Evidence for the use of hearing assistive technology by adults: the role of the FM system

Factors in the Effective Use of Hearing Aids among Subjects with Age-Related Hearing Loss: A Systematic Review

Objectives: Investigate factors contributing to the effective management of age-related hearing loss (ARHL) rehabilitation. Methods: A systematic review was conducted following PRISMA guidelines. The protocol was registered in PROSPERO (CRD42022374811). Articles were identified through systematic searches in the Scopus, PubMed, Web of Science, and Cochrane databases in May 2024. Only articles published between January 2005 and May 2024 were included. Studies were assessed for eligibility by two independent researchers and evaluated using the Crowe Critical Appraisal Tool v1.4 (CCAT). Results: Of the 278 articles identified, 54 were included. Three factors explain effective HA use. First, hearing aid signal processing, with directional microphones and noise reduction, improves user comfort and understanding regarding noise. Second, there is hearing aid fitting, with the NAL prescription rules as the gold standard, and bilateral, high-level HA performance for spatial localization and noise comprehension. Third, there is a patient-centered approach, using patient-related outcome measures (PROMs), questionnaires, counseling, and regular follow-up to involve patients in their therapeutic rehabilitation. Conclusions: Reaching a consensus on acoustic parameters is challenging due to variability in audiological results. Involving patients in their rehabilitation, addressing their needs and expectations, and offering individualized care are crucial.

Hearing rehabilitation of adults with auditory processing disorder: a systematic review and meta-analysis of current evidence-based interventions

Background

For adults with auditory processing disorder (APD), listening and communicating can be difficult, potentially leading to social isolation, depression, employment difficulties and certainly reducing the quality of life. Despite existing practice guidelines suggesting treatments, the efficacy of these interventions remains uncertain due to a lack of comprehensive reviews. This systematic review and meta-analysis aim to establish current evidence on the effectiveness of interventions for APD in adults, addressing the urgent need for clarity in the field.

Methods

Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic search across MEDLINE (Ovid), Embase (Ovid), Web of Science and Scopus, focusing on intervention studies involving adults with APD. Studies that met the inclusion criteria were grouped according to intervention with a meta-analysis only conducted where intervention, study design and outcome measure were comparable.

Results

Out of 1,618 screened records, 13 studies were included, covering auditory training (AT), low-gain hearing aids (LGHA), and personal remote microphone systems (PRMS). Our analysis revealed: AT, Mixed results with some improvements in speech intelligibility and listening ability, indicating potential benefits but highlighting the need for standardized protocols; LGHA, The included studies demonstrated significant improvements in monaural low redundancy speech testing (p < 0.05), suggesting LGHA could enhance speech perception in noisy environments. However, limitations include small sample sizes and potential biases in study design. PRMS, Demonstrated the most consistent evidence of benefit, significantly improving speech testing results, with no additional benefit from combining PRMS with other interventions.

Discussion

PRMS presents the most evidence-supported intervention for adults with APD, although further high-quality research is crucial for all intervention types. The establishment and implementation of standardized intervention protocols alongside rigorously validated outcome measures will enable a more evidence-based approach to managing APD in adults.

Central Auditory Processing Dysfunction in Service Members and Veterans: Treatment Considerations and Strategies

PURPOSE

Military risk factors such as blast exposure, noise exposure, head trauma, and neurotoxin exposure place Service members and Veterans at risk for deficits associated with auditory processing dysfunction. However, there is no clinical guidance specific to the treatment of auditory processing deficits in this unique population. We provide an overview of available treatments and their limited supporting evidence for use in adults, emphasizing the need for multidisciplinary case management and interdisciplinary research to support evidence-based solutions.

METHOD

We explored relevant literature to inform the treatment of auditory processing dysfunction in adults, with emphasis on findings involving active or former military personnel. We were able to identify a limited number of studies, pertaining primarily to the treatment of auditory processing deficits through the use of assistive technologies and training strategies. We assessed the current state of the science for knowledge gaps that warrant additional study.

CONCLUSIONS

Auditory processing deficits often co-occur with other military injuries and may pose significant risk in military operational and occupational settings. Research is needed to advance clinical diagnostic and rehabilitative capabilities, guide treatment planning, support effective multidisciplinary management, and inform fitness-for-duty standards. We emphasize the need for an inclusive approach to the assessment and treatment of auditory processing concerns in Service members and Veterans and for evidence-based solutions to address complex military risk factors and injuries.

