Hearing Devices - Academic Studies

Hearing Devices: Directory of Academic Studies

By Maurice

On this page we've assembled all the scientific studies we could find on hearing devices, including the benefits of personal sound amplification products, hearing amplifiers, and more. 

If you know of a study that's missing from our directory, please let us know!


Table of Contents


Study Name

Types of Device(s)

Hearing amplifier/Sound amplifier

Model(s)

Sound World Solutions CS50+; Soundhawk; Etymotic BEAN; Tweak Focus; MSA 30X Sound Amplifier

Publication

JAMA

Purpose

Presently, hearing aids can only be purchased in the United States through a licensed professional, with a mean cost of $4700 for 2 hearing aids (uncovered by Medicare). 1-3 According to nationally representative estimates based on 2605 adults from 1999 through 2006, less than 20% of adults with hearing loss report hearing aid use.


4 Personal sound amplification products (PSAPs) are less-expensive, over-the-counter devices not specifically labeled for hearing loss treatment, but some are technologically comparable with hearing aids and may be appropriate for mild to moderate hearing loss. 1 We compared a sample of these devices with a conventional hearing aid among individuals with mild to moderate hearing loss.

Methods

Participants completed the AZBio sentence-in-noise task,5 a routinely used measure of speech understanding to assess functional hearing. Participants repeated sentences in the presence of background noise under 7 conditions: unaided, with a hearing aid, and with 5 PSAPs.


To control for order effects, sentence lists and devices were randomly ordered using a Latin square design balancing first-order carryover effects. Accuracy (percentage of words repeated correctly; range, 0%-100%) was recorded for each condition (20 sentences per condition).

Results

Of 63 adults screened, 42 met inclusion criteria (mean age, 71.6 years; women, 67%). The change in accuracy in speech understanding from unaided to aided varied by device (Table). The hearing aid and 4 of the PSAPs improved speech understanding from the unaided condition. The mean unaided accuracy was 76.5%. The hearing aid improved speech understanding accuracy to 88.4% for an absolute improvement difference of 11.9 percentage points (95% CI, 9.8 to 14.0).


Three of the PSAPs demonstrated an improvement that was within 5 percentage points of the hearing aid (Sound World Solutions CS50+: accuracy, 87.4%, difference, 11.0 percentage points [95% CI, 8.8 to 13.1]; Soundhawk: accuracy, 86.7%, difference, 10.2 percentage points [95% CI, 8.0 to 12.3]; Etymotic BEAN: accuracy, 84.1%, difference, 7.7 percentage points [95% CI, 5.5 to 9.8]). For 1 PSAP, mean aided speech understanding was worse than the unaided condition (MSA 30X: accuracy, 65.3%, difference, −11.2 percentage points [95% CI, −15.2 to −7.3]).

Conclusion

Select PSAPs were associated with improvements in speech understanding for individuals with hearing loss that were similar to results obtained with a hearing aid, whereas 1 demonstrated little improvement and 1 degraded speech understanding. To our knowledge, this is the first study of PSAPs that controlled for between-participant variability and order effects. The study was limited by a modest number of participants, sampled by convenience, who were tested in a controlled audiological setting under unilaterally aided conditions and with only a limited sample of currently available hearing technologies.


Whether similar results would have been obtained with other devices or if the user self-programmed the device is unknown. Results lend support to current national initiatives from the National Academies,1 White House,2 and bipartisan legislation3 requesting that the US Food and Drug Administration create a new regulatory classification for hearing devices meeting appropriate specifications to be available over the counter.

Study Name

Types of Device(s)

Hearing amplifier/Sound amplifier; Hearing aid

Model(s)

Bean; Bean T; CS-50+; LifeEar; MD Hearing Aid AIR; SongBird Ultra; SoundHawk; Tweak Basic; Tweak Focus; MSA30x

Publication

Otol Neurotol.

Purpose

Recent national initiatives from the White House and Institute of Medicine have focused on strategies to increase the accessibility and affordability of hearing loss treatment given the average cost of $4700 for bilateral hearing aids. More affordable direct-to-consumer hearing technologies are increasingly gaining recognition, but the performance of these devices has been poorly studied. We investigated the technical and electroacoustic capabilities of several direct-to-consumer hearing devices in order to inform otolaryngologists who may be asked by patients to comment on these devices.

Methods

Nine direct-to-consumer hearing devices ranging in retail cost from $144.99 to $395.00 and one direct-to-consumer hearing device with a retail cost of $30.00.

Results

Five devices met all four electroacoustic tolerances presented in this study, 2 devices met three tolerances, 1 device met two tolerances, 1 device met one tolerance, and 1 device did not meet any tolerances. Nine devices were able to approximate 5 of 9 NAL targets within 10 dB while only three devices were able to approximate 5 of 9 NAL targets within a more stringent 5 dB.

Conclusion

While there is substantial heterogeneity among the selection of devices, certain direct-to-consumer hearing devices may be able to provide appropriate amplification to persons with mild-to-moderate hearing loss and serve as alternatives for hearing aids in specific cases.

