Instant-fit OTC hearing aids VS custom hearing aids : an US study challenges conventional wisdom about hearing aids for presbycusis

By seriniti , on 10 January 2022 - 13 minutes to read
Appareillage de la presbyacousie et appareil auditif prérèglerai

This article is a translation of the 2012 American clinical trial available here in its original version.
Conducted in a double-blind, placebo-controlled setting, the trial aims to compare sales of hearing aids with service (sale by a hearing care professional) and without (pre-tuned, over-the-counter device), as well as to identify the impact of purchase price on user satisfaction and daily use of the hearing aid.

Untreated hearing loss, particularly among older Americans, is a major national problem. Only a fraction of consumers who need hearing aids obtain and use hearing aids, largely because of high costs, complex preparation procedures, social stigma, and performance deficiencies[1]

USA : USA: a hearing aid rate as low as in France

According to the 2012 U.S. Census National Projections, approximately 50 million Americans are over the age of 65, representing 15% of the population[2]. 35% of them, or nearly 17.5 million individuals, have enough hearing loss to make them candidates for hearing aids[3].

Yet :

  • Less than 20% of affected Americans seek hearing aids,
  • Of those who do get hearing aids, only 50% to 70% are satisfied with their hearing aids and use them regularly[4].

The gap between the number of Americans affected by hearing loss and the number of Americans who have hearing aids motivated the creation of the National Institute on Deafness and Communication Disorders, whose objective is to identify all the actions that will allow for the qualitative and financial improvement of health care for adults with a mild to moderate hearing loss[5].

Several questions were thus raised, giving rise to this clinical trial :

  • How can the current delivery system be modified to improve accessibility to hearing aids ?
  • What is the best delivery system between over-the-counter and fee-for-service for a given technology ?
  • What is the minimum service required to ensure satisfactory results and quality care ?
  • How does a user define the value of a hearing aid (performance, satisfaction, cost benefits) ?

Hearing loss, whether progressive or acute, mild or severe, present from birth or acquired later, can have significant effects on communication skills, quality of life, social participation and health. Despite this, many people with hearing loss do not seek or receive hearing care. The reasons are many, complex and often interconnected. For some, hearing care is not affordable. For others, appropriate services are difficult to access, or individuals do not know how or where to access them. Hearing health care needs are not being met. It is estimated that 67% to 86% of adults who could benefit from hearing aids do not use them. This study focuses on improving the accessibility of hearing health care for adults of all ages, a socioeconomic model that emphasizes the multiple levels of support and action needed throughout society to promote hearing and communication and thereby reduce hearing loss and its effects.

The National Academies of Sciences, Engineering, and Medicine (NASEM) report recommended that the Food and Drug Administration (FDA) create a new technology category for “preset, over-the-counter hearing aids.

Background on the clinical trial

In 2012, the price per hearing aid in the United States ranged from $1,200 to $2,900[7], with costs ranging from $2,400 to $5,800 per person for a bilateral fitting. Assuming a hearing aid life expectancy of 5 years, seniors can expect to pay tens of thousands of dollars for their hearing care. These prices are purchase prices only, they do not include annual maintenance expenses or the purchase of batteries (estimated at $100 per year minimum).

This selling price includes two elements :

  • The cost of the hearing aids provided by the manufacturer,
  • The cost of the services rendered by the professionals / hearing aid acousticians, who dispense the hearing aids.

The production costs of hearing aids are relatively low.
For example, the hearing aids used in this clinical trial – good quality hearing aids with multi-channel compression, feedback protection, noise reduction and directional microphones – cost about $100 at the beginning of the trial.

Wholesale prices from low-volume distributors ranged from $900 to $1,200.

The average resale price from the dispensers was between $2,000 and $3,000 per hearing aid. The cost premium from the dispenser to the consumer has been justified on the basis of superior outcomes associated with the hearing care professional service delivery model. However, no studies have documented the differences in outcomes between the higher-priced hearing aid dispensing model and the over-the-counter pre-fitted models.

Preset, off-the-shelf hearing aids are designed to address affordability issues by bypassing the additional professional services often associated with hearing aid prices, i.e., it is assumed that a hearing aid sold by a hearing care professional using the best services would be sold at a higher price than the same off-the-shelf hearing aid[8]. However, the trial reports that it has not found any previous publications that measure the impact of purchase price on outcomes.

Objectives of the clinical trial

In this context, the 2012 US clinical trial has 2 identified objectives, to determine :

  1. The respective effectiveness of different sales practices for hearing aids in older adults, comparing the sales model including a service benefit (prescription) and the over-the-counter model (non-prescription, pre-set) ;
  2. The influence of purchase price on these two different service models.

Participants

188 people participated in this trial.
Adults between 55 and 79 years of age, with mild to moderate hearing loss, they responded favorably to various criteria including :

  • No previous experience with hearing aids,
  • Pure air conduction hearing thresholds consistent with age-related hearing loss (presbycusis).