Effect of Hearing Device Use on Speech-in-Noise Performance in Children with Severe-to-Profound Unilateral Hearing Loss

OBJECTIVES

Limited evidence exists for the use of rerouting devices in children with severe-to-profound unilateral sensorineural hearing loss. Many laboratory studies to date have evaluated hearing-in-noise performance in specific target-masker spatial configurations within a small group of participants and with only a subset of available hearing devices. In the present study, the efficacy of all major types of nonsurgical devices was evaluated within a larger group of pediatric subjects on a challenging speech-in-noise recognition task.

DESIGN

Children (7-18 years) with unaided severe-to-profound unilateral hearing loss (UHL' n = 36) or bilateral normal hearing (NH, n = 36) participated in the present study. The signal-to-noise ratio (SNR) required for 50% speech understanding (SNR-50) was measured using BKB sentences in the presence of proprietary restaurant noise (R-SPACE BSIN-R) in the R-SPACE Sound System. Subjects listened under 2 target/masker spatial configurations. The target signal was directed toward subjects' NH or hearing-impaired ear (45º azimuth), while the interfering restaurant noise masker was presented from the remaining 7 loudspeakers encircling the subject, spaced every 45º. Head position was fixed during testing. The presentation level of target sentences and masking noise varied over time to estimate the SNR-50 (dB). The following devices were tested in all participants with severe-to-profound UHL: air conduction (AC) contralateral routing of signal (CROS), bone conduction (BC) CROS fitted on a headband with and without the use of remote microphone (RM), and an ear-level RM hearing assistance technology (HAT) system.

RESULTS

As a group, participants with severe-to-profound UHL performed best when the target signal was directed toward their NH ear. Across listening conditions, there was an average 8.5 dB improvement in SNR-50 by simply orienting the NH ear toward the target signal. When unaided, participants with severe-to-profound UHL performed as well as participants with NH when the target signal was directed toward the NH ear. Performance was negatively affected by AC CROS when the target signal was directed toward the NH ear, whereas no statistically significant change in performance was observed when using BC CROS. When the target signal was directed toward participants' hearing-impaired ear, all tested devices improved SNR-50 compared with the unaided condition, with small improvements (1-2 dB) observed with CROS devices and the largest improvement (9 dB) gained with the personal ear-level RM HAT system. No added benefit nor decrement was observed when RM was added to BC CROS using a 50/50 mixing ratio when the target was directed toward the impaired ear.

CONCLUSIONS

In a challenging listening environment with diffuse restaurant noise, SNR-50 was most improved in the study sample when using a personal ear-level RM HAT system. Although tested rerouting devices offered measurable improvement in performance (1-2 dB in SNR-50) when the target was directed to the impaired ear, benefit may be offset by a detriment in performance in the opposing condition. Findings continue to support use of RM HAT for children with severe-to-profound UHL in adverse listening environments, when there is one primary talker of interest, to ensure advantageous SNRs.

A Qualitative Investigation of Clients, Significant Others, and Clinicians' Experiences of Using Wireless Microphone Systems to Manage Hearing Impairment

This study aimed to explore the perceptions and experiences of adults with hearing impairment (HI), their significant others (SOs), and clinicians regarding the use and provision of wireless microphone systems (WMS). A qualitative descriptive methodology was used, with a total of 43 participants across three groups: (1) 23 adults with HI who used WMS; (2) 7 SOs of adults who used WMS; and (3) 13 clinicians who provided WMSs to adults with HI. Participants completed an individual semi-structured in-depth interview to explore their experiences, with the data analysed using thematic analysis. The analysis revealed five themes encompassing the perceptions and experiences of WMSs: (1) with experience and clear expectations, users believe that WMS can make a difference; (2) the trial and decision-making process is important; (3) clients' experiences using WMS; (4) issues with WMS and technology; and (5) users require ongoing training and support to use WMS. These findings highlight the complexities of providing and using WMS with adults with HI. However, clients, SOs, and clinicians all reported that, with appropriate experience, expectations, training, and support, WMS can make a real difference in listening and communicating in different situations. There is also an opportunity to involve SOs more throughout the rehabilitation process.

