by Wayne Staab, PhD

Historically, we think of the U.S. hearing aid market being served primarily by independent dispensers.  Following the very early years of hearing aid franchises, sales were made mostly by what we now refer to as independent hearing aid dealers (actually, at one time, called hearing aid audiologists). Over time, audiologists also entered the business of hearing aid sales.  

The question to be asked, however is, do these two selling groups, identified as hearing aid dispensers, continue to be independent?

 

U.S. Hearing Aid Sales

 

In 2016, the last full year of data, between 3.28 and 3.65 million hearing aids were sold in the U.S.1,2  This consists of 22% sold (roughly 1/5th) through the VA (Veterans Administration) hearing aid program and 78% sold in the private market (Figure 1).2   This percentage is minimally changed with those reported on this site in 2015

 

hearing aid sales private vs veterans administration

Figure 1. U.S. Hearing aid sales for 2016. (Sources: HIA, Bernstein analysis, author analysis)

 

In Table 1, below, the yearly percentage growth of these two sales markets is shown over the past 17 years as reported and estimated by the hearing aid industry.  

These figures do not include PSAP (Personal Sound Amplification Products) and other amplification devices used by the hearing-impaired population and which serve essentially as hearing aid devices to assist those with hearing loss, which, if included, would change the percentages, but to what extent, is unknown.3

 

hearing aid sales by year va vs private

 

Most U.S. Hearing Aid Sales Represented by a Handful of Manufacturers

 

According to the data collected by Bernstein, the so-called “big six” hearing aid manufacturers richly deserve the term, since among them they accounted for 98% of the world market in 2016.  

These six companies are GN ReSound, Sivantos, William Demant, Sonova, Starkey, and Widex.  Four of these companies (the first four) are public-traded companies, so relatively reliable information about them is available, although not necessarily easily accessible.  The last two companies are privately held, and as a result, more detailed data about their sales is limited.  These same big six companies are believed to represent a similar high percentage of hearing aids sold in the U.S., but the percentage is not clear, with various unreferenced citations listing this number from 80% to 90%.

 

Private vs. Independent Sellers of Hearing Aids

 

This is an important distinction, and necessary to understand how the POS (point of sales) channels contribute to U.S. hearing aid sales.

 

Although Figure 1 provides an interesting general overview, it does not show the market split contributions between the various groups comprising the private market.  More specifically, it does not provide a breakdown between actual independent chains and the various buying groups, all of which are covered in the general term “private” market.  

To show this breakdown, Figure 2 provides a 2016 split of the U.S. private market.2   This takes into consideration the manufacturers’ own retail (when the manufacturer owns the store and thus employs the sales people), or in the case of Beltone or Miracle Ear where it is a clear franchise situation. While the latter two are considered independent, they are to be viewed as separate from a pure independent. For the buying groups like Amplifon’s Elite, GN’s Audigy, Demant’s American Hearing Aid Associates, these would be considered independent, although they should still be seen as separate from a pure independent.  

As a result of these differentiations, and based on referenced calculations, only 26% of the market consists of true, largely unaffiliated independents.  And, even within this largely unaffiliated independent group, even they are captive to a large extent, because many of their purchasing agreements include loans, etc. that lock them in with one of the manufacturers.  The difference is that they still run their own business.

 

 

 

private hearing aid market by point of sale

Figure 2. The U.S. private hearing aid market by split of unit sales by POS (point of sale).* Sources: Corporate Reports, HIA, Bernstein analysis4, Staab (author) analysis.5 The percentage does not equal 100% (adds to 99%) due to rounding calculations.

 

What Defines an Independent Hearing Aid Retailer?

 

Many individuals may think that they operate independently.  But, in addition to, and reiterating descriptions provided in an earlier report, the following points are to be considered when defining independent retail sales in general:  

 

  • Completely responsible for his or her own business
  • Makes all the decisions for the store
  • Not accountable to shareholders
  • Every business decision rests on the owner
  • If independent of another, it is separated and not connected, so the first one is not affected or influenced by the second
  • The business relies solely on its unique name and reputation (i.e., does not “wear” a regionally or nationally recognized brand name)
  • Full decision making function for the business is held by the local owner(s), including the name, signage, brand, appearance, purchasing, etc.
  • The business is solely responsible for paying its own rent, marketing, and other expenses
  • It is not a vendor (i.e., does not sell wholesale)
  • And, perhaps the best indicator: when the owner lays awake at night wondering how the next payroll will be made

 

Major Drawback to Being Independent

 

Prices charged are likely to be higher than those charged at a retail chain or store.  This generally results in being unable to order in bulk, and as a result, cannot offer bulk discounts to compete.

 

*A number of financial research firms in the United States and abroad follow the hearing industry on behalf of their clients. These include individual investors as well as institutional investors such as pension and hedge fund managers.

 

References:

  1. Industry News.  (2017).  US hearing aid unit sales increased by 8.7% in 2016. The Hearing Review, January 16, 2017.
  2. Bernstein. (2017).  Hearing aids: private market sees strong November with +9% growth (+4% YTD).  VA posts +1% volume growth (+1% YTD).  December 14, 2017.
  3. Staab, W.  (2015).  The independent hearing aid dispenser, Hearing Health and Technology Matters, July 21, 2015.  http://hearinghealthmatters.org/waynesworld/2015/the-independent-hearing-aid-dispenser/.  
  4. Sanford C. Bernstein. Founded in 1967, Bernstein is a leading sell-side Wall Street research firm.
  5. Staab, W.  (2015).  Independent hearing aid dispenser directions.  (2015).  Hearing Health and Technology Matters, July 28, 2015.  Independent hearing aid dispenser directions.  (2015).  Hearing Health and Technology Matters.

 

 

Wayne Staab, PhD, is an internationally recognized authority on hearing aids. His professional career has included University teaching, hearing clinic work, hearing aid company management and sales, and extensive work with engineering in developing and bringing new technology and products to the discipline of hearing. Dr. Staab is the Founding Editor of Wayne’s World and served as the Editor-In-Chief of HHTM from 2015 to 2017.

Energy Harvesting Approaches to Powering Hearing Aids

 

Poem 40Note:  For those expecting to find the continuation of Directional Microphone Mismatch, as mentioned in last week’s post, please note that some recent information has been presented that will relate to improving the robustness of matching two omnidirectional microphones to create a directional listening experience.  As a result, the second part is being delayed.

The Battery as a Power Supply

Hearing aids operate using a battery (actually a cell) power supply. These are generally zinc-air cells, but more recently, zinc/silver was introduced as a potential option. The output of the hearing aid battery, or power supply, is advertised as 1.4 Volts, although the actual operation voltage is closer to 1.28 with continued operation down to approximately 1.1 Volts.

The quest for efficient miniaturized energy harvesting devices is an age-old and on-going activity. Before batteries, energy scavenging or energy harvesting was the only way to get useful power (water wheels, windmills, etc.). And, even though energy harvesting is still an active program for many miniature (and larger) devices, current developments have not yet been directed toward hearing aids. The required voltage and current drain requirements for hearing aids appear to be too great at this time for the general energy harvesting approaches employed. Still, energy harvesting (power harvesting; energy scavenging) provides interesting speculation.

Approaches to Energy Harvesting 

Energy harvesting is a process of powering an embedded system by “harvesting” energy from the environment. The approaches to date that are most likely to apply to hearing aids are those that attempt to harvest energy to supply the power and storage to autonomously operate miniature electronic devices, such as wireless sensor networks, watches, and biomedical implants. These are devices where battery replacement or recharging is difficult, or where continuous, non-maintenance operation is desired. Whether such operation is desirable for hearing aids is debatable. Regardless, questions about energy harvesting and hearing aids are bound to arise. This short post attempts to describe those harvesting approaches that are most applicable to low-voltage and low-current drain requirements.

Low-voltage energy harvesting generally utilizes ambient energy sources. These consist of:

  1. Photovoltaic energy,
  2. Mechanical energy,
  3. Thermal energy,
  4. Radio frequency energy, and
  5. Acoustic energy

Other sources exist for harvesting energy, such as wind energy, salinity gradients, etc., but these are not normally associated with micro-energy harvesting.

Batteries for Hearing Aids

With current hearing aid batteries, it would seem desirable for them to be designed with higher energy density. Unfortunately, battery energy is among the slowest trends in electronic technology. Even though new materials come into play, the energy density doesn’t scale exponentially (Figure 1)[1]. A comparison of battery energy density trend (blue boxes at the bottom of the scale) against recognizable mobile electronic trends is shown in Figure 2 illustrates that battery energy is the slowest trend in mobile computing. Even with new materials, energy density does not scale exponentially[2]. This seemingly intractable problem of how to increase the energy density of batteries has led some to begin thinking about abandoning them altogether, at least for some devices. However, this seems remote for hearing aids at this time, especially if one is looking at energy harvesting for battery replacement.

Figure 1. Energy density by mass, shows that for the batteries listed, that essentially the processing power doubles every 2 years, but battery capacity doubles only every 10 years. Even though current hearing aid cells (zinc air) are not shown, their growth in energy density does not exceed the battery types listed.

Figure 1. Energy density by mass shows that for the batteries listed, essentially the processing power doubles every 2 years, but battery capacity doubles only every 10 years. Even though current hearing aid cells (zinc air) are not shown, their growth in energy density does not exceed the battery types listed.

Figure 2. Improvement multiples of computer functions since 1990, with battery energy density improvement shown in comparison (lower blue boxes). It is obvious that battery energy density moves at a much slower pace.

Figure 2. Improvement multiples of computer functions since 1990, with battery energy density improvement shown in comparison (lower blue boxes). It is obvious that battery energy density moves at a much slower pace.

