This article is the fifth in our special Hearing / Hearing Aids theme, aimed at providing comprehensive answers to a range of questions commonly asked by our customers and web users. Find the other articles of this theme on the summary.
In order to answer the question “How to choose a (good) hearing aid ?” it is important to provide some basic information to the readers, so that they know how a hearing aid works, what makes it good and what technical characteristics to keep in mind when choosing it. This seems to us to be all the more important as physical stores (hearing aid specialists, opticians), the web and marketplaces (La Fnac, Darty, Boulanger, Amazon, Ali Baba) are full of hearing aids whose external shells all look the same, but whose prices vary from 10€ to more than 2000€. However, most of the time, the fundamental technical characteristics are not specified, leaving the uninformed Internet user with a choice to make that is based solely on price !
We would like to point out that this article is intended for people with presbycusis and not for people with a hearing handicap / deafness. People with a hearing handicap must necessarily follow a traditional care path (ENT medical consultation, appointment at the hearing aid specialist, personalized hearing aid of the BTE type and excellent care / refund, as we mentioned in our previous article) ; while presbycusis sufferers have the choice between a traditional care path (custom hearing aid, sold with a follow-up service over several years) or an over-the-counter hearing aid (pre-configured, without additional follow-up service), they also have the choice between an in-the-ear hearing device and a behind-the-ear device. This is why clarification is needed, through a factual explanation of how these hearing aids work.
How does the hearing system work ?
To better understand how a hearing aid works (and its limitations), the first thing to consider is how the hearing system itself works. Schematically, each of us is born with an average of 15,000 hair cells (found in the inner ear). These cells are distributed at the base of the cochlea (the cochlea is the organ of hearing, shaped like a snail). Their role is to detect the sound vibration (captured, as we will see later, at the level of the external ear, auricle and auditory canal) to generate the nerve impulse which is sent to the brain by the auditory nerve. These hair cells are sensitive to the passing of time (aging, presbycusis), to sound and pressure aggressions. The first frequencies affected are the high frequencies because they are located at the base of the cochlea, opposite the stapes.
When these cells are damaged or even destroyed, they do not grow back (to this day, although research is underway, we still do not know how to make these cells “grow back”) and the hearing loss is then permanent. To regain hearing comfort, the only remaining solution is hearing aids. Whatever its type (in-the-ear hearing aid or behind-the-ear hearing aid), its setting (custom-made with a prescription or pre-configured without a prescription) or its price (from 10€ to more than 2000€), a hearing aid is a sound amplifier, i.e. a device that will amplify sounds on the hearing frequencies lost with the destruction of the hair cells. Understanding this point is fundamental, because it means accepting the idea that a hearing aid is an imperfect solution that will never give you back the hearing you had when you were 20. It also means accepting the idea that some people may need time to adapt. When this information is clearly expressed to the user, any disappointment they may feel is better understood.
How does a hearing aid work ?
All hearing aids work in the same way. They consist of a microphone (which picks up sounds, i.e. external sound vibrations), an amplifier (which analyzes the acoustic signal and adjusts the amplification according to the sound environment), and an earphone (which reproduces the amplified sounds or sound signal in the ear canal). A hearing aid works with a battery (in the case of small hearing aids such as in-the-ear hearing aids) or can be recharged (in the case of larger hearing aids such as behind-the-ear hearing aids).
• The microphone
The microphone is located on the outer shell of the hearing aid. Thus, in the case of a BTE hearing aid, the microphone is placed behind the ear (behind the pinna), whereas in the case of an ITE hearing aid, the microphone is placed at the entrance to the ear canal. This point is of great importance. Why is this important? Because a BTE hearing aid (which by definition “bypasses” the ear) does not use the pinna, whereas an ITE hearing aid does. However, the ear is an anatomical amplifier (the pavilion and the auditory canal are shaped like a horn, like that of Professor Tournesol). In the outer ear, it is the pinna which – by its shape and folds – naturally captures, spatializes and amplifies the sound waves which are then guided to the eardrum by the ear canal.