Study Name

Types of Device(s)

Pocket talker; Amplified telephone; Talking clock

Model(s)

Pocketalker Pro Personal Amplifier by Williams Sound; Serene Amplified Corded Phone, Model HD-65; Analogue Talking Clock by MagAids

Publication

Disability and rehabilitation. Assistive technology

Purpose

This study examines the performance of individuals with both hearing and vision loss when using assistive listening devices.

Methods

Older adults (age 60-100) with low vision only (n = 23), combined vision and hearing loss (n = 25) and a control group (n = 12) were asked to assemble a pocket talker, and operate a talking clock and an amplified telephone. They either received minimal or no instruction. Success at using the devices properly, as well as performance speed, was recorded.

Results

The proportion of individuals with sensory loss that was able to complete our naturalistic tasks without mistakes ranged from 20% to 95%, depending on the device, the task complexity and the instruction provided. Both instruction as well as simple repetition had statistically significant and separate beneficial effects; however, neither was able to bring success to 100% on any device. Speed and task success were linked in an intuitive way, whereby individuals who succeeded at a task also performed it faster.

Conclusion

Even minimal explanation during the introduction of assistive listening devices to persons with low vision facilitates user success. Device visibility, cognitive and motor complexity of the task, as well as manual dexterity warrant further investigation as potential barriers to device use.

Study Name

Types of Device(s)

Personal Sound Amplification Product (PSAP) (Soundworld Solutions Sidekick) versus a traditional hearing aid (Oticon Nera miniRITE) 

Model(s)

PSAP and traditional hearing aid devices

Publication

Towson University Graduate Theses and Dissertations

Purpose

The purpose of this pilot study was to compare the objective benefit of a Personal Sound Amplification Product (PSAP) (Soundworld Solutions Sidekick) versus a traditional hearing aid (Oticon Nera miniRITE) in localization performance using an audiologist fit condition. Three participants with mild to moderate sensorineural hearing loss were evaluated with both PSAPs and traditional hearing aids. 

Methods

 Electroacoustic analysis was performed for each PSAP and traditional hearing aid prior to each test session and compared to manufacturers’ specifications to confirm proper functioning of the devices. Real ear measurements were obtained and compared to NAL-NL2 targets. Each participant's speech-in-noise understanding was evaluated using the AzBio speech-in-noise test and speech identification ability was evaluated using speech-on-speech masking techniques.


Lastly, localization ability was assessed in an unaided, PSAP, and traditional hearing aid condition. The electroacoustic analysis measurements for both devices were in relatively good agreement with the manufacturers’ specifications and indicate that the PSAP and hearing aid had relatively similar outputs.

Results

Both the PSAP and traditional hearing aid devices when fit in a gold-standard fitting protocol were able to meet NAL-NL2 targets relatively well. Speech-in-noise testing with the AzBio sentence test revealed similar performance in all three test conditions (Unaided, PSAP, traditional hearing aid). Speech-on-speech masking revealed mixed speech identification abilities. Overall, all the participants performed better in the spatially separated condition compared to the co-located condition. On average the traditional hearing aid condition produced the highest spatial release from masking.


However, statistical analysis was not completed due to the small sample size. When assessed for localization ability the participants were generally able to localize the low frequency stimulus (500 Hz) more accurately than the high frequency stimulus (3150 Hz). During localization tasks participant performance was variable based on hearing condition.

Conclusion

On average participants performed better in the unaided conditions for both high and low frequency stimuli. Collectively, the results of the pilot study are in good agreement with previous studies that suggest that advanced PSAPs have the ability to perform similarly to a traditional hearing aid for individuals with a mild to moderate sensorineural hearing loss.


The localization results from this pilot study are generally in good agreement with previous hearing aid localization research, but further research is needed to draw conclusions based on device performance.

Study Name

Types of Device(s)

Personal sound amplification product (PSAP) or a basic hearing aid (HA)

Model(s)

 personal sound amplification product (PSAP)

Publication

Journal of Audiology and Otology

Purpose

This study aimed to compare functional hearing with the use of a personal sound amplification product (PSAP) or a basic hearing aid (HA) among sensorineural hearing impaired listeners.

Methods

Nineteen participants with mild-to-moderate sensorineural hearing loss (SNHL) (26-55 dB HL; pure-tone average, 0.5-4 kHz) were prospectively included. No participants had prior experience with HAs or PSAPs. Audiograms, speech intelligibility in both quiet and noisy environments, speech quality, and preference were assessed in three different listening conditions: unaided, with the HA, and with the PSAP.

Results

The use of PSAP was associated with significant improvement in pure-tone thresholds at 1, 2, and 4 kHz compared to the unaided condition (all p<0.01). In the quiet environment, speech intelligibility was significantly improved after wearing a PSAP compared to the unaided condition (p<0.001), and this improvement was better than the result obtained with the HA. The PSAP also demonstrated similar improvement in the most comfortable levels compared to those obtained with the HA (p<0.05).


However, there was no significant improvement of speech intelligibility in a noisy environment when wearing the PSAP (p=0.160). There was no significant difference in the reported speech quality produced by either device or in participant preference for the PSAP or HA

Conclusion

The current result suggests that PSAPs provide considerable benefits to speech intelligibility in a quiet environment and can be a good alternative to compensate for mild-to-moderate SNHL.

