Non-linear frequency compression (NLFC) hearing aids aim to deliver high-frequency sound to a better functioning, lower frequency region of the cochlea. Despite the widespread use of frequency lowering technology, it continues to be difficult to predict candidacy. Since the aim of NLFC is to improve high-frequency audibility, possible predictors of benefit may include high-frequency hearing thresholds. NLFC alters the harmonic relationship of speech, and it has frequently been proposed that auditory training may help users adapt to the distorted acoustic signal. The aim of this thesis was twofold: firstly, to identify audiometric predictors of benefit from NLFC, and secondly to explore the role of auditory training in adaptation to NLFC. The first study aimed to determine if outcome with NLFC was related to hearing thresholds. Twenty-one experienced adult hearing aid users, with mild-to-profound high-frequency hearing loss, completed speech recognition and self-report measures with NLFC enabled and disabled over 16 weeks. The additional benefit gained on phoneme detection and word recognition tasks with NLFC enabled was positively correlated with average high-frequency hearing loss. Additional benefit began to emerge as average high-frequency hearing thresholds exceeded 70 dB HL. There was some evidence of a ‘roll-off’ in additional benefit when hearing thresholds exceeded 100 dB HL. The second study aimed to identify which training method, if any, may help adaptation to NLFC. Forty young normally hearing adults were randomly allocated to one of four groups: a training group (sentence or consonant) or a control group (passive exposure or test-only). Training led to significant improvements on novel measures of speech recognition. Generalisation was limited to near transfer i.e. sentence training led to improved sentence recognition whilst consonant training led to improved consonant recognition. Improvements following passive exposure to frequency compressed sentences were equivalent to those achieved by active sentence training. Results from this second study suggest that auditory training may improve outcome for users of NLFC hearing aids, but passive exposure may be an important confounding variable. In the final study high-frequency focused sentence and consonant training was compared to sham training (passive exposure to a talking book). Twenty-six hearing-impaired adults who were new users of NLFC were allocated to either an auditory training or a sham training group. Measures of speech recognition and self-report benefit were administered before and after four weeks of home-based training. Auditory training significantly improved speech reception thresholds. In conclusion, benefit from NLFC was dependent on hearing thresholds; as hearing thresholds increased so did benefit. Participants with severe-to-profound high-frequency hearing loss gained most benefit from NLFC. Auditory training provided alongside NLFC significantly improved speech recognition in noise but changes to all other outcome measures were not significant.

Introduction: Disabling hearing loss is one of the most common sensory deficits; affecting approximately 466 million people worldwide. In the South African context, public health facilities have an uneven ratio between audiologists and patients in need and thus audiological services are often minimal. Successful application of tele-health may increase the scope of audiological services for hearing aid (HA) users. Research is needed to investigate feasibility of tele-health for audiological rehabilitation programmes such as auditory training (AT). Aim and Objectives: This study aimed to investigate the feasibility of implementing a telerehabilitation programme in a South African public health context. Objectives included: 1) determining online AT compliance; 2) determining the effect of online AT on speech perception in noise; 3) assessing experience and benefit of tele-rehabilitation through questionnaires and interviewing; and 4) cost estimation around tele-rehabilitation implementation. Research Design: A convergent mixed methods design with a feasibility approach was utilized. Data collection was through questionnaires, in-booth speech assessments, online AT and face-to-face interviewing. Participants undertook online AT over four weeks. Pre-/post- online AT: the APHAB, QuickSIN, Entrance/Exit Questionnaires, Interviews and System Usability Scale were administered. Descriptive statistics were used to analyse the quantitative data collected, and descriptive thematic analysis was used for the qualitative data. Study sample: Purposive sampling was used and three female adult (35 - 55 years) HA users from a public health facility participated. Results: 1) High compliance rate (84.82%) with 3 hours 25 minutes total clinician contact time, 2) clinical benefit with improvement in listening skills and perceived HA benefit, 3) positive participant feedback, and 4) estimated cost at R1350.00 per person. Conclusions: Findings from this feasibility study can be seen as positive indicators towards the use of tele-health as a delivery modality for audiological rehabilitation, also a tele-health hybrid model is recommended. However, larger-scaled research is needed.

