Nonlinear frequency compression is a signal processing technique used to increase the audibility of high frequency speech sounds for hearing aid users with sloping, high frequency hearing loss. However, excessive compression ratios may reduce spectral contrast between sounds and negatively impact speech perception. This is of particular concern in infants and young children, who may not be able to provide feedback about frequency compression settings. This study explores use of an objective cortical auditory evoked potential that is sensitive to changes in spectral contrast, the auditory change complex (ACC), in the verification of frequency compression parameters. We recorded ACC responses in adult listeners to a spectral ripple contrast stimulus processed with a range of frequency compression ratios (1:1 to 4:1). Vowel identification, consonant identification, speech recognition in noise (QuickSIN), and behavioral ripple discrimination thresholds were also measured under identical frequency compression conditions. In Experiment 1, these measures were completed in ten adult normal hearing individuals to determine the effects of this type of signal processing in individuals with optimal hearing. In Experiment 2, these same measures were repeated in ten adults with sloping, high frequency hearing loss, which is the clinical population for whom this signal processing technique was intended. No significant relationship of compression ratio and vowel identification was found in the normal hearing listeners, though a significant negative effect of increasing frequency compression ratio was observed in the hearing impaired group. Significant effects of compression ratio on ACC amplitude, consonant identification, ripple discrimination threshold, and speech perception in noise were found for both the normal hearing and hearing impaired groups. These results indicate that the ACC response, like speech and non-speech perceptual measures, is sensitive to frequency compression ratio. Further investigation of this technique with hearing impaired individuals is needed to determine optimal stimulus and recording parameters for the ACC in both adults and children.

Bilaterally independent (mismatched) hearing aids cannot replicate the natural timing and level cues between ears, and hence, may result in negative consequences for localization and speech perception in spatially-separated noise performance. Five gain reduction patterns were used to evaluate the impact of bilaterally mismatched gain reduction schemes on localization and speech perception performance in noise, compared to an unaltered bilaterally linear time-invariant amplification scheme (reference scheme), in which audibility was optimized. The bilaterally mismatched gain reduction schemes were later matched (synchronized) between ears to explore the possibility of restoring the deteriorated performance due to the mismatched schemes. Sound quality and listening-effort ratings among different gain reduction patterns were assessed, as well as the relationship between self-reported localization ability in daily life and measured localization performance in a laboratory setting. Twenty-four bilateral hearing aid users were enrolled in this study and tested in a virtual environment with insert earphones. The results indicated that bilaterally mismatched gain reduction schemes had a negative impact on localization, compared to the reference scheme; whereas matching gain reduction schemes between ears improved the deteriorated localization performance. In contrast, the use of bilaterally mismatched gain reductions did not negatively impact the speech perception performance in noise. Matching the gain reduction scheme between ears actually resulted in reduced speech perception performance, compared to the mismatched gain reductions. Self-reported localization abilities were not found to be strongly related to the measured localization performance in this study. Finally, these five different gain reduction patterns did not result in significantly different overall sound quality ratings and listening-effort ratings for hearing aid users. However, the use of gain reductions (mismatched or matched) reduced the perceived noise intrusiveness, compared to the use of reference schemes. It is unclear why there was a discrepancy between the results of the localization and speech perception performance in the present study. It is likely that hearing-impaired listeners do not use binaural cues in the localization task in the same manner as in the speech perception task.

Current methods of selection of amplification are not readily applicable to children, and relatively few alternatives have been explored. Consequently, the audiologist must make a number of rather arbitrary judgements with little concrete information to support his recommendation of a given instrument. He has limited means of clinically determining the sustainability of the instrument for the child. This study was designed to explore the relationship between several factors which may add to the existing body of data related to the problems of amplification in children. In brief, the problem was to determine the various electrical and acoustical characteristics of hearing aids worn by children under study. A comparison of this information with hearing loss data would be studied to aid in understanding what relationships (if any) exist between the two measures. If in fact there is a relationship between the factors of hearing loss and hearing aid characteristics, this information may provide a more comprehensive and precise means of examining a given hearing aid in view of the hearing loss specific to each child. While this information may be preliminary in nature, it has application in the development of ongoing programs of evaluation and maintenance of hearing aids. A brief comparison of the present performance of the instrument with both the original performance levels and the child’s current needs would appear to be an integral part of such a program.