What are the consequences ?
In the case of a BTE hearing aid, the microphone is necessarily directional, so that it can focus on sounds coming from the front. Otherwise, being placed behind the ear, the sounds captured would be those located behind the individual. However, when someone speaks to us, he often speaks to us while facing us. It should also be noted that the microphone of a BTE hearing aid is exposed to wind noise: in addition to being directional, it must therefore incorporate a wind noise reduction system. In the case of an in-the-ear hearing aid, the microphone does not have to be directional, as it is placed inside the ear canal and naturally uses the outer ear. An in-the-ear hearing aid is naturally omnidirectional, i.e. it picks up sounds from all directions (thanks to the use of the pinna). Furthermore, since the microphone is housed in the ear canal, it is not subject to wind noise.
Finally, it should be noted that the microphones are mass-produced. All hearing aids are equipped with the same type of microphone: miniature electret microphones, initially developed for American espionage. They are a civilian spin-off of military research. These microphones are equipped with two staggered inputs which allow a directional effect to be created: low-pitched sounds are filtered out (diminished) while the directional effect is observed over a certain frequency range. However, the quality of the hearing aid depends on the intrinsic quality of the microphone, which is a fundamental component of the hearing aid. In this respect, users are advised to choose hearing aids that have the CE mark, which validates the quality of this component.
• The amplifier
The amplifier amplifies and transmits sound. It is at the heart of the quality of a hearing aid, whatever its type (BTE, ITE, custom, pre-configured). In recent years, amplifiers have undergone many technical advances. Today’s digital hearing aids differ from the (analog) ones of the 70s and 80s only in the pre-amplifier: there is now a converter and a processor. The performance of today’s devices is very close to that of yesterday’s analog devices. The amplifier is defined by its gain (in dB) calculated in a measurement chain. The gain is the ratio of the output voltage to the input voltage, it is adjustable by a potentiometer. The gain is expressed in current or in power. By concern of quality, we also recommend to be directed on hearing aids carrying the CE label.
• The earphone
The earphone is placed directly in the auditory canal, for greater performance (tympanic proximity). It translates the electrical signal into an acoustic signal. For CE marked hearing aids, there is only one type of earpiece, regardless of the hearing aid or brand. The earpiece is very small: it is the weakest link in the hearing aid. To achieve satisfactory performance, the earphones are electromagnetic. However, the bandwidth remains narrow, uneven because the metal membrane is the object of many resonances. The earphone can bring distortions to the sound signal, particularly on the low frequencies (we speak about harmonic distortions), which is generally not felt on devices for presbycusis (the hearing loss being mainly on the high frequencies).
• Other electronic components
A hearing aid also contains
- A potentiometer, which allows the manual adjustment (by the user) of the volume of the amplification ;
- A switch, which allows the hearing aid to be turned off or on. The potentiometer and switch can be combined into a single knob on some hearing instruments.
These two components do not guarantee the quality of a hearing aid, but they do ensure that it is easy for the user to handle, especially in the case of in-the-ear devices, as they are very small.
• A word about the outer shell
Many people are surprised that there is such a wide variation in price between hearing aids, even though they look similar on the outside. This comparison is simplistic. To illustrate, let’s give the following example: it would be like considering that a glass of water and a glass of vodka are the same thing, both liquids being transparent! The reality is however quite different and it is wise to recall here that what makes the quality of a hearing aid is not the external shell but the electronic components embedded in this shell and whose quality is certified by the CE standard. The vast majority of external shells are manufactured in China and then exported worldwide to hearing aid manufacturers. In France, the production of this shell is difficult, even with a 3D printer, because the smallness and the interconnection of the embedded elements with the elements of the external face of the hearing aid makes this production perilous with companies whose know-how is not this one. When choosing a hearing aid, do not rely on the external shell, but on the technical characteristics of the latter (often missing, unfortunately) and the CE label.
How to choose a hearing aid ?