Study Name

Types of Device(s)

Personal Sound Amplification Products and Hearing Aids

Model(s)

Personal Sound Amplification Products and Hearing Aids

Publication

American Journal of Audiology

Purpose

The aim of this study was to compare the benefit of self-adjusted personal sound amplification products (PSAPs) to audiologist-fitted hearing aids based on speech recognition, listening effort, and sound quality in ecologically relevant test conditions to estimate real-world effectiveness.

Methods

Twenty-five older adults with bilateral mild-to-moderate hearing loss completed the single-blinded, crossover study. Participants underwent aided testing using 3 PSAPs and a traditional hearing aid, as well as unaided testing. PSAPs were adjusted based on participant preference, whereas the hearing aid was configured using best-practice verification protocols.


Audibility provided by the devices was quantified using the Speech Intelligibility Index (American National Standards Institute, 2012). Outcome measures assessing speech recognition, listening effort, and sound quality were administered in ecologically relevant laboratory conditions designed to represent real-world speech listening situations.

Results

All devices significantly improved Speech Intelligibility Index compared to unaided listening, with the hearing aid providing more audibility than all PSAPs. Results further revealed that, in general, the hearing aid improved speech recognition performance and reduced listening effort significantly more than all PSAPs.


Few differences in sound quality were observed between devices. All PSAPs improved speech recognition and listening effort compared to unaided testing.

Conclusion

Hearing aids fitted using best-practice verification protocols were capable of providing more aided audibility, better speech recognition performance, and lower listening effort compared to the PSAPs tested in the current study. Differences in sound quality between the devices were minimal.


However, because all PSAPs tested in the study significantly improved participants' speech recognition performance and reduced listening effort compared to unaided listening, PSAPs could serve as a budget-friendly option for those who cannot afford traditional amplification.

Study Name

Types of Device(s)

Personal Sound Amplifiers

Model(s)

Bean T-Coil, CS-50+

Publication

The American Journal of Medicine

Purpose

The purpose of this review is to provide a practical guide for physicians who work with older adults who are experiencing hearing and communication difficulties.

Methods

Due to the increasing availability of direct-to-consumer hearing devices via Internet sales and the continued widespread lack of treatment among adults with hearing loss, we undertook a technical evaluation of a sample of direct-to-consumer hearing devices to determine if these hearing devices could provide suitable amplification for the average adult with some hearing complaints.


In-depth electroacoustic analysis of the tested devices (n = 12) is available in a companion paper. The findings presented here represent practical information on how to provide guidance to patients with complaints of hearing loss or communication difficulties who may be interested in the “do-it-yourself” approach.

Results

Age-related hearing loss generally affects low and high frequencies differently, with high-frequency hearing loss significantly more common in older patients. The result of this frequency-specific hearing loss is the common complaint, “I hear you—I just don't understand you.” Often, with age-related hearing loss, the individual continues to have good hearing for low-frequency sounds, which in speech include robust vowel sounds like “ah” (“father”).


Meanwhile, soft, high-frequency speech sounds, such as “th” (“bath”), “f” (“fat”), “s” (“toss”), become inaudible. Consequently, one hears the words but they lack clarity. Earlier generations of self-fit hearing devices typically provided too much amplification for low-frequency sounds (ie, in the region that many people still have good hearing) while offering little to no amplification for the high-frequency sounds (ie, the sounds necessary to improve speech clarity). To appropriately meet the needs of persons with age-related hearing loss, devices must use multiple-channel processing so that amplification can be provided in different amounts at different frequencies.


We analyzed the frequency-specific gain for each product and compared them with prescriptive targets commonly used in audiology for best speech understanding. Table 1 indicates whether each device was appropriate for an adult with typical age-related hearing loss.

Conclusion

Communication fundamentally connects people to life and each other. The importance of hearing should not be downplayed as a function of age. There are many options ranging from communication strategies to direct-to-consumer hearing devices to professionally fitted hearing aids that can improve communication and quality of life for the millions of older adults with age-related hearing loss. With improving access to hearing technologies available via Internet sales, the burgeoning direct-to-consumer hearing device market offers a stepping stone by which people can address hearing loss in small steps and begin using amplification.

Study Name

Types of Device(s)

PSAP, basic HA, and premium HA 

Model(s)

Two pairs of HAs and 1 pair of PSAPs were used in this study. The Opn1 (Oticon Ltd) was chosen as the premium HA, and the Ria2Pro (Oticon Ltd) was used as the basic HA. PSAP (Ps2500amp; Able Planet Inc)

Publication

JAMA Network

Purpose

To evaluate the clinical efficacy of a PSAP by comparing its performance with that of a basic HA and a premium HA in participants with mild, moderate, and moderately severe hearing impairment.

Methods

All hearing devices (PSAP, basic HA, and premium HA) were applied by a clinician to prevent bias and order effects; participants were blinded to the device in use, and sequence of devices was randomized.

