In the 1940s, television sets were often the size of small cabinetry; ENIAC [Electronic Numerical Integrator and Computer]—often considered the first electronic, digital computer—occupied 1,800 square feet; and hearing aids were body-worn instruments, requiring the wearer to carry a cigarette pack–sized receiver, often on the chest or waist, with tubing that ran up to the ear.

But the invention of the transistor in the mid-40s changed all that, permitting electronic devices, including televisions, computers, and hearing aids, to become smaller. Behind-the-ear (BTE) hearing instruments debuted in the early 1950s and, with their cosmetic appeal, became the dominant model by the 1980s, accounting for more than three quarters of the market.

By the turn of the century, however, the popularity of BTEs had reversed; custom devices, designed to fit in the ear, were even more cosmetically appealing and displaced BTEs as the dominant model in the United States—despite challenges with maintenance and occlusion.

Michael Howitz, GN
Michael Howtiz, GN

But advances in BTEs, technologically as well as cosmetically, have swung the pendulum once again. According to Michael Howitz, director of product technology at GN ReSound, Bloomington, Minn, custom devices now account for slightly more than half of the market—down from three quarters previously.

David Fabry, Phonak
David Fabry, Phonak

David Fabry, PhD, vice president of professional relations and education at Phonak Inc USA, Warrenville, Ill, notes that micro-BTEs alone account for roughly 25% of the market. “The mini- or micro-BTE is bringing in a new generation of user, lowering the average age of the BTE market to 60 years from 69 years. Baby Boomers are looking for different features than earlier generations, and BTEs have evolved in terms of design and performance,” Fabry says.

Honey, I Shrunk the BTE

Thomas Powers, Siemens Hearing
Thomas Powers,
Siemens Hearing

Baby Boomers love the streamlined look of the micro-BTEs. Manufacturers have been able to make the open-fit devices smaller by reducing the size and number of components in the case. “In general, BTEs are getting more streamlined and slimmer. They are completely digital, with a single chip to act as the amplifier so there are fewer components: the chip, microphone, loudspeaker, battery, and a few others,” says Thomas Powers, PhD, vice president of audiology and professional relations for Siemens Hearing Instruments Inc, Piscataway, NJ.

The open-fit devices also tend to have thinner tubing, which is less visible and therefore more cosmetically appealing. “These devices are intended for persons with mild to moderate hearing loss, which is the biggest [potential] population we serve,” Powers says.

Francis Kuk, Widex Hearing Aid Co
Francis Kuk,
Widex Hearing Aid Co

Thinner tubing doesn’t work for everyone, however. “Most BTEs today use tubing that typically has an inner diameter of 1.9 mm. Open-fit BTEs use tubing, which is clear and less visible, that is roughly .9 mm in diameter,” says Francis Kuk, PhD, director of audiology for Widex Hearing Aid Co, Long Island City, NY. “The problem with thinner tubing is that it compromises the high-frequency or pitch sound.”

Open-fit BTEs may therefore not work for everyone, particularly Boomers. “Many Baby Boomers suffer from high-frequency hearing loss, characteristic of nonoccupational exposure—music, motorcycles, portable devices,” Fabry says.

Don Schum, Oticon
Don Schum, Oticon

Some open-fit BTEs, however, get around the high-frequency problem by placing the receiver inside the patient’s ear. “Receiver-in-the-ear models bring some significant sound quality improvements,” says Don Schum, PhD, vice president of audiology with Oticon Inc, Somerset, NJ. But Schum concurs that there are limits to functionality with micro-BTEs.

Listen, No Hands

Micro BTEs are often unable to offer all of the features available with more traditional BTE models, primarily to save space. “The primary reason open products are smaller in terms of design is that many do not have features such as volume control, telecoil, or direct audio input connections,” Siemens’ Powers says. These three particular items have become nearly standard in traditional BTE models.

Other fairly standard features include feedback cancellation and directional microphones. Most current feedback cancellation systems adapt to the feedback before or very shortly after it occurs. Advanced technology is able to tailor the feedback cancellation to different settings, adjusting automatically. “Sophisticated circuitry enables feedback levels to be different in each programming environment,” Phonak’s Fabry says.

