Q: This topic is very difficult for me to understand and also boring. Explain me this in a very very simplified manner and make me memorise this instantly so that I donβt forget about it. A: Pure-Tone Audiometry PTA - Made Super Simple! π§ Let me break this down like you're hearing it for the first time pun intended. --- π§ THE BIG IDEA IN ONE SENTENCE PTA = A test where you play beeps at different volumes & frequencies to find out the softest sound a person can hear. --- ποΈ THE 5 BUILDING BLOCKS 1. π§ THE MACHINE = Audiometer Think of it as a fancy beep remote control that plays sounds at exact frequencies and volumes. --- 2. π§ HOW SOUND GETS TO YOUR EAR = Two Pathways Air Conduction AC Bone Conduction BC --------- How Headphones/earphones Vibrator on skull behind ear Tests Outer + Middle + Inner ear Inner ear cochlea mostly Analogy Sound travels through the air-filled tunnel of your ear Sound bypasses the tunnel and vibrates directly to the cochlea Golden Rule: Compare AC and BC to figure out WHERE the problem is. --- 3. π THE GRAPH = Audiogram Imagine a grid where: - X-axis horizontal = Frequency pitch β Low pitch 250 Hz on left, High pitch 8000 Hz on right - Y-axis vertical = Loudness β Goes DOWN louder numbers at bottom = worse hearing Memory trick: "The worse your hearing, the deeper you sink on the graph" β¬οΈ Symbols to remember: Symbol Meaning ------ O open circle Right ear, Air conduction X Left ear, Air conduction β³ triangle Bone conduction unmasked or Bone conduction masked Right = Red = O 3 R's Left = bLue = X --- 4. π WHAT THE AUDIOGRAM TELLS YOU = 3 Types of Hearing Loss Think of the ear as a pipe system: Outer ear β Middle ear β Cochlea inner ear β Nerve β β β AC tests all of these BC bypasses to here π΄ Conductive Loss pipe is blocked - BC = Normal β AC = Bad β β Big gap between them = Air-Bone Gap ABG - Cause: wax, fluid, perforated eardrum - Fix: usually treatable with medicine/surgery π΅ Sensorineural Loss SNHL cochlea/nerve damaged - Both BC and AC are equally bad β No gap - Cause: noise damage, aging, genetic - Fix: hearing aids, cochlear implant π£ Mixed Loss - Both AC and BC are bad, but AC is worse β Gap still present - Combination of both above Mega memory trick: "ABC Gap" - AC bad only = Conductive has gap - AC + BC both bad, no gap = Sensorineural - AC + BC both bad, gap still there = Mixed --- 5. π― HOW THE TEST IS DONE = The "10 Down, 5 Up" Bracketing Method Think of it like a guessing game: 1. Play a clearly audible beep β patient responds β 2. Turn it down 10 dB until they can't hear it β 3. Turn it up 5 dB until they hear it again β 4. Repeat until consistent β That's the threshold! Standard frequency order tested: 1000 β 2000 β 4000 β 8000 β 500 β 250 Hz Start at 1000 Hz because it's the most reliable, retest it at the end --- BONUS: π MASKING The Tricky Part Problem: When you test one ear, the sound might sneak through the skull to the other better ear and give a false result. This is called cross-hearing. Solution: Play noise masking into the non-test ear to keep it busy, so it can't "cheat" and hear the test signal. When to mask simple rules: - AC difference between ears β₯ 40 dB with regular headphones β mask! - BC of one ear is 10 dB better than the AC of either ear β mask! --- π©Ί DEGREES OF HEARING LOSS Degree Average Threshold ------ Normal 0-20 dB Mild 21-40 dB Moderate 41-70 dB Severe 71-95 dB Profound 96+ dB Memory trick - "My Mother Sings Profusely" = Mild, Moderate, Severe, Profound --- β‘ INSTANT RECALL CHEAT SHEET PTA = Find softest beep a person can hear AC headphones vs BC skull vibrator β Compare them to find WHERE the problem is GAP AC worse than BC by 10dB = Conductive problem NO GAP both bad equally = Sensorineural problem GAP + both elevated = Mixed Audiogram: Right=Red=O, Left=bLue=X Y-axis goes DOWN = worse hearing Method: 10dB DOWN, 5dB UP until threshold found Masking = noise in good ear to