Audiology Content PDF

OAF_right left BIOS1165 – Audiology content Week 8 By right left Dr Isabelle Boisvert Senior Lecturer and audiologist 28 marks...

OAF_right left BIOS1165 – Audiology content Week 8 By right left Dr Isabelle Boisvert Senior Lecturer and audiologist 28 marks 6 SAQ Ilmeq 17marks The University of Sydney Lecture Outline Audiometric masking - What is “masking” when doing an audiometric assessment? - When do we need to use masking? - How to interpret audiometric results with masked and unmasked symbols? The University of Sydney Page 4 Masking in (relatively) simple terms  Masking means using a sound to keep the non-test ear busy  A masking noise is used to confirm which ear is responding to the pure-tones (is it really the tested ear?)  Masking is not always required  When masking is required, then it needs to be done well  Masking can be done when finding auditory thresholds, with either air conduction or bone conduction The University of Sydney Page 5 Bone conduction masking Remember when I mentioned that 2 different symbols are used on the audiogram for bone conduction (BC) thresholds? < > unmasked [ ] masked The University of Sydney Page 6 Bone conduction: based on the skull transferring the sound through a vibration to both cochleas The University of Sydney Page 7 Bone conduction masking < > unmasked: this is the hearing threshold of the better hearing cochlea (not always the tested ear) [ ] masked: confirms that it is the threshold of the tested ear The University of Sydney Page 8 Air conduction masking O X unmasked: sometimes, the other ear might be responding to the sounds masked: confirms that it is the tested ear that is responding to the sounds The University of Sydney Page 9  With masking we “isolate” each ear to confirm the auditory thresholds measured. The University of Sydney Page 10 1st: Unmasked air-conduction audiometry results You measure a unilateral moderate hearing loss on the left ear. But wait… you notice that there is at least 40dB difference between the thresholds of each ear! **you will need to mask the good ear to confirm the results of the poorer ear** The University of Sydney Page 12 2nd: Masked air-conduction audiometry for left ear With masking noise on the right ear, you find slightly poorer thresholds on the left ear. But it remains a unilateral moderate hearing loss. Next step: to know the type of hearing loss, you need the bone- conduction thresholds. The University of Sydney Page 13 3rd: Unmasked bone-conduction results You place the bone- conductor on the mastoid bone behind the right ear. The bone-conduction thresholds that you find overlap within 10dB with the air-conduction thresholds of the right ear. This tells you: there is no conductive component on the right ear. The University of Sydney Page 14 4th: Unmasked bone-conduction results But what about the left ear? The bone-conductor makes both cochleas vibrate at the same time (via the skull). The unmasked bone- conduction is therefore the result for the better ear. If you have time, you can verify by testing the poorer ear without masking. However, this is not a necessary step The University of Sydney Page 15 4th: Unmasked bone-conduction results Because there is more than 10dB difference between the unmasked BC and the AC results for the left ear: We need to occupy the better ear (non-test ear) with a masking noise to know the true bone- conduction thresholds of the left ear. We put a masking noise in AC in the right ear, and test the left ear BC again. The University of Sydney Page 16 5th: Masked bone-conduction results (left ear) This is the final audiogram, showing the true result for both ears. Is the left ear showing a conductive, mixed or sensorineural hearing loss? The University of Sydney Page 17 Masking in Audiology Masking is one of the most complex technical skill to acquire during audiology training. Specific rules exist to guide:  When to mask  How much masking noise to use (not too little and not too much) The University of Sydney Page 18 What is masking A noise is presented to the non-test ear to keep it busy (to mask the perception of the pure-tone), while we test the other ear (the test ear). Type of noise: a narrow-band noise centred around the frequency that is being tested Symbols on the audiogram (can vary in different clinics – see legend): Air conduction (AC) Bone conduction (BC) right ear (RE) left ear (LE) right ear (RE) left ear (LE) Unmasked O X < > Masked ∆ The University of Sydney  [ ] Page 19  When to mask with air conduction (AC) testing? When the difference at any thresholds in AC between each ear is: ≥ 40dB (that is: >35dB) Need to use masking noise Masking was used when Need to use masking noise Masking was used when on the RE to know the true testing the LE. We now on the LE to know the true testing the RE. We now AC threshold of the LE know the true LE AC AC threshold of the RE know the true RE AC threshold. threshold. Actual Actual AC AC threshold threshold The University of Sydney Page 20  When to mask with bone conduction (BC) testing? When the difference between unmasked BC of either ear and the AC threshold is: ≥ 15 dB (that is: >10dB) Need to use masking noise Masking was used when Need to use masking noise Masking was used when on the RE to know the true testing the LE BC. We now on the LE to know the true testing the RE BC. We now BC threshold of the LE know the true BC LE BC threshold of the RE know the true BC RE threshold. threshold. Actual Actual BC BC threshold threshold The University of Sydney Page 24 When is masking required? Masking is needed when there is a possibility that the client’s non-test ear is responding to (hears) the pure-tones that you are presenting to the test ear. In AC: you need to mask when there is a difference between ears (AC) ≥ 40dB In BC: you need to mask when there is a difference (≥15dB) between AC of the test ear and the unmasked BC of either ear. The University of Sydney Page 26 What are the risks with masking? Risk 1: The clinician forgot or did not have time to mask the non- test ear Risk 2: The masking noise was not loud enough to mask the non-test ear Risk 3: The masking noise was too loud and crossed back to affect the test ear Consequences: If masking is needed but not done correctly, the audiogram will be incomplete or not valid (not showing the true thresholds for each ear). This will impact the recommendations and interventions for this client. The University of Sydney Page 27  Interpreting audiograms with and without masking symbols Helpful for speech pathologists to know when an audiogram is incomplete