No description available.

Auditory situation awareness (ASA) is essential for safety and survivability in military operations where many of the hazards are not immediately visible. Unfortunately, the Hearing Protection Devices (HPDs) required to operate in these environments can impede auditory localization performance. Promisingly, recent studies have exhibited the plasticity of the human auditory system by demonstrating that training can improve auditory localization ability while wearing HPDs, including military Tactical Communications and Protective Systems (TCAPS). As a result, the U.S. military identified the need for a portable system capable of imparting auditory localization acquisition skills at similar levels to those demonstrated in laboratory environments. The purpose of this investigation was to develop and validate a Portable Auditory Localization Acclimation Training (PALAT) system equipped with an improved training protocol against a proven laboratory grade system referred to as the DRILCOM system and subsequently evaluate the transfer-of-training benefit in a field environment. In Phase I, a systems decision process was used to develop a prototype PALAT system consisting of an expandable frame housing 32-loudspeakers operated by a user-controlled tablet computer capable of reproducing acoustically accurate localization cues similar to the DRILCOM system. Phase II used a within-subjects human factors experiment to validate whether the PALAT system could impart similar auditory localization training benefits as the DRILCOM system. Results showed no significant difference between the two localization training systems at each stage of training or in training rates for the open ear and with two TCAPS devices. The PALAT system also demonstrated the ability to detect differences in localization accuracy between listening conditions in the same manner as the DRILCOM system. Participant ratings indicated no perceived difference in localization training benefit but significantly preferred the PALAT system user interface which was specifically designed to improve usability features to meet requirements of a user operable system. The Phase III investigation evaluated the transfer-of-training benefit imparted by the PALAT system using a broadband stimulus to a field environment using gunshot stimulus. Training under the open ear and in-the-ear TCAPS resulted in significant differences between the trained and untrained groups from in-office pretest to in-field posttest. / Doctor of Philosophy / Auditory situation awareness (ASA) is essential for safety and survivability in military operations where many of the hazards are not immediately visible. Unfortunately, the Hearing Protection Devices (HPDs) required to operate in these environments can impede sound localization performance. Promisingly, recent studies have exhibited the ability of the human auditory system to learn by demonstrating that training can improve sound localization ability while wearing HPDs. As a result, the U.S. military identified the need for a portable system capable of improving sound localization performance at similar levels to those demonstrated in laboratory environments. The purpose of this investigation was to develop and validate a Portable Auditory Localization Acclimation Training (PALAT) system equipped with an improved training protocol against a proven laboratory grade system referred to as the DRILCOM system and subsequently evaluate the transfer-of-training benefit in a field environment. In Phase I, a systems decision process was used to develop a prototype PALAT system consisting of an expandable frame housing 32-loudspeakers operated by a user-controlled tablet computer capable of reproducing similar sounds as the DRILCOM system. Phase II used a within-subjects human factors experiment to validate whether the PALAT system could impart similar sound localization training benefits as the DRILCOM system. Results showed no significant difference between the two localization training systems at each stage of training or in training rates for the open ear and with two HPDs. The PALAT system also demonstrated the ability to detect differences in localization accuracy between listening conditions in the same manner as the DRILCOM system. Participant ratings indicated no perceived difference in localization training benefit but significantly preferred the PALAT system user interface which was specifically designed to improve usability features to meet requirements of a user operable system. The Phase III investigation evaluated the transfer-of-training benefit imparted by the PALAT system using a broadband stimulus to a field environment using gunshot stimulus. Training under the open ear and in-the-ear TCAPS resulted in significant differences between the trained and untrained groups from in-office pretest to in-field posttest.

