Audiovestibular

AUDIOVESTIBULAR BASICS—-DANIEL TODD, MD SOUND=AN ALTERNATING CONDENSATION AND RAREFACTION OF MOLECULES WITHIN AN ELASTIC MEDIUM SPEED OF SOUND=344M/S=777MILES/HR AT 20 DEGREES CELCIUS AT SEA LEVEL IN AIR(MUCH GREATER IN H2O OR NS)—SPEED RELATED TO THE DENSITY OF THE MEDIUM—IVORY>>NS>>>AIR AMPLITUDE=LOUDNESS=INTENSITY—–MEASURED IN Db A 40 DB INCREASE = 100 X INCREASE IN AMPLITUDE Db=1/10 BEL=A LOGORYTHMIC RATIO TO A REFERENCE POINT REFERENCE = SPL = SOUND PRESSURE LEVEL 0.0002 DYNES/CM2 = 0 dB SPL = 10-16WATTS/CM2 = 20 MICROPASCALS IR = INTENSITY OF THE REFERENCE = 10 – 16 WATTS/CM2 = 10 – 12 WATTS.M2 PR = PRESSURE OF THE REFERENCE = 0.0002 DYNES/CM2 = 20 MICROPASCALS INTENSITY = PRESSURE 2 THUS: IR = PR2 DB SPL = 10 LOG (PO2/PR2)=THE LOGORITHMIC RATIO OF TWO SOUND POWERS HL=WHAT MOST AUDIOMETERS ARE ZEROED TO—THE NORMAL HUMAN PERCEPTION OF SOUND FOR A GIVEN FREQUENCY—= 0 DB nHL (NORMAL HEARING)—RARELY TEST PEOPLE TO SEE IF THEIR HEARING IS BETTER THAN THIS HL TAKES THE “U” SHAPED SPL CURVE OF AUDIBILITY AND STRAIGHTENS IT OUT ON THE NL AUDIOGRAM—-THERE IS AGAIN A CURVE “SPEECH BANNANA” = FREQ OF NL CONVERSATION SL=THE INDIVIDUALS REFERENCE TO THE HL (SDS PRESENTED AT 35 DB SL) PURE TONE= A SINGLE FREQUENCY–A SINE WAVE—DOES NOT HAPPEN IN THE REAL WORLD–VS—COMPLEX SOUND NOISE=APERIODIC COMPLEX SOUND WHITE NOISE CONTAINS ALL THE FREQUENCIES OF THE SPECTRUM NARROW BAND NOISE=WHITE NOISE WITHIN A CERTAIN FREQUENCY RANGE(FREQUENCIES ABOVE AND BELOW FILTERED OUT) SPEECH NOISE= A TYPE OF NARROW BAND NOISE BETWEEN 300-3000HZ WARBLE TONE NOISE= NARROW BAND NOISE LIKE A SIREN—USED IN INFANT BOA FREQUENCY=PITCH—MEASURED IN HERTZ TIMBRE = QUALITY OCTAVE=DOUBLING OF THE FREQUENCY TEST PURE TONES REFERENCED TO HL WITH HUGHES AND WESTLAKE PROCEDURE—DROP 10 DB IF PT HEARS THE TONE—-ADD 5 DB IF THEY DO NOT IAA=INTRA AURAL ATTENUATION–40-50 DB MINIMALLY FOR AIR—O DB FOR BONE HUMAN EAR DETECTS FREQ 20-20,000HZ SPEECH = 300-3000HZ = A TYPE OF NARROW BAND NOISE BETWEEN 300-3000HZ—-CONSONANT ENERGY IS LESS INTENSE AND IS CONCENTRATED IN THE HIGHER FREQUENCIES (“FFFF’ AND “SHHH” AND “THHH”) EXT EAR COMPLEX—MADE UP OF PINNA, CONCHAL BOWL AND EAC GIVE YOU ABOUT A 10-15 DB BOOST IN THE SPEECH FREQ (PEAKING AT 2700 HZ) PINNA FLANGE GAINS YOU ABOUT 3 DB AT 4000 HZ CONCHA CAVUM = GIVE ABOUT 10 DB AT 5000-6000 HZ EAC = 2500-3500 HZ—-RESONATES AT 4 TIMES ITS LENGTH—-2.5 CM = 3430 HZ RESONANT FREQUENCY=THE FREQUENCY AT WHICH A MASS