and more tests are required The University of Sydney General guidance: 1- is there a difference of at least 40dB between the AC of the right and the left ear? no: all good - no masking was needed yes: masking should have been used to confirm the results of the poorer ear (the masking noise would be placed on the non- test ear) 2- is there a difference of at least 15dB between the AC and the BC of either ear? no: all good – no masking needed, this confirms a sensorineural hearing loss. yes: masking should have been used to confirm the BC thresholds. The University of Sydney Page 29 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) incomplete BC threshold The University of Sydney Page 30 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 31 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 32 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 33 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 34 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 35 In summary – If masked symbols are used: this confirms that these are the results for that specific ear – If masked symbols are not used: – Were they required? – If so, we cannot confirm the results are for that ear. More information is needed. The University of Sydney Page 36 BIOS1165 – Audiology content Week 9 Dr Isabelle Boisvert Senior Lecturer and audiologist The University of Sydney  Conductive hearing loss – a recap The University of Sydney Page 5 Clinical context example: Amy, 4 years old You are ready to see your next client: Amy. Amy’s file says that she is 4 years old. It is the first time that she is seen at your clinic and you do not have more information about her. You go to the waiting room and call her name. A man stands up and indicates with a head nod that he is with Amy, who is playing on the floor with her back turned towards you. The father repeats Amy’s name again… no response. He walks closer to her, touches her arm and Amy immediately turns towards him with a large smile. She then looks at you, stands up and is ready to follow you to your office. Amy’s father mentions that she doesn’t seem to hear "Child" by Cristyan González Alfonso is licensed under CC BY-NC 2.0 when she does not see your face, but mum and him did not want to worry too much about it… The University of Sydney Page 6 Clinical context example: Amy, 4 years old Case History, as reported by Amy’s dad: - Language seems to develop slower compared to her peers - Has always preferred to do her own things/ play on her own - Is generally a happy child and in good health, although she often seems to have a cold - No known history of hearing loss in the family - The GP did not see anything particular when they looked into Amy’s ears (otoscopy). "Child" by Cristyan González Alfonso is licensed under CC BY-NC 2.0 The University of Sydney Page 7 Clinical context example: Amy, 4 years old Audiological testing results: – Otoscopy – Tympanometry Flat tympanogram Note: similar results for both ears Images from: otitismediaguidelines.com cahs.health.wa.gov.au The University of Sydney Page 8 Clinical context example: Amy, 4 years old Audiological testing results: – Pure-tone audiometry S S S S S The University of Sydney Page 9 Clinical context example: Amy, 4 years old Interpretation: Amy is likely to have fluid behind her eardrums (in the middle ear), bilaterally. Likely an otitis media with effusion (OME), also called “glue ear”, or serous or secretory otitis media (SOM). "Child" by Cristyan González Alfonso is licensed under CC BY-NC 2.0 The University of Sydney Page 10 OM in the community – Anyone can develop OM, but the incidence is higher in children under 5 years. – 10.85% of the global population is affected by AOM each year. – 80% of children have at least one episode of OME by the age of four years. World report on hearing: executive summary. Geneva: World Health Organization; 2021. Licence: CC BY-NC-SA 3.0 IGO. Daly, K. A., & Giebink, G. S. (2000). Clinical epidemiology of otitis media. The Pediatric infectious disease journal, 19(5), S31-S36. The University of Sydney Page 11 OM in the community – The children of Aboriginal and Torres Strait Islander populations have one of the highest global rates of otitis media in children – particularly for those living in rural and remote areas. Image from: Deadly Kids, Deadly Futures Closing the Gap Clearinghouse (AIHW & AIFS) 2014. Ear disease in Aboriginal and Torres Strait Islander children. Resource sheet no. 35. DeLacy, J., Dune, T. & Macdonald, J.J. (2020) The social determinants of otitis media in Aboriginal children in Australia: are we addressing the primary causes? A systematic content review. BMC Public Health 20, 492. The University of Sydney Page 12 Impact of OM – Remember: hearing loss associated with OM is equivalent to blocking your fingers in your ears. i.e., conversational speech is softer/muffled. – Recurrent or chronic OM may lead to short and long-term impacts, such as: Australian Institute of Health and Welfare 2018. Australia’s health 2018. Australia’s health series no. 16. AUS 221. Canberra: AIHW Burns, J. F., & Thomson, N. J. (2013). Review of ear health and hearing among Indigenous Australians. Australian Indigenous Health Bulletin, 13(4), 1-22. The University of Sydney Page 13 Management of OM – Refer to GP or ENT: Wait and monitor Prescribe antibiotics (if infected and if appropriate to do so) Drainage of the middle ear Image from: kidshealth.org.nz Placement of ventilation tubes (grommets) Monitor after interventions and overtime (otoscopy, tympanometry) – Other considerations to ensure communication support: Use of classroom amplification systems to improve sound for all students. Reducing noise sources, ensuring face is visible when talking. At home, include the child in activities, ensuring communication skills continue to develop (i.e., read stories, have conversations). Are referrals to other professionals needed? Language delays, rehabilitative audiology, emotional support? The University of Sydney Page 14 Other middle ear conditions that can cause CHL Eardrum perforation Cholesteatoma opposite Ossicular-chain dislocation Otosclerosis The University of Sydney Page 15 Audiograms showing CHL The University of Sydney Page 16 Complementary information beyond audiometry The audiogram tells us: 1. About the hearing acuity –is there a hearing loss? –if so, what’s the hearing loss severity? 