POSSIBLE CHALLENGES BASED ON DEGREE OF HEARING LOSS

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.

BESIDES HEARING LOSS, IS THERE ANY OTHER REASONS WHY ALL INFANTS NEED TO UNDERGO 2ND HEARING SCREENING???UNHS

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.

NEWBORN HEARING SCREENING (NHS)

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

5 RULES IN TEOAE INTERPRETATION

Today, one of my student asked me how to interpret TEOAE results using Biologic Scout OAE. I think it better for me to share with you about the interpretation of TEOAE.

Click on the image below for the better view

Credit to: Dr Nashrah Maamor

Head of Audiology Programme / Lecturer of Universiti Kebangsaan Malaysia

PLEASE DO CHECK YOUR HEARING NOW!!!

 EARLY INTERVENTION HAVE BETTER OUTCOME

Go get Audiologist's consultation if you had these symptoms:

a) Asked others to repeat themselves.
b) Misunderstanding what others say.
c) Others seem mumbling when they are speaking to you.
d) Turned up high volume when watching television or listening to radio.
e) Low self-esteem in making conversation with others.
f) Feeling stressed as you need concentrate more while listening to others speech.
g) Always speaks very loudly.

If you have a baby or toddler or children, go get hearing test if:

a) Your baby did not startled to loud sound.
b) Your baby did not produce any word yet when they grow at the age of 1 year old.
c) Your baby did not respond toward his/her name when being called from behind.
d) Your baby did not searching for the sound source by the age of 4 months old.


It better to get early intervention as possible for better outcome in speech and language development especially in baby and children before they reach the age of 4 years old which is the critical period in development of speech and language.

PERFORMING OTOSCOPIC EXAMINATION

Otoscopic Examination

After completing the case history, the audiologist should perform otoscopic examination of the patient's ear. An otoscope is the instrument for examining the ear, as illustrated in picture below.

Example of otoscope used for examining the ear with reusable speculum. The speculum is the cone shaped attachment that is inserted into the ear canal

Procedure in performing the otoscopic examination

1) Choose appropriate speculum size according to patient's ear canal size.

2) Attache the speculum to the otoscope.

3) Inspect whether there are any signs of infections or ear abnormalities and palpate patient's pinna. 

To note: please do on the better ear first in order to avoid from spreading the infection to the good ear.

3) Hold the otoscope like a pen and use the little finger to hold at the cheek of the patient to prevent any trauma to the ear.

4) Please be reminded that use our right hand for examine the right ear or vice versa.

5)  Then straighten the ear canal by gently pulling the pinna upwards and backwards for adult.
 

In paediatric, the pinna should be pulled downward and backward.

6) Observe the condition of patient's ear canals and tympanic membranes by rotating your otoscpoce.

The audiologist should see the condition of the pinna and the external auditory meatus and must rule out collapse of the external auditory canal. The audiologist should use insert phone instead of headphone to prevent collapse of the ear canals especially when conducting pure tone audiometry test that can give high frequency conductive hearing loss when using headphone.

UNDERSTANDING THE PRINCIPLES OF PROBE EAR AND STIMULUS EAR (ACOUSTIC REFLEX)

OK let straight to the point.

In understanding the probe ear and stimulus ear principles you need to understand the basic of Acoustic Reflex measurement first. Then you will understand about this 2 principles and when to apply its during the acoustic reflex test.

Basically, the probe ear and stimulus ear principles always associate with the effect of conductive hearing loss. When someone was diagnosed with conductive hearing loss, most probably the results of acoustic reflexes will be elevated or absent.

The reasons why the acoustic reflexes will be elevated or absent is behind the principles of probe ear effect and stimulus ear effect.

PROBE EAR EFFECT

It referring to the absent of acoustic reflexes when the probe is in the pathologic ear.

Why it absent? It because of the conductive element in that probe ear blocks the changes of acoustic immitance even though the stapedius muscle able to contract.

STIMULUS EAR EFFECT

It referring to the stimulus level is reduced by the amount of air-bone (AB) gap of conductive element in reaching the cochlea.


Please understand yourself by clicking the below diagram:

Based on the diagram above, we can conclude that the ipsilateral test is very sensitive in detecting the presence of conductive element 

Why? Because the ipsilateral test has double effect of these 2 principles (probe ear and stimulus ear effect) 

References:

1) Katz, Jack (Ed.). Handbook of Clinical Audiology. 5th Ed. Philadelphia: Lipincott Williams & Wilkins, 2002.

WHAT IS MY DEGREE OF HEARING LOSS????

Yes, I'm just finished supervised my students in Audiology & Speech Sciences Clinic UKM. I'm very thankful to my god that I'm able to taught and gave the better knowledge during the clinical practice to my students. Most of them just enter to 3rd year and starting to practice the audiology clinical skills to the real patients.

So today I'm want to share with you all about the degree of hearing loss. This is the basic part of audiology student need to know how to read and explain to the parent what their level of hearing after finish the hearing test.

Maybe the patients or parents who has a child diagnosed with hearing loss would appreciate this post.  

The Y-axis refer to the intensity of the sound (loudness) and X-axis refer to the frequency of the sound (pitch).

Here the diagram that shows us about the degree of hearing loss:

 NORMAL HEARING
 MILD HEARING LOSS
 MODERATE HEARING LOSS
 SEVERE HEARING LOSS
 PROFOUND HEARING LOSS

On the next post, I will discuss how to read and interpret the audiogram which is will be benefit to audiology student or audiologist. Interpretation of audiogram is a crucial part for all audiologists in order to diagnose patient's hearing status correctly. I will end here and see you you on the next post. 

CASE HISTORY TAKING (CRUCIAL STEP BEFORE START TESTING)

Ok, let give us in 2 minutes to read this short post in order to know the reason why we need to take case history from our patient.
 

IMPORTANT OF HISTORY TAKING

a)  It gives necessary information about the nature of auditory complaints 

To know which side of the ear having a problem whether one or both ears, the progression of the of the hearing loss or the current level of sounds that the patient can hear for example.

b) It help the audiologist to plan clinical testing strategies 

Selection of transducer whether headphone, insertphone or loudspeaker or to select which the appropriate behavioural hearing assessment whether play audiometry test, visual reinforcement audiometry (VRA) or pure tone audiometry test (PTA).

c) To know the possible factors contributing to the hearing impairment.

d) To know what is likely to be found during the audiologic evaluation. 

Certain types of hearing loss configuration are relate to certain causative factors, for example basically the patient's audiogram will show of high frequency hearing loss with slopping configuration if the patient reported of noise exposure or the usage of ototoxic medication.

e) Consideration for potential use of hearing aid amplification or assistive listening devices.

f) To observe client's behaviour and their speech performance.

g) To build rapport with the patient and/or caregivers.

 References: 
1) Gelfand, S. (2009). Essentials of Audiology. (3rd Edition). New York, NY: Thieme. 
2) Katz, J., Medwetsky, L., Burkard, R. & Hood, L. (2009).Handbook of Clinical Audiology (6thEdition).Baltimore, MD: Lippincott, Williams and Wilkins.

HEARING ANATOMY AND PROCESS

Learning about the auditory system is fascinating and enjoyable but learning about it for the 1st time means that we will face many new terms, concepts and relationships especially for the audiology students.

For this reason it is better that we begin with the general view of how our ear is set up and how a sound can be interpreted by the brain.

Figure 1.0 shows the major parts of the ears

Our auditory system is divided to 3 main sections.

1) The outer ear

The outer ear includes the pinna/auricle, external auditory meatus ending at the tympanic membrane (eardrum). To note that the tympanic membrane is considered part of the middle ear system.

a) Pinna/Auricle- concha, sebaceous glands present in the concha, helix, the crus of the helix, earlobe/lobule, scaphoid fossa, anthelix, crura of antihelix, tragus, antitragus, intratragis notch,

b) External auditory meatus-ear canal has 2 bends forming S shaped pathway, the outer third is composed of cartilage and inner two-thirds is composed of bone, the cartilage part consists of hair, sebaceous (oil) glands and ceruminous (wax) glands.

c) Tympanic membrane-umbo

Function of the outer ear

1) To collect and direct the sound waves to the tympanic membrane
2) To provide directional cues that help in front-back and vertical sound localization
3) Amplifies the sound energy of frequencies important for speech since the resonance of the auricle and ear canal increase the soundpresure in the 2-to-7 kHz range
       

2) The middle ear

The middle ear is the air filled cavity behind the tympanic membrane which is consists of 3 tiny bones (malleus, incus and stapes), known as ossicular chain.

a) Malleus-attached to tympanic membrane at the manubrium
b) Incus- connects the malleus to the stapes
c) Stapes- attached to oval window by the annular ligament of the footplate. The neck of stapes is connected to the stapedius muscle which innervated facial nerve.