Directional microphones on BTEs were first introduced in the early 1970s. “Until then, BTEs used only one microphone, but with directional microphones and signal processing algorithms, we gained the ability to filter noise,” Powers notes. Additionally, these early directional models rarely featured an omnidirectional mode to complement the directional mode.

Using digital noise reduction algorithms, hearing instruments have been fairly successful in reducing or even eliminating nonspeech, stationary background noises, such as fans and cars, for years. Newer algorithms have expanded that capability to filter more “startling” noises, such as clanging silverware or a grandfather clock. “Impulsive sounds are quick—short, spiky noises—that require a specialized algorithm to analyze and reduce the annoyance of these signals for the user,” Powers says, adding that Siemens developed its algorithm in response to customer needs.

“We surveyed new patients and asked them to write down all the things that annoyed them about their hearing instruments. Our analysis indicated that about one third of the sounds identified as annoying were impulsive sounds,” Powers says.

Advanced algorithms can also be applied to the patient’s volume control adjustments to create “smarter” hearing instruments: The device monitors how the patient adjusts the volume control and corrects the settings. “The instrument sums up the changes at the end of the day and applies a correction factor to adjust the volume for the patient automatically,” Fabry says.

Jerry Ruzicka, Starkey
Jerry Ruzicka, Starkey

Other new automated features include automatically switching to T-mode. “BTEs no longer need physical switches,” says Jerry Ruzicka, president of Starkey Laboratories Inc, Eden Prairie, Minn. “The hearing aid knows when the phone signal is in its presence and will switch to a mode specific to that telephone. It eliminates the need to switch between memories or adjust volume, and is essentially hands-free.”

Wireless communication, binaural integration, and the transfer of information between hearing aids is almost certainly a future avenue for the hearing industry, in general. One of the first examples of this technology is the ear-to-ear communication and enhanced automated setting selection in the Siemens Acuris. As one ear detects a change in the listening environment, it wirelessly communicates with the other ear to confirm and change the setting for both. “As we walk into an environment, we get signals from both ears,” Powers says. “Ear-to-ear communication enables both ears to use the same signal processing, which is really how our ears work normally. We are trying to mimic that system. We can’t restore it, but we can optimize a true binaural input signal.”

Making the Right Choice

Naturally, today’s most advanced functions tend to be more costly, and are typically available only with high-end hearing aids. Depending upon a patient’s hearing loss and lifestyle, he or she may be able to forgo some features for a less expensive or smaller-sized model. Obviously, this decision should be reached through consultation with the hearing health care professional, who can review the relevant factors. “The professional needs to be comfortable that the patient can live without those features,” Oticon’s Schum says.

Hearing loss should be the primary influencer. “If the patient has a severe to profound hearing loss, an open-fit or mini-BTE will often not generate enough power,” GN ReSound’s Howitz says.

Typically, patients with profound to severe hearing loss have been limited to larger models, which have the space to house equipment needed to generate the necessary power. However, power BTEs are growing smaller as well, and new micropower BTEs offer a more cosmetically appealing option.

Schum notes that hearing loss will also impact necessary features, such as the telecoil. “The use of a T-coil tends to be more frequent in patients with more hearing loss,” Schum says. Patients with moderate to severe losses who have telecoils on their home phones may not be able to function optimally without one in their hearing aid, eliminating some of the micromodels as options.

Schum suggests that a patient’s experience with a hearing aid may also affect the choice of features. “Long-standing wearers may be used to volume controls. Some will be willing to give it up for a smaller model, but other patients really want that volume control,” he says.

Schum suggests that the choice between two specific models really boils down to needs.

Outside of hearing loss, needs are typically dependent on lifestyle. “Hearing instruments are fairly flexible. What really matters is the lifestyle of the individual,” Starkey’s Ruzicka says.

The hearing professional should ask about the number and type of environments and activities patients regularly engage in: How often are patients in noisy environments? How much difficulty hearing do they have in those environments? Are they often in a windy environment? Are they around a lot of noise? Do they have the dexterity to handle the device and its batteries?

“If patients can’t see the batteries, they may need a larger device with larger batteries to be able to change them,” Powers says.

Larger batteries provide longer life, giving BTEs an advantage for smaller devices, particularly those that fit completely in the canal.

