hearing - Lessons in Speech with Nanette

This post collaborates with Dr. Eve Leinonen, an experienced audiologist serving clients ages four and up in Naperville, Illinois. Dr. Eve Leinonen earned her Doctorate in Audiology from Wayne State University in 2007. She has diverse experience in office and outreach settings. She has been the owner and principle audiologist of Affordable Hearing Solutions since 2015. Diagnosed with hearing loss at age 17, Dr. Leinonen can relate on a more personal level to the struggles and frustration that many with hearing loss face daily. She ensures patients select optimal treatment for their hearing loss and lifestyle, aiding their continued thriving in daily life.

These are the Topics Addressed in our post:

Hearing screening vs. diagnostic evaluation distinctions
Justifying diagnostic hearing evaluations despite apparent hearing ability
Varieties of diagnostic hearing tests
Exploring types of hearing impairments
Understanding the effects of ear fluid and pressure on hearing

How is a hearing screening different than a diagnostic hearing evaluation?

It’s important to understand the difference between a hearing screening, and a diagnostic hearing evaluation. Schools and doctor’s offices typically conduct screenings to assess whether a child may have a hearing loss. This only looks at how the child hears via air conduction (how we hear with sound traveling through the ear canal to the middle ear, inner ear, and then the brain).

Diagnostic hearing evaluations look at all aspects of the hearing mechanism. It looks at how we hear via air conduction, bone conduction (how the auditory nerve itself is responding), word recognition scores (Speech Audiometry), tympanometry and/or otoacoustic emissions (OAE).

My child can hear me whisper, so why does (s)he need a diagnostic hearing evaluation?

One of the essential components to a dynamic speech and language assessment is a diagnostic hearing evaluation. If they haven’t already, I strongly encourage families seeking my private speech and language services to schedule a diagnostic hearing evaluation before I assess articulation, expressive, and receptive language skills. It is critical to rule out a medical factor for a speech and/or language delay that could negatively influence assessments and speech-language therapy.

Specifically, a hearing loss can impact vocabulary development, sentence structure, articulation, and academic performance. Our sounds are produced at many, different frequencies. Hearing difficulties affect a child’s ability to accurately produce certain sounds, especially quieter ones like /s/, /sh/, /f/, /t/, and /k/. It also impacts comprehension and expression. Insufficient information may hinder progress and communication development.

Common Misconception

A common misconception is that intact comprehension negates a probable hearing loss. While this may be true, the only way to be certain that a child does not have difficulty hearing is to complete diagnostic hearing testing. It is very possible that a child with a temporary hearing loss can continue to follow routine, familiar directions; respond to subtle gestural cues such as eye gaze; and seemingly attend to conversational tasks. However, it would be challenging for this same child to imitate a variety of speech sounds, especially if they are hearing sounds as though they are swimming underwater.

There are some telltale signs and/or symptoms that indicate a need for a diagnostic hearing evaluation. Here is a list of the ones that I am most concerned about as a speech pathologist:

Delay in speech and/or language skills in comparison to siblings/peers
History of re-occurring ear infections or sinus infections
Difficulty imitating speech sounds
Trouble following directions
Excessively loud talkers

What are the different types of diagnostic hearing tests?

There are also different types of diagnostic testing available depending on the child’s age and ability to task during testing. Visual reinforcement audiometry (VRA) engages children aged 6 months to 3 years or with developmental delays to respond to environmental sounds. It utilizes external speakers and toys for positive reinforcement. Tympanometry and OAEs check for fluid and inner ear hair cell responsiveness.

Play audiometry is utilized for children who are old enough (4 years or older) to task to a game or toys, but may not quite be old enough to raise their hand for each beep. Usually the game involves dropping toys into a bucket when they hear a beep to help the audiologist establish thresholds. Tympanometry and OAE’s can be performed as well as speech recognition testing.

Older children may be asked to raise their hand or push a button when they hear pure tone “beeps”, repeat words for word recognition score testing, and also tympanometry and OAEs (if necessary).

What are the types of hearing losses?

There are three kinds of hearing loss: conductive, sensorineural, and mixed. A conductive loss is often a temporary condition brought on by: fluid accumulation, ear infections, or a blockage of the Eustachian tube caused by an allergy. A sensorineural hearing loss can be the result of a viral infection such as measles, meningitis, or mumps. This damage to the middle ear may also be caused by head trauma or exposure to extremely loud noise. Some people are born with a sensorineural loss while others may acquire one in old age. These videos help explain causation for these losses and common interventions.

Conductive Hearing Loss

Sensorineural Hearing Loss

Mixed Hearing Loss

How does fluid and negative pressure in the ears impact hearing?

Understanding the effect of fluid on hearing is crucial, especially for young children. Fluid can give the appearance of normal air conduction levels at times, but the child is losing important speech sounds and cues. Though it appears normal on paper, to them it sounds as though they are hearing underwater. Speech and environmental sounds are muffled, thus effecting a child’s ability to hear and understand sounds correctly. It’s possible that their “normal” levels of hearing without fluid are even better than what is appearing with fluid.

