Unit 3: Identification of Deafness and Assessment of Hearing
3.1 Formal and informal assessment of hearing
3.2 Conditioning for auditory assessment
3.3 Audiometery for children
3.4 Audiograms and its interpretation
3.5 Speech banana and its interpretations
3.1 Formal and informal assessment of hearing
There are two general categories of assessments: formal and informal. Formal assessments provide data which support the conclusions for the test. These types of formal assessments are also known as standardized measures. Formal tests are usually administered when student s communication skill is below average his or her age. The data is mathematically computed and summarized. In formal assessment scores are on percentiles, stanines, or standard scores.
Informal assessments are usually based on the content and performance and usually does not provide any data. The example of informal assessment can be a reading task. It indicates how well a student is reading a book. Scores such as 10 correct out of 15, percent of words read correctly, are given in this type of assessment.
Whenever taking about the assessment of communication and language it is important to know about the communication and language in brief. Communication is mainly an active an intentional two way process of exchange of messages. Language is the main vehicle for communication. Language is a set of arbitrary symbols used by a group of people for the purpose of communication.
Formal Audiological Tests
There are 2 major categories of formal audiological testing: physiological tests and behavioral tests.
Physiological tests
Physiological tests include auditory brainstem response testing (ABR or BSER), oto-acoustic emission audiometry (OAE), and tympanometry. These tests are functional in the truest sense of the word: they describe the neurological or mechanical functioning of the auditory system. They do not involve active participation of the person being tested. Audiologists can hypothesize about how results on these tests will affect an individual s use of auditory information but there is not an exact one-to-one correspondence between neurological or mechanical function and what an individual can and cannot do with his or her hearing.
Objective hearing tests are done for those who cannot reliably respond on their own during a behavioral hearing test. Behavioral testing is typically used with older infants and small children. There are two types of common objective hearing tests: Otoacoustic Emissions (OAEs) and Auditory Brainstem Response (ABR). Either of these may have been done in the hospital after your child was born as his or her newborn hearing screen.
Otoacoustic emissions are sounds recorded from the ear. The tester puts a small probe in the ear and the child hears a series of sounds. The test equipment records the response from the ear without the child having to respond. An abnormal otoacoustic emissions test indicates either a hearing loss or perhaps fluid in the ear (such as an ear infection).
Auditory brainstem responses record the neural response to sound. Sticker electrodes are placed on the child s head and a sound is played in the ears. The audiologist records the brain s response to this sound and can provide an estimate of the child s hearing loss
It is important to remember that objective hearing tests do not tell audiologists what the child actually hears, but confirms that the pathways needed to understand sound are functioning. Once a child is old enough, he or she will be tested using behavioral tests.
The purpose of a comprehensive and person-centered audiologic assessment is to
Otoacoustic emissions (OAEs) screening;
An OAE is a sound generated from the cochlea in response to an auditory stimulation. The measurement of OAEs is used to assess cochlear function and is helpful in the process of differential diagnosis. Absent OAEs may be a sign of hearing loss or a blockage in the outer or middle ear.
A quiet environment and a snug probe fit are essential for valid and reliable recordings of OAEs. Ears are tested one at a time. Acceptable OAE protocols include the following:
Transient evoked otoacoustic emissions (TEOAEs) are elicited using one level (e.g., 80 dB pSPL) of click stimuli. Distributions for this condition for normal hearing are documented in the literature (Hussain et al., 1998).
Distortion product otoacoustic emissions (DPOAEs) are elicited using two pure-tone frequencies simultaneously at either equal or unequal intensities (e.g., 65/55 dB SPL). Distributions for this condition for normal hearing are documented in the literature
Auditory brainstem response (ABR); and/or
ABR testing can be used to detect hearing loss and estimate auditory thresholds in cases where the completion of other testing (e.g., behavioral) is difficult. ABR testing can also be used for a differential diagnosis of cochlear hearing loss versus retrocochlear hearing loss (e.g., caused by tumors of the vestibulocochlear nerve/CN VIII). The procedure involves placing electrodes on the skin in specified areas and then administering sound stimuli (e.g., clicks) through insert earphones. Auditory evoked potentials (i.e., evoked responses to auditory stimuli) originating from the vestibulocochlear nerve/CN VIII and auditory brainstem structures can be recorded on a waveform that typically consists of five to seven identifiable peaks. The peaks represent neural function of the auditory pathways and nuclei. Both latency measures and amplitude measures can be derived from the ABR waveform. Abnormalities in these measurements may be associated with pathology.
Tympanometry is a measurement of middle ear function. During testing, a tympanometry probe is placed in the ear canal and generates a pure tone. The response (mobility) of the tympanic membrane to this sound is measured at different air pressure levels. The results are represented in a graph called a tympanogram. The middle ear compliance (i.e., response to sound) is plotted vertically on the tympanogram, and air pressure is indicated on the horizontal axis. Maximum compliance of the middle ear system occurs when the pressure in the middle ear cavity is equal to the pressure in the external auditory canal. The maximum compliance value (static acoustic admittance) occurs at the highest peak of the curve on the graph. Various middle ear pathologies (e.g., otitis media, otosclerosis, tympanic membrane perforation) yield distinctive tympanograms.
