LEARN HOW TO INTERPRET THE AUDIOGRAM BELOW

COMING SOON WE WILL INTERPRET THE OTHER AUDIOGRAM

The reasons why they unable to identify are:

a) The speech stimulus presented by the speaker most of the time was monotonous.

Truly human voice has variable of speech tone to make other to understand. Monotonous mean lacking in variation of tone or pitch or flat speech and toneless.

b) No visual cues involvement went presented via speaker.

Most of hearing aid user depend a lot on lip reading in order to make them better understanding in others speech.

c) Unavailable of FM system

They not use the FM system to help them in to get better signal-to-noise ratio (SNR) in understanding the speech especially in hearing speech in noise situation.

MRL is acronym for minimum response level. MRL is referring to the supra-threshold stimuli where the children will respond appropiately. Please note that the MRL is not the patient hearing thresholds.

MRL can be useful especially in conditioning the children during the visual reinforcement audiometry testing. 

PLEASE CLICK THE IMAGE BELOW FOR UNDERSTANDING THE PROCEDURE

References: 
1) AUDIOLOGY TEST PROTOCOL For Klinik Audiologi & Sains Pertuturan Fakulti Sains Kesihatan Bersekutu Universiti Kebangsaan Malaysia Kuala Lumpur 2004

During pure tone audiometry testing (PTA), responses from the patient is very crucial in obtaining the correct patient's hearing threshold. The mistake from taking wrong responses from the patient will lead to wrong diagnosis of hearing level. That why, understanding the patient's responses is very important during PTA session.

 Situation where the patient give clear and consistent response during testing:

False responses can be divided into 2 categories:

1) False-positive response
Refer to the patient responds when he should not have responded.

Note: Please do non-stimulus trial to check for false positive response especially in pediatric cases. How? Just don't present the stimulus about 5 seconds to see whether the child wait for stimulus or not.

Situation where patient give false positive response:

Examples:
a) Patient confused by his tinnitus
b) Patient probably not understood the instructions.
c) It could be due to tactile stimulation or acoustic radiation.
d) Clinician presenting the stimulus very rhythmic since the patient can expect the tones at certain times.

2) False negative response
Refer to patient fails to respond when he should have responded.

Situation where patient give false negative response:This patient actually has normal hearing in both ears but he is malingering his response to get poor hearing result.

Examples:
a) Equipment problems (ex: the stimulus cannot be presented at the headphone cord was faulty)
b) Clinician errors that can prevent a signal from reaching the patient (Clinician press the wrong button to present the signal).
c) Some elderly patient, they want to be very sure the signal is there before they will respond.
d) Malingerer patient (patient who trying to make their hearing to be worse for claim SOCSO)
e) Can be due to technical reasons ( collapsing ear canal and standing wave by presenting the pure tone signal through speaker) 

Air conduction testing

The air-conduction tests the entire ear system, the signal from the headphone need to be processed along the outer ear, middle, inner ear and auditory nerve pathway. Thus, all this parts need to be work  normally in order to make air conduction threshold to be normal. If something happen to one of this conduction system it will cause the air conduction threshold to be poor. Thus the air conduction testing is considered to test for both conduction and sensorineural mechanism. Meaning that the air conduction test the whole ear system.

Bone conduction testing

The bone-conduction tests only stimulate the cochlea and above. The signal by the bone conductor will directly stimulates the cochlea and bypassing the outer and middle ear system. Hence, bone conduction testing is considered to test only sensorineural mechanism.

As a deduction

The difference between the air and bone conduction is very important for audiologist to diagnose the type of hearing loss whether it considered to be normal, conductive, sensorineural or mixed hearing loss based on the air-bone gap (AB gap) after masking if needed.

Many of student still do not know about this conventional audiology test APR. APR is a audiology test that require us to introduce /BA/ sound at high intensity level to validate our hearing test especially in young children that seems to have profound hearing loss with fair reliability. However, this test provides limited information about hearing levels.

just illustration only

Procedure:

1) This test need to be carried out on each side of patient's ear separately.

2) Please remember to warn the caregivers that you want to present a loud sound to their child.

3) Then you need to stand behind to the patient about 1 meter. 

