techtopic
`
`Bringing Rechargeable Hearing Aids
`Into the Mainstream Market
`
`BY JERRY YANZ, PhD, JÖRG ELLESSER, MS, AND HOLGER KAEMPF, MS
`
`In their roughly 30-year history, rechargeable hearing instruments have
`yet to become the chosen alternative for most hearing aid wearers. This
`article details two new hearing systems designed to bring rechargeable
`hearing instruments out of the niche market and into the mainstream.
`
`Sales of rechargeable consumer elec-
`
`tronic devices have blossomed in
`recent years. Surprisingly, however, in
`their roughly 30-year history, rechargeable
`hearing instruments have yet to become
`the chosen alternative for most hearing
`aid wearers. The operating time per charge
`(OTPC) has simply not been sufficient to
`get most hearing aid wearers through the
`day, and other design and durability issues
`have prevented widespread acceptance.
`Battery life, cost, and ease of use are
`important concerns for hearing aid
`wearers.1 If designs can be developed that
`meet the needs of consumers, rechargeable
`hearing instruments may become the
`solution to their concerns. This article
`introduces two new hearing systems from
`Hansaton Acoustics that promise to bring
`rechargeable hearing instruments out of the
`niche market and into the mainstream.
`
`Why Rechargeable Aids?
`There are at least two motivations to use
`renewable power sources in hearing aids.
`The first is ease of use. While a small battery
`size allows manufacturers to build very small
`cosmetically appealing hearing instruments,
`small size is also a liability. Rare is the hearing
`aid wearer who has not chased a battery
`under the kitchen table or put batteries in
`the compartment up-side-down, sometimes
`resulting in a jammed or broken battery
`compartment. People dealing with physical
`
`or visual impairments are further challenged
`by conventional batteries. And every hearing
`aid user’s manual contains a warning about
`swallowing hazards. A hearing instrument
`with batteries that the wearer does not need
`to handle would be a significant boon.
`The second motivation is environmental.
`Even though the button cells in hearing
`instruments are minute compared to many
`batteries, there is growing awareness of the
`cumulative effect of metals and chemicals
`building up in landfills.2 Switching to
`rechargeable cells in this and many other
`applications, large and small, appears to be a
`worthwhile and growing trend.
`In spite of the motivations to find
`an alternative to replaceable batteries,
`rechargeable batteries have not made major
`inroads into the hearing instrument market.
`To put it simply, the benefits they have offered
`to date have not outweighed the limitations
`and frustrations they have presented.
`That picture has now changed.
`
`New Rechargeable Technology
`Hansaton Acoustics recently introduced
`two rechargeable hearing instruments that
`promise to change the way the market
`views rechargeable hearing aids. In the
`spring of 2010, the latest version of the AQ
`Custom Rechargeable ITE appeared, and in
`July 2011 the company launched the AQ
`X-Mini Rechargeable Receiver-in-the-Canal
`(RIC) device (Figure 1). The patented
`
` This article was submitted to HR by Jerry L.
`Yanz, PhD, director of audiology at Hansaton
`Acoustics, Plymouth, MInn, and Jörg Ellesser,
`MS and Holger Kaempf, director of audiol-
`ogy at Hansaton Akustik, Hamburg, Germany.
`Correspondence can be addressed to HR or Dr
`Yanz at jerry.yanz@hansaton.com.
`
`features of these instruments promise to
`change the market’s view of rechargeable
`instruments.
`Hearing instrument wearers should be
`aware of a number of performance criteria
`when considering a rechargeable hearing
`instrument:
`
`■ Operating time per charge (OTPC);
`■ Recharge time;
`■ Battery longevity before needing
`replacement; and
`■ Ease of use.
`
`Furthermore, a potential user of
`rechargeable instruments needs to be
`confident that the rechargeable hearing
`instruments perform as well as conventional
`instruments. The remainder of this article
`addresses the performance of Hansaton’s
`AQ systems with regard to each of these
`questions.
`i s h i g h - l e v e l b a t t e r y
`H o w
`performance achieved? The three main
`electrical attributes of the Hansaton AQ
`rechargeable system—operating time per
`charge, recharge time, and battery longevity
`—are achieved through a patented
`charging process that is unique to the AQ
`instruments.
`A control circuit inside the hearing
`aid precisely monitors battery status and
`communicates wirelessly with a circuit
`inside the Charging Station (Figure 2). If
`a charge is needed, it initiates the charging
`process and signals that status to the user
`
`Figure 1. A) Eight color options in the Hansaton AQ X-Mini
`rechargeable RIC. The dot on the back of the case is an infrared
`communication port; B) AQ Rechargeable custom full-concha ITE.
`C) AQ Rechargeable custom half-concha ITE.