Acoustic Reflexes
The acoustic reflex threshold (ART) is the sound pressure level at which the acoustic reflex will be triggered. Ipsilateral and contralateral evaluation of acoustic reflexes is performed to assess the integrity of the acoustic reflex pathway. ARTs are measured at 500 Hz, 1000 Hz, and 2000 Hz. Testing at 4000 Hz is not recommended because many people with typical hearing have elevated reflexes at this frequency.
Behavioral tests
Behavioral tests require the participation of the individual being tested. The most common behavioral tests involve pure tones. Pure tones are sounds generated by a machine. These sounds are very controlled for their pitch and loudness. Pure tones do not exist in nature. Even individual musical notes are not pure tones. All natural sounds, especially speech, contain a combination of different frequencies (pitch) of varying intensity (loudness). During pure tone testing, audiologists are trying to find an individual s threshold at various frequencies. Threshold is the intensity level where a sound can just be detected. There is not an exact one-to-one correspondence between auditory thresholds and what an individual can do with her or his hearing, but pure tone testing is important to use as a starting point for predictions and to use as the basis for hearing aid fitting. Procedures very similar to pure tone testing are also necessary for the fitting of cochlear implants, during the procedure known as mapping.
Pure tones can be delivered to the ear either through the air, by using headphones or speakers, or through bone conduction, which involves a special vibrator being placed on the head. Differences in air conduction and bone conduction thresholds give information to audiologists and doctors about what part of the auditory system might be having difficulty.
There is another type of behavioral testing that many students who are deafblind never have administered. Instead of using pure tones, speech is used. Using speech, an audiologist can determine:
a speech detection threshold (how loud speech needs to be for a person to just detect it),
a speech reception threshold (how loud a special type of 2-syllable word needs to be before an individual can correctly identify a specific proportion of them), and
speech discrimination (what percentage of words at a fixed loudness an individual can correctly identify).
Both physiological and behavioral tests were designed to give specific information about the auditory system. The conditions under which they are given and the type of input used is carefully controlled so that results of one person s tests can be compared to another person s tests. And so that performance on a test one day can be compared to performance on the same test on another day. This gives us the opportunity to talk about the integrity of the auditory system with as little regard to other factors, such as cognitive or physical ability, as possible.
The advantage of this is that we can identify where in the auditory system a problem might exist. This has very important medical implications and for this reason alone formal audiological testing should never be replaced with informal testing. The two kinds of testing are complementary.
Formal testing allows for the careful evaluation of hearing aids and the adjustment of cochlear implants. Finally, while pure tone testing done in an audiological test booth is a different listening situation than trying to carry on a conversation in a car, pure tone tests can give a ballpark prediction of the success of that conversation. Physiological and behavioral tests give us a very important starting point.
The Informal Hearing Assessment Process
The goal of informal hearing process is to:
develop an idea of how the child uses his or her hearing in various environments across the course of the day; and
try to discover what variables support the best use of hearing in order to continuously improve the use of hearing.
During the process, observation will be used to determine what, if any, sounds the child seems to react to and what, if any, meaning the child is getting from auditory information. Observation, of course, is also supported with information from formal hearing tests. Observation also includes setting up situations and seeing how the child responds.
Behavioral Hearing Tests
Once a child is approximately 6 months old, the audiologist will start to introduce behavioral testing. There are different types of tests based on the age and capabilities of the child.
A regular (behavioral) audiological evaluation measures degrees of hearing for different tones. This test is performed in a sound-treated room to find out whether your child can hear soft sounds at all of the important levels for hearing spoken words clearly.
Visual Reinforcement Audiometry (VRA) is typically used for children ranging from 6 months to 2 years of age. The child is trained to turn toward a reward (puppet, video) when he or she hears a sound.
Conditioned Play Audiometry (CPA) is used for children between 2 and 5 years of age. The child is taught to play a listening game such as putting a block in a bucket when he or she hears a sound.
Conventional Audiometry is used for children 5 and older. The child is asked to raise his or her hand, push a button, or say I hear it when he or she hears a sound.
Children with suspected hearing loss should be evaluated as soon as possible. Audiologists are able to provide reliable information about hearing loss for children of any age.
Behavioral observation audiometry is a test of hearing loss waged for your new born babies and infants where their counteraction to sound is gauged during breastfeeding or bottle feeding. This test entails rendering sounds to your babies and heeding their counterstand in order to test hearing. This test is often fixed for infants less than six months of age or who are progressively not able to turn their head towards a sound. It not only helps to sink in the presence of hearing loss, but also perceives which hearing aid is recommended for your baby. This test examines the behavioural shift in reactive to different sounds in your babies. Your child s counteraction to each sound is kept on record and your baby s hearing potency is analysed.