Research has shown that re-learning to understand speech in noise can be a difficult task for adults with hearing aids (HA). If HA users want to improve their speech understanding ability, specific training may be needed. Auditory training is one type of intervention that may enhance listening abilities for adult HA users. The purpose of this study was to examine the behavioral effects of an auditory training program called Listening and Communication Enhancement (LACE™) in the Digital Video Display (DVD) format in new and experienced HA users. No research to date has been conducted on the efficacy of this training program. An experimental, repeated measures group design was used. Twenty–six adults with hearing loss participated in this experiment and were assigned to one of three groups: New HA + training, Experienced HA + training or New HA – control. Participants in the training groups completed twenty, 30 minute training lessons from the LACE™ DVD program at home over a period of 4-weeks. Trained group participants were evaluated at baseline, after 2-weeks of training and again after 4- weeks of training. Participants in the control group were evaluated at baseline and after 4-weeks of HA use. Findings indicate that both new and experienced users improved their understanding of speech in noise after training and perception of communication function. Effect size calculations suggested that a larger training effect was observed for new HA users compared to experienced HA users. New HA users also reported greater benefit from training compared to experienced users. Auditory training with the LACE ™ DVD format should be encouraged, particularly among new HA users to improve understanding speech in noise.

Purpose: To examine the role of compliance in the outcomes of computer-based auditory training with the Listening and Communication Enhancement (LACE) program in Veterans using hearing aids. Method: The authors examined available LACE training data for 5 tasks (i.e., speech-in-babble, time compression, competing speaker, auditory memory, missing word) from 50 hearing-aid users who participated in a larger, randomized controlled trial designed to examine the efficacy of LACE training. The goals were to determine: (a) whether there were changes in performance over 20 training sessions on trained tasks (i.e., on-task outcomes); and (b) whether compliance, defined as completing all 20 sessions, vs. noncompliance, defined as completing less than 20 sessions, influenced performance on parallel untrained tasks (i.e., off-task outcomes). Results: The majority, 84% of participants, completed 20 sessions, with maximum outcome occurring with at least 10 sessions of training for some tasks and up to 20 sessions of training for others. Comparison of baseline to posttest performance revealed statistically significant improvements for 4 of 7 off-task outcome measures for the compliant group, with at least small (0.2 < d < 0.3) Cohen's d effect sizes for 3 of the 4. There were no statistically significant improvements observed for the noncompliant group. Conclusion: The high level of compliance in the present study may be attributable to use of systematized verbal and written instructions with telephone follow-up. Compliance, as expected, appears important for optimizing the outcomes of auditory training. Methods to improve compliance in clinical populations need to be developed, and compliance data are important to report in future studies of auditory training.

Purpose: To examine the role of compliance in the outcomes of computer-based auditory training with the Listening and Communication Enhancement (LACE) program in Veterans using hearing aids. Method: The authors examined available LACE training data for 5 tasks (i.e., speech-in-babble, time compression, competing speaker, auditory memory, missing word) from 50 hearing-aid users who participated in a larger, randomized controlled trial designed to examine the efficacy of LACE training. The goals were to determine: (a) whether there were changes in performance over 20 training sessions on trained tasks (i.e., on-task outcomes); and (b) whether compliance, defined as completing all 20 sessions, vs. noncompliance, defined as completing less than 20 sessions, influenced performance on parallel untrained tasks (i.e., off-task outcomes). Results: The majority, 84% of participants, completed 20 sessions, with maximum outcome occurring with at least 10 sessions of training for some tasks and up to 20 sessions of training for others. Comparison of baseline to posttest performance revealed statistically significant improvements for 4 of 7 off-task outcome measures for the compliant group, with at least small (0.2 < d < 0.3) Cohen's d effect sizes for 3 of the 4. There were no statistically significant improvements observed for the noncompliant group. Conclusion: The high level of compliance in the present study may be attributable to use of systematized verbal and written instructions with telephone follow-up. Compliance, as expected, appears important for optimizing the outcomes of auditory training. Methods to improve compliance in clinical populations need to be developed, and compliance data are important to report in future studies of auditory training.