The aim of this study was to measure the effects of audiologic intervention on self-perceived quality of life in the elderly hearing-impaired population. The tested hypothesis was that hearing aid use would result in improved quality of life as measured by utilities. In this study, utilities were obtained using the U-Titer II, an interactive software program designed to measure an individual's health state preference or utility. This study also examined the issue of numeracy, which is described as an understanding of basic probability, and its effect with an individual's ability to accurately complete utilities. Data from 54 individuals fit with hearing aids in this randomized, controlled, pre-test/post-test experimental design study were analyzed. The participants completed the U-Titer II, a test of numeracy and the International Outcome Inventory for hearing Aids (IOI-HA). Three utility approaches were used in this study: Time Trade-Off (TTO), Standard Gamble (SG) and Rating Scale (RS). With each of the utility approaches, disease-specific (e.g., deafness vs. perfect hearing) and generic (death vs. perfect health) anchors were incorporated. Several research questions were posed to examine the sensitivity of utilities to hearing aid intervention. Question 1: Can the effects of hearing aid intervention be determined with a utility approach? Statistically significant differences between pre- and post-intervention utility scores were measured with disease-specific and generic anchors for only the TTO and RS approaches. These findings suggest that hearing aid intervention outcomes can be measured using either the TTO or RS utility approaches. Question 2: Is numeracy ability a factor in the usefulness of a utility approach for assessing the effects of hearing aid intervention? Statistical analysis showed that mean utility scores changed very little as a function of numeracy ability. These findings suggest that numeracy ability does not appear to affect utility scores. Question 3: What, if any, are the relationships between hearing aid benefit as measured by a utility approach and hearing aid benefit as measured by the IOI-HA? Spearman Rho correlations were conducted on the benefit data obtained from the two self-report measures (IOI-HA and utilities). The major findings from these analyses determined that the IOI-HA total scores were significantly correlated with utility outcomes as measured by TTO generic, TTO disease-specific, and RS disease-specific anchors. In general, correlations between the measures were higher with the disease-specific anchors than the generic anchors. Also, none of the correlations between any IOI-HA outcome domains and utility change scores with generic anchors obtained with the RS scale were significant. For utilities measured with disease-specific anchors, significant correlations were found with two IOI-HA outcome domains (benefit and satisfaction) and utility change scores as measured by the TTO technique. When the RS technique was utilized, significant correlations were found for four of the seven outcome domains (benefit, satisfaction, participation and impact of others). Thus, if the IOI-HA is used as a measure against which to validate the utility approach as a measure of hearing aid outcomes, the measure with the most face validity is a RS method with disease-specific anchors. However, if one wished to compare hearing aid intervention to intervention in other areas of health care, these data support the use of a TTO approach.