Behavioural tests are based on reckling a change in behaviour in counteraction to a sound. The behavioral observation audiometry test is featured in order to evaluate the reactance of auditory child when opting a hearing aid or to appraise the boons of the hearing aid for your new born. As the name signifies it is based on the perusal of behavioral and involuntary mirror of your child. This is a pattern for testing hearing in infants before they can manifest the systematic reactive to sounds. The aim of this test is to scrutinize the accuracy of unconditioned behavioral observation audiometry in anticipating the hearing acuity in babies and check the esteem of test upshots at various frequencies.
Behavior observation audiometry is an audiometric test for hearing level estimation in BABIES as young as 6-9 months. In this test the baby is seated with caregiver in a sound proof room and an audiologist is presenting various calibrated or measured sounds through speakers. The babies response to sounds presented is then OBSERVED and noted and measured. An estimation of babies hearing loss is made through this audiometric test.
BOA is a time consuming test as it is difficult to get a reliable & repeatable response from babies as young as 6 months for the same test stimulus.
BOA can take sometimes days & weeks to establish reliable hearings thresholds across various frequencies.
BOA cannot be ear specific test as we are presenting sound in a free field setup, hence always a better ear will response & in case of asymmetric hearing loss, we cannot establish each ear hearing levels.
Parents needs to understand that this test may need immense patience to establish reliable response from their babies & this may require several repeats
BOA is generally used to augment or add value to other objective tests. Therefore, this test should not be treated or interpreted as a standalone test to confirm diagnosis of hearing loss & also to fit amplification device.
Summary
Audiologic Tests for Infants and Children
|
Developmental Age of Child |
Auditory Test/ Average Time |
Type of Measurement |
Test Procedures |
Advantages |
Limitations |
|
All ages |
Evoked OAEs/10-min test |
Physiologic test specifically measuring cochlear (outer hair cell) response to presentation of a stimulus; stimuli may be clicks (transient evoked OAEs) or tone pairs (distortion product OAEs) |
Small probe containing a sensitive microphone is placed in the ear canal for stimulus delivery and response detection |
Ear-specific results; not dependent on whether patient is asleep or awake; quick test time; screening test |
Infant or child must be relatively inactive during the test; not a comprehensive test of hearing, because it does not assess cortical processing of sound; OAEs are very sensitive to middle-ear effusions and cerumen or vernix in the ear canal |
|
Birth to 9 mo |
Automated ABR/15-min test |
Electrophysiologic measurement of activity in auditory nerve and brainstem pathways |
Placement of electrodes on child's head detects neurologic response to auditory stimuli presented through earphones or ear inserts 1 ear at a time |
Ear-specific results; responses not dependent on patient cooperation; screening test |
Infant or child must remain quiet during the test (sedation is often required); not a comprehensive test of hearing, because it does not assess cortical processing of sound |
|
9 mo to 2.5 y |
VRA/15- to 30-min test |
Behavioral tests measuring responses of the child to speech and frequency-specific stimuli presented through speakers or insert earphones |
Technique conditions the child to associate speech or frequency-specific stimuli with a reinforcer, such as a lighted toy or video clips; VRA requires a calibrated, sound-treated room |
Assesses auditory perception of child; diagnostic test. |
When performed with speakers, only assesses hearing of the better ear; not ear specific; if VRA is performed with insert, earphones can rule out a unilateral hearing loss |
|
2.5 to 4 y |
Play audiometry/ 15 30 min |
Behavioral test of auditory thresholds in response to speech and frequency-specific stimuli presented through earphones and/or bone vibrator |
Child is conditioned to respond when stimulus tone is heard, such as to put a peg in a pegboard or drop a block in a box |
Ear-specific results; assesses auditory perception of child; screening or diagnostic test. |
Attention span of child may limit the amount of information obtained |
|
4 y to adolescence |
Conventional audiometry/15- to 30-min test |
Behavioral test measuring auditory thresholds in response to speech and frequency-specific stimuli presented through earphones and/or bone vibrator |
Patient is instructed to raise his or her hand when stimulus is heard |
Ear-specific results; assesses auditory perception of patient; screening or diagnostic test |
Depends on the level of understanding and cooperation of the child |
|
All ages |
Diagnostic ABR |
Electrophysiologic measurement of activity in auditory nerve and brainstem pathways |
Placement of electrodes on child's head detects auditory stimuli presented through insert earphones 1 ear at a time |
Ear-specific results; multiple frequencies are tested, creating a map of hearing loss similar to an audiogram; responses not dependent on patient cooperation; diagnostic test |
Infant or child must remain quiet during the test (sedation is often required); not a true test of hearing, because it does not assess cortical processing of sound |
|
All ages |
Tympanometry |
Relative change in middle-ear compliance as air pressure is varied in the external auditory canal |
Small probe placed in the ear canal and pressure varied in the ear canal |
Tests for possible middle-ear pathology and pressure-equalization tube function |
Not a test of hearing; depends on ear canal seal; high-frequency tone probe needed for infants younger than 6 mo |
3.2 Conditioning for auditory assessment
In auditory assessment, conditioning is the process of teaching the child to associate a specific response with the presentation of a sound. This is done by rewarding the child with a positive reinforcer, such as a sticker or a toy, whenever they make the desired response.