We remind you that this article is intended for people affected by presbycusis and not for those with a hearing disability. In our previous article, we mentioned that people with presbycusis have the choice between a traditional hearing aid (called “custom-made”) and a pre-configured hearing aid. The former is only available from hearing care professionals with a medical prescription, while the latter is available over the counter. Let’s take a look at these two options.
The choice of a hearing aid via a “classic” care pathway
The so-called “classic” care pathway is the one in which a person who has difficulty hearing decides (in 42% of cases under pressure from those around him) to consult an ENT doctor, who will carry out an audiometric assessment. It is important to remember that the law formally prohibits hearing aid practitioners from canvassing customers with the promise of a free hearing test. By doing so, the hearing aid acoustician would be substituting himself for the doctor (illegal practice of medicine) and could be “tempted” to increase the individual’s hearing loss in order to refer him to a more expensive hearing aid: it is common sense to remember that no one can be judge and jury. If the hearing loss on high frequencies is greater than 30dB, the ENT doctor, who is the only one authorized to perform an audiometric examination, will prescribe a unilateral (on one ear) or bilateral (on both ears) hearing aid. The individual, from this moment on, will have the choice between getting a hearing aid from an audioprosthesist or buying a pre-configured hearing aid (without a prescription). Here we take the case of a fitting at the hearing aid specialist.
Based on the ENT audiogram that the patient will present to the audioprosthesist, the audioprosthesist is obliged to propose a hearing aid that meets the patient’s needs in terms of hearing and aesthetics. It is important to specify several points on this subject :
- In the fitting of presbycusis, the patient has the choice between a BTE hearing aid or an ITE hearing aid, both of which are perfectly suited to this hearing loss. The patient should be informed of this so that they can express their aesthetic preference. To date, there are no contraindications to wearing an ITE hearing aid. If, today, 80% of the worldwide sales of hearing aids are BTE type devices, this does not mean, in any case, a preference of individuals for this type of hearing aid (remember that less than 25% of the world population is equipped with a hearing aid and that one of the first reasons for rejecting a hearing aid is the aesthetic criterion and the “fear of getting old”), but rather a preferential orientation of certain professionals in the sector on this type of hearing aid. Numerous studies show, moreover, a preference of the users for the devices of type intra-auricular, which – using the ear – allow an amplification and a more natural restitution of the sounds while being of a great discretion (positioned in the auditory canal). The preferential orientation of patients by certain unscrupulous brands has been pointed out several times in a study by UFC Que Choisir (dated September 2015, refer to our previous article) and by a study by 60 millions de consommateurs (dated September 2022, refer to our previous article).
- It also seems important to remember thata person with presbycusis is perfectly eligible for CLASS I hearing a ids (in France, this is the RAC0 offer): this offer, thought for them, must be mentioned on the quote. The above-mentioned study by 60 millions de consommateurs points to a preferential orientation of patients towards CLASS II hearing aids (which are not included in the RAC0 offer) and an omission of this RAC0 offer from the estimate.
Concerning the technical characteristics to be taken into account in the choice of a hearing aid, we mention them in the paragraph below: in fact, in a traditional care pathway, it is – as we have mentioned – the hearing aid specialist who will “advise” the client and the latter will not necessarily have access to the technical information of the device. This is why, in this case, we thought it would be interesting to remind you of some basics :
- Have an audiogram performed by an ENT doctor and not by a hearing care professional,
- Make sure that your aesthetic criteria are met (in-the-ear or behind-the-ear),
- Try a RACO device (CLASS I).
On the other hand, when choosing a pre-configured hearing aid, the client should refer to the technical data sheet of the product in question since he will be choosing his own device: this is why we detail below, in the case in question, the important characteristics to take into account in this choice.
The choice of a preconfigured hearing aid
An American clinical trial, carried out in double blind and controlled by a placebo test, praises the merits of preconfigured hearing aids to compensate for presbycusis. In view of the wide range of products on offer, the diversity of prices and in order to ensure that you choose a quality hearing aid, certain technical characteristics must be taken into account. We detail them below.