Psychosocial Impact of Assistive Devices and Other Technologies on Deaf and Hard of Hearing People

Deaf and hard of hearing people use a variety of assistive devices and technologies as a strategy to mitigate, counter or compensate for life difficulties resulting from hearing loss. Although outcome measures are commonly used with hearing aids, few studies have explored the perceived psychosocial impact of other assistive devices and technologies or the factors leading to their abandonment or lack of use. Therefore, the main aim of this study was to assess the psychosocial impact of different assistive devices on deaf and hard of hearing people using the Psychosocial Impact of Assistive Devices Scale. The sample was made up of 291 individuals, 176 women and 115 men, with an average age of 56.12 years (standard deviation (SD) = 25.11), who were all users of different assistive devices. Overall, the results of the study showed that the use of assistive devices had a positive psychosocial impact, although this impact varied slightly depending on the specific type of device. Moreover, a relationship was identified between the psychosocial impact and the probability of future abandonment of a hearing aid or a cochlear implant. The results point to the importance of considering the psychosocial impact derived from the use of a device as a relevant variable in the adoption process of assistive technologies for deaf and hard of hearing people.

Design and verification of a measurement setup for wireless remote microphone systems (WRMSs)

OBJECTIVE

This work presents the design and verification of a simplified measurement setup for wireless remote microphone systems (WRMSs), which has been incorporated into guidelines of the European Union of Hearing Aid Acousticians (EUHA).

DESIGN

Three studies were conducted. First, speech intelligibility scores within the simplified setup were compared to that in an actual classroom. Second, different WRMSs were compared in the simplified setup, and third, normative data for normal-hearing people with and without WRMS were collected.

STUDY SAMPLE

The first two studies include 40 older hearing impaired and the third study 20 young normal-hearing adults.

RESULTS

Speech intelligibility with WRMS was not different across actual classroom and simplified setup. An analog omnidirectional WRMS showed poorer speech intelligibility and poorer quality ratings than digital WMRSs. The usage of a WRMS in the simplified setup resulted in significantly higher speech intelligibility across all tested background noise levels.

CONCLUSIONS

Despite being a simplified measurement setup, it realistically emulates a situation where people are listening to speech in noise from a distance, such as in a classroom or meeting room. Hence, with standard audiological equipment, the individual benefit of WRMSs can be measured and experienced by the user in clinical practice.

Guidelines for Best Practice in the Audiological Management of Adults with Severe and Profound Hearing Loss

Individuals with severe to profound hearing loss are likely to present with complex listening needs that require evidence-based solutions. This document is intended to inform the practice of hearing care professionals who are involved in the audiological management of adults with a severe to profound degree of hearing loss and will highlight the special considerations and practices required to optimize outcomes for these individuals.

Age-related hearing loss and tinnitus, dementia risk, and auditory amplification outcomes

Age-related hearing loss (ARHL) or presbycusis, as the third leading cause of chronic disability in older adults, has been shown to be associated with predisposing cognitive impairment and dementia. Tinnitus is also a chronic auditory disorder demonstrating a growth rate with increasing age. Recent evidence stands for the link between bothersome tinnitus and impairments in various aspects of cognitive function. Both ARHL and age-related tinnitus affect mental health and contribute to developing anxiety, stress, and depression. The present review is a comprehensive multidisciplinary study on diverse interactions among ARHL, tinnitus, and cognitive decline in older adults. This review incorporates the latest evidence in prevalence and risk factors of ARHL and tinnitus, the neural substrates of tinnitus-related cognitive impairments, hypothesized mechanisms concerning the association between ARHL and increased risk of dementia, hearing amplification outcomes in cases with ARHL and cognitive decline, and preliminary findings on the link between ARHL and cognitive impairment in animal studies. Given extensive evidence that demonstrates advantages of using auditory amplification in the alleviation of hearing handicap, depression, and tinnitus, and the improvement of cognition, social communication, and quality of life, regular hearing screening programs for identification and management of midlife hearing loss and tinnitus is strongly recommended.

Death, Depression, Disability, and Dementia Associated With Self-reported Hearing Problems: A 25-Year Study

Background

Hearing loss in older adults is suspected to play a role in social isolation, depression, disability, lower quality of life, and risk of dementia. Such suspected associations still need to be consolidated with additional research. With a particularly long follow-up, this study assessed the relationship between hearing status and four major adverse health events: death, dementia, depression, and disability.