Once the child is conditioned, they will learn to make the response automatically whenever they hear the sound. This allows the audiologist to measure their hearing thresholds without having to rely on their cooperation.
Conditioned play audiometry is a method used to assess the hearing abilities of pediatric patients. It is a type of behavioral audiometry, which means that the child s response to sound is measured.
In conditioned play audiometry, the child is first trained to perform a specific enjoyable task whenever a sound is presented. For example, the child may be given a toy that makes a noise when it is squeezed. The audiologist will then present sounds at different frequencies and intensities, and the child will be asked to perform the task whenever they hear the sound.
The child s responses are then recorded and used to determine their hearing thresholds. Hearing thresholds are the softest sounds that the child can hear at different frequencies.
Conditioned play audiometry is a valuable tool for assessing the hearing of pediatric patients. It is a versatile procedure that can be used to assess the hearing of children of all ages, including those with special needs. Conditioned play audiometry is a safe and effective way to measure hearing thresholds in children.
One example of conditioned play audiometry is the Visual Reinforcement Audiometry (VRA) procedure. In VRA, the child is placed in a sound-proof booth and is presented with a toy that makes a noise when it is squeezed. The audiologist will then present sounds at different frequencies and intensities, and the child will be asked to squeeze the toy whenever they hear the sound.
If the child squeezes the toy when they hear the sound, they will be rewarded with a sticker or another small prize. This positive reinforcement helps to train the child to respond to the sound.
Conditioned play audiometry can be used to assess the hearing of children as young as 6 months old. However, the age range for this type of testing will vary depending on the specific procedure that is being used.
For example, VRA can be used to assess the hearing of children as young as 6 months old, while other conditioned play audiometry procedures may not be appropriate for children under the age of 2 or 3.
In the subjective test, in order to determine a potential hearing loss, the cooperation of the patient is required. Usually, noises, sounds or words are played and a specific reaction sought. From the results of various tests, your ear, nose and throat doctor or audiologist can determine whether you have a conductive, sensorineural, or mixed hearing loss.
A subjective hearing test requires your cooperation whereas the objective hearing test does not. During a subjective hearing test, the specialist will play certain noises, sounds, or words and ask you to make a gesture in response to these sounds. This will allow the specialist to assess the severity of your hearing loss and recommend an appropriate treatment. Subjective hearing tests include pure-tone audiometry, speech audiometry, and reflex audiometry.
A pure-tone audiometry requires you to sit in a quiet room with headphones/earphones on. The specialist will then play a variety of pure tones at different volumes, and you will be asked to give a signal (i.e. raise a finger, press a button) once you hear each tone. Your answers will indicate the tones you are having trouble hearing and will be recorded on your audiogram. Your threshold for a certain tone is determined by the softest level you are able to hear.
The results of your exam will show how well your outer and middle ear structures can process sounds. This is also referred to as an air-conduction test. When this air-conduction test shows a hearing loss, the specialist may perform a bone-conduction test to differentiate between conductive hearing loss and sensorineural hearing loss. The bone-conduction test is similar to the air-conduction test in the sense that the same process is utilized. Instead of headphones, a device comfortably placed behind your ear is used to transmit the tones that will pass through your skull and inner ear, bypassing your outer and middle ear. You will then be asked to respond to the tones in the same way as the air-conduction test. This method may provide a more accurate assessment of your inner ear s hearing capacity without any interference from your outer or middle ear.
Speech is another tool that can help determine how well you hear. A hearing test that utilizes speech requires you to repeat two-syllable words while a tone gradually decreases to lower levels. The results of this test will indicate the level you are able to hear and understand certain sounds. A hearing test that utilizes speech may also include a word-recognition exam, where the specialist will ask you to repeat certain words to determine how well you are able to hear and understand speech. Comprehension is also examined by listening and repeating one-syllable words that are played at a comfortable listening level.
An objective hearing test is useful in identifying damage to the inner ear and assessing your quality of hearing. Objective hearing tests do not require your cooperation and are typically performed on newborns and infants. Objective hearing tests include otoacoustic emission (OAE), acoustic brainstem response (ABR), acoustic reflex test, and tympanometry.
A way to identify inner ear (cochlea) damage leading to a hearing impairment is to perform an otoacoustic emision test. During this hearing evaluation, a doctor inserts a probe that emits sounds into your ear canal. These sounds stimulate the inner ear, causing the outer hair cells to vibrate. The doctor will use the probe to measure the inner ear s ability to produce the soft sounds created by the vibration (emissions). If the inner ear does not produce emissions, a hearing impairment may be present.
An audiologist may perform this test to gain more information about your hearing sensitivity. The audiologist places a few electrodes on your head, which will measure how the hearing nerves respond to the sounds made through earphones. The information travels from the electrodes to a computer that will record the results. The audiologist will review the data and look for the softest intensity in a specific frequency range at which your hearing nerves respond.
An acoustic reflex test locates the possible location of a hearing impairment. This hearing test uses sounds to determine if an acoustic reflex is working properly. Depending on the loudness of the sound and your acoustic reflex (or lack of acoustic reflex), the audiologist will be able to assess the severity of your hearing loss.