2. Whether there is any issue impacting on sound transmission: – either in the outer and/or the middle ear (conductive hearing loss, or conductive component to the hearing loss) – and/or with the inner ear (sensorineural hearing loss) But the audiogram does not tell us exactly what might be happening in the different parts of the ear. This needs to be deduced using more information. The University of Sydney Page 17 Tympanometry To verify the functioning of the middle ear The University of Sydney Page 18 Tympanometry Measures how the middle ear system responds to sound energy and how it reacts dynamically to changes in atmospheric pressure. It can help understand: whether there is a blockage in the outer ear which may block the transmission of sound whether there is fluid or something else behind the eardrum that may block the transmission of sound whether the eardrum is perforated, which may impact on the transmission of sound The University of Sydney Page 19 How is tympanometry performed? The client needs to be still, not swallow, speak, or cough. Background noise does not affect the test. The University of Sydney Page 20 How is tympanometry conducted? Video: https://www.boystownhospital.org/knowledge-center/tympanograms The University of Sydney Page 21 How is tympanometry conducted? 1. A probe is placed in the entrance of the ear canal (sealing required). 2. A tone is continuously presented (most often 226Hz at ~ 80 dB SPL). 3. Air pressure is delivered from a positive value to a negative value. 4. The level of sound that remains within the ear canal while the pressure is varied is monitored by a microphone (absorbed or reflected by eardrum). 5. These levels are interpreted by the equipment representing either an increase or a decrease in admittance. 6. Changes in admittance are plotted on a graph (tympanogram) displaying a pressure/admittance function. The University of Sydney Page 22 Image from: cochlea.eu Interpreting tympanograms Sound is most effectively transmitted to the inner ear when the pressure on both sides of the eardrum is the same = around 0 daPa. 1. Shape (is there a peak?) 2. Height of the peak (admittance or compliance) 3. Pressure at which the peak occurred (normal between -150 and 100 daPa) 4. Ear canal volume (cm3) Typical ear canal volume Children (3-5 years) 0.4 – 1.0 cm3 Adults 0.6 – 1.5 cm3 Note: The ear canal volume (ECV) may be expressed as “ml”, “cc” or “cm3. The University of Sydney Page 23 Interpreting tympanograms – Tympanometric shapes can be described as: Liden (1969), Jerger (1970), Feldman (1976) The University of Sydney Page 24 Interpreting tympanograms Type A (Normal) Type B (Flat) Type C (Retracted) Images adapted from: https://www.msdmanuals.com/en-pt/home/ear,-nose,-and-throat-disorders/middle-ear-disorders/barotrauma-of- the-ear; audiologyonlinej The University of Sydney Page 25 Interpreting tympanograms – Type Ad (deep/hypermobile): consistent with ossicle-chain dislocation, or a thin eardrum that healed from a perforation. – Type As (shallow/stiff): consistent with otosclerosis, fixation of the ossicular chain. The University of Sydney Page 26  Typical ear Interpreting flat tympanograms Children (3- canal volume 0.4 – 1.0 cm3 If flat, the ear canal volume value will give us 5 years) the needed clues Adults 0.6 – 1.5 cm3 Ear canal volume Results consistent with Action A. Within norms Fluid in the middle ear Refer to GP (most common) OR grommet blocked with wax or middle ear fluid B. Smaller than There may be something Wax removal expected taking the space in the required by a outer ear, such as wax health professional. blockage. If it is close to 0cm3: probe Repeat the test tip placed against ear canal wall. C. Larger than Perforated eardrum Refer to GP or ENT expected if the perforation is new Grommet If it is a grommet, it Image from : Rosenfeld, R.M., et al. (2016). means it is working Clinical Practice Guideline: Otitis Media with well Effusion (Update). Otolaryngology–Head and The University of Sydney Neck Surgery, 154, S1 - S41. Page 27  Tympanometry in practice The University of Sydney Tympanometry in practice – provides useful information about how the middle ear is functioning (movement of the eardrum and ossicles). Can improve confidence when interpreting otoscopy and pure-tone audiometry findings. – It is non-behavioural (physiological test) and quick to conduct. – Can be used in screening programs. The University of Sydney Page 29 Tympanometry as part of the standard audiology testing Step 1: Otoscopy – to have a look (is there anything that could be blocking sound transmission?). Step 2: Tympanometry – how is the middle ear system functioning? Gives clues about what could lead to a gap between AC and BC thresholds on the audiogram. Step 3: Air conduction (AC) thresholds – this will tell us the severity (i.e., degree) of the hearing loss. Step 4: Bone conduction (BC) thresholds – to know the type of hearing loss (Sensorineural? Conductive? Mixed?). The University of Sydney Page 30 Equipment Ear tips Tympanometer Probe and probe tip The University of Sydney Page 31 Shape matching – the tympanometer introduces air pressure into the ear canal, so a good seal is needed between the entrance of the ear canal and the ear tip. Image from: https://www.interacoustics.com/guides/probe-tip/select-correct-ear-tip The University of Sydney Page 32 Shape matching The University of Sydney Page 33 Tympanograms- exercise 1 The University of Sydney Page 34 Exercise 2 Volume (ml) 0.68 Pressure (daPa) 3 Volume (ml) 0.75 Pressure (daPa) 3 Compliance (ml) 0.28 Gradient (daPa) 89 Compliance (ml) 0.23 Gradient (daPa) 93 The University of Sydney Page 35 Exercise 3 Volume (ml) 1.81 Pressure (daPa) -34 Compliance (ml) 0.81 Gradient (daPa) 49 The University of Sydney Page 36 Exercise 4 Would you interpret this example differently if this is an adult compared to a 3 years old child? The University of Sydney Page 37 Exercise 5 Volume (ml) 2.31 Pressure (daPa) - Volume (ml) 2.88 Pressure (daPa) - Compliance (ml) - Gradient (daPa) - Compliance (ml) - Gradient (daPa) - The University of Sydney Page 38 Exercise 6 Would you interpret this example differently if this is an adult compared to a 3 years old child? The University of Sydney Page 39 Exercise 7 The University of Sydney Page 40 Exercise 8 The University of Sydney Page 41 BIOS1165 – Audiology content Week 10 Dr Isabelle Boisvert Senior Lecturer and audiologist The University of Sydney Lecture outline - The “hierarchy” of listening abilities - Speech audiometry - Integrating concepts of speech acoustics - Consolidating audiological information to guide recommendation options / hearing devices The University of Sydney Page 4  “hierarchy” of listening abilities The University of Sydney To hear or to listen? - Think of examples