Results

The study included 56 participants with a mean age of 56 years (interquartile range, 48-59 years); 29 (52%) were women. In the mild and moderate hearing loss groups, there was no meaningful difference between PSAP, basic HA, and premium HA for speech perception (Cohen d = 0.06-1.05), sound quality (Cohen d = 0.06-0.71), listening effort (Cohen d = 0.10-0.92), and user preference (PSAP, 41%; basic HA, 28%; premium HA, 31%). However, for the patients with moderately severe hearing loss, the premium HA had better performance across most tests (Cohen d = 0.60-1.59), and 70% of participants preferred to use the premium HA.

Conclusion

The results indicate that basic and premium HAs were not superior to the PSAP in patients with mild to moderate hearing impairment, which suggests that PSAPs might be used as an alternative to HAs in these patient populations. However, if hearing loss is more severe, then HAs, especially premium HAs, should be considered as an option to manage hearing loss.

Study Name

Types of Device(s)

 representative PSAP (RPSAP) and conventional hearing aid (HA)

Model(s)

Three basic (BeethoSOL, EarJJang, and Geniesori2) and three high-end PSAPs (Hearing Able, Olive Smart Ear, and SoriIn)

Publication

europepmc.org

Purpose

To confirm the feasibility of personal sound amplification products (PSAPs), the study was conducted for three purposes: 1) to investigate electroacoustic characteristics of PSAPs, 2) to identify whether PSAPs provide adequate gain and output for three common hearing loss configurations, and 3) to compare the benefit of one representative PSAP (RPSAP) to a conventional hearing aid (HA) based on clinical hearing outcomes as a pilot study.

Methods

The study consisted of three phases: electroacoustic analysis, simulated real-ear measurements (REMs), and clinical hearing experiments. Electroacoustic analysis and simulated REMs were performed in three basic (BeethoSOL, EarJJang, and Geniesori2) and three high-end PSAPs (Hearing Able, Olive Smart Ear, and SoriIn) using the Aurical Hearing Instrument Test box with a 2cc coupler. With regards to electroacoustic analysis, four electroacoustic characteristics (maximum output sound pressure level at 90 dB SPL, frequency range, equivalent input noise, and total harmonic distortion) were investigated.


By simulated REMs, the appropriate level of the six PSAPs for three common hearing loss configurations (mild-to-moderate high-frequency hearing loss, moderate to moderately severe sloping hearing loss, and moderate flat hearing loss) was determined. Clinical experiments were carried out for the purpose of comparing the performance of RPSAP to HA. Before conducting clinical experiments, both RPSAP and HA were fitted by audiologists using REMs. Clinical experiments were administered using functional gain, a word recognition test, and the Korean version of the Hearing in Noise Test in six participants with bilateral moderate sensorineural hearing loss.

Results

With regards to electroacoustic analysis, two high-end devices met all tolerances. In the case of simulated REMs, one basic and two high-end PSAPs showed appropriate level for three common hearing loss configurations. As for the clinical experiments, the RPSAP showed better performances than unaided, but slightly worse than HA under all test conditions.

Conclusion

Our results demonstrated that certain PSAPs met all specified tolerances for electroacoustic analysis and had ability to approximate prescriptive targets in a well-controlled laboratory condition. The pilot clinical experiments explored the possibility that RPSAP could be served as a hearing assistive device for patients with moderate hearing loss.

Study Name

Types of Device(s)

personal sound amplification product (PSAP) or a basic hearing aid (HA)

Model(s)

PSAP (PS2500AMP, Able Planet, North Wheat Ridge, CO, USA) and an HA (AudéoTM Q, Phonak AG, Stäfa, Switzerland)

Publication

Journal of Audiology and Otology

Purpose

This study aimed to compare functional hearing with the use of a personal sound amplification product (PSAP) or a basic hearing aid (HA) among sensorineural hearing impaired listeners.

Methods

Nineteen participants with mild-to-moderate sensorineural hearing loss (SNHL) (26-55 dB HL; pure-tone average, 0.5-4 kHz) were prospectively included. No participants had prior experience with HAs or PSAPs. Audiograms, speech intelligibility in both quiet and noisy environments, speech quality, and preference were assessed in three different listening conditions: unaided, with the HA, and with the PSAP.

Results

The use of PSAP was associated with significant improvement in pure-tone thresholds at 1, 2, and 4 kHz compared to the unaided condition (all p<0.01). In the quiet environment, speech intelligibility was significantly improved after wearing a PSAP compared to the unaided condition (p<0.001), and this improvement was better than the result obtained with the HA. The PSAP also demonstrated similar improvement in the most comfortable levels compared to those obtained with the HA (p<0.05).


However, there was no significant improvement of speech intelligibility in a noisy environment when wearing the PSAP (p=0.160). There was no significant difference in the reported speech quality produced by either device or in participant preference for the PSAP or HA.

Conclusion

The current result suggests that PSAPs provide considerable benefits to speech intelligibility in a quiet environment and can be a good alternative to compensate for mild-to-moderate SNHL.

Study Name

Types of Device(s)

personal sound amplification products; hearables), as well as assistive listening devices (ALDs)

Model(s)

FM, Bluetooth, 900 MHz wireless, 2.4 GHz wireless

Publication

International Journal of Audiology 

Purpose

Recent technological advances have led to a rapid increase in alternative listening devices to conventional hearing aids. The aim was to systematically review the existing evidence to assess the effectiveness of alternative listening devices in adults with mild and moderate hearing loss.