`
`via an LED display. When the charge is
`complete, the circuit turns the charger off
`precisely at the point of 100% charge and
`likewise signals a full charge to the user.
`Importantly, the wireless communication
`between hearing aid and charger prevents
`the battery from ever overcharging, even
`by a few percent. It is this exquisite control
`that gives the AQ systems unparalleled
`battery performance.
`Operating time per change
`(OTPC). The AQ X-Mini RIC rechargeable
`instruments provide at least 20 hours of
`operation per charge when the strongest
`(65 dB gain) RIC receiver is used; operating
`time is longer with the optional lower-gain
`45 and 55 dB receivers. AQ Custom ITEs
`achieve up to 30 hours per charge. With
`this operating time per charge, users rarely
`face the prospect of their hearing aid failing
`before day’s end.
`Long-term OTPC (the “battery
`memory” issue). Previous rechargeable
`hearing aids have been susceptible to a
`decline in OTPC over the life of the battery.
`Commonly known as the battery memory
`issue, this is due to at least two factors:
`
`1) Failure to follow a strict schedule
`of completely discharging and
`completely recharging the battery,
`and
`2) Overcharging the battery by even a
`small amount.
`
`So, a battery that offers, for example, 15
`hours OTPC when new may begin to lose
`operating time as it is used. As soon as it
`declines to a point that it fails to operate for
`the user’s typical day, it essentially defeats
`the purpose of a rechargeable system. (For
`example, an online ad for one competitive
`product acknowledges this issue and
`suggests replacing the rechargeable battery
`when its OTPC approaches 8 hours—
`clearly not enough for a regular hearing aid
`wearer.)
`If the operating time of your MP3
`player drops from 6 hours to 4 hours, you
`can probably cope. But, if you depend on
`hearing aids and failure means losing your
`ability to communicate, then adequate and
`reliable battery life is essential.
`The Hansaton AQ system is not
`susceptible to battery memory issues—no
`rigid recharging regimen is required. You
`can charge a battery when it is near the
`end of its usable charge or when it is only
`minimally discharged; neither alternative
`will compromise performance. The precise
`control over the charge cycle offered by the
`control circuit prevents even the slightest
`degree of overcharging, ensuring long
`operating time over the life of the battery.
`
`Substituting a primary cell for a
`rechargeable cell. Typical rechargeable
`aids allow the user to remove the battery
`and to substitute a primary cell as a
`backup when the rechargeable battery
`fails before day’s end. This approach not
`only negates the convenience of using a
`rechargeable battery—you still have to
`change batteries—but also presents another
`issue. Primary zinc-air batteries cannot be
`recharged, and if a user mistakenly places a
`hearing aid containing a primary cell in the
`charger, there is risk of the cell expanding
`or bursting inside the hearing aid, with
`resultant release of electrolyte and damage
`to the hearing aid. The same risk arises if
`the rechargeable battery is placed in the
`compartment upside down.
`Hansaton’s design decision, to seal the
`battery compartment and eliminate the
`option of substituting a primary cell, is
`based on a desire to avoid such problems
`and is made possible by the patented AQ
`design. The OTPC of the AQs eliminates
`any need for battery substitution.
`As an ancillary benefit, eliminating a
`manually operated battery compartment
`also enhances cosmetic appeal and moisture
`resistance and eliminates the old problem
`of broken battery doors. Your patient never
`has to see or touch a battery.
`Recharge time. Recharging an AQ
`instrument takes on average 2 to 4 hours. If
`the battery is fully depleted, it may take up
`to 8 hours. This rapid recharge time ensures
`that the hearing aid will be ready to go each
`morning after a night in the Charging Station.
`Battery longevity. Battery service life
`is also optimized by Hansaton’s patented
`control circuit and charging process. AQ
`batteries have a 5-year guarantee. If a
`battery fails within that time frame, it will
`be replaced at no charge.
`Ease of use/reliability. Ease of use
`and reliability go hand-in-hand in the AQ
`instruments. Recharging is achieved via
`an inductive link between the Charging
`Station and the hearing instrument. To
`
`Figure 2. On the case of the AQ X-Mini is an infrared port for the
`control circuit to communicate with the Charging Station and con-
`trol the inductive charging process. In the custom AQ, the wireless
`communication passes through the shell.
`
`Figure 3. Diagrams of a primary cell (top) and secondary cell
`(bottom).
`
`More About Batteries...
`Batteries are electrochemical systems
`that convert chemical energy into electrical
`energy to power devices (Figure 3). In a
`typical zinc-air battery, the cell fails when
`its supply of electrolyte is depleted; at this
`point, we throw it away and replace it
`with a new cell. A rechargeable cell also
`depletes electrolyte as it powers the device,
`but unlike the primary cell, the original
`electrolyte balance is restored by recharging
`the battery so that it can provide portable
`power again and again.