Brain Stem Evoked Response Audiometry (BERA) is a useful tool for suspected hearing impairments in deeper areas of the brain. This test also provides evidence of other neurological diseases, which can result in loss or decreased sensitivity with respect to noise exposure such as those experienced during war zones where there were prolonged loud sounds frequently heard among soldiers who were deployed overseas.
The stapedius reflex test is a quick and easy way to check if your ear has any damage. It consists of applying pressure on one side, causing it to turn red in response this happens because when we hear sounds our brain tells both sides what sound should be coming from so they contract together. If there s no tone being sent then that means something might have gone wrong with either the outer or inner portion(s) which could result in chronic issues such as hearing loss
A tympanometry allows hearing specialists to diagnose problems in the middle ear and any disorders causing hearing loss. During a tympanometry, you will hear loud tones from a probe inserted in your ear canal. This probe will measure your hearing ability, as well the movements of your eardrum as the air pressure in your ear changes during the exam. A tympanogram will record your results, and the audiologist will use this information to properly diagnose any complications with your hearing.
The results of your hearing tests are typically recorded on an audiogram. Therefore, it is important you understand how to read your audiogram. The purpose of the audiogram is to visually demonstrate the sounds you can hear normally and the sounds you are missing.
The audiologist charts the results of your
hearing tests on a graph called an audiogram. Graphed results usually include
your hearing threshold (the softest sounds you can hear) for a range of
frequencies for both ears.
By comparing the figures, the audiologist can
assess your degree of hearing loss and find clues to its origin. For example,
if the air and bone conduction results are the same, then the audiologist knows
that the hearing loss is caused by problems of the inner ear, and not the outer
or middle ear.
3.3 Audiometry for children
Audiometry is a technique used to measure the ability to hear sounds. The process of audiometry is quite simple, consisting of three parts:
An audiometer is a subjective device that is used to evaluate the hearing threshold of a person. An audiologist or other trained personnel uses an audiometer together with special audiometric testing techniques to determine the hearing threshold and to identify as well as quantify the degree of hearing loss of a person. From these results the appropriate referral for medical treatment or possible hearing aid fitting can be prescribed. With the audiometer tones of different frequencies are presented at different levels to the patient s ear. The hearing threshold is that level at which the person can just hear the stimulus. An audiometer is a subjective testing device, a response from the patient is needed.
An audiometry test is performed to determine how well you can hear. This may be done as part of a routine screening or in response to a noticeable loss of hearing.
The common causes of hearing loss include:
Damage to the ear or exposure to loud sounds for a long period can cause hearing loss. Sounds louder than 85 dB, such as you hear at a rock concert, can cause hearing loss after only a few hours. It s good to use hearing protection, such as foam earplugs, if you re exposed to loud music or industrial noise on a regular basis.
Sensorineural hearing loss occurs when hair cells in the cochlea aren t working properly. The cochlea is the part of the ear that translates sound vibrations into nerve impulses to be sent to the brain. Sensorineural hearing loss can also occur due to damage to the nerve that carries sound information to the brain or damage to part of the brain that processes this information. This type of hearing loss is usually permanent. It can be mild, moderate, or severe.
Audiometers can be divided into two general categories: screening and clinical. Screening audiometers perform rapid, semi-automated determinations of threshold hearing levels. They are used to quickly determine whether or not there is a measurable hearing loss. Some are capable of testing multiple individuals simultaneously and are used in schools for mass screening programs and in industrial operations to periodically test the workforce. Some screening audiometers adjust the results for age.
Parts of Audiometer
All legacy audiometers are comprised of four sections the oscillator, amplifier, attenuator, and headphones. The oscillator produces the audio frequencies generated during the examination. The amplifier increases the sound level of the output of the oscillator. The attenuator controls output of the amplifier and provides a precise sound level. The headphones provide the precise sound level to each of the test subject's ears. Microprocessor and computer-controlled audiometers perform the same functions, but the sections are less discernible since the process is software controlled. During the hearing test, a tone is repeatedly presented at an increased sound level (volume) until the person acknowledges hearing the sound. The lowest sound level at which the test subject hears the tone is called the threshold. The oscillator is changed to the next frequency being tested and this process is repeated with the new tone.
.Attenuators / Hearing level dials to change dB HL level presented to the patient
Interrupter Switch to turn the beep on and off and control the duration of the beep
Function Selector to change between Air, Bone and Speech Sounds
Talk Forward- To talk to the patient through the headphones
Earphones/Headphones, Bone conduction oscillator receiver
Frequency Indicator to change with frequency
Presentation Indicator to change the tone from steady state, continuous, pulsed continuous to warble
Microphone
Voice VU Meter to change the volume of your own voice in the audiometer
Masking indicator to produce white, narrow-band or speech noise
More In depth Audiometer Parts
Oscillator- The part that generates the pure tones, very accurate +/- 3% accurate
Equalization Circuit- Contains resisters that equalize the sound generated since the human ear more sensitive to its resonance frequencies around 2,700 Hz
Output Power Amplifier- Signals produced by the amplifier are amplified here, almost no distortion produced here
Output Transducers- The earphone, bone conduction receiver, loud speakers
An audiometry test of sound assesses a person s hearing abilities. The loudness (intensity) of sounds and the speed at which sound waves vibrate varies (tone).