Methods

Prior to commencing the systematic review, the protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (registration number, CRD42015029582) and published in a peer-reviewed publication (Maidment et al. 2016). Methods are reported according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) checklist (Moher et al. 2009).

Results

As the aim of the review was to assess the clinical-effectiveness of alternative listening devices, studies were restricted to outcomes associated with the consequences of hearing loss. There were no restrictions as to the duration of follow-up. Primary outcomes included one or more of the following: (i) behavioural measures of speech intelligibility (e.g. intelligibility of syllables, words or sentences presented in quiet or in noise); (ii) hearing-specific health-related quality of life (QoL), where participation was the key domain, measured using any self-reported questionnaire (e.g. Hearing Handicap Inventory for the Elderly: Ventry and Weinstein 1982) and (iii) adverse effects of patient, reported as pain, discomfort, tenderness, skin irritation or ear infection as a consequence of device fitting. Secondary outcomes included any of the following self-reported outcomes: (i) General health-related QoL (e.g. Health Utilities Index Mark 3: Furlong et al. 2001); (ii) listening ability (e.g. Abbreviated Profile of Hearing Aid Benefit: Cox and Alexander 1995); (iii) cognition (e.g. working memory); (iv) feasibility (e.g. usability, adherence); (v) adverse effect of noise-induced hearing loss (e.g. due to over-amplification from inappropriate hearing aid fitting).

Conclusion

In summary, the evidence included in this review suggests that alternative listening devices improve behavioural measures of speech intelligibility relative to unaided and/or conventional hearing aids. There is no robust evidence as to whether alternative listening devices improve self-reported outcomes.


Furthermore, the evidence was judged to be poor to good quality and subject to bias due to limitations in study design. On this basis, we argue that high-quality studies (i.e. RCTs) investigating the clinical- and cost-effectiveness of alternative listening devices are needed in this area. Such evidence, though currently unavailable, is necessary to guide healthcare commissioners and policymakers when considering new service delivery pathways to benefit adults living with hearing loss. Moreover, given that this field is likely to continue to develop in new and unexpected ways, we envisage that the current systematic review will require updating, and it is our intention to do so in two to three years. These rapid developments reflect the innovative nature of the field, which not only has the potential to transform hearing healthcare service delivery in the future but also increase the likelihood that people will seek and use amplification to successfully manage their hearing loss.

Study Name

Types of Device(s)

assistive listening device (ALD)

Model(s)

N/A

Publication

Contemporary Nurse 

Purpose

 A study of 20 older Australians living in a Queensland retirement village and residential hostel complex was undertaken to investigate how communication might be advanced through an assistive listening device (ALD).

Methods

Most participants were women aged over 85 years; almost all had hearing loss and wore hearing aids. Tests with an ALD found very high levels of satisfaction with understanding speech and sound quality amongst participants. 

Results

few had heard previously of ALDs, all required individualised assistance to fit and use the device and rated ease of use less highly. The findings affirm those of previous studies that ALD technology has a role in communication for older hearing impaired people and for hearing rehabilitation.

Conclusion

In summary, the evidence included in this review suggests that alternative listening devices improve behavioural measures of speech intelligibility relative to unaided and/or conventional hearing aids. There is no robust evidence as to whether alternative listening devices improve self-reported outcomes.


Furthermore, the evidence was judged to be poor to good quality and subject to bias due to limitations in study design. On this basis, we argue that high-quality studies (i.e. RCTs) investigating the clinical- and cost-effectiveness of alternative listening devices are needed in this area. Such evidence, though currently unavailable, is necessary to guide healthcare commissioners and policymakers when considering new service delivery pathways to benefit adults living with hearing loss.


Moreover, given that this field is likely to continue to develop in new and unexpected ways, we envisage that the current systematic review will require updating, and it is our intention to do so in two to three years. These rapid developments reflect the innovative nature of the field, which not only has the potential to transform hearing healthcare service delivery in the future but also increase the likelihood that people will seek and use amplification to successfully manage their hearing loss.

Study Name

Types of Device(s)

personal sound amplification products (PSAPs) and a traditional hearing aid

Model(s)

N/A

Publication

American Journal of Audiology

Purpose

The aim of this study was to compare the benefit of self-adjusted personal sound amplification products (PSAPs) to audiologist-fitted hearing aids based on speech recognition, listening effort, and sound quality in ecologically relevant test conditions to estimate real-world effectiveness.

Methods

Twenty-five older adults with bilateral mild-to-moderate hearing loss completed the single-blinded, crossover study. Participants underwent aided testing using 3 PSAPs and a traditional hearing aid, as well as unaided testing. PSAPs were adjusted based on participant preference, whereas the hearing aid was configured using best-practice verification protocols.


Audibility provided by the devices was quantified using the Speech Intelligibility Index (American National Standards Institute, 2012). Outcome measures assessing speech recognition, listening effort, and sound quality were administered in ecologically relevant laboratory conditions designed to represent real-world speech listening situations.