The type of hearing aid : in-the-ear or behind-the-ear ?
As we have seen before, both types of hearing aids are suitable. The choice is therefore up to the user, depending on aesthetic criteria and possible difficulties in handling.
• A few words about the BTE hearing aid
In the case of a BTE hearing aid, the microphone is placed behind the ear, which has several consequences :
- A delay in the restitution of the sound which, captured from the back of the ear, is routed in the auditory canal via a tube which passes above the pavilion, causing a delay between the captured sound and the restituted sound: to harmonize this delay on both ears, a bilateral fitting is recommended ;
- Exposure of the microphone to wind noise: it will be necessary to be vigilant that the device integrates a system of reduction of the wind noise ;
- An unused auricle (bypassed ear) : it will be necessary to be vigilant that the device integrates a directional microphone system (which is today the case of all microphones of the devices having the CE standard). On the other hand, to optimize the spatialization of the sounds, the bilateral fitting (on both ears) is also recommended.
The (mini) BTE is relatively large: it is easier to hold and manipulate than an in-the-ear device and is therefore more suitable for people with reduced manual dexterity or shoulder mobility problems. On the other hand, because of its size, the BTE hearing aid often integrates rechargeable technology, which can be a plus for people with poor vision and therefore potential difficulties in sliding a small battery into a small hearing aid.
In terms of discretion and wearing comfort, if you have a long or medium-length haircut, the BTE will be hidden by your hair and therefore relatively discreet. However, if you already wear glasses, you may feel some discomfort at the end of the day, as the branches of the glasses, added to the BTE, will weigh down your ear. It is here a feeling of the user.
• A few words about the in-the-ear hearing aid
The intra-auricular hearing aid uses the ear (pavilion and auditory canal) and is positioned close to the eardrum: it is therefore very discreet and allows a natural restitution of sounds. The spatialization of the sounds is optimal, because the pinna plays its role fully here. In addition, sound reproduction is immediate (close to the eardrum), which provides hearing comfort even in the case of a unilateral hearing aid (on only one ear). The microphone being sheltered in the auditory canal, there is no concern related to the amplification of wind noise.
There are a few drawbacks to consider, however. Due to its intra-channel position, there is a feedback phenomenon when introduced into the ear canal. This phenomenon is normal, lasts only a few seconds and occurs even if the device has an anti-feedback system, the user must be informed. On the other hand, the ear being a resonance chamber, the wearing of an ITE may require a few days of adaptation, to get used to the feeling of having a device in the ear on the one hand but also to the resonance phenomenon. Subjected to the humidity of the auditory canal and to the cerumen, which settles on the exit of the sounds, the maintenance of an in-ear hearing aid must be daily, after each use. Finally, because of its small size, the user must be informed of the need to have good manual dexterity to hold the device and change the battery (once a week).
The amplification of the hearing aid
Hearing discomfort is felt when it is equal to or greater than 30dB on the high frequencies. It is also from this threshold of hearing loss that the ENT doctor prescribes a hearing aid. To compensate for this, the user should choose a hearing aid with an amplification of more than 30dB. The pre-configured hearing aids sold in pharmacies are, by law, limited to a maximum amplification of 20dB: they can only be suitable in the case of a first hearing loss or a simple punctual discomfort. Hearing aids that amplify to more than 20dB are sold on the Internet (refer to the characteristics of the products and the CE standard), in independent opticians and in certain paramedical stores.
• A few words on the BTE hearing aid
In the case of a behind-the-ear hearing aid, it is necessary to take into account the positioning of the device, behind the ear. As we have seen, this device is placed behind the ear and does not have the characteristics of the pinna, which captures and amplifies sounds: the amplification of a BTE hearing aid must therefore be superior to that of an ITE and can vary from 30dB to 40dB for quality devices aimed at compensating for a mild to moderate presbycusis hearing loss (up to 90dB, the limit of hearing impairment).