4) Then introduce /BA/ sound near the ear want to be tested at high intensity level. Usually introduced at 100dBA level (please use Sound Level meter (SLM) to monitor your /BA/ sound level).

5) Then record the level at which the patient's reflex was obtained (corresponding to startle or eye blinking).

6) If the patient did not show any response toward or /BA/ sound, please record as a 'NO RESPONSE' at the level that we presented. 

For example: No response observe even at 100dBA at i meter distance. 

TACTILE RESPONSES

Patient with profound hearing loss who unable to hear the signal being presented might still respond if they sense the vibrations that produced by the bone vibrator or earphones (Nober, 1970). The tactile responses usually occur at low frequencies where our skin is more sensitive to vibration. 

 

Tactile responses can cause 2 problems. 

First problem:

The tactile responses can give wrong impression to the patient's hearing thresholds. For example, the tactile threshold at 250Hz is at 80dB HL but patient actual hearing threshold would have been 90 dBHL or no response. 

Second problem:

The tactile response can create an artificial air-bone gap (A-B gap), thus a sensorineural hearing loss would appear to be mixed hearing loss. For example, suppose a patient should have 70 dBHL sensorineural hearing loss. A tactile response to bone conduction threshold at 40 dBHL could give wrong impression that patient would be have mixed hearing loss. Thus we need to ask the patient if the stimulus was heard (can diagnose as mixed hearing loss) or felt (can diagnose as sensorineural).

Reference: 

 1) Gelfand, S. (2009). Essentials of Audiology. (3rd Edition). New York, NY: Thieme.

Previously, I have discussed with you about the degree of hearing loss. As we learned previously, the degree of hearing loss are categorized as mild, moderate, severe and profound. Each of degree of hearing loss have their on effect or possible challenges when someone diagnosed with certain degree of hearing loss.

Please look at at the table that will guide you to the different degrees of hearing loss and each degree of hearing loss will bring to different challenges and the needs.

Please parents don't worries  too much if your child had failed the first hearing screening. It does not mean that your child has hearing loss. It might be due to the other factors need to be considered. 

There are the reason why the babies had failed the first screening:

a) Too much background noise during the hearing screening test was carried out.
b) Presence of vernix caseosa in your child's ear canal. Click here for more details.
c) Too much movement from the infant.
e) Presence of fluid in your child's the middle ear.
f) Your baby is crying during the screening test.

credit to Indian J Dermatol. 2008; 53(2): 54–60 about vernix infomation.

WHAT?NEWBORN HEARING SCREENING?

Have you heard about newborn hearing screening? Many develop country such as America and United Kingdom have done Universal Newborn Hearing Screening as their compulsory task before the parent and their babies can go home. 

In Malaysia, many hospital has started this screening program such Universiti Kebangsaan Medical Centre (UKMMC), most of general hospital as well as private hospital (Prince Court Hospital).

WHY DO WE NEED TO SCREEN YOUR BABIES HEARING?

Have you see children use sign language as a tool for communication to the others? YES or NO?

Thus, the reason is to get early identification of hearing loss among the newborn babies as well as give early intervention in order to provide babies better chances to develop their speech and language skills.

The goal of early hearing detection and intervention (EHDI) is to maximize linguistic and communicative competence and literacy development for children who are deaf or hard of hearing. (JCIH, 2007).

Please read JCIH Effective Summary 2007 to know detail about the principal of newborn hearing screening. Click here.

I HAVE SUMMARIZE THE PRINCIPLES OF UNHS BASED ON JCIH, 2007: 

1) All infants below 1 month old need to undergo physiologic hearing screening.

2) If the infant did not pass for the first hearing screening, they need to undergo second hearing screening before 3 months of age in order to confirm the presence of hearing loss.

3) All infants with detected permanent hearing loss should receive intervention services before 6 months of age.

4) The early hearing detection and intervention should be family centered.

5) The child with permanent hearing loss should have immediate access to hearing aids or any other assistive listening devices (FM system).

6) All infants should be monitored for hearing loss at home.

7) All infants with confirmed hearing loss should have appropriate interdisciplinary  intervention program.

8) Information system should be used to measure outcomes of effectiveness of EHDI.

Reference:

Executive Summary Of Joint Committee On Infant Hearing Year 2007 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs