Three years ago I noticed I was not hearing well through my stethoscope. I decided to try an in-line analog amplifier that would work with my standard stethoscope. I was pleased with the result.
Explore This IssueACEP Now: Vol 39 – No 08 – August 2020
Unfortunately, over time my hearing continued to deteriorate. I often asked patients and nurses to repeat themselves or speak loudly. I could hear people speak but not understand the words. People speaking behind me thought I was ignoring them. I needed to turn up the volume on the radio and TV, and I found hearing my cell phone challenging.
I made an appointment with an audiologist, and she performed an audiogram. The audiogram showed high-end hearing loss, and she recommended hearing aids. We talked about my work environment and stethoscope use and made a plan. I now wear behind-the-ear hearing aids with a fenestrated dome, which allows me to continue using my same amplified stethoscope. My hearing is greatly improved, and I rarely ask people to repeat themselves.
This approach worked for me, but everyone is different. Below, I discuss the various considerations and options in stethoscopes and hearing aids.
Keep in Mind
When thinking about stethoscope solutions, we first must understand that many heart, lung, and bowel sounds are low-frequency signals, and many current hearing aids don’t provide amplification of those frequencies. Therefore, it may not help you to send the stethoscope signal through certain hearing aids.
The good news: Most individuals with hearing loss retain hearing in the low frequencies. Those individuals can use open-fit hearing aids, which leave the ear canal largely open allowing low-frequency sounds to come in naturally. With such hearing aids, you can route the stethoscope signal past them.
Keep in mind that when an individual with normal hearing uses a stethoscope, their ears are blocked and their listening is focused on the stethoscope’s sounds. In contrast, when using a stethoscope with hearing aids, the hearing aid microphone remains on while you listen to the stethoscope. This may prove distracting because the sounds in the room will continue to be amplified through the hearing aids. If it is distracting, the audiologist can create a hearing aid program in which the microphones can be turned off at the hearing aid or remotely prior to using the stethoscope.
Last but not least, remember that if you do or will wear hearing aids, the goal is always to leave them in place. Removing and replacing hearing aids with each use of the stethoscope is not realistic.
No Hearing Aids: If you do not use hearing aids but know you aren’t hearing through your standard stethoscope as well as you used to, you can, like me, purchase an amplified stethoscope (see Figure 1). These are typically battery-operated, and you’ll want to become familiar with the on/off and volume up/down features.
Invisible Hearing Aids: If you use the tiny, invisible-in-the-canal hearing aids and they are seated deeply in your ear canals, you may be able to use a regular or amplified stethoscope if it is comfortable to put the stethoscope earpieces in your ears. If not, you’ll want to use a stethoscope connected to a headset that clamps over the ears (see Figure 2).
Open Fit, Behind the Ear: Individuals with normal low-frequency hearing will often use open-fit, behind-the-ear hearing aids (see Figure 3). A small dome at the end of the tube fits in the ear, leaving the canal largely open. Depending on ear canal size and the placement of the dome in the ear canal, these hearing aid users may also be able to place an amplified stethoscope tip in the ear canal along with the dome. If this is not comfortable, use a stethoscope connected to a headset.
In the Ear and Completely In the Canal: If these hearing aid users have some low-frequency hearing and wear open-fit hearing aids, they can also consider a stethoscope connected to a headset.
Behind the Ear with Earmold: If you use behind-the-ear hearing aids connected to a standard earmold (see Figure 4), have the audiologist remake the earmold to include a stethoscope vent. This is a large air hole in the earmold into which you can insert the stethoscope’s metal tip (see Figure 5). You’ll want to use an amplified stethoscope because it will go directly to the ear with hearing loss. An earmold with a large vent also can use a headset.
Direct Connections: Behind-the-ear hearing aids can be outfitted with a connector that will allow a cord to run directly from the stethoscope to the bottom of the hearing aid. This sends the stethoscope signal directly through the hearing aid’s signal processor (see Figure 6). The audiologist should verify the hearing aid can transmit the needed low frequencies.
If your behind-the-ear hearing aid is equipped with a telecoil (ie, circuitry that picks up electromagnetic induction signals), you could plug a silhouette connection to the stethoscope (see Figure 7). The silhouettes are placed behind the hearing aids, and the signal is transmitted wirelessly. The listener must change the hearing aid program to the telecoil program setting. Again, the audiologist should verify the telecoil circuity can produce the needed low frequencies.
Wireless Connections: No stethoscopes transmit a Bluetooth signal directly to hearing aids. If a hearing aid user wants a wireless connection, a gateway device that can transit a signal to the hearing aid wirelessly from a digital stethoscope (see Figure 8) might do the trick. Again, the audiologist should verify the hearing aid can transmit the needed low frequencies. This solution can work for cochlear implant users as well.