So, if future energy-harvesting approaches might possibly become involved with hearing aid batteries (don’t expect anything soon), what are some of these approaches?

Photovoltaic Energy (PV)

This process converts light energy into electrical energy. The light source is usually sunlight, and the energy conversion uses a photoelectric effect. The problems for micro-miniature devices are that the solar panel(s) has to be large relative to the device, and that use is limited when sunlight is not present.

Interestingly, the use of solar power for hearing aids was attempted back in 1958. However, the hearing aid for which it was developed was a large eyeglass instrument with a fairly long and wide upward-facing surface, something not available in hearing aids today. That device could best be described as “experimental,” and the continued movement toward miniaturization of hearing aids eliminated the solar surface area available. More recent solar rechargeable batteries have been presented, but use a pocket-size recharger for either a wall outlet or solar panel. The energy harvesting is remote from the hearing aid.

Mechanical Energy (PZT)

This energy form arises from mechanical vibrations or body motion. For micro-miniature devices, the random or dedicated body motion (less than about 10 Hz) has been tapped as an energy source. Piezoelectric materials bend to mechanical energy of vibration or stress (Figure 3).

Figure 3.   Operation of a piezoelectric illustrating how stress produces a voltage.

Figure 3. Operation of a piezoelectric illustrating how stress produces a voltage.

Figure 4. Energy harvesting by motion of an oscillating mass.

Figure 4. Energy harvesting by motion of an oscillating mass.

Mechanical vibration energy harvesting has increased in popularity because of the rather abundant availability of such vibrations in many environments. Mechanical vibrations are converted into electricity using electromagnetic induction (vibration leading to motion of a magnetic field), piezoelectricity (to bend or strain a material), and electrostatics (motion of an oscillating mass, Figure 4)[3]. These authors report that magnetostrictive materials, magnetic shape memory alloys, and triboelectrification have also been proposed for vibration energy harvesting. They offer a vibration energy-harvesting scheme based on the charging phenomenon occurring naturally between two bodies having different work functions. They report that WFEH (work function energy harvester) is similar to electrostatic energy harvesting, with the distinction being that neither external power supplies nor electrets are needed. WFEH (Figure 5) is projected to be operated as a charge pump that pushes charge and energy into an energy storage element.

Figure 5. Work function energy harvester (WFEH). Natural vibrations caused by two surfaces with different work functions, repelling and attracting each other to generate electricity. (Image: VTT).

Figure 5. Work function energy harvester (WFEH). Natural vibrations caused by two surfaces with different work functions, repelling and attracting each other to generate electricity. (Image: VTT).

Thermal Energy (TEG)

Figure 6. The thermogenerator converts the heat flow existing between the body part heat and the ambient in electrical energy.

Figure 6. The thermogenerator converts the heat flow existing between the body part heat and the ambient in electrical energy.

TEG (thermoelectric energy generator) uses temperature difference to generate electric potential. Using the Seebeck Effect (a phenomenon in which a temperature difference between two dissimilar conductors produces a voltage difference between the two substances), this form of energy harvesting is considered reliable and maintenance free, but is costly and inefficient. It often uses the temperature difference between the human body and the surrounding environment (Figure 6). Because this variation between the internal and external temperature is only a few degrees, this would normally produce only about 200 millivolts, which is insufficient to power an electronic device such as a hearing aid that normally requires about 1.2 Volts. [4]. The TEG is limited by Carnot efficiency (Carnot efficiency improves as the range of temperature difference becomes wider).

Radio Frequency Energy

This form of energy harvesting scavenges energy from wireless systems present in our environment (TV, radio broadcast, mobile networks, wireless networks, radar, etc.). It does require that the harvested energy be rectified and filtered to recover DC (direct current).

Acoustic Energy

This is an abundant source of energy harvesting, but it is said to require a Helmholz resonator containing a piezoelectric cantilever beam.

Energy Storage Options

Scavenged energy is not constant, and as a result, power is not available “on demand.” Because of this, the energy storage may be so demanding that it cannot be met by traditional rechargeable batteries, traditional capacitors, or, most likely, not even by super capacitors.

Summary

It is most likely going to be difficult to beat hearing aid batteries for their all-around versatility and flexible space application. However, as with most things, the future is bound to change, most likely initiated by environmental interests.

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Footnotes    (↵ returns to text)

  1. Valenzuela, A. (2008). Texas Instruments
  2. Paradiso, et al. (2005). Pervasive computing, IEEE
  3. Varpula, A., Laakso, S., Havia, T, Kyynäräinen, J., and Prunnila, M. (2014). Harvesting vibrational energy using material work function. Scientific Reports 4, Article number: 6799
  4. Generating electricity from body heat, Oct. 2, 2011, http://hassam.hubpages.com/hub/Generating-Electricity-From-Body-Heat