VIBRATES WITH THE LEAST AMOUNT OF EXTERNAL FORCE—DETERMNED BY THE STIFFNESS AND MASS OF THE OBJECT—-THE RF OF THE MIDDLE EAR SYTEM (TYPANO-OSSICULAR UNIT) IS LIMITED IN THE HIGH FREQ BY MASS AND LIMITED IN THE LOW FREQ BY STIFFNESS—THE 2 CURVES TUNE THE SOUND THROUGH THE SPEECH FREQUENCIES——MOST ME PATH (SOM/OME) BOTH INCREASES THE STIFFENESS AND MASS TO CAUSE A FLAT CHL NL RESONANT FREQUENCIES—-TM = 1000 HZ, ME = 500-2000 HZ A LOSS IN THE NL ME RESONACE CAUSES AN ARTIFICIAL DROP IN BONE SCORES AROUND 2000 HZ CARHARTS PHENOM IS A RESONANT FREQUENCY BASED PHENOM—-2000HZ CARHART’S NOTCH = ARTIFACTUAL DROP IN BONE SCORE—-BONE SCORE IS NOT A TRUE MEASURE OF COCHLEAR FUNCTION BUT RATHER A MEASURE OF THE VIBROTACTILE CHARACTERISTICS OF THE SKULL AND MIDDLE EAR THIS IS WHY OSSIFICATION DISORDERS OF THE SKULL MESS UP BONE SCORES (PAGET’S DZ) REVERSE CARHART = I – S JOINT PROBLEMS (ARTIFACTUAL RISE IN AIR SCORE) TYMPANO-OSSICULAR SYSTEM HAS 3 MECHANISM OF AMPLIFICATION THE AREA RATIO—TM = 87.5MM2 WITH AN EFFECTIVE VIBRATING PORTION = 55MM2—ANNULUS IS LIKE THE HINGE AND THE UMBO IS THE POINT OF MAXIMAL VIBRATION—-17:1 SIZE ADVANTAGE OVER OVAL WINDOW(1.41 X 2.99MM)—--22.5 DB ADVANTAGE MECHANICAL LEVER ADVANTAGE—1.3:1 —-2.5 DB GAIN PHASE DIFFERENCE ADVANTAGE—IF SOUND WAVE HIT BOTH OW AND RW AT SAME INSTANT LOOSE 16 DB IN CANCELLING WAVE—-TM (SONIC SHIELD) AND DIFFERENT ORIENTALTION OF RW (FACES ANT ON THE PROMONTORY) FROM OW PROTECT IT FROM INTERFERING SOUND WAVES 22:1 OVERALL MECHANICAL ADVANTAGE = 25 db GAIN ALMOST EQUALS OUT THE 27 DB LOSS FROM CHANGING FROM AN AIR TO FLUID MEDIUM—AS 99.9% OF THE SOUND WAVES ARE REFLECTED AT AN AIR-FLUID INTERFACE THE MIDDLE EAR TRANSFORMER EFFECT IS NECESSARY MAX CHL = ABOUT 50 DB- 60 DB (INTACT TM WITH DISSOCIATED OSSICULAR CHAIN) PAN TM PERF WITH DISSOCIATED OSSICULAR CHAIN–45 DB–GET OW AND RW CANCELLING WAVES
 TM PERF WITH OSSICLES—30 DB—-SOUND ACTUALLY TRAVELS RETROGRADE FROM RW TO OW IF THE STAPES SUPERSTRUCTURE IS INTACT CHL WITH A TM PERF VARIES WITH BOTH SIZE AND LOCATION (ALTERING PHASE DIFFERENCE ADVANTAGE) TENSOR TYMPANI PROVIDES ABOUT 10 DB ATTENUATION FROM SUSTAINED SOUNDS—STAPEDIUS REALLY DOES NOT DO MUCH BEKESY(1960)TRAVELING WAVE THEORY=ACOUSTIC FILTRATION—-PROBABLY OLD DOGMA LOCATION OF MAXIMAL DISPLACEMENT OF BASILAR MEMBRANE = FREQUENCY DETECTED—REALLY IS TH SHORTENING (DEPOLARIZATION) AND LENGTHENING (HYPERPOLARIZATION) OF THE OHC = “THE COCHLEAR AMPLIFIER”—HELPS SHARPENT THE