BTEs also offer other advantages, including easier maintenance. “Because custom devices go in the ear, wax can get trapped in the receiver and must be cleaned carefully,” Kuk says. Wax that has collected on a BTE can be cleaned with a wire or brush; the same method, however, could damage an ITE receiver.

Because they tend to be larger than other devices, BTEs have room for more features, such as greater power, telecoils, and direct and FM audio input. Most employ directional microphones, which are not typically available in completely-in-the-canal models. BTEs have also been the better choice for those sensitive to occlusion. ITE devices were typically preferred by those frequently in windy conditions or with cosmetic concerns, but the advances in BTE technology have targeted those issues.

In general, BTEs are seen as more robust, more adaptable, and less problematic than custom devices. “Most professionals are happy to see a shift in the field back to BTEs from custom. BTEs are generally sturdier and easier to fit and customize for a patient,” Schum says.

This does not mean, however, that companies are abandoning their custom ITE lines.

Hearing Aids of the Future

Generally, manufacturers seek to introduce new features in BTE and ITE devices. As is the case with many modern electronics, these advances are occurring at a more rapid rate than in the past. “The industry’s history suggests that hearing aids have generally had about a 5-year life cycle between new models with significant advances. That has changed dramatically, so that we now see advances occurring on about an 18-month cycle,” Ruzicka says.

The future will likely bring greater connectivity and functionality through wireless devices, as well as improved signal processing. Models will get smaller and use thinner tubing while maintaining functionality. Power sources will become more efficient, and style will continue to evolve. Directionality, including beam-forming technology, detachable microphones, wider bandwidths, and the blurring of the lines between a “hearing aid” and a “total communication device” are also possibilities. “The BTEs we will see in the future will look much different than the product we see today,” Ruzicka predicts.

Already, BTEs can blend into the consumer landscape, where iPods, cell phones, and Bluetooth® devices are ubiquitous. “Wireless headsets for Bluetooth are uglier than any hearing aids ever made, but are increasing in popularity for consumer applications. This has blurred the distinction between a hearing aid and general consumer electronics,” Fabry says.

This means that, much like its counterpart from the 1940s, the hearing aid of 2040 is likely to be indistinguishable from the other electronics we will use—if we can see it at all.

Renee DiIulio is a contributing writer for Hearing Products Report. For more information, contact .

On The Market

When it comes to purchasing a hearing aid, as with many other purchases, essentially, the more money you spend, the more amenities you can expect. Most hearing instrument manufacturers offer a range of models and styles designed to fit every need and budget. Subsequently, most manufacturers have a line of low-end, midrange, and high-end products available in every model, including BTEs. Here is a look at some of the newer models from the manufacturers interviewed for this article:

GN ReSound’s Metrix

“Every BTE we have for standard to mild hearing loss can be fit in an open configuration, which eliminates feedback and occlusion,” says Michael Howitz, director of product technology for GN ReSound.

The company’s four BTE lines are the ReSound Metrix™, its premier line; ReSound Pixel™, the mid-range family; ReSound Plus5™, the lower-cost product; and ReSound Pulse™, which debuted in late 2006.

ReSound Pulse is a micro-BTE that features an open fit, which allows air to flow around the loudspeaker, eliminating occlusion; WindShield™, which mitigates the effects of wind; advanced digital feedback processing; a range of colors; and SuperTune™, an intelligent charging system. “The ReSound Pulse permits about 24 hours of use before needing to be recharged,” Howitz says.

One of the most recent additions to GN ReSound’s line is its mini-BTE, the ReSound AIR™. The fully functional device is designed for closed, standard settings and open BTE settings.

Oticon’s Delta

One of Somerset, NJ-based Oticon’s newest hearing instruments is the Delta line, which features a mini-BTE design. The style has introduced a new design concept for hearing aids: Small, triangular, and available with custom covers and in various colors, the instrument resembles a consumer Bluetooth® device. The receiver-in-the-ear technology offers improved sound and three levels to fit every budget.

According to Don Schum, PhD, Oticon’s vice president of audiology, the electronic “guts” of the Delta are the same as those offered in the company’s top-of-the-line product family, Syncro. Syncro offers automatic adaptation to different listening environments and can be customized with up to four settings.