The student with hearing loss who must learn to use a stethoscope is different from an experienced health care worker who gradually experiences hearing loss after practicing for years. A student does not know what they are listening for and may not be able to judge if they are hearing adequately. Such students should be encouraged to obtain an amplified stethoscope with a second listener port that an instructor can plug into and listen with the student. This will allow the instructor to judge whether the student is hearing adequately through the amplified stethoscope by asking the student to describe the signals they hear.
If your health care setting typically provides stethoscopes, the workplace should purchase an amplified stethoscope for you, too. If not, you will need to supply your own device.
Finally, if you haven’t yet purchased hearing aids, let the audiologist know you are a stethoscope user so the hearing aid recommendation can be at least partly based on ease of access to sounds through a stethoscope.
Q&A with a Hearing Loss Expert
The author interviewed Catherine Palmer, PhD, to discuss hearing issues relevant to our challenges as emergency physicians. She is president of the American Academy of Audiology and an associate professor at the University of Pittsburgh.
DB: Dr. Palmer, what are the typical abnormal findings on an audiogram?
CP: The most common cause of hearing loss is damage to the inner ear, which is permanent and is typically treated with hearing aids provided by an audiologist. Cochlear implants can be used in cases of total hearing loss.
DB: Why is it that people with sensory hearing loss can hear people speak but sometimes not understand what they are saying?
CP: We hear a range of frequencies (low pitches to high pitches) over a range of input levels (soft to loud). Hearing loss often differs at different frequencies, which means a person may have good low-frequency hearing but hearing loss in the high frequencies. If so, the individual will know someone is talking (hearing the low frequencies) but won’t have the clarity of the message, which is carried primarily by the mid to high frequencies.
Although well-fit hearing aids provide tremendous benefit to communication, they do not return normal hearing. Damage to the inner ear causes sensory problems in distinguishing between frequencies and temporal processing issues. Well-fit hearing aids bring back sound, but the sensory system remains damaged and distorts the signal. This means the individual will still need good communication strategies, such as facing the talker, reducing background noise, etc.
DB: What can one expect from hearing aids?
CP: Hearing aids are fit by placing a microphone in the ear canal and measuring the hearing aid’s output across frequencies and input levels. The audiologist adjusts the output to achieve audibility.
People getting hearing aids for the first time typically have had untreated hearing loss for at least seven years. The brain has adapted to this reduced input and considers it normal. If hearing aids are fit well, the individual will not like the sound at first because the brain is not used to pitches that were previously inaudible. If, in response, the hearing aids are adjusted based on patient preference, the hearing aid would be tuned to replicate their hearing loss. This is why the initial fitting is done through objective measurements so the audiologist can confidently counsel the patient to wear the hearing aids full time so the brain can adapt to the new inputs. This adaptation typically takes about three weeks, at which time the audiologist can make tuning changes based on the patient’s perceptions after ongoing exposure.
Individuals who try to be part-time hearing aid users aren’t usually successful because this puts the brain in a constant state of adaptation. These individuals usually report that sounds are sharp and/or too loud. Audible fitting and full-time use are the ingredients for success.
DB: What hearing aid features are best for physicians?
CP: Different physicians have different communication needs depending on their specialty and lifestyle, so as with any patient, the audiologist must work with the physician to find the right solution. The emergency department physician typically works in a noisy environment. Noise-reduction signal processing may make this environment more comfortable, but that will compromise the physician’s ability to hear speech, so this feature may need to be reduced. The directional microphone, which is a signal-processing technique that helps the hearing aid user hear what is directly in front of them, helps people hear in noise. The ED physician, however, may not want sound to the sides and rear reduced in their work environment. The audiologist will work with the ED physician to select and tune these features and may provide more than one listening program so the physician will have options depending on the listening environment.
DB: What are some advanced features in the latest generation of hearing aids?
CP: The most recent hearing aid features are focused on connectivity to cellphones so calls, music, and podcasts can transfer wirelessly to the hearing aids. The cellphone can be used as a remote control as well, allowing the user to make changes in specific listening environments. In addition, we are starting to see hearing aids that track steps and detect falls. Some hearing aids can be set to change programming based on GPS location.
DB: Could my hearing loss be related to ED noise?
CP: Whether a particular sound exposure can damage hearing is based on dose, which consists of sound level and length of exposure. If you are worried about the level of sound in your ED, you can download a free app to measure the sound level around you. Most of the available apps are reasonably accurate. OSHA suggests you should not be exposed to sound higher than 90 dB SPL (sound pressure level) for eight hours. Louder sounds are dangerous in shorter amounts of time.
Dr. Baehren is an emergency physician in Ohio.