Results

All devices significantly improved Speech Intelligibility Index compared to unaided listening, with the hearing aid providing more audibility than all PSAPs. Results further revealed that, in general, the hearing aid improved speech recognition performance and reduced listening effort significantly more than all PSAPs.


Few differences in sound quality were observed between devices. All PSAPs improved speech recognition and listening effort compared to unaided testing.

Conclusion

Hearing aids fitted using best-practice verification protocols were capable of providing more aided audibility, better speech recognition performance, and lower listening effort compared to the PSAPs tested in the current study. Differences in sound quality between the devices were minimal.


However, because all PSAPs tested in the study significantly improved participants' speech recognition performance and reduced listening effort compared to unaided listening, PSAPs could serve as a budget-friendly option for those who cannot afford traditional amplification.

Study Name

Types of Device(s)

1) personal sound amplification products (PSAPs), 2) direct-mail hearing aids, and 3) over-the-counter (OTC) hearing aids.

Model(s)

N/A

Publication

National Library of Medicine

Purpose

This systematic literature review is aimed at investigating applications of direct-to-consumer hearing devices for adults with hearing loss.

Methods

 A literature review was conducted using EBSCOhost and included the databases CINAHL, MEDLINE, and PsycINFO. After applying prior agreed inclusion and exclusion criteria, 13 reports were included in the review.

Results

Included studies fell into three domains: 1) electroacoustic characteristics, 2) consumer surveys, and 3) outcome evaluations. Electroacoustic characteristics of these devices vary significantly with some meeting the stringent acoustic criteria used for hearing aids, while others producing dangerous output levels (ie, over 120-dB sound pressure level). Low-end (or low-cost) devices were typically poor in acoustic quality and did not meet gain levels necessary for most adult and elderly hearing loss patterns (eg, presbycusis), especially in high frequencies.


Despite direct-mail hearing aids and PSAPs being associated with lower satisfaction when compared to hearing aids purchased through hearing health care professionals, consumer surveys suggest that 5%-19% of people with hearing loss purchase hearing aids through direct-mail or online. Studies on outcome evaluation suggest positive outcomes of OTC devices in the elderly population. Of note, OTC outcomes appear better when a hearing health care professional supports these users.

Conclusion

While some direct-to-consumer hearing devices have the capability to produce adverse effects due to production of dangerously high sound levels and internal noise, the existing literature suggests that there are potential benefits of these devices. Research of direct-to-consumer hearing devices is limited, and current published studies are of weak quality. Much effort is needed to understand the benefits and limitations of such devices on people with hearing loss.

Study Name

Types of Device(s)

representative PSAP (RPSAP) to a conventional hearing aid (HA)

Model(s)

N/A

Publication

National Library of Medicine

Purpose

To confirm the feasibility of personal sound amplification products (PSAPs), the study was conducted for three purposes: 1) to investigate electroacoustic characteristics of PSAPs, 2) to identify whether PSAPs provide adequate gain and output for three common hearing loss configurations, and 3) to compare the benefit of one representative PSAP (RPSAP) to a conventional hearing aid (HA) based on clinical hearing outcomes as a pilot study.

Methods

The study consisted of three phases: electroacoustic analysis, simulated real-ear measurements (REMs), and clinical hearing experiments. Electroacoustic analysis and simulated REMs were performed in three basic (BeethoSOL, EarJJang, and Geniesori2) and three high-end PSAPs (Hearing Able, Olive Smart Ear, and SoriIn) using the Aurical Hearing Instrument Test box with a 2cc coupler. With regards to electroacoustic analysis, four electroacoustic characteristics (maximum output sound pressure level at 90 dB SPL, frequency range, equivalent input noise, and total harmonic distortion) were investigated.


By simulated REMs, the appropriate level of the six PSAPs for three common hearing loss configurations (mild-to-moderate high-frequency hearing loss, moderate to moderately severe sloping hearing loss, and moderate flat hearing loss) was determined. Clinical experiments were carried out for the purpose of comparing the performance of RPSAP to HA. Before conducting clinical experiments, both RPSAP and HA were fitted by audiologists using REMs. Clinical experiments were administered using functional gain, a word recognition test, and the Korean version of the Hearing in Noise Test in six participants with bilateral moderate sensorineural hearing loss.

Results

With regards to electroacoustic analysis, two high-end devices met all tolerances. In the case of simulated REMs, one basic and two high-end PSAPs showed appropriate level for three common hearing loss configurations. As for the clinical experiments, the RPSAP showed better performances than unaided, but slightly worse than HA under all test conditions.

Conclusion

Our results demonstrated that certain PSAPs met all specified tolerances for electroacoustic analysis and had ability to approximate prescriptive targets in a well-controlled laboratory condition. The pilot clinical experiments explored the possibility that RPSAP could be served as a hearing assistive device for patients with moderate hearing loss.