Methods

Prospective community-based study of 3,777 participants aged ≥65 followed up for 25 years. At baseline, 1,289 reported hearing problems and 2,290 reported no trouble. The risk of occurrence of the negative outcomes, including death, dementia, depressive symptoms, disability in activities of daily living (ADL), and instrumental ADL (IADL), was assessed with Cox proportional hazards models.

Results

Adjusting for numerous confounders, an increased risk of disability and dementia was found for participants reporting hearing problems. An increased risk of depression was found in men reporting hearing problems. In additional exploratory analyses, such associations were not found in those participants using hearing aids. Mortality was not associated with self-reported hearing loss.

Conclusions

Our study confirms the strong link between hearing status and the risk of disability, dementia, and depression. These results highlight the importance of assessing the consequences of treating hearing loss in elders in further studies.

Otolaryngology for the Internist: Hearing Loss

Hearing loss is the third most common chronic condition but can be secondary to a range of conditions encountered in primary care. This article reviews the presentation, evaluation, differential diagnosis, and associated treatments for both acute and chronic causes of hearing loss. As the most common cause of hearing loss, this article provides an overview of age-related hearing loss, its consequences, and pragmatic treatment approaches, including over-the-counter hearing technology.

Conventional Amplification for Children and Adults with Severe-to-Profound Hearing Loss

The primary goal of amplification is to restore audibility without causing discomfort; for someone with severe-to-profound hearing loss, the reduced dynamic range poses unique challenges in hearing-assistive device fitting. These challenges, including physiological limitation, processing difficulties, technology constraints, and other confounding factors, must be considered when selecting, fitting, and counseling for appropriate amplification. Many of the advanced features in hearing aids do not adequately address the unique characteristics of patients with severe-to-profound hearing loss. This review article will attempt to unravel some of the challenges and associated considerations when fitting adults and children with severe-to-profound hearing loss.

Hearing loss and associated medical conditions among individuals 65 years and older

BACKGROUND

Hearing loss is prevalent, but few studies have investigated its associations with common medical conditions.

OBJECTIVE

The objective was to assess the prevalence of medical conditions among individuals with hearing loss, compared to those without hearing loss, in people aged 65 years and older.

METHODS

The National Health Interview Survey (NHIS) collects data on a variety of health-related topics, including disability. Three years of NHIS data (2011-2013; unweighted n = 53,111) were pooled to examine subpopulations of individuals with hearing loss. Comparisons were made between adults aged 65 and older with, and without, self-reported hearing loss. Statistical analysis included descriptive frequencies, Chi-square tests, and multiple logistic regressions. The outcomes of interest included self-reported diagnosis of arthritis, cardiovascular disease, diabetes, high blood pressure, emphysema, stroke, cancer, asthma, multiple chronic conditions, health status, and obesity.

RESULTS

Hearing loss prevalence was nearly 37%. After adjusting for sociodemographics, smoking status, and disability, hearing loss was independently associated with the following conditions: arthritis (OR 1.41; 1.27-1.57), cancer (OR 1.35; 1.21-1.5), cardiovascular disease (OR 1.48; 1.33-1.66), diabetes (OR 1.16; 1.03-1.31), emphysema (OR 1.41; 1.14-1.74), high blood pressure (OR 1.29; 1.17-1.43), and stroke (OR 1.39; 1.12-1.66). There was an association with worse health status over the past year (OR 1.5 (1.3-1.73).

CONCLUSIONS

Hearing loss among older individuals is independently associated with increased disease burden and poorer self-reported health. Future studies are needed to investigate the mechanistic nature of these associations, and whether improved access to hearing healthcare surveillance can reduce the overall health burden among these individuals.