of sentences that use: “hear” - Think of examples of sentences that use: “listen” The University of Sydney Hierarchy of hearing abilities - Detection: I heard a sound - Discrimination: I heard there was a difference between the sounds - Identification: This is what I heard - Comprehension: I know what the sound/word/sentence I heard means How much cognitive capacity you have to listen may affect how you will detect/discriminate/identify or comprehend what you hear. The University of Sydney “listening” and the hierarchy of hearing abilities - Detection: I hear a sound “you did not hear this? Listen again or more carefully”, “I was not listening, I just heard something” - Discrimination: I hear there is a difference between the sounds “I’ll listen again, but they sound the same to me”. “I’m listening, but I can’t hear the difference” - Identification: This is what I hear [and it is correct] “ I was not listening, but I heard you say my name” - Comprehension: I know what the sound/word/sentence that I hear means “ It’s only when I listened to the full sentence that I understood what they meant” The University of Sydney  Speech audiometry The University of Sydney Speech audiometry Multiple speech perception tests exist in audiology The 2 most common ones are: 1. the speech recognition threshold (STR), uses familiar 2-syllable words 2. word identification tests also called speech recognition test, such as the AB word lists (monosyllables). The University of Sydney 1- Speech Recognition Threshold (SRT; the result is in dB) What is the softest sound level that a word can be identified 50% of the time. This test is done to help confirm the reliability of the pure-tone thresholds. The SRT is expected to be very close to the 3-frequency pure-tone average (PTA) on the audiogram. Pure-Tone Average (PTA) = average pure-tone thresholds at 500, 1000 and 2000Hz PTA RE: ? PTA LE: ? The University of Sydney 12 1- Speech Recognition Threshold (SRT; in dB) e This test uses a small selection of two- syllable words that have equal stress on both syllables. The words have a high level of word familiarity, phonetic dissimilarity, and homogeneity with respect to audibility, between the words. Aim: to find the softest volume(dB) at which words can be identified 50% of the time. The University of Sydney 13 2- Word identification test (assesses performance; scored in percentage [%]) Sound level of the test can be set to either: – A conversational level (55dB) – A comfortable level (based on client’s preference) Listening condition: – Aided and/or unaided (with or without hearing devices) – Each ear individually, or both ears together Material: – Recorded soundtracks of words, presented in quiet or with background noise (part of the soundtrack) The University of Sydney 14 Integrating different audiological tests The University of Sydney Integrating different audiological tests Mse The University of Sydney  Integrating concepts of speech acoustics The University of Sydney Speech Banana = Speech Range The speech banana indicates the area in which different speech sounds are detected - At around 1 meter - In quiet The University of Sydney From Tricia McCabe’s Acoustic phonetics’ class in CSCD1034: Speech sounds contain different frequencies The University of Sydney Adding speech sounds to the speech banana These are the levels and main frequency content that allow to detect each sounds. If you have a mild hearing loss (example: 30dB across all frequencies), you would NOT hear the sounds softer than 30dB. Depending on the hearing loss configurations, there are sounds that you will not hear, and other sounds that will sound softer. The University of Sydney Speech acoustics overview Consonants 250Hz required to identify nasal sounds (m, n, gn) 500Hz required to detect plosive burst for /b/ and /d/ 2000Hz is required to discriminate /r/ and /l/, hear plosive burst /p/ and /k/, affricate bursts /ch/ and /j/, fricative noise /sh/ and /zh/ 4000Hz is required to identify /f/, /s/, /θ/ The University of Sydney Speech acoustics overview Vowels With access to frequencies between 250-1000Hz -> all vowels can be detected That is because the first formant of all vowels is low frequency. With access to frequencies between 250-3000Hz -> all vowels can be identified That is because the human brain need the hear the 2 first formants to identify a vowel sound. The University of Sydney  Formants seen on speech spectrograms 2KHz 1KHz Example taken from: https://ocw.mit.edu/courses/electrical-engineering-and- computer-science/6-345-automatic-speech-recognition-spring-2003/lecture- The University of Sydney notes/lecture34new.pdf Ling 6 sounds overview As a screening option, speech pathologists can use a set number of speech sounds to “estimate”: - the audiogram of a person - how much speech is audible - whether a referral to an audiologist is needed The Ling 6 sounds cover the main frequencies relevant for speech identification: mm ss sh ah ii oo [ in year 3, you will learn how to use and interpret Ling 6 sounds results] The University of Sydney  How audiological information guides recommendation options The University of Sydney Discussing and selecting hearing interventions The benefits of different hearing interventions depend on: the needs of the person the integrity of their auditory pathways the person’s ability to use different recommendations Considerations beyond audiological information such as costs, access to different options, or medical fitness for surgery. The University of Sydney Discussing and selecting hearing interventions What is impacting the sound transmission? And what can be done about this?  Is there wax impaction that needs to be removed?  Could a surgery improve the function of the middle ear?  Is there enough residual hearing to benefit from a hearing aid?  Could we use bone transmission to by-pass the outer and middle ear?  Could we use a cochlear implant to replace the function of the hair cells in the cochlea?  Will the auditory nerve be able to transmit the sounds from the hearing devices? The University of Sydney Keep in mind: o No hearing device can bring back a normal sense of hearing While devices can be a tremendous help, there are always limitations, and outcomes are variable. o The use of a local sign language is always an option but as for any languages, this needs to be learned by the deaf or hard-of-hearing person as well as their communication partners. o Hearing devices are most useful when: - well-fitted for the person - the person uses them (usually not worn 24h per day) - with working batteries in them o Communication strategies and environmental adaptations are always helpful. The University of Sydney Page 28 Communication strategies and environmental adaptations most people benefit from: Easier when face and lips Camera on are visible Keep eye contact Hands away from your mouth Good lightning on your face (not behind) Easier when speech is Normal speed (not too quick) clear Good articulation (but not exaggerated) Good voice level (no shouting) Use microphone when they are available Easier in quiet Turn noise sources off (TV, music, A/C) Close doors Move away from others speaking Easier with known topics State the conversation topic at the beginning Easier when repair Verify understanding strategies are used Repeat or rephrase what was misheard Write if it helps, or use captions Many more ideas!! The University of Sydney Be creative, trial strategies, or ask the person Hearing aids Hearing aids deliver an acoustic output. Different styles exist, but the basic components are the same. 1. one or more microphones detect and 3. convert sound into an electrical signal 2. an amplifier increases the strength of the 1. electrical signal (in the process it will also alter the balance of the sound, usually giving more emphasis to high-frequency sounds and weak sounds than it does to low-frequency sounds and intense 5. 2. sounds) 3. a receiver (a miniature loudspeaker), 4. turns electricity back into sound 4. the amplified sound is transmitted into the ear canal via an earmould 5. a battery provides the power needed by the system. The University of Sydney Hearing aids have different physical styles For each style there are advantages relating to the appearance, acoustic performance, comfort, and security of retention of the hearing aid. Larger hearing aids can accommodate more components and processing power, as they accommodate larger/stronger batteries. A: Completely-in-the-canal (CIC); B: In-the-canal (ITC); C: In-the-ear (ITE); D: Behind-the-ear (BTE); E: Receiver-in-the-ear (RITE); F: Open-fit BTE Image from: https://www.mayoclinic.org/diseases-conditions/hearing-loss/in-depth/hearing-aids/art-20044116 The University of Sydney Bone-conduction hearing aids Delivers a mechanical output. Vibrates the structures within the cochlea without the sounds passing through the middle ear. May be suitable for people with: -Permanent conductive hearing loss -Frequent outer ear infections or eczema -Malformation of the outer or middle ear Conventional skin-drive bone-conduction devices, attached with (A) a steel spring headband, and (B) with frames for glasses Bone conduction band Image from: https://pubmed.ncbi.nlm.nih.gov/25653565/ The University of Sydney Bone-anchored hearing aid Like bone-conduction hearing aids, the bone-anchored hearing aid uses a mechanical vibration. However, because it is surgically implanted, it does not compress the skin (more comfortable) and can provide greater stimulation. The University of Sydney Cochlear implant Especially useful when conventional hearing aids provide limited speech perception benefit or cannot be used. Bypass the middle- and inner-ear structures, Electrode array implanted via surgery in the cochlea to replace the function of the hair cells and stimulate the auditory nerve. Examples of external sound processors Implanted component of the cochlear implant The University of Sydney Cochlear implant The University of Sydney Auditory brainstem implant Bypasses the auditory nerve. The electrodes are positioned on the surface of the brainstem – in the cochlear nucleus complex. Implanted component of the auditory brainstem implant Electronic paddle The University of Sydney Assistive listening devices Any device that help detect sounds or understand speech, but that are not worn totally on the head or body. Can be used in conjunction with hearing aids or hearing implants, or instead of hearing aids/implants. Can be used for one-to-one communication, such as for listening to a conversation partner in a car or in a noisy or reverberant place. Wireless microphone (FM system) Wireless microphone (Bluetooth) The University of Sydney Assistive listening It devices Group listening systems, such as sound-field systems, infra-red systems, and magnetic loop systems. A. B. C. Sound-field amplification systems (figure c) Induction loops convert sound into electrical uses loudspeakers to improve the signal-to- current that flows through a loop of wire (that noise ratio for all people in the room. can be placed around a room) and hence into a magnetic field that can travel through the atmosphere. The coil that picks up the magnetic signal is mounted inside the listener’s hearing device. Can also be picked up by a receiver and headset (figure b) for those who do not wear hearing devices. The University of Sydney Hearables Are not classified as hearing aids, but can be purchased rather easily to help with listening. Can be useful with or without hearing loss (in particular with mild hearing loss). No prescription needed. Utilises user’s hearing abilities to improve the ability to hear certain frequencies, focus on speech sounds, support localisation, or cancel out certain types of noise. The University of Sydney Advanced technologies and connectivity Most hearing devices can now connect to phones/tablets/computers/smart watches, and stream using Bluetooth. Most hearing devices are like small computers that can be adjusted in multiple ways to make sounds audible and comfortable. The University of Sydney  Devices are often used in combination + Assistive listening devices + Communication Same type of device in both strategies ears (HA + HA; CI + CI) + Auslan … Single device or different devices in each ear (HA + CI; NH + HA; NH + CI) The University of Sydney BIOS1165 – Audiology content Week 11 Dr Isabelle Boisvert Senior Lecturer and audiologist The University of Sydney Lecture Outline Behavioural measures with young children Physiological measures – Behavioural audiometry techniques with children – Overview of different test techniques and what each technique assesses – When are they useful? – Newborn Hearing Screening Program The University of Sydney Page 4  Audiometry with children The University of Sydney Page 5 Selecting the appropriate task The task that you select for behavioral hearing testing with a child must be appropriate for their ability. Age is a good guide to select the task, but keep in mind that the child may have undiagnosed comorbidities. This means that other disabilities, that we don’t yet know about, may also be present and affect how the child may respond during the hearing test. The University of Sydney Page 6 Play audiometry [from about 2.5yo to 5 yo] – The audiologist teaches the child to engage in an activity each time they hear a test signal. – Wait → stimulus → response → reinforcement – “Listen” “Beep” child plays “Yay!!! Let’s do that again!” The University of Sydney Page 7 Visual reinforcement audiometry (VRA) [6mo-2.5yo] Based on Skinner’s (1953) principles of operant conditioning. – https://www.youtube.com/watch?v=ne6o-uPJarA Skinner BF. (1953) Science and Human Behavior. New York: Macmillan The University of Sydney Page 9 Visual reinforcement audiometry It [6mo to 2.5yo] How audiologists conduct this test with toddlers: Usually requires 2 clinicians: Audiologist controls the stimuli presentation; The other clinician distracts the child and encourages the desired behavior. Often done through a loudspeaker (no headset) Picture from: https://cluasahearing.ie/childrens- The University of Sydney hearing/ Page 10 Visual reinforcement audiometry e [6mo to 2.5yo] – Wait → stimulus → response → reinforcement – Distracts → “Beep” → Child turns head to see toy → Toy appears Examples: – https://www.youtube.com/watch?v=y78XWQktpEI – https://www.youtube.com/watch?v=S45H3i2ulto The University of Sydney Page 11 Testing via a loudspeaker Testing via a loudspeaker means that you cannot test the hearing for each individual ear.  If hearing is equal on both sides: it doesn’t matter  If hearing is better in one ear: that ear will be the one responding  You will only know the result for the better ear The University of Sydney Page 12 What if we cannot measure reliable thresholds? What if the child is younger than 6 months? We can use physiological tests that do not need a behavioural response from the client! The University of Sydney Page 13  Physiological measures in Audiology The University of Sydney Page 14  A word on semantics Objective measures often used to mean physiological measures. “Objective” in those cases is contrasted to “subjective”. The problem is that what is considered to be objective or subjective is also…. a subjective decision. I recommend the use of: physiological measures Physiological measures can be contrasted to behavioural or self-reported measures The University of Sydney Page 15 Physiological measures of health Physiological measures do not rely on the person’s response. Examples: Physiological Behavioural Heart rate Feeling palpitations Skin conductance Stress questionnaire Auditory brainstem responses Audiometric test The University of Sydney Page 16 Physiological measures of hearing Useful to confirm reported or behavioural measures or when the client/patient cannot provide reliable responses (for example with babies or adults with dementia) or when we want to verify whether the hearing loss is related to the auditory pathway beyond the cochlea (eg. the auditory nerve or brainstem) The University of Sydney Page 17 Using our understanding of the auditory system Image from: http://www.indiaspeechandhearing.com/know-your-ear.html The University of Sydney Page 18 Physiological measures in audiology Structure assessed Name of physiological test Eardrum/ossicles Tympanometry Cochlea Otoacoustic emissions (OAE) Labyrinth (balance) Vestibulo-ocular reflex (VOR) Vestibulo-spinal reflex (VSR – cVEMP) Auditory Nerve Stapedius Reflex Electrocochleography (ECochG) Magnetic Resonance Imaging (MRI) Auditory brainstem responses (ABR) + OAE Brainstem (sound Auditory brainstem response (ABR) detection) Auditory steady-state responses (ASSR) Auditory cortex Cortical auditory-evoked potentials (sound The University of Sydney discrimination) Page 19 Otoacoustic emissions (OAE) Pass or fail measure To verify the function of the outer hair cells in the cochlea *the outer ear and the middle ear must be ok to let the sound and OAE pass through* – A sound is sent in the ear canal, and an “echo” can be measured back if the outer hair cells in the cochlea are working well – The presence of OAE means hearing is Image from relatively ok, or a mild hearing loss at https://www.researchgate.net/figure/Anatomy-of- the-Cochlea-Cartoon-illustration-of-the-cochlea- worse Panel-a-A-split-cochlea_fig3_319038975 The University of Sydney Page 20 Otoacoustic emissions The “echo” must be larger than the background noise that is recorded OAE testing can detect hearing loss Videos: https://www.youtube.com/watch greater than mild (that is: when ?v=c9BmtEFNuCo there is no measurable OAE, despite a type A tympanogram, https://www.babyhearing.org/ne there may be a hearing loss that is wborn-hearing-screening-tests moderate, severe or profound. The University of Sydney 21Page 21 Stapedius reflex (often done routinely together with tympanometry) To verify the integrity of the auditory nerve Uses the activation of the stapedius muscle in response to loud sounds (protective response), pulling on the eardrum The response is bilateral both ears at once The University of Sydney Page 22 Katz (2015) figure 10.1 Stapedius reflex – Uses the same equipment as for the tympanometry (both based on admittance principles) Loud sounds are sent in the ear at different frequencies The remaining sound that does not go through the eardrum is measured via a microphone. When the reflex activates (pulls on the eardrum) the sound measured in the ear canal changes. The University of Sydney Page 23 Stapedius reflex If abnormal results are found (the acoustic reflex cannot be measured or is not maintained), the client will be referred for further testing. For example, magnetic resonance imaging (MRI) could be recommended to verify if there is anything that compresses the auditory nerve. Video: https://www.youtube.com/watch?v=QVMWx4nVbWEMin 5:00 (reflex threshold) and 8:00 (decay) The University of Sydney Page 24  Going up after the cochlea: From the auditory nerve to the brainstem The University of Sydney Page 25 Auditory Brainstem Responses To verify the integrity of the auditory nerve and brainstem (part of the auditory pathway) Analyses of electrical waveform patterns, which are generated when groups of neurons are activated and firing together The University of Sydney Page 26 Auditory Brainstem Responses – Electrodes are placed at the ear level and on top of the head (or forehead) – Sounds are sent to the ears – The electrode on top of head measures the electrical current generated by the firing of neurons at different site in the auditory pathway over time. – This electrical current is compared to the current measured at the reference electrodes (ear level) The University of Sydney 27Page 27 The University of Sydney 28Page 