Participants were randomly assigned to one of the following groups:

Group AB : best practice group (service delivery and follow-up);
Group CD : self-selecting and self-managing hearing aid group;
Group P : placebo group receiving the same services as group AB, i.e. the best practices in the field (service provision and follow-up over time). The hearing aids were, however, programmed to be acoustically neutral (0dB insertion gain).

Hearing equipment

All participants received the same Resound Alera 9 digital mini BTE hearing aid, representative of the most popular devices sold in the US to seniors :

  • 9 frequency channels,
  • 4 programs, configured to serve as a volume control,
  • Fixed directional microphones,
  • Anti-Larsen,
  • Noise reduction.

All participants wore a binaural fitting (right and left ears).

Hearing aid selection and handling

These procedures differed depending on the condition of the group.

Group AB and group P

All measurements were performed in a sound attenuation room that complied with the relevant standards.
The procedures were nearly identical between these 2 groups :

  • The participant examined 3 hearing aid colors, then selected the desired color ;
  • The hearing care professional selected the appropriate earmold size (S, M, L or Tulip) and tubing length (0, 1, 2 or 3) ;
  • ReSound’s Aventa software was used to program the hearing instruments differently, depending on the group :

> Group AB :

Participants’ audiograms were used to generate target gain prescriptions that compensated for hearing loss and the maximum power of each hearing aid was adjusted individually.

Group AB and the first 20 participants in Group P, were given the following programming :

  • Binaural correction : OFF,
  • Microphone directionality : fixed,
  • Feedback suppression : moderate,
  • Noise reduction depending on the environment,
  • Wind noise reduction : OFF,
  • Environmental Optimizer : 0dB,
  • Tinnitus Generator : OFF.

-> Group P :
The hearing aids were programmed for an insertion gain of 0dB.
For the next 35 participants in Group P, the microphone settings were changed from fixed to omnidirectional.

Comparison of prescribed targets (solid circles) in dB SPL and measured levels (empty circles) of the real ear for the left (top) and right (bottom) ears of the Audiology Best Practice Group (AB Group).
The stimulus was a 65dB SPL speech signal for the speech mapping measurements (Verifit test system).
Symbol = mean value; error bar +or- 1 standard deviation.

Average real-ear insertion gain measured in the left (right) and right (bottom) ears of the P (placebo) group.
Data are displayed separately for each subgroup of P: directional microphones (Placebo – Dir) and those with omnidirectional microphones (Placebo – Omni).
The “target” gain for the P group is 0dB.
In addition, the average real-ear insertion gain measured for group AB is shown (X).
All real-ear insertion gain values are shown for pure tone input stimuli of 65dB SPL.
Error bar + or – 1 standard deviation.

For these 2 groups (AB and P), the hearing care professional then conducted a 45-60 minute information session[9] during which training was provided on :
• Components and accessories,
• Battery insertion and removal,
• Inserting and removing batteries, Inserting hearing aids into the ears,
• Maintenance practices,
• Using the telephone with hearing aids,
• Adjusting the volume,
• Recommendations for progressive use: Quiet listening conditions 4 hours/day the first week; then an increase in the difficulty of the listening conditions and the duration of use (+ 2 hours/day) each week.

Practical exercises were also carried out.

Group CD

Participants had access to 3 hearing aids differing only in color and preset to match the acoustic output prescriptions of the 3 most common types of hearing loss (X, Y, Z) among older adults in the US[10].

They self-selected :

  • The hearing aid based on the desired color,
  • The earmold,
  • Appropriate tube size,
  • Desired acoustic characteristics (X, Y or Z).

The participants were provided with user manuals and videos of the hearing aid.

Ciletti and Flamme’s (2008) X, Y, and Z audiograms, among the most common audiometric configurations, were used to pre-match hearing aids to the self-determining consumer / OTC benefit.

Payment for the hearing aid

To measure the impact of purchase price on outcomes, half of the participants paid $3,600 for the pair of hearing aids while the other half paid $600.

Payment was made when all participants had selected their hearing aids.

Participants were not informed of the use of two different purchase prices until the payment stage. This deception was necessary to assess the impact of purchase price on outcomes.

Protocol related to the use problems

If participants experienced problems with their hearing aids during the 6-week trial, they were asked to contact the study center by phone.

The study center protocol was as follows:

  • Ask the participant to refer to the user guide for assistance;
  • If the problem persisted and the problem was with only one hearing aid, ask the participant to remove both hearing aids and compare them to see if there was a difference between the two with respect to the tubing, dome or battery;
  • If a problem persisted, the study center would schedule an unscheduled visit.
    During this unscheduled visit, the study center visually inspected the devices to try to solve the problem.
    If the problem could not be resolved in this manner, the study center would then ask the participant to contact the hearing healthcare professional who had initially adjusted the hearing aids.