Aphasia and Auditory Processing after Stroke through an International Classification of Functioning, Disability and Health Lens

Aphasia is an acquired language impairment affecting speaking, listening, reading, and writing. Aphasia occurs in about a third of patients who have ischemic stroke and significantly affects functional recovery and return to work. Stroke is more common in older individuals but also occurs in young adults and children. Because people experiencing a stroke are typically aged between 65 and 84 years, hearing loss is common and can potentially interfere with rehabilitation. There is some evidence for increased risk and greater severity of sensorineural hearing loss in the stroke population and hence it has been recommended that all people surviving a stroke should have a hearing test. Auditory processing difficulties have also been reported poststroke. The International Classification of Functioning, Disability and Health (ICF) can be used as a basis for describing the effect of aphasia, hearing loss, and auditory processing difficulties on activities and participation. Effects include reduced participation in activities outside the home such as work and recreation and difficulty engaging in social interaction and communicating needs. A case example of a young man (M) in his 30s who experienced a left-hemisphere ischemic stroke is presented. M has normal hearing sensitivity but has aphasia and auditory processing difficulties based on behavioral and cortical evoked potential measures. His principal goal is to return to work. Although auditory processing difficulties (and hearing loss) are acknowledged in the literature, clinical protocols typically do not specify routine assessment. The literature and the case example presented here suggest a need for further research in this area and a possible change in practice toward more routine assessment of auditory function post-stroke.

Systematic Review of the Effectiveness of Frequency Modulation Devices in Improving Academic Outcomes in Children With Auditory Processing Difficulties

This systematic review describes the published evidence related to the effectiveness of frequency modulation (FM) devices in improving academic outcomes in children with auditory processing difficulties. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were used to identify articles published between January 2003 and March 2014. The Cochrane Population, Intervention, Control, Outcome, Study Design approach and the American Occupational Therapy Association process forms were used to guide the article selection and evaluation process. Of the 83 articles screened, 7 matched the systematic review inclusion criteria. Findings were consistently positive, although limitations were identified. Results of this review indicate moderate support for the use of FM devices to improve children's ability to listen and attend in the classroom and mixed evidence to improve specific academic performance areas. FM technology should be considered for school-age children with auditory processing impairments who are receiving occupational therapy services to improve functioning in the school setting.

Speech understanding in noise with the Roger Pen, Naida CI Q70 processor, and integrated Roger 17 receiver in a multi-talker network

Roger is a digital adaptive multi-channel remote microphone technology that wirelessly transmits a speaker’s voice directly to a hearing instrument or cochlear implant sound processor. Frequency hopping between channels, in combination with repeated broadcast, avoids interference issues that have limited earlier generation FM systems. This study evaluated the benefit of the Roger Pen transmitter microphone in a multiple talker network (MTN) for cochlear implant users in a simulated noisy conversation setting. Twelve post-lingually deafened adult Advanced Bionics CII/HiRes 90K recipients were recruited. Subjects used a Naida CI Q70 processor with integrated Roger 17 receiver. The test environment simulated four people having a meal in a noisy restaurant, one the CI user (listener), and three companions (talkers) talking non-simultaneously in a diffuse field of multi-talker babble. Speech reception thresholds (SRTs) were determined without the Roger Pen, with one Roger Pen, and with three Roger Pens in an MTN. Using three Roger Pens in an MTN improved the SRT by 14.8 dB over using no Roger Pen, and by 13.1 dB over using a single Roger Pen (p < 0.0001). The Roger Pen in an MTN provided statistically and clinically significant improvement in speech perception in noise for Advanced Bionics cochlear implant recipients. The integrated Roger 17 receiver made it easy for users of the Naida CI Q70 processor to take advantage of the Roger system. The listening advantage and ease of use should encourage more clinicians to recommend and fit Roger in adult cochlear implant patients.

Comparison of speech recognition with adaptive digital and FM remote microphone hearing assistance technology by listeners who use hearing aids

PURPOSE

The purpose of this study was to compare the benefits of 3 types of remote microphone hearing assistance technology (HAT), adaptive digital broadband, adaptive frequency modulation (FM), and fixed FM, through objective and subjective measures of speech recognition in clinical and real-world settings.

METHOD

Participants included 11 adults, ages 16 to 78 years, with primarily moderate-to-severe bilateral hearing impairment (HI), who wore binaural behind-the-ear hearing aids; and 15 adults, ages 18 to 30 years, with normal hearing. Sentence recognition in quiet and in noise and subjective ratings were obtained in 3 conditions of wireless signal processing.

RESULTS

Performance by the listeners with HI when using the adaptive digital technology was significantly better than that obtained with the FM technology, with the greatest benefits at the highest noise levels. The majority of listeners also preferred the digital technology when listening in a real-world noisy environment. The wireless technology allowed persons with HI to surpass persons with normal hearing in speech recognition in noise, with the greatest benefit occurring with adaptive digital technology.