• A few words about the in-the-ear hearing aid
Unlike the BTE hearing aid, the in-the-ear hearing aid makes use of the pinna, which helps amplify sounds. With this type of device, hearing comfort is immediate and the stereo effect is present even with a unilateral fitting (only one ear). Choose hearing aids with a wide amplification spectrum (from 10dB to more than 30dB), which will cover all mild to moderate presbycusis hearing losses.
The number of frequency channels
The number of frequency channels of a hearing aid is the main argument of certain professionals in the sector who, counting on the ignorance of consumers on the subject, tend to orient them preferentially towards hearing aids with numerous frequency channels, easily denigrating hearing aids with fewer frequency channels. On this subject, let’s simply recall the wise words of Phonak (Sonova Group, one of the world leaders in hearing aids): “Some hearing aid models now have 12 frequency channels, whereas the top-of-the-line devices of a few years ago only had 10 (…) What counts is not the number of frequency channels but the user’s need, which must be met
It is high time to clarify this point.
• Frequency channels do not mean setting channels
There is a lot of confusion between frequency channels (which are the frequencies covered by the amplification of the hearing instrument) and tuning channels (which are the channels that the hearing care professional can use to fine tune the intrinsic amplification of the hearing instrument). It is important to note that all hearing aids, preconfigured or not, have an initial preset, which corresponds to the intrinsic functioning of the hearing aid. On this presetting, made by the manufacturer, no one can act: neither the hearing aid acoustician, nor the client.
By law, hearing aids marketed by hearing aid practitioners must be adjusted: they therefore have a certain number of adjustment channels (3, 6, 9, 12, 15 in the case of atypical pathologies) on which the professional can refine the intrinsic amplification of the hearing aid according to the patient’s audiogram. The greater the number of adjustment channels, the greater the risk of error (hearing discomfort). On the other hand, the more the number of adjustment channels increases, the more the price of the hearing aid increases while the on-board electronic components (guaranteeing the quality of the device) are the same. This is a subject that caused a scandal in 2015 (UFC Que Choisir), when some professionals in the sector admitted that similar hearing aids (brands, components) were “limited” in terms of adjustment channels, to allow a range of prices increasing according to the “number of channels”.
In the case of pre-configured hearing aids, these adjustment channels are non-existent, as the aids in question are ready to use, i.e. fully pre-configured to a typical presbycusis hearing loss curve. These are simply called frequency channels.
• Frequency channels and sound quality
Does the number of frequency channels in a hearing aid guarantee sound quality for the user? The answer is no. As we mentioned earlier, the intrinsic quality of a hearing aid is based on the quality of its on-board electronic components, in particular the microphone (which picks up the sounds), the processor (which processes them) and the amplifier (which transmits them). Let’s quote Audiologys, the hearing aid brand, who is perfectly honest: “In terms of listening quality, a patient who wears a 9-channel hearing aid one day and a 16-channel one the next would be unable to differentiate between the two. Hearing care professionals often claim that a 16-channel hearing aid provides a better listening experience than a 9-channel hearing aid, but we don’t agree
• So, what to choose ?
That’s the right question. Preconfigured or custom-made, to compensate for presbycusis, a minimum of 9 frequency channels is a good choice. 12 or even 14 is a premium choice, which is more than enough. When choosing a pre-configured device, make sure that the frequencies cover the entire spectrum, from 200Hz to 8000Hz. Of course, always lock in your choice by opting for a hearing aid with the CE label, which guarantees the quality of the onboard components.
Reduction of ambient noise
In the case of presbycusis, people complain less about “hearing loss” than about “difficulty understanding words in noisy environments”: rightly so, because this typical hearing loss is characterized by a decrease in hearing acuity on high frequencies (frequencies carrying sibilant and fricative consonants, vowels, women’s and children’s voices) while low frequencies (ambient noise, for example) are more or less well retained. It is therefore mainly in noisy environments that these people have difficulty following conversations and this is precisely why the reduction of ambient noise is a fundamental technical characteristic to be taken into account when choosing a hearing aid, whether preconfigured or not. In the case of a BTE hearing aid, it is important to ensure that the ambient noise reduction is accompanied by a wind noise reduction system (as explained above). Active ambient noise reduction of 9dB is a good start. Beyond that, it’s a premium choice: 12dB to 13dB is an excellent choice, which is the maximum possible in terms of techniques without distorting sounds.