The hearing care professional would then perform an otoscopy, tympanometry or other tests to determine the nature of the problem and to remedy it.

Summary of problems encountered during the 6-week clinical trial, according to group (AB, CD, P).

Outcome Measures

• Main outcome measures

Overall PHAB :

Measures the relative advantage. It is the difference between scores without a hearing aid and scores with a hearing aid (at 6 weeks). Based on an average of 5 communication-related subscales: familiar speakers, ease of communication, reverberation, reduced background signals, background noise.

PHABavds :

Obtained from the overall PHAB and the average of two other subscales: sound aversion, sound distortion.


• Secondary endpoints:

The hearing aid outcome in older adults is a three- or four-dimensional construct[11].
Therefore, all participants had additional outcomes that included:

  • Self-reported benefit,
  • A 32-item satisfaction survey regarding hearing aid function,[12] called the Hearing Aid Satisfaction Survey (HASS),
  • Average daily use of the bilateral hearing aid in hours/day.


• Tertiary endpoints:

  • HASShaf and HASSdisp satisfaction scores, produced to represent satisfaction with the hearing instruments and the dispenser, respectively,
  • All participants completed the Hearing Aid Competency Test to assess the ability to use and maintain hearing aids.

Results

This trial demonstrated the effectiveness of the follow-up delivery model (AB) and the effectiveness of the over-the-counter model (OTC).

The AB group’s results on the primary outcome measure (PHABGlobal), secondary outcome measure, and other tertiary measures were significantly better than the P group. However, the use of best practices in audiology, including individual assessment and setting of maximum hearing aid power based on the listener’s unpleasant volume judgments, did not result in better perception of sounds (aversive or distorted), compared with the Placebo group. The use of best practices also did not have an impact on the daily use of hearing aids (group AB and group P).

The CD group’s results on the primary outcome measure (PHABGlobal), secondary outcome measure and other tertiary measures were significantly better than those of the P group. There were no differences between groups AB, CD, and P on individual assessment and setting of maximum hearing aid power as well as perception of sounds (aversive or distorted) and daily use of hearing aids (group AB and group P).

Problems with hearing aid use were found, with no significant difference between groups. The problems were:

  • Tubing, 88% of the time,
  • Insertion into the ear, 36% of the time,
  • Low or exhausted batteries, 17.5% of the time.
  • Hearing aid maintenance problems at the end of the 6-week trial were not inconsequential, as they resulted in a significant decrease in speech amplification and significantly poorer aided speech comprehension performance.

There were no significant differences between the groups in the use of the user manual. In general, all groups tended to use the user guide and the guide was found to be useful, equally, for all 3 groups.

At the conclusion of the study, 134 of the 154 participants (87%) mentioned their intention to keep the hearing aids, including :

  • 81% of the AB group,
  • 55% in group CD,
  • 36% in group P.

These results may give a slight advantage to the AB group of good audiology practices. It should be noted, however, that participants in the CD group tended to choose amplification that was slightly lower than their actual needs. This could explain the previous result. However, this lower amplification did not impact the number of hours per day of hearing aid use (about 7 hours), similar to the AB and P groups.

85% of the participants who finally returned their hearing aids at the end of the trial were those who paid the highest typical purchase price ($3,600). The purchase price therefore influenced the final decision about whether or not to keep the hearing aid.

Conclusions

Analysis of the results showed that hearing aids are effective in older adults for both the AB (best practice) and CD (over-the-counter, non-prescription) benefit models. Effective preset devices can therefore significantly increase the accessibility of hearing aids for millions of older adults.


Sources :

Larry E. Humes, Sara E. Rogers, Tera M. Quigley, Anna K. Main, Dana L. Kinney, Christine Herring
The Effects of Service-Delivery Model and Purchase Price on Hearing-Aid Outcomes in Older Adults: A Randomized Double-Blind Placebo-Controlled Clinical Trial”


Notes:

[1] President’s Council of Advisors on Science and Technology, PCAST – 2015

[2] Ortman, Velkoff, Hogan – 2014

[3] Cruickshanks, Zhan, Zhong – 2010

[4 ] Kochkin – 1993a, 1993b, 1993c, 2000, 2005, 2009; Perez and Edmonds – 2012

[5] Donahue, Dubno, Beck – 2010

[6] National Academies of Sciences, Engineering, and Medicine (NASEM) – Hearing Health Care for Adults: Priorities for Improving Access and Affordability – 2016

[7] Donahue et al – 2010

[8] Kochin et al – 2010; Valente et al – 2006

[9] Considered to be best practice in this area. Kochkin et al – 2010; Valente et al – 2006

[10] Ciletti and Flamme – 2008

[11] Humes – 2001, 2003; Humes & Krull – 2012

[12] Humes, Garner, Wilson and Barlow – 2001; Kochkin – 2000


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