated pure-tone threshold test that obtains an air conduction audiogram at five test frequencies. It was developed to provide increased access to hearing testing and support home telehealth programs. PURPOSE: Test and retest thresholds for 1000-Hz stimuli were analyzed to determine intrasubject variability from two independent data sets. RESEARCH DESIGN: Prospective, repeated measures. STUDY SAMPLE: In the Veterans Affairs (VA) study, results from 26 subjects 44 to 88 years of age (mean = 65) recruited from the Nashville VA audiology clinic were analyzed. Subjects were required to have a Windows PC in the home and were self-reported to be comfortable with using computers. Two subjects had normal hearing, and 24 had hearing losses of various severities and configurations. The National Center for Rehabilitative Auditory Research (NCRAR) sample included 100 subjects (68 males; 32 females) with a complaint of hearing difficulty recruited from the local community and Veteran population. Subjects ranged in age from 32 to 87 years (mean = 63.7 years). They were tested in a quiet room at the NCRAR. DATA COLLECTION AND ANALYSIS: Subjects in the VA study were provided kits for installing HHT on their home computers. HHT was installed on a computer at NCRAR to test subjects in the NCRAR study. HHT obtains a five-frequency air conduction audiogram with a retest of 1000 Hz in both ears. Only the 1000-Hz test-retest results are analyzed in this report. Six statistical measures of test-retest variability are reported. RESULTS: Test and retest thresholds were highly correlated in both studies (r ≥ 0.96). Test-retest differences were within ±5 dB ≥92% of the time in the two studies. Standard deviations of absolute test-retest difference were ≤3.5 dB in the two studies. CONCLUSIONS: Intrasubject variability is comparable to that obtained with manual testing by audiologists in sound-treated test rooms.

Validation of the Home Hearing Test™.

BACKGROUND: The Home Hearing Test™ (HHT) is an automated pure-tone threshold test that obtains an air-conduction audiogram at five test frequencies. It was developed to provide increased access to hearing testing and support home telehealth programs. PURPOSE: The study was conducted as part of an audiology telehealth trial based at the U.S. Department of Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN. Air-conduction audiograms obtained by the HHT were compared to results obtained in the clinic. RESEARCH DESIGN: Prospective, repeated measures. STUDY SAMPLE: Twenty-eight participants, aged 44-88 yr (mean = 65) were recruited from the Nashville U.S. Department of Veterans Affairs audiology clinic. Participants were required to have a Windows personal computer in the home and were self-reported to be comfortable with using computers. Two participants had normal hearing and 26 had hearing loss of various severities and configurations. DATA COLLECTION AND ANALYSIS: Audiograms were obtained in the audiology clinic by experienced audiologists following standard clinical protocols. Participants were provided with a kit for installing HHT on their home computers. The HHT air-conduction audiogram is obtained with Automated Method for Testing Auditory Sensitivity (AMTAS(®)), described in previous publications. Threshold pairs (clinic versus HHT) were analyzed by determining distributions of threshold differences and absolute differences. These were compared to distributions of differences between manual threshold pairs obtained by two audiologists and AMTAS(®) versus manual threshold pairs obtained under laboratory conditions. RESULTS: Threshold differences (clinic versus HHT) were slightly larger than differences between thresholds obtained by two audiologists and AMTAS(®) versus manual threshold differences obtained under laboratory conditions. The differences were not statistically significant. CONCLUSIONS: HHT air-conduction audiograms agree well with audiograms obtained in the clinic. HHT is well suited to home telehealth applications and personal use.

Distribution Characteristics of Air-Bone Gaps: Evidence of Bias in Manual Audiometry.

OBJECTIVES: Five databases were mined to examine distributions of air-bone gaps obtained by automated and manual audiometry. Differences in distribution characteristics were examined for evidence of influences unrelated to the audibility of test signals. DESIGN: The databases provided air- and bone-conduction thresholds that permitted examination of air-bone gap distributions that were free of ceiling and floor effects. Cases with conductive hearing loss were eliminated based on air-bone gaps, tympanometry, and otoscopy, when available. The analysis is based on 2,378,921 threshold determinations from 721,831 subjects from five databases. RESULTS: Automated audiometry produced air-bone gaps that were normally distributed suggesting that air- and bone-conduction thresholds are normally distributed. Manual audiometry produced air-bone gaps that were not normally distributed and show evidence of biasing effects of assumptions of expected results. In one database, the form of the distributions showed evidence of inclusion of conductive hearing losses. CONCLUSIONS: Thresholds obtained by manual audiometry show tester bias effects from assumptions of the patient's hearing loss characteristics. Tester bias artificially reduces the variance of bone-conduction thresholds and the resulting air-bone gaps. Because the automated method is free of bias from assumptions of expected results, these distributions are hypothesized to reflect the true variability of air- and bone-conduction thresholds and the resulting air-bone gaps.

The Acoustic Test Environment for Hearing Testing.

BACKGROUND: Audiology clinics traditionally employ expensive, prefabricated sound rooms to create an environment that is sufficiently quiet for accurate hearing tests. There is seldom any analysis of the need for or benefit from such enclosures. There may be less expensive methods that would decrease the cost of and increase access to hearing testing. PURPOSE: This report provides information concerning the need for and effectiveness of sound rooms and an analysis of the audiometric test ranges for various earphone/room combinations. RESEARCH DESIGN: Acoustic measurements made in four rooms were analyzed with the attenuation provided by various earphone designs to determine the maximum permissible ambient noise levels and the corresponding audiometric test ranges. STUDY SAMPLE: The measurements and calculations were performed with four test rooms and five earphone designs. DATA COLLECTION AND ANALYSIS: Ambient noise levels and earphone attenuation characteristics were used to calculate the noise levels that reach the ear. Those were compared to the maximum permissible ambient noise levels that are provided in ANSI S3.1-1999 or calculated from measured attenuation levels. These measurements were used to calculate testable ranges for each room/earphone combination. RESULTS: The various room/earphone combinations resulted in minimum test levels that ranged from -10 to 20 dB HL at various test frequencies. CONCLUSIONS: When the actual benefits of expensive prefabricated sound rooms are assessed based on the range of hearing levels that can be tested, the effectiveness of that approach becomes highly questionable. Less expensive methods based on planning the clinic space, use of inexpensive sound treatments, and selecting an appropriate earphone can be effective in almost any space that would be used for hearing testing.