This reduction of hearing can appear to the listener as a “hearing loss” despite showing normal response levels. Diagnostic testing is important as it will show whether the normal hearing thresholds reveal a conductive component (related to Conductive Hearing Loss and is a gap between air and bone conduction thresholds), thus indicating middle ear concerns.

Fluid and Development

Infants and toddlers are prone to excessive fluid build-up in the ear canals because the eustachian tube is parallel, giving fluids a cozy place to stay. As toddlers grow, the eustachian tube begins to slant, which supports natural fluid drainage from the ears. This is just one of the reasons why we encourage toddlers to sit upright while drinking to avoid adding more fluids into that ear canal.

Children can fluctuate in and out of temporary hearing loss conditions and even have this fluid in the ears without an infection. There are several misconceptions regarding children and hearing loss. One is that if your child has “normal responses”, then his hearing is fine. One aspect to look at is tympanometry, which analyzes middle ear function. Tympanometry can tell us if there is fluid or negative pressure in the middle ear, which can greatly impact hearing.

If you have any further questions about the impact of hearing on speech and language development, then please visit these links for more details:

Newborn Hearing Screening

Childhood Hearing Screening

How We Hear

Frequency and Decibels

Two measurements evaluate hearing: frequency and decibels. Frequency, also known as Hertz (Hz), denotes sound pitch, ranging from 250 Hz to 8000 Hz. An example of a low pitch would be the sound of thunder; for a midrange pitch, an example would be a telephone ring. A high pitch example would be the sound of cymbals clanging.

Decibels (dB) mean intensity or loudness; and it is measured from 0 dB through 110dB. Normal conversational speech is about 45 dB. It is important to note that 0dB does not mean the complete absence of sound, but rather it is the softest sound that a person with normal hearing ability would be able to detect at least 50% of the time.

We call the softest level at which your child can hear the threshold. In a hearing evaluation, an audiologist tests frequencies from low to high decibels until the client hears each pitch. The audiologist then documents the threshold for each frequency on the audio gram. When testing is completed with headphones, it is called “air” thresholds because the sound must travel through the air of the ear canal to be heard.

Audiogram Symbols

Your child’s audiogram should have a box explaining what the symbols used on the diagram represent. The right ear is marked with an O, and the left ear with an X to indicate air thresholds. When using bone conduction, the audiologist places a small device behind the child’s ear, secured by a metal band. This device sends sounds via direct vibration of the bone and specifically tests the sensitivity of the inner ear. A < symbol denotes the right ear and a > symbol indicates the left ear’s responses to bone conduction. If testing reveals a hearing loss, the audiologist will compare results of air and bone conduction testing to identify the type of loss.

Types of Hearing Loss

There are three kinds of hearing loss: conductive, sensorineural, and mixed. A conductive loss means the outer or middle parts of the ear are not working effectively. Fluid or wax build-up blocks sound from transferring to the intact inner ear. The audiologist confirms this because bone conduction testing showed an intact inner ear, but air conduction indicated a problem.

A conductive hearing is sometimes treatable with medication or surgery and is typically temporary. However, if your child is experiencing a conductive loss during peak learning opportunities, then you may notice limited responses to language and reduced verbalizations. While your child receives treatment, seize every chance to let them watch your lips form sounds and use visuals to aid understanding. Even with one affected ear, they perceive speech as if underwater.

A sensorineural loss occurs when the inner ear is not properly receiving sounds. Your child’s audiogram would indicate an air conduction threshold and bone conduction threshold with the same amount of hearing loss. Several factors cause this loss, including aging, prolonged exposure to loud noises, viral infections, disrupted blood supply to the ear, metabolic disturbances, accidents, and genetic predisposition. About 90% of people with hearing impairments have this type of loss. Regrettably, medications or surgeries cannot treat it, but hearing aids can enhance responses to sounds. Those with a severe hearing loss may benefit from a cochlear implant.

A mixed hearing loss is the combination of a conductive and sensorineural loss. In this case, your child may already have a sensorineural hearing loss and then develop a conductive loss due to excessive fluid or wax in the ears. In an audiogram, you would see bone conduction thresholds indicating a hearing loss and the air conduction thresholds showing an even greater hearing loss.

Ranges

The following indicates results for the average ADULT. It is harder to use the same interpretation with children as children may not respond well in testing for a variety of reasons, but these numbers should give you a general sense of severity levels.

-10 dB to 25 dB = Normal range

26 dB to 40 dB = Mild hearing loss

41 dB to 55 dB = Moderate hearing loss

56 dB to 70 dB = Moderately Severe hearing loss

71 dB to 90 dB = Severe hearing loss

over 90 dB = Profound hearing loss

Next Steps

After an evaluation using headphones in a sound-proof booth setting, your audiologist should be able to answer the following questions based on test results:

How well does my child hear at low, medium, and high pitches?

Does my child have a hearing loss?

If my child has a hearing loss, what part of the ear is affected: outside, middle, or inner?

This article, including the diagram, originates from an Audiology Awareness Campaign article by Glen R. Meier, M.S., CCC-A, FAAA. For more details about audiological hearing evaluations, read my post: Why Does my Child need a Diagnostic Hearing Evaluation?

Why Does My Child Need A Diagnostic Hearing Evaluation?