Does price guarantee the quality of a hearing aid ?
No, as we all know, price is what we call, in marketing, a “psychological variable”. A price is purely theoretical: it defines what a majority of consumers are willing to pay for the product or service purchased.
The psychological price is an evolving concept. Ten years ago, a hearing aid sold at €300 each was considered as “junk” because the monopoly market only offered hearing aids with a zero extra. Today, with the democratization of the offer and the arrival of a multitude of independent Chinese sellers on this market, proposing bilateral hearing aids from 10€ to 100€, a hearing aid sold at 300€ per unit is considered as a good hearing aid. The same is true in the air ticket sector with the advent of low cost airlines. The psychological price is between a lower limit (below this limit, prospects do not consider the product to be credible) and an upper limit (above this limit, prospects consider the product to be too expensive and will not purchase it).
The hearing aid market works like any other. Let’s remember that, worldwide, only 25% of presbycusians are fitted with hearing aids and that the first reason for rejecting hearing aids is… the price! Why is this so ? Because the traditional, expensive offer is similar (behind-the-ear device, adjustments, price, follow-up over several years) for people with a hearing disability (for whom the care is excellent) and for people with presbycusis. The presbycusic people reject the traditional hearing aid, considering it too expensive for a “simple inconvenience”: these people are the first to suffer the risks of progressive isolation and cognitive decline linked to not being fitted.
What is important to remember here are the elements that define the price of a hearing aid today.
Composition of the price of a custom-made (prescription) hearing aid
The price of a traditional hearing aid includes (after the ENT consultation) :
- The price of the hearing aid itself,
- The initial adjustment services,
- The follow-up service over 4 years (40% of the total amount of the bill according to UFC Que Choisir, September 2015).
According to UFC Que Choisir, the price would also include :
- The salary costs,
- The operating costs,
- The net margin,
This price does not take into account insurance and possible repairs.
Composition of the price of a preconfigured hearing aid (over the counter)
The price of a pre-configured hearing aid includes
- The price of the hearing aid itself.
This price does not include insurance and possible repairs.
In conclusion : what is the best hearing aid ?
In conclusion, we would like to remind you that neither the price nor the outer shell determines the quality of a hearing aid. Nor whether it is preconfigured or adapted, whether it is a BTE or an ITE, but the following characteristics:
- The quality of its on-board electronic components and in particular the microphone, the processor and the amplifier (make sure that the CE standard is affixed) ;
- The fineness of its amplification curve (preconfigured in particular) ;
- The global spectrum of frequencies covered (200Hz to 8000Hz) ;
- The number of frequency channels (12 is ideal for presbycusis) ;
- The maximum amplification of the hearing aid (wide spectrum, from 10dB to more than 30dB);
- Active reduction of ambient noise and wind noise in the case of a BTE ;
- The anti-Larsen system in the case of an in-ear hearing aid ;
- The delay in the restitution of sounds (ideally less than 0.3%). In the case of an in-the-ear hearing aid, this delay is naturally almost nil because of the tympanic proximity ;
- The distortion of sounds (ideally lower than 0.3%).
You will probably have understood: the best hearing aid is the one you will enjoy using every day, which will bring you a real listening comfort and which will correspond to your aesthetic criteria as well as to your hearing needs. Try them out: at hearing care professionals, you get a 30-day free trial (make sure this offer is not subject to any purchase commitment) and, in the case of pre-configured hearing aids, most are subject to the Satisfied or Refunded offer within 20 to 30 days.
To go further :
- Can hearing loss be prevented ?
- Noise pollution and hearing risks
- Factors other than noise aggression in the genesis of hearing loss
- The organ of hearing, a sexual marker