Study Name

Types of Device(s)

direct-to-consumer hearing devices (DCHD), traditional hearing aids , OTC hearing devices, PSAPs, and assistive listening devices (ALDs)

Model(s)

ReSound Alera 9 Mini-BTE (Bloomington, MN, USA), TEO First (Meyreuil, France)

Publication

Journal of Audiology and Otology

Purpose

As the population of those with mild to moderate hearing loss increases the need remains for amplification solutions. There is a trend to offer alternative amplification options beyond traditional hearing aids. Due to reduced medical risk associated with the most common types of hearing loss (i.e., presbycusis and noise induced), many individuals with such audiological configurations may have success with direct-to-consumer hearing devices (DCHD). The current paper presents a literature review of studies focused on the outcomes of DCHDs for people with hearing loss.

Methods

Search of electronic databases were used to identify relevant articles for review. Studies on outcomes of DCHDs mainly focused on older adults and reported consistently positive results in clinical and self-reported outcome measures. Improvements in auditory ability, communicative function, social engagement, quality of life, and reduction of self-reported hearing disability were observed.

Results

Accordingly, a majority of the studies conducted on this topic are of low quality of evidence and only provide short-term (i.e., less than one year) outcomes. In addition, results may have been influenced by researcher and/or clinician involvement in choosing the devices and by provision of additional support (i.e., incorporation of a communication partner and communication strategies training).

Conclusion

The literature suggests positive outcomes of DCHD in older adults with hearing loss during short-term (i.e., less than one year) trials. Improvements in auditory ability, communicative function, social engagement, quality of life, and reduction of self-reported hearing disability were observed.


Yet, a majority of studies conducted on this topic are of low quality of evidence. In addition, results may have been influenced by researcher and/or clinician involvement in choosing the devices and by provision of additional support (e.g., incorporation of a CP, communication strategies training). The nature of direct-to-consumer method makes it challenging to design studies that will accurately represent outcomes for patients due to the extensive dissimilarities in patient journey and device selection options.


Hence, additional research utilizing more robust study design, measuring long-term outcomes, alternative product options, and a more traditional direct-to-consumer delivery method should be conducted before generalization of benefits is applied to a wider population.

Study Name

Types of Device(s)

Direct-to-consumer (DTC) hearing devices and hearing aid supplied by the U.K. National Health Service (NHS).

Model(s)

Mini In-Ear Sound Amplifier, Personal Mini Sound Amplifier, BTE Sound Amplifier, 8397 Micro Plus, Silver Sonic XL Personal Sound Amplifier, Mini Ear Amplifying Aid FK-162, HA 20, In the Ear Hearing Amplifier, AXON Hearing Aid rechargeable, Digital Hearing Amplifier VHP-202 S, Rechargeable Ear Hearing Amplifier ZDB-100 A, Hearing Amplifier, Micro Plus ITE Hearing Amplifier, HA 50, ITE voice amplifier ZDC-901 A, Digital Hearing Amplifier VHP-221 T, BTE Amplifier V-185, Digital Personal Audio Amplifier C-125, In Ear Mini, IQ Buds, BLJ-BS05R Mini RIC, VA-3000, RPSA05 Symphonix, G2090 Hearing Amplifier, 821 Receiver In The Canal Hearing Amplifier, CS50+ Personal Sound Amplifier, Companion Hearing Aid, Super Mini VHP-902

Publication

SAGE - Trends in Hearing

Purpose

Direct-to-consumer (DTC) hearing devices can be purchased without consulting a hearing health professional. This project aims to compare 28 DTC devices with the most popular hearing aid supplied by the U.K. National Health Service (NHS). The comparison was based on technical performance, cosmetic acceptability, and the ability to match commonly used gain and slope targets. Electroacoustic performance was evaluated in a 2-cc coupler. Match to prescription target for both gain and slope was measured on a Knowles Electronic Manikin for Acoustic Research using a mild and also a moderate sloping hearing loss.

Methods

Twenty-eight DTC devices were included in this study. The inclusion criteria were as follows: (a) available for purchase online at a cost of less than £400 each and (b) marketed as hearing devices (or able to function as a hearing device). The reference device was the Oticon Spirit Zest (Smørum, Denmark), the most commonly fitted NHS hearing aid at the time the study was completed (Summer 2018).


This hearing aid is an eight-channel programmable thin-tube-delivery behind the ear (BTE) device most commonly used with an open dome. The output can be modified at eight frequencies from 0.25 to 6 kHz. Listening checks were carried out on every device. Two devices were faulty and excluded from all measurements, except cosmetic evaluation.

Results

Table 1 summarizes the device characteristics. Most of the DTC devices were relatively inexpensive. Five had noise reduction algorithms, two were advertised with directional microphones, and eleven DTC devices had nonlinear processing. Bluetooth streaming capability and smartphone application customizers were incorporated into three DTC devices. The latter feature allows wearers to fine-tune their devices’ output based on their listening needs; they can manipulate several parameters, such as output at different frequencies, listening programs, and the amount of noise reduction.


However, they cannot change the maximum output.
Two devices in this study (MEDca BTE and Lifemax Hearing Amplifier) were excluded from all measurements, except the aesthetic rating, because they were nonfunctioning. Six arrived with a user manual that was not in English, and half of the devices were received without any information about their technical specifications. Almost half of them had a poorly functioning volume control (i.e., the volume control did not move freely or it moved but changed the volume in large jumps of uneven level) and some had a malfunctioning rechargeable battery.