To note that:

The middle ear connects posteriorly to the mastoid antrum via the aditus and anteriorly to the nasopharynx by the Eustachian tube (ET). Medial to the middle ear is inner ear. Lateral to the middle ear is outer ear.

I just call MIS bones, MIS stand for (M=malleus, I=Incus, S=stapes). Tips for remember.

Function of the middle ear

a) Overcome the impedance mismatch between the air filled external auditory canal and the fluid-filled inner by acts as a mechanical transformer. But how?so this is the reason, the stapes footplate is smaller that the tympanic membrane, thus it will produce an area ratio hydraulic that provides up to 25 dB of pressure gain.

b) Protection from the loud sound. How?In human, we have stapedius muscle that will make a contraction relatively to loud sounds. The contraction of the stapedius muscle will stiff the ossicular chain and cause the footplate to retract slightly from the oval window, thus produce sound attenuation especially for loud low-frequency sounds.

c) Equalizes the pressure. The middle ear function will be more efficient when its pressure equals that of atmosphere by allowing air to enter/exit the middle ear by the Eustachian tube.



3) The inner ear

The inner ear consists of the cochlear and vestibular organs (balance). The inner ear is located in the petrous part of temporal bone.

a) The cochlea

The cochlea is coiled into a two and three quarters turn and filled with fluid. Reissner's membrane and basilar membrane divide into three partition:

a) scala vestibuli,
b) scala media
c) scala tympani.

Scala vestibuli and scala media are separated by Reissner's membrane while scala tympani and scala media are separated by basilar membrane. Both scala tympani and scala vestibuli contain perilymph and scala media contains endolymph.

Function of the cochlea

Transform the mechanical vibrations of the middle ear into nerve impulses that will be transmitted by the cochlear nerve toward the central auditory pathway.

But how?Ok please see and understand below points

a) A pressure wave in the scala vestibuli will be provoked by the movement of the stapes footplate

b) Then cause basilar membrane to vibrate and the stereocilia on the top of the inner and outer hair cells will be bend.The outer and inner hair cells are located in the organ of corti which is situated in the basilar membrane.

c) Deflection of the stereocilia of the outer hair cells may induces the outer hair cells to change its length.

d) This change of the length causes the tectorial membrane and the basilar membrane to move relative to each other.

e) These movements will enhance the response of the inner hair cells which results in better hearing
sensitivity and better frequency selectivity

f) The place of maximum displacement of the basilar membrane is depend on the frequency. High frequency stimuli will cause maximum displacement at the basal while low frequency stimuli at the apical. This arrangement called tonotopic that is preserved throughtout the auditory system.

The vestibular system is arranged of :

the 3 semicircular canals:

a) lateral/horizontal semicircular canal,
b) anterior/superior semicircular canal
c) posterior semis circular canal

and 2 structures within the vestibule:

a) Utricle
b) Saccule.

The sensory receptors made a contact with neurons that make up the 8th cranial nerve. It connects the peripheral ear to the central nervous system (CNS). The 8th cranial nerve is made up of the auditory branches called cochlear/auditory nerve and the vestibular branches called vestibular nerve. The 8th nerve then connected to the brainstem via the opening of medial side of temporal bone called internal auditory meatus. To note that the auditory nerve go to the cochlear nuclei and vestibular nerve go to vestibuli nuclei.

References: 
1) Gelfand, S. (2009). Essentials of Audiology. (3rd Edition). New York, NY: Thieme. 
2) Katz, J., Medwetsky, L., Burkard, R. & Hood, L. (2009).Handbook of Clinical Audiology (6thEdition).Baltimore, MD: Lippincott, Williams and Wilkins.

audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, audiologis, Audiologis is a practitioner in the field of audiology. They have a degree in Bachelor of Audiology and responsible for identifying, preventing, diagnosing, and managing as well as carrying out the rehabilitation services for patients with hearing loss, balance problems as well as problems related to the auditory.