Both audiologists and hearing instrument specialists (HIS) can assess hearing loss and fit hearing aids; consumers interested in purchasing hearing aids can choose the type of hearing professional they see. However, there are vast differences in required training and scope of practice for each professional and advanced test batteries, such as those associated with vestibular assessment and tinnitus management, may distinguish the two professional groups more thoroughly than standard hearing testing and hearing aid fitting. This study aimed to determine the knowledge and opinions the average individual possesses regarding differences between these two types of hearing professionals in order to identify areas in which audiologists can more effectively differentiate themselves from hearing instrument specialists. A one-time survey was administered at 3 locations to a total of 47 English-speaking participants over the age of 18. Locations included the 2018 Remote Area Medical event in Gray, TN; the Johnson City Senior Center, and the Bristol Public Library. The survey consisted of 8 demographic questions with 3 additional questions if the participant wore hearing aids, followed by 18 questions that covered “Diagnostics,” “Intervention,” and “Interpersonal Patient Interactions.” Responses were analyzed for trends in overall data as well as in sub-categories for gender, household income, education level, age, and hearing aid use. Overall, participants tended to believe audiologists were most likely to perform tasks in the “Diagnostic” category, while a majority of participants believed both professionals could perform tasks in the “Intervention” category. There was no clear trend within the “Interpersonal Patient Interactions” category. Most participants believed that either both professional groups, or only audiologists, could perform most tasks adequately, indicating subjects likely do understand differences between the two professionals. In analyzing results, two issues emerged. The first was that the majority of participants believed that they would not be likely to pay a reasonable price for hearing aids when visiting either professional. One reason may be that only a few hearing aid companies produce most of the world’s hearing aids, leaving little room for low-cost competition. The “bundled” method which most hearing healthcare providers use for selling hearing aids along with services might also exert an influence on the perception of hearing aid pricing and may not be clear to patients who try to understand the actual cost of devices and services. Another issue identified in this survey was access. A significant number of respondents believed it was difficult to make and attend appointments with either professional, signifying a possible deficit in this area in access to hearing healthcare. The barriers to access included income, availability of transportation, inconvenient provider hours, and lack of insurance coverage. The results suggested that audiologists and HISs face challenges when recommending personal hearing devices to support rehabilitative efforts. Additionally, the provision of services that utilize advanced diagnostic batteries, such as balance assessment and tinnitus services, may offer audiologists an opportunity to distinguish their practices from those managed by HISs.

Excerpt: What? You say you don't believe in prescriptive methods for programming hearing aids? Really? Then let me ask you this: Your Monday morning patient has a relatively flat 60 dB loss of cochlear origin. Would you program his hearing aids with 60 dB gain? Of course not. How about 10 dB gain? Not good either, right? Guess what—the moment you reached these conclusions, you're already using a prescriptive fitting approach.

Objective: To examine the effectiveness of the Listening and Communication Enhancement (LACE) program as a supplement to standard-of-care hearing aid intervention in a Veteran population. Design: A multisite randomized controlled trial was conducted to compare outcomes following standard-of-care hearing aid intervention supplemented with (1) LACE training using the 10-session DVD format, (2) LACE training using the 20-session computer-based format, (3) placebo auditory training (AT) consisting of actively listening to 10 hr of digitized books on a computer, and (4) educational counseling - the control group. The study involved 3 VA sites and enrolled 279 veterans. Both new and experienced hearing aid users participated to determine if outcomes differed as a function of hearing aid user status. Data for five behavioral and two self-report measures were collected during three research visits: baseline, immediately following the intervention period, and at 6 months postintervention. The five behavioral measures were selected to determine whether the perceptual and cognitive skills targeted in LACE training generalized to untrained tasks that required similar underlying skills. The two self-report measures were completed to determine whether the training resulted in a lessening of activity limitations and participation restrictions. Outcomes were obtained from 263 participants immediately following the intervention period and from 243 participants 6 months postintervention. Analyses of covariance comparing performance on each outcome measure separately were conducted using intervention and hearing aid user status as between-subject factors, visit as a within-subject factor, and baseline performance as a covariate. Results: No statistically significant main effects or interactions were found for the use of LACE on any outcome measure. Conclusions: Findings from this randomized controlled trial show that LACE training does not result in improved outcomes over standard-of-care hearing aid intervention alone. Potential benefits of AT may be different than those assessed by the performance and self-report measures utilized here. Individual differences not assessed in this study should be examined to evaluate whether AT with LACE has any benefits for particular individuals. Clinically, these findings suggest that audiologists may want to temper the expectations of their patients who embark on LACE training.