CONCLUSION

The use of adaptive digital technology combined with speechreading cues would allow persons with HI to engage in communication in environments that would have otherwise not been possible with traditional wireless technology.

Users' perspectives on the benefits of FM systems with cochlear implants

This study explored: (1) the benefits of an FM system in real-world environments from the perspective of adults with coch-lear implants, and (2) the factors and barriers to using an FM system with a cochlear implant. Using a qualitative research design, 14 adults with unilateral cochlear implants recorded their experiences during a two-month trial period with a personal FM system and responded to a questionnaire at the end of the trial. A detailed analysis of 169 journal entries (230 hours of FM use) permitted a description of the benefits and negative aspects associated with FM use in everyday listening environments. The primary benefits were related to improved access to and quality of sound, improved distance listening, ease of listening, and better social integration. Negative perceptions were associated with the equipment both with regard to physical aspects and adjustments. In addition, technical, individual, social, and environmental factors were identified that can influence the user's decision to use the FM device. Questionnaire responses indicated that the majority of individuals rated the FM system as somewhat or very helpful. The findings suggest that FM systems can improve communication in everyday listening environments for some adults with cochlear implants.

Rehabilitation of Older Adults With Hearing Impairment: A Critical Review

Objectives: Hearing impairment, which affects both peripheral and central structures of the auditory system, is highly prevalent among older adults and has serious consequences both for the people with hearing impairment and for those around them. This article provides an updated overview of the rehabilitation of this population. Methods: This article critically reviews the rehabilitation interventions available to older adults with hearing impairment: hearing aids, hearing assistance technology, and communication programs. Results: Current evidence suggests positive outcomes of similar magnitude for the three rehabilitation interventions, however their availability/uptake and adherence are suboptimal. Discussion: To improve the current situation, two changes to practice are warranted. First, availability of the range of rehabilitation interventions should be improved. Second, in accordance with the self-management of other chronic health conditions, older adults with hearing impairment should be invited to be actively involved in their rehabilitation.

The benefits of remote microphone technology for adults with cochlear implants

OBJECTIVE

Cochlear implantation has become a standard practice for adults with severe to profound hearing loss who demonstrate limited benefit from hearing aids. Despite the substantial auditory benefits provided by cochlear implants, many adults experience difficulty understanding speech in noisy environments and in other challenging listening conditions such as television. Remote microphone technology may provide some benefit in these situations; however, little is known about whether these systems are effective in improving speech understanding in difficult acoustic environments for this population. This study was undertaken with adult cochlear implant recipients to assess the potential benefits of remote microphone technology. The objectives were to examine the measurable and perceived benefit of remote microphone devices during television viewing and to assess the benefits of a frequency-modulated system for speech understanding in noise.

DESIGN

Fifteen adult unilateral cochlear implant users were fit with remote microphone devices in a clinical environment. The study used a combination of direct measurements and patient perceptions to assess speech understanding with and without remote microphone technology. The direct measures involved a within-subject repeated-measures design. Direct measures of patients' speech understanding during television viewing were collected using their cochlear implant alone and with their implant device coupled to an assistive listening device. Questionnaires were administered to document patients' perceptions of benefits during the television-listening tasks. Speech recognition tests of open-set sentences in noise with and without remote microphone technology were also administered.

RESULTS

Participants showed improved speech understanding for television listening when using remote microphone devices coupled to their cochlear implant compared with a cochlear implant alone. This benefit was documented both when listening to news and talk show recordings. Questionnaire results also showed statistically significant differences between listening with a cochlear implant alone and listening with a remote microphone device. Participants judged that remote microphone technology provided them with better comprehension, more confidence, and greater ease of listening. Use of a frequency-modulated system coupled to a cochlear implant also showed significant improvement over a cochlear implant alone for open-set sentence recognition in +10 and +5 dB signal to noise ratios.

CONCLUSIONS

Benefits were measured during remote microphone use in focused-listening situations in a clinical setting, for both television viewing and speech understanding in noise in the audiometric sound suite. The results suggest that adult cochlear implant users should be counseled regarding the potential for enhanced speech understanding in difficult listening environments through the use of remote microphone technology.