stop it cheating --- π¬ THE REAL-WORLD MOVIE ANALOGY Imagine your ear is a movie theatre: - AC = Normal ticket entry through front door, hallway, seats - BC = VIP secret entrance directly to the cinema screen If the hallway is blocked wax/fluid but the screen works fine β Conductive loss front blocked, VIP entry fine If the screen itself is damaged β Sensorineural loss both entrances lead to a bad screen If both the hallway is blocked AND the screen is damaged β Mixed loss --- That's everything in your 10 pages, simplified into one story. The key thing to remember every time: compare AC and BC β gap or no gap β that tells you everything about the type of hearing loss! Q: Pure tone Audiometry , impedance Audiometry, speech Audiometry , tuning fork tests, acoustic reflex, otoacoustic emission, bear, Sisi , recruitment, abbr and different other Audiometry tests all in detail from ENT standard textbooks for exam and teach me whole in simplified language A: I now have all the textbook data I need. Let me write the full comprehensive simplified guide now. --- π§ THE COMPLETE AUDIOMETRY GUIDE Everything from ENT Standard Textbooks - Simplified for Instant Memory --- πΊοΈ THE BIG MAP FIRST Think of the ear as a 3-part factory: OUTER EAR β MIDDLE EAR β INNER EAR Cochlea β NERVE β BRAIN Canal Eardrum+Ossicles Hair cells VIII CN Cortex β β β β β AC tests Impedance OAE / SISI ABR/BEAR Speech all of this Audiometry Audiometry Audiometry Audiometry Every audiometry test is designed to pinpoint WHICH part of the factory is broken. --- π± PART 1: TUNING FORK TESTS Your cheapest, fastest, bedside tool. No electricity needed. The 512 Hz fork is the gold standard. Why NOT below 512 Hz? - Low-frequency forks can be FELT vibrotactile instead of heard - confuses the patient. --- π Test 1: RINNE TEST One word summary: Compares AC vs BC in the SAME ear Air Conduction AC Bone Conduction BC --------- How Fork 2cm from ear canal Fork on mastoid bone Tests Full ear pathway Inner ear only Result: - AC BC = Positive Rinne = Normal OR Sensorineural loss - BC AC = Negative Rinne = CONDUCTIVE LOSS minimum 20 dB gap with 512 Hz Memory trick: "Positive = Perfect" normal or SNHL. "Negative = Not conducting well" conductive loss Watch out: In severe SNHL, the dead ear may give a FALSE negative Rinne! The fork on the mastoid of the deaf ear is actually being heard by the GOOD ear across the skull. This is called a "False negative Rinne." --- π Test 2: WEBER TEST One word summary: Lateralization test - compares BOTH ears Procedure: Fork placed on the MIDLINE forehead, nasal dorsum, central incisors, or chin. Results: Sound goes to... Meaning ------ Midline equal Normal OR equal loss in both ears Affected blocked ear CONDUCTIVE loss in that ear Opposite good ear SENSORINEURAL loss in the bad ear The trick to remember Weber: - Conductive = sound goes to the BAD ear because background bone noise is blocked, so the test signal is clearer - SNHL = sound goes to the GOOD ear because the bad cochlea can't pick it up Mnemonic: "SHE" = SNHL goes to the Healthy Ear --- π Test 3: SCHWABACH TEST One word summary: Compares patient's BC to a normal-hearing EXAMINER - Prolonged Schwabach = Patient hears LONGER than examiner = Conductive loss sound not escaping through middle ear normally - Diminished Schwabach = Patient hears SHORTER than examiner = SNHL damaged cochlea - Equal Schwabach = Normal --- π Test 4: BING TEST Occlusion Effect One word summary: Tests if blocking the ear canal INCREASES bone conduction - Fork on mastoid. Then block the ear canal with a finger. - Positive Bing = Sound gets LOUDER when you block the ear = Normal OR SNHL occlusion effect present - Negative Bing = No change in loudness = CONDUCTIVE LOSS occlusion effect absent - because the middle ear is already "blocked" --- π COMPLETE TUNING FORK SUMMARY TABLE Source: KJ Lee's Essential Otolaryngology, Scott-Brown's, Shambaugh Test Normal