Conclusion

Although previous studies have reported electroacoustic performance, this study is novel in that it examined (a) the ability of the DTC devices to match the prescribed gain and slope targets and (b) cosmetic appearance ratings and willingness-to-wear the DTC devices, using a very large sample of DTC devices. Nearly all of the DTC devices had aesthetically unappealing designs and inflexible adjustments, making it difficult to match widely accepted targets and potentially making sounds uncomfortably loud for people with mild or moderate sloping hearing loss.


Devices with smartphone customizers performed better in terms of electroacoustics and match-to-target gain and slope; however, two of these devices might produce uncomfortably loud sounds and all of them were rated as aesthetically unappealing. The challenge for manufacturers is to develop low-cost products with cosmetic appeal and appropriate electroacoustic characteristics.

Study Name

Types of Device(s)

Direct-to-consumer Hearing Devices

Model(s)

Bean T-Coil, CS-50þ, Tweak Focus, Soundhawk, Songbird

Publication

The American Journal of Medicine

Purpose

Age-related hearing loss is highly prevalent and often untreated. Use of hearing aids has been associated with improvements in communication and quality of life, but such treatment is unaffordable or inaccessible for many adults. The purpose of this review is to provide a practical guide for physicians who work with older adults who are experiencing hearing and communication difficulties. Specifically, we review direct-toconsumer amplification products that can be used to address hearing loss in adults. 

Methods

Speak face-to-face When the speaker’s face is turned toward the listener, there is improved signal-to-noise ratio, and the listener uses facial cues to fill in the gaps that he/she may not have heard. Reduce background noise The ability to understand speech in the presence of background noise or distractors (eg, television or restaurant noise) declines as a function of age, even for older adults without hearing loss. Speak slower, instead of louder When someone speaks loudly or shouts, it actually distorts the speech, often making it more difficult to understand.


Also, shouting can make both the speaker and the listener more stressed. State the topic By making the topic of conversation clear at the beginning, the listener can more effectively use context cues to fill in the gaps. Rephrase the statement Repeating oneself becomes frustrating for the speaker and the listener. When the question or statement is rephrased, the listener has more context cues to fill in the gaps. In addition, some words are actually easier to hear, depending on the person’s hearing loss and the frequencies of the sounds in the word.

Results

As highlighted throughout this review, amplification is the primary tool used to improve communication for people with hearing loss. Nevertheless, amplification does not address all communication challenges that are typical of age-related hearing loss. This important fact differentiates age-related hearing loss from presbyopia and the use of over-thecounter glasses wherein the visual problem is generally due to a refractive error rather than an underlying sensorineural loss in the retina.


Education and coaching on the use of communication strategies improves communication regardless of amplification use.28 There are available resources from consumer advocacy groups (eg, www.hearingloss.org) for providing communication strategies to individuals and families in primary care clinics. Table 2 provides examples and rationales for some of the most commonly used communication strategies.29 These communication strategies should be recommended to patients with hearing difficulties and their communication partners. The person with hearing loss needs to advocate for him-/herself and use these strategies to prevent withdrawing from conversation.

Conclusion

Communication fundamentally connects people to life and each other. The importance of hearing should not be downplayed as a function of age. There are many options ranging from communication strategies to direct-to-consumer hearing devices to professionally fitted hearing aids that can improve communication and quality of life for the millions of older adults with age-related hearing loss.


With improving access to hearing technologies available via Internet sales, the burgeoning direct-to-consumer hearing device market offers a stepping stone by which people can address hearing loss in small steps and begin using amplification.

Study Name

Types of Device(s)

personal sound amplification products (PSAPs).

Model(s)

N/A

Publication

American Journal of Audiology

Purpose

The purpose of this study was to preliminarily investigate the sentiments associated with consumer opinions of personal sound amplification products (PSAPs).

Methods

Online reviews of 21 popular PSAPs were collected from the Amazon.com website. The reviews for each product were exported to compile individual product-specific text files. A sentiment mining analysis was completed to aggregate the number of positive and negative comments for each product.


In addition, the effect of value for money, available features, perceived benefit, and overall perception of PSAPs was evaluated. A correlational analysis was completed to examine the relationship between different PSAP features and the number of positive and negative comments.

Results

Mixed-model analysis of variance showed a significantly higher number of positive comments for high- and mid-cost products in terms of overall perception and perceived benefit compared to low-cost products. For feature attribute, high-cost products had significantly higher positive comments compared to mid- and low-cost products.


There was a strong correlation between price and positive comments and a moderate correlation between price and negative comments. Also, there was a significant moderate correlation between presence of compression and feedback suppression PSAP features and positive comments.

Conclusion

Positive sentiments expressed toward PSAPs were found to favor high- and mid-level products. However, there was a considerably high number of negative sentiments reported across all the PSAPs investigated. The noticeable thing is that the negative comments do not change significantly across price ranges.


However, the positive comments significantly increase with an increase in product price range. This indicates a possible increase in benefit with high-cost products. However, this claim requires further empirical evidence through controlled studies.


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