Sound waves activate the nerves in the inner ear, which causes hearing. The sound then gets to the brain through nerve connections.
The eardrum, ear canal, and middle ear bones can all carry sound waves to the inner ear (air conduction). They can also travel through and behind the ear s bones (bone conduction).
Types of Audiometers
Pure-tone audiometry is widely regarded as the gold standard for assessing auditory sensitivity. Pure-tone audiometry is used to detect the amount of hearing loss and its etiology. It aids in the determination of hearing thresholds at various frequencies.
Pure-tone audiometry ranges from basic, low-cost devices to complicated, high-cost diagnostic audiometers. A pure tone is supplied to the ear through an earphone in this test, and the decibel level at which the tone is perceived 50% of the time is measured (dB). The term threshold refers to this measurement. The audiogram is a graph that represents the output. Specific frequencies spanning from 250 to 8000 Hz are used in the testing method.
The goal of speech audiometry is to evaluate the hearing abilities and examine the integrity of the complete auditory system. Speech audiometry can be used to identify the type of hearing loss that is occurring. Speech reception threshold and speech discrimination tests are two types of speech audiometric tests.
Both tests are designed to find the lowest decibel level at which a patient can properly repeat 50% of the phrases. Speech reception threshold tests employ two-syllable words with equal stress (sometimes known as spondees ), whereas speech discrimination tests use monosyllable test items.
Suprathreshold audiometry is a kind of audiometry that measures sound levels above the threshold. Patients with varying degrees of hearing loss in both ears have a rise in perceived loudness in response to a slight increase in intensity, which is known as recruitment.
Suprathreshold audiometry is a type of recruitment detection test. It aids in determining if the listener can properly recognize the speech at a regular conversational speech level. This test can also identify the benefits to a patient from wearing a hearing aid.
Bekesy audiometry is another name for self-recording audiometry. George von Bekesy was the first to offer this test of sound in 1947. With the aid of a motor, the frequency and intensity are automatically modified in this method.
The frequency may be adjusted in either a forward or backward direction. A recording attenuator is used in this hearing test. The attenuator may either decrease or increase the signal strength at a set rate of so many dB per second. The listener can control the attenuator s activity.
Impedance audiometry measures the air pressure and mobility of the middle ear reflexes and also the middle ear system.
In 1975, the first microprocessor audiometer for commercial purposes was released. A multifunctional keypad is found on most microprocessor audiometer instruments. Microprocessor audiometers have several benefits over manual and self-recording audiometers.
The individuals are instructed to reply when they hear the delivered sound in this test. This audiometric test of sound may offer the subjects a variety of sound stimuli and record their reactions.
Unlike subjective audiometry, this test does not rely on the patients replies. The subjects, on the other hand, are requested to cooperate when the probes and measuring electrodes are attached for the objective test.
Sound field testing refers to the method of audiology testing that takes place in a sound-isolated room via speakers. It is performed without the use of headphones or in-ear sound devices. It s commonly used for young children who are unwilling to wear headphones during aided testing. Adults can also use this testing if they prefer it over alternative methods. An additional reason for sound field testing is to evaluate hearing aid performance.
Pure-tone audiometry is a behavioral test used to measure hearing sensitivity. This measure involves the peripheral and central auditory systems. Pure-tone thresholds (PTTs) indicate the softest sound audible to an individual at least 50% of the time. Hearing sensitivity is plotted on an audiogram, which is a graph displaying intensity as a function of frequency.
Conditioned play audiometry may rely on one or more of the following games:
Blocks or balls: Using positive reinforcement, the screener "trains" the child to place blocks or balls in a basket whenever he hears a tone.
Pegs: As with blocks, the screener teaches the child to place pegs in a hole whenever she hears a sound.
Rings: Like the above, the screener teaches the child a simple game. In this case, the child places a ring over a cone when he hears the beep.
Tablet games: A 2013 study found that a tablet-based audiometer might give audiologists another way to perform hearing tests on young kids in the future. The child plays simple games on an iPad or other device and receives rewards similar to the above.
Conditioned play audiometry takes place in a soundproof booth or sound-treated room. There are two parts to CPA: conditioning and screening.
Conditioning: During this phase, the audiologist will tell your child that they are going to play a game. She will begin by pressing the tone and getting the child excited by saying, "Wow, you get a block!" The screener then gives the child the toy. She then tells the child to place the block in a basket every time she hears the beep. She will then work with your child to perform the task as quickly as possible. Once the child understands the game, screening can begin.
Screening: For screening, the audiologist will place headphones (or earphones) on your child. If necessary, bone conduction testing may be employed (in the case of wax or fluid in the ears). The test continues as above, while the audiologist reduces the intensity of the sound until the child's minimum hearing threshold is achieved.
Tests continue using different frequencies until the audiologist has a complete set of data about your child's hearing in both ears.