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.

No description available.

Hearing protection can mitigate the harmful effects of noise, but for Service Members these devices can also obscure auditory situation awareness cues. Tactical Communication and Protective Systems (TCAPS) can restore critical cues through electronic circuitry with varying effects on localization. Evidenced by past research, sound localization accuracy can improve with training. The investigator hypothesized that training with a broadband stimulus and reducing the number of presentations would result in training transfer. Additionally, training transfer would occur with implementation of more user-engaged training strategies. The purpose of the experiments described in this study was to develop an optimized auditory azimuth-training protocol for use in a field-validated portable training system sensitive to differences among different TCAPS. A series of indoor experiments aimed to shorten and optimize a pre-existing auditory localization training protocol. Sixty-four normal-hearing participants underwent localization training. The goal of training optimization included the following objectives: 1) evaluate the effects of reducing stimulus presentations; 2) evaluate the effects of training with a broadband stimulus (but testing on untrained military-relevant stimuli); and 3) evaluate performance differences according to training strategies. Twenty-four (12 trained and 12 untrained) normal-hearing listeners participated in the field-validation experiment. The experiment evaluated localization training transfer from the indoor portable system to live-fire blanks in field. While training conducted on the portable system was predicted to transfer to the field, differences emerged between an in-the-ear and over-the-ear TCAPS. Three of four untrained stimuli showed evidence of training transfer. Shortening the training protocol also resulted in training transfer, but manipulating training strategies did not. A comparison of changes in localization scores from the indoor pretest to the field posttest demonstrated significant differences among listening conditions. Training improved accuracy and response time for the open ear and one of two TCAPS. Posttest differences between the two TCAPS were not statistically significant. Despite training, localization with TCAPS never matched the open ear. The portable apparatus employed in this study offers a means to evaluate the effects of TCAPS on localization. Equipped with a known effect on localization, TCAPS users can render informed decisions on the benefits or risk associated with certain devices. / Doctor of Philosophy / Hearing protection can mitigate the harmful effects of noise, but for Service Members these devices can obscure auditory situation awareness cues. Certain powered hearing protection can restore critical cues through electronic circuitry with varying effects on localization. Evidenced by past research, sound localization accuracy can improve with training. The investigator hypothesized that training with a broadband stimulus and reducing the number of presentations would result in auditory learning. Additionally, implementing more user-engaged training strategies would demonstrate more auditory learning. The purpose of the experiments described in this study was to develop an optimized auditory azimuth-training protocol for use in a field-validated training system sensitive to differences among active hearing protection. A series of indoor experiments aimed to shorten and optimize a pre-existing auditory localization training protocol. Sixty-four normal-hearing participants underwent localization training. The goal of training optimization included the following objectives: 1) evaluate the effects of reducing stimulus presentations; 2) evaluate the effects of training with a broadband stimulus (but testing on untrained military-relevant stimuli); and 3) evaluate performance differences in localization performance according to training strategies. In the field-validation study, 12 trained and 12 untrained normal-hearing listeners participated. The experiment evaluated localization learning from the indoor portable training system to live-fire blanks in a field. Training conducted on the portable system was predicted to transfer to the field, but differences would emerge between an in-the-ear and an over-the-ear TCAPS. Three of four untrained stimuli showed evidence of localization learning. Shortening the protocol also resulted in localization learning, but manipulating training strategies did not. A comparison of changes in localization scores from the indoor pretest to the field posttest demonstrated significant differences among listening conditions. Training improved performance for the open ear and one of two active hearing protectors. Posttest differences between the two devices were not significant. Despite training, performance with hearing protection never equaled the open ear. The portable apparatus employed in this study offers a means to evaluate the effects of hearing protection on localization. Knowing the effects of hearing protection on localization apprises users of the benefits and/or risk associated with the use of certain devices.