Conductive Loss SNHL ------------ Rinne AC BC +ve BC AC -ve AC BC +ve Weber Midline To BAD ear To GOOD ear Schwabach Equal to examiner Prolonged Diminished Bing Positive louder with occlusion Negative no change Positive --- π PART 2: PURE TONE AUDIOMETRY PTA Already covered in the previous session - quick recap with new exam points The 10 DOWN, 5 UP Bracketing Method: Start audible β β10dB until NO response β β5dB until RESPONDS Repeat until 2 out of 3 ascending responses = THRESHOLD Standard test order: 1000 β 2000 β 4000 β 8000 β 500 β 250 Hz retest 1000 Hz at the end Why start at 1000 Hz? Most reliable frequency, easiest for patients to detect. Air-Bone Gap ABG: Difference between AC and BC thresholds at same frequency. - ABG β₯ 10 dB = Conductive component - ABG β₯ 15 dB = Clinically significant --- π« PART 3: IMPEDANCE AUDIOMETRY Immittance Think of the middle ear as a spring system. Impedance = how much it resists sound. Admittance = how easily sound flows through. The machine measures ADMITTANCE compliance. 3A: TYMPANOMETRY What it does: Varies air pressure in the sealed ear canal +200 to -400 daPa and measures how compliant floppy/stiff the eardrum is at each pressure. The output = TYMPANOGRAM Jerger Classification of Tympanograms: Type Peak Pressure Meaning Example --------------- Type A Normal peak Near 0 daPa Normal middle ear Normal Type As Shallow peak low compliance Near 0 daPa Stiff middle ear Otosclerosis, tympanosclerosis Type Ad Deep/tall peak high compliance Near 0 daPa Discontinuity or lax TM Ossicular discontinuity, flaccid TM Type B Flat line NO peak - Fluid or perforation Otitis media with effusion, perforation Type C Peak present but shifted LEFT Negative pressure Eustachian tube dysfunction Early OME, negative ME pressure Memory trick: "A = Aight fine, As = Arthritic stiff, Ad = Abnormally floppy, B = Blocked no peak, C = Can't equalize pressure" Type B with: - Small ear canal volume = Fluid in middle ear intact drum - Large ear canal volume = Perforated drum or patent grommet --- 3B: ACOUSTIC REFLEX Stapedial Reflex The reflex arc: Sound β VIII Nerve β Cochlear nucleus β Superior olive β VII nerve β Stapedius muscle β Contracts β Stiffens ossicular chain Normal reflex threshold: 70-100 dB above HTL Hearing Threshold Level Two ways to measure: Ipsilateral Contralateral --------- Signal & measurement Same ear Different ears Tests Whole reflex arc Full crossed pathway both sides What Acoustic Reflex Tells You: Finding Meaning ------ Reflex present At minimum, VII nerve and stapedius are working; cochlea must be working somewhat Reflex absent - normal tympanogram Suspicion of retrocochlear lesion VIII nerve/brainstem Reflex at lower-than-normal level Cochlear loss with RECRUITMENT Reflex absent - flat tympanogram Middle ear problem already expected Acoustic Reflex DECAY Test: - Stimulus held for 10 seconds at 10 dB above reflex threshold - Normal: Reflex amplitude stays the same - Abnormal decay: If reflex amplitude falls to 50% within 5 seconds = retrocochlear lesion VIII nerve tumor = Acoustic Neuroma/Vestibular Schwannoma Memory trick: "Decay = Dying nerve" --- π£οΈ PART 4: SPEECH AUDIOMETRY Tuning forks use pure beeps. PTA uses pure tones. Speech audiometry uses REAL WORDS - tests how well the brain actually understands speech. Three Main Measures: 1. Speech Detection Threshold SDT / Speech Awareness Threshold SAT - Lowest level at which patient can DETECT speech is present doesn't need to understand it - Used in: infants, non-verbal patients, language barrier 2. Speech Recognition Threshold SRT - THE MAIN ONE - Lowest level at which patient can correctly repeat SPONDEES in 50% of presentations - Spondee = 2-syllable word with EQUAL stress on both syllables railroad, eardrum, sidewalk, icecream, cowboy - Gold rule: SRT should be within Β±6 dB of the Pure Tone Average PTA at 500, 1000, 2000 Hz - If SRT and PTA disagree by more