Additional Oticon lines that feature BTEs include Safran, a premium line; Tego Pro, for midrange products; and Tego for value. A dedicated line of SuperPower products, Sumo, features BTEs only—no ITEs—for patients with more severe hearing loss.

Phonak’s Savia Art

Phonak Inc USA, Warrenville, Ill, has a broad range of hearing instrument lines, all of which feature a micro-BTE, according to David Fabry, PhD, vice president of professional relations and education.

The company’s first-class family is the Savia Art™, which is available in all styles, including a power BTE. The device features four settings, to which the instrument can adapt automatically. It also offers advanced feedback cancellation and intelligent volume settings.

The business-class Eleva™ offers similar though less broad features. It, too, will automatically adjust between settings, but to three rather than four environments. The directional microphones adapt to a single source rather than multiple sources.

The eXtra™, or economy family, is well suited for smaller budgets. It will adjust automatically between two settings and features two directional microphones, though it does not adapt to a source.

Phonak also has introduced its microPower line, which provides a smaller, more cosmetically appealing device for patients with more severe hearing loss. The instrument uses in-the-ear or canal receiver technology to improve the sound quality, and features a number of additional features that include automated programming and a wind and weather protector.

Siemens’ CENTRA

Siemens Hearing Instruments Inc, Piscataway, NJ, offers a number of product lines. Its top-end families include CENTRA™ and ACURIS™; its midrange products include ARTIS™ and CIELO™; and its value family is INTUIS™.

The top-of-the-line CENTRA adds advanced signal processing and feedback cancellation. DataLearning™ provides intelligent volume control; SoundSmoothing™ corrects for impulsive sounds; and e2e wireless™ technology permits wireless ear-to-ear communication to better mimic true binaural input.

INTUIS’ features include directional microphone technology (in most models), feedback cancellation, noise reduction, and an automated telecoil (in most models).

Starkey’s Destiny

The top product line of Starkey Laboratories Inc, Eden Prairie, Minn, is the Destiny™ family, which features a number of products. The 400 models include entry-level devices, the 800 models are midlevel, and the 1200 models are its premium.

All feature nFusion™ technology, which incorporates nanoscience. The devices do not use switches but change settings automatically. The 400 model offers Active Feedback Intercept (AFI), Environmental Adaptation, Directional Speech Detector (DSD), and Autocoil. The 800 adds Automated Telephone Response, which senses an analog telephone and automatically switches. The 1200 offers Acoustic Signature, intelligent environmental setting control.

“These devices eliminate the need for people to switch between memories, adjust volume, or switch to a T-setting,” Starkey president Jerry Ruzicka says.

Starkey will launch some new enhancements to its Destiny line at the American Academy of Audiology show in Denver. The Destiny 1600 will introduce automated real-ear measurements, data that guide adjustments to optimize amplification. “We’ve integrated this capability so that [the device] is virtually a totally automatic hearing aid,” Ruzicka says. He suggests the technology significantly increases measurement accuracy.

Diagnostics have also been automated. The hearing aid can test itself to ensure that it is in good working order. If it detects any problems, it will alert the user to schedule maintenance.

Those alerts may be spoken; rather than tones for maintenance and alert functions, the Destiny 1600 will use speech indicators. “The hearing aid will tell a user that it’s time to change the battery or, if preset, to come in for a scheduled maintenance,” Ruzicka says.

Widex’s Inteo

Widex Hearing Aid Co, Long Island City, NY, offers multiple lines of hearing instruments: Inteo™, Flash™, élan™, AIKIA™, Senso Diva, Senso Vita, Bravissimo™, Bravo™, Senso, and Senso P. Each features a BTE model, and mini-BTEs (the élan line) have been introduced in the Inteo, AIKIA, Senso Diva, Senso Vita, and Bravissimo families.

The Inteo 9 and Inteo 19 offer similar features, but are designed for different levels of hearing loss; the Inteo 19 can assist patients with hearing loss above 60 dB. The Inteo élan provides an open-fit option.

The Flash family offers Integrated Signal Processing in a variety of models. Additional features include five channels and bands, a speech intensification system, adaptive directionality, and in-situ measurement of the user’s hearing through the instrument.

—Renee DiIulio