An audiometer is a device that measures hearing acuity. They typically comprise an embedded hardware unit coupled to a set of headphones and a feedback button for the test participant, which is occasionally operated by a conventional PC. To assess conductive hearing processes, such devices can be combined with bone vibrators.
ENT (ear, nose, and throat) clinics and audiology facilities include audiometers as standard equipment. Software audiometers, which come in a variety of configurations, are an alternative to hardware audiometers. A regular computer is used to screen PC-based audiometers. Hospitals, audiology centers, and research institutions are the most typical places to find them. Industrial audiometric testing is also done using these audiometers.
3.4 Audiograms and its interpretation
One of the most fundamental hearing tests is pure tone audiometry. For this test, a hearing professional, or an audiologist, uses an audiometer to generate tones. These tones vary in frequency, or pitch, measured in Hertz (Hz), and volume, measured in decibels (db).
The test assesses a person s left and right ear separately.
When an audiologist plays a pure tone, or a sound with a single frequency, a person needs to signal when they hear the sound, typically by raising their hand or pressing a button.
An audiologist determines a person s hearing threshold for various frequencies. The hearing threshold is the softest sound a person can hear at least 50% of the time. A person needs to wear a headphone and a bone conductor during an audiometer test. These measure a person s hearing thresholds through air conduction and bone conduction, respectively.
Sometimes, an audiologist may apply a masking noise on the non-test ear to prevent it from participating in the other ear s test. Most specialists mask during bone conduction tests. Also, most mask for air conduction tests when thresholds reach 40 db or louder in over-the-ear earphones, or 60 db for in-ear earphones.
An audiogram records a person s left and right ear s air and bone conduction threshold.
An audiogram is a hearing test conducted under ideal listening conditions in a soundproof booth.
The test includes different pitches and intensities, with the results conveyed in graphical form. If there is hearing loss, an audiogram helps distinguish conductive loss (outer/middle ear) from sensorineural loss (cochlea/cochlear nerve).1
As well as differentiating hearing loss (conductive vs sensorineural), specific patterns seen on audiograms can aid in identifying the underlying cause of the hearing loss.
Hearing thresholds
Normal hearing: can hear quiet sounds of less than 20dB
Mild hearing loss: hearing loss between 20 40dB
Moderate hearing loss: hearing loss between 41 70dB
Severe hearing loss: hearing loss between 71 95dB
Profound hearing loss: hearing loss over 95dB
The space between the normal hearing area and your threshold symbols represents all of the sounds you re missing because of your hearing loss. The bigger the space, the more sounds you re not hearing. For most people with hearing loss, hearing aids can be a solution to bridge that gap and give you back the sounds you re missing.
Looking at the audiogram graph, you will see two axes:
The horizontal axis (x-axis) represents frequency (pitch) from lowest to highest. The lowest frequency tested is usually 250 Hertz (Hz), and the highest is usually 8000 Hz. You can think of the frequency axis like the keys on a piano where the sounds become higher pitched as you progress from left to right. Most speech falls into the 250 to 6000 Hz range, with the vowel sounds among the lowest frequencies and the consonants such as S, F, SH, CH, H, TH, T and K sounds among the highest frequencies.
The vertical axis (y-axis) of the audiogram represents the intensity (loudness) of sound in decibels (dB), with the lowest levels at the top of the graph. Although the top left of the chart is labeled -10 dB or 0 dB, that does not mean the absence of sound. Zero decibels actually represents the softest level of sound that the average person with normal hearing will hear, for any given frequency. (It's actually a normative curve that has been straightened out!)
O = Right ear unmasked
△ = Right ear masked
X = Left ear unmasked
▢ = Left ear masked
< = Right ear unmasked
[ = Right ear masked
> = Left ear unmasked
] = Left ear masked
Conductive Hearing Loss
Audiological Implications
Hearing loss may be bilateral (both ears) or unilateral (one ear)
Hearing loss may be fluctuating, permanent, or temporary
Children may have difficulty
With auditory reception and consistently organizing auditory information
Understanding speech
Understanding in adverse listening conditions
Localizing sounds and understanding speech in the presence of competing noise (unilateral hearing loss)
Loss of binaural listening advantage (unilateral hearing loss)
Medical consultation and/or monitoring may be indicated
The use of personal and/or group amplification and/or hearing assistive technology should be considered if hearing loss cannot be resolved through medical treatment
Communication Implications
Children may have
Difficulty forming linguistic categories (plurals, tenses)
Difficulty differentiating words and sounds
Receptive and/or expressive language delay
Problems with articulation
Academic Implications
Children may have
Lower scores on achievement and verbal IQ tests
Poor reading and spelling performance
Greater need for enrolment in special education or support classes
Lower performance on measures of social maturity
Sensorineural Hearing Loss
Audiological Implications
Hearing loss may be bilateral or unilateral
Children can exhibit
Difficulty understanding speech and with auditory discrimination
Significant problems listening and understanding in noisy and reverberant environments
Difficulty localizing sounds and understanding speech in the presence of competing noise (unilateral hearing loss)
Loss of binaural listening advantage (unilateral hearing loss)
Use of personal and/or group amplification and/or hearing assistive technology should be considered
Communication Implications
Children typically exhibit delays and/or difficulty with
Tasks involving language concepts
Auditory attention and memory, and comprehension
Receptive and expressive language
Syntax, semantics, and vocabulary development
Speech perception and production
Academic Implications
Children typically exhibit
Lags and deficits in academic achievement, including language arts, vocabulary development, reading, spelling, arithmetic, and problem-solving
Verbally based learning difficulties
Progressive educational delays
In addition, children with sensorineural hearing loss may have
High rates of grade repetition and academic failure
Self-described feelings of isolation, exclusion, embarrassment, annoyance, confusion, and helplessness
Less independence in the classroom
Lags in psychosocial development
Increased need for special education and/or classroom supports
Mixed Hearing Loss Implications
Hearing loss may be bilateral or unilateral, with various components of both sensorineural and conductive hearing losses.