than 10 dB β suspect pseudohypacusis fake hearing loss 3. Word Recognition Score WRS / Speech Discrimination Score SDS - Percentage of Phonetically Balanced PB monosyllabic words correctly repeated at 25-35 dB above SRT - Tests the quality of hearing, not just the quantity Interpretation of WRS: Score Meaning ------ 90-100% Normal 76-88% Slight difficulty 60-74% Moderate difficulty 40-58% Poor β€ 40% Very poor Performance-Intensity PI Function & ROLLOVER: Plot WRS at multiple intensity levels. The curve should RISE then PLATEAU. - Cochlear loss: Rises normally, may plateau slightly lower - Retrocochlear VIII nerve lesion: Rises then FALLS sharply at high intensities = "Rollover" - Rollover ratio = PB max - PB min / PB max - Rollover ratio β₯ 0.30 = VIII nerve lesion retrocochlear Memory trick: "Rollover = nerve is rolled over and not working at high volumes" --- β‘ PART 5: OTOACOUSTIC EMISSIONS OAE One of the coolest discoveries in audiology! Healthy cochlear outer hair cells OHCs don't just RECEIVE sound - they also EMIT sound back out! We can record these emissions. The principle: When sound goes IN, OHCs vibrate and produce a faint echo that travels BACK through the middle ear and into the ear canal, where we record it with a tiny microphone. OAEs are present ONLY if: 1. The middle ear is healthy to transmit the emission out 2. The outer hair cells are healthy to generate the emission Two Types of OAE: TEOAE Transient Evoked OAE DPOAE Distortion Product OAE --------- Stimulus Clicks broad frequency Two simultaneous pure tones f1 and f2 Response Echo after the click Distortion product at 2f1-f2 Frequency range 500-4000 Hz 1000-8000 Hz better for high freq Best for Newborn hearing screening Detailed cochlear mapping, ototoxicity monitoring Clinical use Neonatal screening quick pass/fail Serial monitoring, detailed assessment OAE Clinical Rules: - OAE Present + Normal hearing = Outer hair cells fine β - OAE Absent + Normal ABR = Possible central issue - OAE Present + Absent ABR = Auditory Neuropathy Spectrum Disorder ANSD - outer hair cells fine but nerve is not conducting - OAE Absent = Hearing loss 25-30 dB OR middle ear problem Memory trick: "OAE = Outer hair cells' Answer to Everyone. If they're alive, they reply." --- π§ PART 6: ABR / BEAR Brainstem Evoked Auditory Response This test bypasses the patient's cooperation entirely. It records electrical brain waves in response to clicking sounds. The patient can be asleep, sedated, or a newborn baby. Full name: Auditory Brainstem Response ABR = BERA = BEAR = BAER Setup: Electrodes on scalp. Clicks or tone pips presented. Computer averages hundreds of responses to produce a waveform. The 5 Waves & Their Origins: Wave Origin Latency --------- I Distal VIII nerve cochlear nerve 1.5 ms II Proximal VIII nerve / cochlear nucleus 2.5 ms III Superior olivary complex pons 3.5 ms IV Lateral lemniscus 4.5 ms V Inferior colliculus midbrain 5.5 ms Memory trick: "Ear Enters Every Lateral Inferior" = VIII nerve β Cochlear nucleus β Superior olive β Lateral lemniscus β Inferior colliculus Clinically we focus on Waves I, III, and V most reliable How to Interpret ABR: Finding Meaning ------ All waves delayed increased absolute latency Conductive hearing loss Normal wave I, delayed wave V increased I-V interpeak latency Retrocochlear lesion VIII nerve or brainstem Wave V threshold elevated Hearing loss can estimate audiogram No waves at all Profound deafness OR no response pathway Present OAE + Absent ABR Auditory Neuropathy Key interpeak intervals: - I-III = 2 ms normal - III-V = 2 ms normal - I-V = 4 ms normal - I-V 4.4 ms = ABNORMAL = retrocochlear pathology Clinical Uses of ABR: 1. Newborn hearing screening universal 2. Threshold estimation in non-cooperative patients infants, malingerers 3. Acoustic neuroma detection vestibular schwannoma 4. Intraoperative monitoring during posterior fossa surgery --- π¬ PART 7: SITE-OF-LESION TESTS SISI, ABLB, Tone Decay, Recruitment, Bekesy These tests help determine: Is the hearing loss in the COCHLEA or in the VIII NERVE? Note: Most are now replaced by ABR + MRI, but still tested in exams --- 7A: RECRUITMENT What is it? An abnormal rapid growth of loudness. A person with cochlear hearing loss cannot hear soft sounds raised threshold, but once the sound crosses threshold, it becomes loud VERY quickly - almost normally loud. Imagine: A light switch that only turns ON when you push it very hard, but once it turns on, it's BLINDING bright. - Recruitment = COCHLEAR inner hair cell damage - No recruitment = RETROCOCHLEAR nerve damage How to detect recruitment: - Acoustic reflex at low levels above threshold - ABLB test - SISI test high score - Loudness discomfort level UCL is not raised despite elevated threshold --- 7B: SISI TEST Short Increment Sensitivity Index What it does: Tests if a person can detect tiny 1 dB increases superimposed on a continuous tone at 20 dB above threshold. Procedure: 20 brief 1 dB increments are given. Patient presses button when they notice a change. Scoring: % of increments detected out of 20 presentations. Score Site of Lesion ------ β₯ 70% High SISI COCHLEAR lesion recruitment present - they detect tiny changes β€ 30% Low SISI RETROCOCHLEAR / Neural lesion OR Normal hearing 30-70% Equivocal Memory trick: "High SISI = Cochlear they're SISIitive to small changes" --- 7C: ABLB TEST Alternate Binaural Loudness Balance Used in: Unilateral SNHL only What it does: Patient alternately hears a tone in the GOOD ear and the BAD ear. They balance the loudness - adjust one until both feel equally loud. Interpretation: - Recruitment present Cochlear: Equal loudness is reached at EQUAL intensity levels dB HL - i.e., the bad ear "catches up" to the good ear in loudness - No recruitment Retrocochlear: Equal loudness requires MORE intensity in the bad ear the bad ear never catches up Memory trick: "ABLB: A Balance test. Loudness Balance = cochlear recruitment found" --- 7D: TONE DECAY TEST Auditory Adaptation / Fatigue Test What it does: Plays a continuous tone at threshold level. The patient indicates when they can no longer hear it. If they stop hearing it, intensity is raised by 5 dB and timing restarts. Principle: Normal ears can hear a continuous tone indefinitely. Damaged VIII nerve "fatigues" rapidly. Decay Meaning ------ 0-5 dB Normal β€ 25 dB Normal to cochlear 25 dB Retrocochlear VIII nerve lesion - ACOUSTIC NEUROMA Memory trick: "Tone Decay 25 = Nerve is Decaying acoustic neuroma" --- 7E: BEKESY AUDIOMETRY What it does: Patient controls their own threshold using a button. The audiometer sweeps across frequencies automatically. Two runs: one with pulsed tone, one with continuous tone. Bekesy Types: Type Pattern Meaning --------- Type I Pulsed = Continuous overlap NORMAL or Conductive Type II Continuous drops 20 dB below pulsed especially at high freq COCHLEAR Type III Continuous drops 20 dB, keeps falling VIII NERVE lesion acoustic neuroma Type IV Continuous drops 20 dB across ALL frequencies VIII NERVE lesion Type V Continuous is BETTER than pulsed reverse Functional non-organic hearing loss Memory trick: "Type I = Innocent. Type II = Cochlea. Type III/IV = Three/Four Nerve damage. Type V = V for Very fake" --- π PART 8: MASKING RULES Clinical Source: Scott-Brown's, Table 51.1 When do you MASK put noise in the non-test ear? Rule Situation Action --------- Rule 1 AC thresholds differ by β₯40 dB supra/circum-aural headphones OR β₯55 dB insert earphones Retest AC of worse ear while masking better ear Rule 2 BC threshold of one ear is better than the AC threshold of EITHER ear by β₯10 dB Retest BC while masking opposite ear Rule 3 Rule 1 not applicable, but BC of ear A is β₯40 dB or 55 dB insert better than not-masked AC of ear B Retest AC of ear B while masking ear A --- π§ͺ PART 9: OTHER TESTS 9A: STENGER TEST for