Background: The International Outcome Inventory for Hearing Aids (IOI-HA) was develo developed as a global hearing aid outcome measure targeting seven outcome domains. The published norms were based on a private-pay sample who were fitted with analog hearing aids. Purpose: The purpose of this study was to evaluate the psychometric properties of th the IOI-HA and to establish normative data in a veteran sample. Research Design: Survey. Study Sample: The participants were 131 male veterans (mean age of 74.3 years, SD = 7.4) who were issued hearing aids with digital signal processing (DSP). Intervention: Hearing aids with DSP that were fitted bilaterally between 2005 and 2007. Data Collection and Analysis: Veterans were mailed two copies of the IOI-HA. The participants were instructed to complete the first copy of the questionnaire immediately and the second copy in two weeks. The completed questionnaires were mailed to the laboratory. The psychometric properties of the questionnaire were evaluated. As suggested by Cox and colleagues, the participants were divided into two categories based on their unaided subjective hearing difficulty. The two categories were (1) those with less hearing difficulty (none-to-moderate category) and (2) those who report more hearing difficulty (moderately severe severe+ category). The norms from the current veteran sample then were compared to the original, published sample. For each hearing difficulty category, the critical difference values were calculated for each item and for the total score. Results: A factor analysis showed that the IOI-HA in the veteran sample had the ident identical subscale structure as reported in the original sample. For the total scale, the internal consistency was good (Chronbach's α = 0.83), and the test-retest reliability was high ( λ = 0.94). Group and individual norms were developed for both hearing difficulty categories in the veteran sample. For each IOI-HA item, the critical difference scores were <1.0. This finding suggests that for any item on the IOI-HA, there is a 95 percent chance that an observed change of one response unit between two test sessions reflects a true change in outcome for a given domain. Conclusions: The results of this study confirmed that the psychometric properties of th the IOI-HA questionnaire are strong and are essentially the same for the veteran sample and the original private-pay sample. The veteran norms, however, produced higher outcomes than those established originally, possibly because of differences in the population samples and/or hearing on aid technology. Clinical and research applications of the current findings are presented. Based on the results from the current study, the norms established here should replace the original norms for use in veterans with current hearing aid technology.

Recall of hearing aid orientation (HAO) information by new hearing aid users was assessed in this pilot study. Twenty-eight older adults completed a 25-item recall test of hearing aid knowledge that contained questions targeting information presented during a typical HAO. The mean recall score immediately following the HAO was 80%. The mean recall score at the hearing aid follow-up 4 weeks later was 77%, indicating that most of the information was retained. Recall scores were not significantly different based on time of testing. Although a substantial amount of hearing aid use and care information was reported at the hearing aid follow-up, some important information was forgotten by several participants. These preliminary results suggest the need for greater focus on certain important hearing aid use and care information during the HAO.

abstract: Purpose: The goal of this study was to examine how vocabulary size and inhibitory control affect word learning in bilingual (English-Spanish) children with hearing loss. Experiment 1 examined whether children with larger vocabularies learn and retain more words than children with smaller vocabularies. Experiment 2 examined whether children with better inhibitory control learn and remember more words than children with poorer inhibitory control. In addition, monolingual and bilingual children with and without hearing loss were compared on word learning and inhibitory control tasks. Method: Seventy-three children between 8 and 12 years of age participated in the study. Forty children had normal hearing (20 monolingual and 20 bilingual) and 33 had hearing loss (20 monolingual and 13 bilingual). For Experiment 1, children completed a receptive vocabulary test in English and Spanish and three word learning tasks consisting of a training and a retention component in English, Spanish, and Arabic. For Experiment 2, children completed the flanker task for inhibitory control. Results: In Experiment 1, larger total (English + Spanish) receptive vocabularies were predictive of better word training outcomes in all languages and better Spanish word retention, after controlling for age, degree of hearing loss, and maternal education. Children with hearing loss performed more poorly in Spanish and Arabic word training and retention than children with normal hearing. No differences were observed between children with normal hearing and hearing loss in English word learning. In Experiment 2, inhibitory control only predicted English retention outcomes. Children with hearing loss showed poorer inhibitory control than hearing peers. No differences were observed between monolingual and bilingual children, with and without hearing loss, in word learning or inhibitory control. Conclusions: Language experience (measured by total vocabulary size) helps children learn new words and therefore children with hearing loss should receive well-fitted hearing aids and school accommodations to provide them with access to spoken language. Bilingual exposure does not impair nor facilitate word learning. Bilingual children showed similar difficulties with word learning and inhibitory control as monolingual peers with hearing loss. Hearing loss, probably via language deprivation, has broad effects on children’s executive function skills. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2019