As with conductive and sensorineural hearing losses, a variety of audiological interventions and referrals may be indicated.
Children can exhibit some or all of the audiological, communication, and academic implications of sensorineural and conductive hearing losses.
Central Auditory Processing Disorder Implications
Hearing sensitivity is typically normal but a hearing loss could be present.
Children may
Behave as if they have hearing loss
Score lower on measures of verbal IQ than on measures of performance
Require more help with organization in the classroom
Have difficulty following multiple step directions
Refuse to participate in class discussions or respond inappropriately
Act withdrawn or sullen
Have a history of chronic ear infections or other otologic and/or neurologic problems
Have poor singing and music skills
Have deficiencies in fine and/or gross motor skills
3.5 Speech banana and its interpretations
Speech Banana Audiogram
The audiogram graph below is a tool that can be used to understand sounds we can hear (or can t hear) based on hearing thresholds. Common sounds are plotted on the graph to indicate their average pitch and volume. Louder sounds (e.g. are toward the bottom of the graph, softer sounds are toward the top. Low pitched sounds are on the left, higher pitched sounds are on the right.
Hearing test results can be transferred onto this graph to show which sounds are inaudible (above/softer than the hearing thresholds) and audible (below/louder than the hearing thresholds). For example, if an individual s threshold of hearing was determined to be 60 dB HL at 250 Hz, the graph suggests that this individual would hear a dog barking but average volumes of the j, m, etc. sounds cannot be heard.
Speech banana is a term used to describe the area where most sounds of average conversational speech occur on this graph. Because the area resembles the shape of a banana, professionals refer to these plotted speech sounds as the speech banana. While many other sounds fall outside of the speech banana, audiologists are most concerned with the frequencies within the speech banana because a hearing loss in those frequencies can affect a child's ability to learn language.
In children, it is particularly important to consider the different sounds of speech. A child that can hear the speech sounds will have an easier time imitating, understanding, and learning spoken language when compared to a child who cannot hear all the speech sounds.
The speech banana is important because of the way hearing loss works. Generally, hearing loss tends to develop subtly in most people over time. The early stages of hearing loss can happen, and people don t even realize it. This could mean that your ability to hear very high-pitched or very low-pitched sounds are fading, while your ability to hear all those medium pitch sounds are just fine.
But as time continues, certain letter combinations like th , ch , sh , and ng , which are in the speech banana, can be difficult for deaf and hard-of-hearing people to hear and understand. This means that your ability to understand human speech might not be as clear as they once were, although every single background noise is heard as well as you ve always heard them.
How to read a speech banana
For this part, we know you may not be an audiologist or professional but we want to teach you how one would theoretically read the Speech Banana Audiogram. First let's cover the X and Y axis. On the X axis or the horizontal axis we will be measuring frequency in Hertz (Hz) and on the Y axis or the vertical axis we will be measuring volume level in Decibels. When measuring frequencies or pitch, the Speech Banana Audiogram will begin with lower frequencies or deeper pitches on the left then move up once frequencies are higher. Some examples of what one may hear at low frequency is something like a dog barking but on the other spectrum, something that would be in the high frequency range would be birds chirping outside. On the speech banana, there are all of the letters of the alphabet except for q, w, x, and y plus there are some letter combinations that are usually troublesome for those hard of hearing. These combinations would be like ch or sh .
Communication is vital for everyone s health and safety. It is important for us and our audiologists to constantly seek ways to help serve the community who is not fortunate enough to hear all the many sounds within the speech banana. This tool is so important to us because it allows us to also identify if there is an oral communication difficulty. In most cases, when someone is suffering from some hearing loss that is within the speech banana region they also will have difficulty with their oral communications like pronunciation. Little issues like this can often lead to bigger ones like someone losing confidence because they can no longer say things the way they previously had or isolation where someone will just withdraw totally because of their incapability to communicate well.
Another reason that the speech banana is so important for us is because of what exactly it tells us about someone's hearing! Yes, it can help identify what sounds someone is having difficulty hearing but let's talk about those sounds within the banana. A normal person with healthy active hearing can hear all the sounds within the speech banana and outside of it. The speech banana was developed because audiologists determined that the sounds within the banana are the most important for humans to communicate effectively with each other.