functional/malingering hearing loss Principle: When the same tone is presented to both ears simultaneously, only the louder one is perceived Stenger principle. Used when: Suspecting unilateral non-organic faked hearing loss. - Present tone at 10 dB ABOVE the supposed bad ear's threshold and at 10 dB BELOW the good ear's threshold. - Positive Stenger: Patient DENIES hearing the tone because they can't admit the "bad" ear is hearing β CONFIRMS functional/fake loss - Negative Stenger: Patient admits hearing the tone β organic loss --- 9B: SPEECH BANANA on the Audiogram The region on the audiogram where all speech sounds fall = frequency 500-4000 Hz, levels 20-60 dB HL. Looks like a banana shape. Any hearing loss covering the speech banana = communication difficulty. --- 9C: AUDITORY PROCESSING DISORDER APD - PTA can be NORMAL - Patient complains of difficulty understanding speech in NOISE - Tests: Dichotic listening, speech in noise tests, gap detection, time-compressed speech - Site: Central auditory nervous system above brainstem --- π MEGA SUMMARY TABLE: THE CHEAT SHEET FOR EXAMS Test What it measures Cochlear finding Retrocochlear finding ------------ PTA Hearing threshold Elevated threshold, config varies Elevated threshold, often asymmetric Rinne AC vs BC AC BC +ve AC BC +ve Weber Lateralization To good ear To good ear Tympanometry Middle ear compliance Normal Type A Normal Type A Acoustic reflex Stapedial reflex Present at low SL recruitment Absent or decays Reflex decay Nerve fatigue Absent/minimal POSITIVE 50% in 5 sec OAE OHC function Absent if 30 dB loss Usually PRESENT if cochlea OK ABR Neural pathway Normal I-V interval Prolonged I-V 4.4 ms SISI Small increment detection HIGH β₯70% LOW β€30% ABLB Loudness balance Recruitment present equal HL No recruitment Tone decay Auditory fatigue β€25 dB 25 dB Bekesy Auditory adaptation Type II Type III/IV WRS/Rollover Speech discrimination Normal/slight rollover ROLLOVER β₯0.30 --- π§ INSTANT MEMORY ANCHORS For Tuning Fork Tests: "Weber SHE CONFERS" - SNHL β Healthy Ear - CONductive β FERS to the bad ear confers = conferring with the bad side For Impedance Types: "A = OK, As = Stiff, Ad = Dangling, B = Blocked, C = Can't equalize" For Site of Lesion: "Cochlea = HIGH, Neural = LOW" SISI scores "Cochlea = Recruits, Neural = Decays" loudness growth vs fatigue For ABR Waves: "Eight-Eleven-Five" = Wave I at 1.5, Wave III at 3.5, Wave V at 5.5 ms Or: "Ear Enters Every Lateral Inferior" anatomical pathway For Speech Audiometry: "SRT Β± 6 dB from PTA" if bigger gap = suspect fake/non-organic hearing loss "Rollover β₯ 0.30 = VIII nerve" Degrees of Hearing Loss: "My Mother Sings Professionally" = Mild 21-40, Moderate 41-70, Severe 71-95, Profound 96+ --- π― EXAM QUICK FIRE Q&A Q: Weber lateralizes to right ear. What does it mean? A: Either RIGHT ear has conductive loss OR LEFT ear has SNHL. Q: OAE present but ABR absent. Diagnosis? A: Auditory Neuropathy Spectrum Disorder ANSD - outer hair cells fine, nerve not conducting. Q: Type B tympanogram with small ear canal volume. Diagnosis? A: Fluid in middle ear otitis media with effusion - intact TM. Q: Type B tympanogram with large ear canal volume. Diagnosis? A: Tympanic membrane perforation OR patent grommet. Q: Tone decay 25 dB. Diagnosis? A: Retrocochlear lesion - acoustic neuroma vestibular schwannoma. Q: High SISI + present recruitment + Bekesy Type II. Site? A: COCHLEA. Q: Absent SISI + absent recruitment + Bekesy Type III + ABR prolonged I-V interval. Site? A: RETROCOCHLEAR VIII nerve - acoustic neuroma. Q: SRT is 40 dB but PTA average is 20 dB. What do you suspect? A: Pseudohypacusis non-organic/functional hearing loss. Q: Acoustic reflex decays to 50% within 5 seconds. What lesion? A: Retrocochlear - VIII nerve lesion. --- Sources: Scott-Brown's Otorhinolaryngology Vol 2, KJ Lee's Essential Otolaryngology, Shambaugh Surgery of the Ear, Cummings Otolaryngology