`Let’s review a few terms. A conventional
`replaceable battery is also known as a
`primary cell, while a rechargeable battery is
`known as a secondary cell or accumulator,
`in that it accumulates charge overnight
`and then uses that charge to power an
`instrument the next day.
`Secondary batteries have realistic
`limitations. Like every primary cell, they
`have a finite supply of chemicals to provide
`electrical current before being depleted.
`While a primary cell supplies current for
`a number of days before depletion, a
`secondary cell provides current on the order
`of hours before needing a recharge.
`No secondary cell lasts forever;
`eventually, when the cell loses its ability
`to recharge, replacement is needed. The
`difference here is that, while primary cells
`must be replaced after a week or two, a
`secondary cell continues working for a much
`longer time before replacement is needed.
`
`28 hearingreview.com JANUARY 2012
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`JANUARY 2012 hearingreview.com 29
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`Figure 4. AQ Custom ITE and AQ X-Mini RIC Charging Stations. To charge the hearing aid, the user simply places the hearing aid into the charging
`cradle. The Charging Station then automatically switches the aids off and begins and (importantly) ends the charging when 100% complete.
`
`charge the instrument, the user simply slips
`it into a charging cradle (Figure 4). Since
`there are no contacts to engage, demands
`on manual dexterity are minimal, and
`there is no chance of the process being
`compromised by electrical contacts that
`corrode or wear.
`The Charging Station switches the aid
`off automatically and begins and ends
`the charging process automatically. The
`charging cradle for the AQ Custom ITE is
`molded from the shell of the instrument
`itself, so that it drops naturally into the
`proper position in the Charging Station. An
`LED display on the Charging Station shows
`time of day and charge status, plus a service
`reminder that appears after 200 charges.
`
`Sound Processing and
`Performance
`Although this article concentrates on the
`topic of rechargeability, the AQ family of
`instruments competes at the front of the pack
`relative to sound processing performance.
`Both the AQ X-Mini RIC and the AQ Custom
`ITE are available in three technology levels—
`First Class, Business Class, and Comfort
`Class—to meet the needs and preferences of
`a wide range of patients.
`i n t o d e t a i l e d
`W i t h o u t g o i n g
`descriptions of their operation, a partial
`list of digital processing features includes
`Active Feedback Block 2G, Speech Beam,
`Multi-channel Adaptive Directionality,
`Acclimatization Manager, Situation
`Optimizer, Hifi Sound, Natural Sound,
`Speech Detection, Noise Reduction,
`Impulse Sound Management, Active Wind
`Block 2G, icom-2 wireless synchronization,
`and Bluetooth connectivity. A hearing aid
`user can be assured that having the best
`in rechargeability requires no sacrifice in
`state-of-the-art sound processing.
`
`Summary
`For new technologies to be accepted in
`the market, they must satisfy requirements
`
`for usefulness and ease of use. The
`usefulness of the Hansaton AQ rechargeables
`is clear from the performance features just
`mentioned: 20+ hours of operation per
`charge, 2 to 4 hours to recharge, and a
`5-year battery guarantee. The other essential
`element for market acceptance, ease of use,
`is achieved by eliminating the need to ever
`see or touch a battery.
`During a presentation at the American
`Academy of Audiology 2011 AudiologyNOW!
`convention in Chicago,3 the first author
`polled the audience by asking them to identify
`the target patient populations for rechargeable
`hearing aids. They responded with a list
`including visually impaired, physically
`impaired (amputees, people with tremors),
`the elderly, children—all clearly important
`target patient populations. However, the most
`obvious, and perhaps most important, target
`group was identified last: the entire population
`of hearing-impaired individuals.
`Indeed, with a system that offers
`superb sound processing and overcomes
`the issues that have limited previous
`rechargeable systems, it is indeed time to
`lift rechargeable hearing instruments out of
`the small market niche they have occupied
`for 30 years and bring them fully into the
`mainstream market. ◗
`
`References
`1. Kochkin S. Consumers rate improvements
`sought in hearing instruments. Hearing Review.
`2002;9(11):18-22. Available at: http://www.
`hearingreview.com/issues/articles/2002-11_01.
`asp. Accessed December 5, 2011.
`2. Campbell W. Innovations in technology: mercury
`falling. Hearing Review Products. November/
`December 2008. Available at: http://www.
`hearingreview.com/issues/articles/HPR_2008-
`11_03.asp. Accessed December 5, 2011.
`3. Yanz J, Ellesser J. Hansaton AQ: A
`revolutionary rechargeable hearing instrument.
`Seminar presented at: American Academy of
`Audiology Annual Convention; April 7, 2011;
`Chicago.
`
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