28 Wave peaks = Sites along the auditory pathway The University of Sydney Page 29  Wave peaks = Sites along the auditory pathway (approximation) I. Auditory nerve close to the cochlea II. Auditory nerve at the other end III. Cochlear nucleus IV. Superior olivary complex V. Junction of lateral lemniscus and inferior colliculus The University of Sydney Page 30 Auditory Brainstem Responses – Height / amplitude of wave= how loud the signal is when it is transferred at that site, dependent on neurons firing together. – Distance between peaks= how long it takes for the signal to travel between the sites The University of Sydney Page 31 Auditory Brainstem Responses – Conductive loss: delay of wave I, but pattern is normal – Sensory (cochlea) loss: smaller amplitude but timing is right – Neural loss (ex. tumor): delay between the waves – Neuropathy: no clear waveform www.audiologyonline.com/articles/update-on-auditory-evoked-responses-17434 The University of Sydney 32Page 32 Going up: from the brainstem to the brain Image from: https://teachmeanatomy.info/neuroanatomy/pathways/auditory-pathway/ Page 33 The University of Sydney 33 Cortical evoked response (later waveform patterns) – Use of speech sounds and continuous speech possible – Good measure of detection and discrimination, but not precise enough yet to inform on recognition of speech The University of Sydney Page 34 Example of software for cortical testing HEARLab See video tab here: https://hearworks.com.au/technology/hearlab/ Munro et al. (2020). Recording Obligatory Cortical Auditory Evoked Potentials in Infants: Quantitative Information on Feasibility and Parent Acceptability. Ear and Hearing, 41(3), 630-639. Bott et al. (2020). Is cortical automatic threshold estimation a feasible alternative for hearing threshold estimation with adults with dementia living in aged care? International Journal of Audiology, The 1-8. University of Sydney 35Page 35 How to choose which test to use? – Less expensive – Less invasive – Takes less time for the clinician and the client – And provides reliable results Having access to fancy equipment is not a good reason to do tests if these tests are not necessary. The University of Sydney Page 36 Rough guidance on results and ear conditions Test General interpretation Abnormal tympanograms Conditions of the outer and/or middle ear. Abnormal acoustic reflexes Severe hearing loss, or condition that may be affecting the auditory nerve. More tests needed to confirm. Abnormal otoacoustic emissions The outer hair cells of the cochlea may not be (OAE) functioning normally. Suggests a sensory hearing loss greater than mild if tympanograms are ok. Abnormal auditory brainstem May relate to condition in middle ear or cochlea response (ABR) (confirmation of results). But if tympanograms are ok AND otoacoustic emissions are ok -> this suggests a neural condition. For example, an The University of Sydney auditory neuropathy. Page 37 Newborn Hearing Screening in Australia For NSW: Statewide Infant Screening – Hearing (SWISH) Program Full guideline found: https://www1.health.nsw.gov.au/pds/ActivePDSDocuments/GL 2010_002.pdf The University of Sydney Page 38 Newborn Hearing Screening in Australia https://www1.health.nsw.gov.au/pds/ActivePDSDocuments/GL2010_002.pdf The University of Sydney Page 39  Newborn Hearing Screening in Australia https://www1.healt h.nsw.gov.au/pds/A ctivePDSDocumen ts/GL2010_002.pdf The University of Sydney Page 40 BIOS1165 – Audiology content REVIEW Week 13 Dr Isabelle Boisvert Senior Lecturer and audiologist The University of Sydney Based on your understanding of the auditory system Image from: http://www.indiaspeechandhearing.com/know-your-ear.html The University of Sydney Page 4 Week 4: Degrees (severity) of hearing loss Based on air conduction test results Frequencies (Hz) *** note that different classifications are used by different clinics, but in this UoS, we will use: Hearing loss Decibels severity Normal -10 to 20 Mild 21+ Moderate 41+ Severe 71+ Profound 91+ The University of Sydney Page 5  Hearing loss Decibels severity Normal -10 to 20 Mild 21+ Moderate 41+ Severe 71+ Profound 91+ The University of Sydney Page 6  Hearing loss Decibels severity Normal -10 to 20 Mild 21+ Moderate 41+ Severe 71+ Profound 91+ The University of Sydney Page 7  Hearing loss Decibels severity Normal -10 to 20 Mild 21+ Moderate 41+ Severe 71+ Profound 91+ The University of Sydney Page 8  Hearing loss Decibels severity Normal -10 to 20 Mild 21+ Moderate 41+ Severe 71+ Profound 91+ The University of Sydney Page 9  Week 5: Air conduction vs Bone conduction Bone Conduction (bypasses outer and middle ear) Air Conduction The University of Sydney Page 10 Bone oscillator: for bone conduction testing Rarely used out of audiology clinics But required to confirm the type of hearing loss The bone oscillator is placed on the mastoid bone The University of Sydney Page 11 Bone conduction hearing thresholds Bone conduction (BC) auditory thresholds are analysed relative to the air conduction (AC) thresholds. The type of hearing loss can be deduced when bone conduction thresholds are compared with the air conduction thresholds. The University of Sydney Page 12 2 different symbols are used on the audiogram for bone conduction (BC) thresholds < > unmasked [ ] masked (we’ll see how we use one or the other in week 8) The University of Sydney Page 13 Types of hearing loss Types of hearing Ear structure affected On the audiogram What does that mean? loss -Overlap (≤10dB) between air and bone conduction thresholds There is a hearing loss, and Inner ear and/or auditory Sensorineural and nothing is blocking the outer or nerve - Air conduction thresholds show a middle ear. hearing loss (>20dB) -Air-bone gap (>10db) The inner ear (cochlea) is and hearing fine, but there is Conductive Outer and/or middle ear -Bone conduction thresholds are within something blocking the sound normal limits before it reaches the inner ear Outer and/or middle ear -Air-bone gap (>10db) There is both a conductive and and and a sensorineural component to Mixed inner ear and/or auditory -Bone conduction thresholds also show the hearing loss, in the same nerve a hearing loss (>20dB) ear. The University of Sydney Page 14 Examples: Interpreting the type of hearing loss on audiograms Type of hearing loss ? Sensorineural ⃝ Conductive ⃝ Mixed ⃝ Explain your response: The University of Sydney Page 15 Examples: Interpreting the type of hearing loss on audiograms Type of hearing loss ? Sensorineural ⃝ Conductive ⃝ Mixed ⃝ Explain your response: The University of Sydney Page 16 Examples: Interpreting the type of hearing loss on audiograms Type of hearing loss ? Sensorineural ⃝ Conductive ⃝ Mixed ⃝ Explain your response: The University of Sydney Page 17  Describe the severity and type of hearing loss for each ear The University of Sydney Page 18  Describe the severity and type of hearing loss for each ear The University of Sydney Page 19 Week 8: General guidance for masking 1- is there a difference of at least 40dB between the AC of the right and the left ear? no: all good - no masking was needed yes: masking should have been used to confirm the results of the poorer ear (the masking noise would be placed on the non- test ear) 2- is there a difference of at least 15dB between the AC and the BC of either ear? no: all good – no masking needed, this confirms a sensorineural hearing loss. yes: masking should have been used to confirm the BC thresholds. The University of Sydney Page 20 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 21 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 22 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 23 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 24 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 25 Is this audiogram complete or incomplete? (can we consider these thresholds to be confirmed?) The University of Sydney Page 26 Week 9: Interpreting tympanograms Sound is most effectively transmitted to the inner ear when the pressure on both sides of the eardrum is the same = around 0 daPa. 1. Shape (is there a peak?) 2. Height of the peak (admittance or compliance) 3. Pressure at which the peak occurred (normal between -150 and 100 daPa) 4. Ear canal volume (cm3) Typical ear canal volume Children (3-5 years) 0.4 – 1.0 cm3 Adults 0.6 – 1.5 cm3 Note: The ear canal volume (ECV) may be expressed as “ml”, “cc” or “cm3. The University of Sydney Page 27  Typical ear Interpreting flat tympanograms Children (3- canal volume 0.4 – 1.0 cm3 If flat, the ear canal volume value will give us 5 years) the needed clues Adults 0.6 – 1.5 cm3 Ear canal volume Results consistent with Action A. Within norms Fluid in the middle ear Refer to GP (most common) OR grommet blocked with wax or middle ear fluid B. Smaller than There may be something Wax removal expected taking the space in the required by a outer ear, such as wax health professional. blockage. If it is close to 0cm3: probe Repeat the test tip placed against ear canal wall. C. Larger than Perforated eardrum Refer to GP or ENT expected if the perforation is new Grommet If it is a grommet, it Image from : Rosenfeld, R.M., et al. (2016). means it is working Clinical Practice Guideline: Otitis Media with well Effusion (Update). Otolaryngology–Head and The University of Sydney Neck Surgery, 154, S1 - S41. Page 28 Tympanograms- exercise 1 The University of Sydney Page 29 Exercise 2 Volume (ml) 0.68 Pressure (daPa) 3 Volume (ml) 0.75 Pressure (daPa) 3 Compliance (ml) 0.28 Gradient (daPa) 89 Compliance (ml) 0.23 Gradient (daPa) 93 The University of Sydney Page 30 Exercise 3 Volume (ml) 1.81 Pressure (daPa) -34 Compliance (ml) 0.81 Gradient (daPa) 49 The University of Sydney Page 31 Exercise 4 Would you interpret this example differently if this is an adult compared to a 3 years old child? The University of Sydney Page 32 Exercise 5 Volume (ml) 2.31 Pressure (daPa) - Volume (ml) 2.88 Pressure (daPa) - Compliance (ml) - Gradient (daPa) - Compliance (ml) - Gradient (daPa) - The University of Sydney Page 33 Exercise 6 Would you interpret this example differently if this is an adult compared to a 3 years old child? The University of Sydney Page 34 Exercise 7 The University of Sydney Page 35 Exercise 8 The University of Sydney Page 36 Week 10: Hierarchy of hearing abilities - Detection: I heard a sound - Discrimination: I heard there was a difference between the sounds - Identification: This is what I heard - Comprehension: I know what the sound/word/sentence I heard means The University of Sydney Page 37 Speech audiometry – The 2 most common speech perception tests in audiology are: 1. the speech recognition threshold (SRT), uses familiar 2- syllable words. Result is in dB. 2. word identification tests also called speech recognition test, such as the AB word lists (monosyllables). Result is in percent (%). The University of Sydney Page 38 Communication strategies and environmental adaptations most people benefit from: Easier when face and lips are Camera on visible Keep eye contact Hands away from your mouth Good lightning on your face (not behind) Easier when speech is clear Normal speed (not too quick) Good articulation (but not exaggerated) Good voice level (no shouting) Use microphone when they are available Easier in quiet Turn noise sources off (TV, music, A/C) Close doors Move away from others speaking Easier with known topics State the conversation topic at the beginning Easier when repair strategies Verify understanding are used Repeat or rephrase what was misheard Write if it helps, or use captions Many more ideas!! The University of Sydney Be creative, trial strategies, or ask the person Page 39 Hearing devices – Hearing aids – Bone-conduction hearing aids – Bone-anchored hearing aids – Cochlear implants – Auditory brainstem implants – Assistive listening devices * All devices and strategies might also be combined What might influence a person to use a device or strategy over another? The University of Sydney Page 40 Week 11: Physiological measures in audiology How to choose which test to use? What information each test give you? Structure assessed Name of physiological test Eardrum/ossicles Tympanometry Cochlea Otoacoustic emissions (OAE) Auditory Nerve Stapedius Reflex Auditory brainstem responses (ABR) + OAE Brainstem (sound Auditory brainstem response (ABR) detection) Auditory cortex Cortical auditory-evoked potentials (sound discrimination) The University of Sydney Page 41 Rough guidance on results and ear conditions Test General interpretation Abnormal tympanograms Conditions of the outer and/or middle ear. Abnormal acoustic reflexes Severe hearing loss, or condition that may be affecting the auditory nerve. More tests needed to confirm. Abnormal otoacoustic emissions The outer hair cells of the cochlea may not be (OAE) functioning normally. Suggests a sensory hearing loss greater than mild if tympanograms are ok. Abnormal auditory brainstem May relate to condition in middle ear or cochlea response (ABR) (confirmation of results). But if tympanograms are ok AND otoacoustic emissions are ok -> this suggests a neural condition. For example, an The University of Sydney auditory neuropathy. Page 42