PEAK OF THE WAVE AT MAXIMAL DISPLACEMENT—-HEAR IT AS EVOKED OAE’S BASILAR PORTION (NEAR OW) THINNEST(LEAST MASS) AND STIFFEST—HIGHEST FREQUENCIES (LOST FIRST) APICAL PORTION (HELICOTREMA) THICKEST (MOST MASS) AND LEAST STIFF—-LOWERE FREQUENCIES–(HYDROPIC REGION OF SNHL) STRIA VASCULARIS IS EXTREMELY ACTIVE METABOLICALLY—GENERATES ABOUT A 90 MV POSITIVE ENDOCOCHLEAR POTENTIAL (SCAL MEDIA IS + (K+) IN REFERENCE TO THE (-) PERILYMPH HEARING LOSS 0-20=NL 20-40=MILD 40-60=MODERATE——-AVG LEVEL SPEECH DISCRIM = 55dB 60-80=SEVERE >80=PROFOUND VESTIBULOPATHY DIZZINESS=ANY ALTERED SENSATION OF ORIENTATION IN SPACE ATAXIA=FAILURE OF MUSCLE CONTRACTION OR COORDINATION VERTIGO=MISPERCEPTION (ILLUSION OR HALLUCINATION) OF MOTION—-DOES NOT HAVE TO BE ROTATORY—-CAN PE PULSION—-THIS IS WHAT THE OTOLOGIST IS LOOKING FOR—-OFTEN A GOOD IDEA TO GET ENG WITH CALORICS SO YOU CAN ASK THE PT IF THAT IS THE SENSATION THEY ARE EXPERIENCING!!!   Hx PARENT OR CAREGIVER’S HISTORY IS ONLY ACCURATE FOR EXTREME PATHOLOGY (FOR KIDS WITH MEE RELATED CHL—-ASK ABOUT SMOKING EXPOSURE, DAY CARE (#), ALLERGY SYMPTOM AND FAMILY HISTORY, AND POSSIBLE REFLUX OF SINUS SYMPTOMATOLOGY)—-FOOD INTOLERANCE OR CRAVING? AGE OF ONSET TYPE OF ONSET (SUDDEN VS INSIDIOUS) DURATION FLUCTUATION PROGRESSION ASSOC OTOLOGIC Sx (TINNITUS, OTALGIA, AURAL FULLNES, VERTIGO, OTORRHEA) TEMPORAL PATTERN OF VERTIGO SECONDS BPPV VS TIA VS DYSAUTONOMIA MINUTES-HOURS HYDROPS VS TIA VERTIGO LASTING A DAY OR LONGER VESTIBULAR (VIRAL) NEURONITIS OR NEUROLABYRINTHITIS—VS MS VS VBI VESTIBULAR NEURONITIS OR NEUROLABYRINTHITIS IS ONLY ASSOC WITH PRECEEDING URTI IN ABOUT 30% OF CASES CONSTANT METABOLIC, PSYCOGENIC, PHARMICOLOGIC, OR TOXIC ASSOC TRAUMA OR VERTIGO WITH INCREASED ICP (SNEEZING, LIFTING, OR STRAINING) THINK FISTULA VERTIGO IN A POSITION OR WITH CHANGING POSITION Fhx (A FAMILIAL FORM OF UNILAT SNHL HAS BEEN DESCRIBED) AQUIRED——-OTOTOXIC DRUGS (ASA,QUININE, AMINOGLYCOSIDES,VANC,CISPLATININ,OTHER CHEMO) HEAD TRAUMA—COMMOTIO (CONCUSSION) LABYRINTHI—T-BONE Fx BAROTRAUMA NOISE EXPOSURE ANOXIC BIRTH TRAUMA APGARS (0-3) BIRTH WEIGHT < 1500 G MECHANICAL VENTILATION > 5 DAYS HYPERBILI—EXCHANGE TRANSFUSIONS, KERNICTERUS RADIATION THERAPY CONGENITAL—-CRANIOFACIAL ABNL, COCHLEAR MALFORMATIONS, LARGE VESTIBULAR AQUEDUCT SYNDROME INFXOUS–——-ANTECEDENT VIRAL INFXNS, EAR INFXNS, EAR SURGERY, MENINGITIS, PERIONATAL INFXNS(TORCHES), SCARLET FEVER, MUMPS, MEASELS, CHICKEN POX, SYPHILIS EXPOSURE, HIV METABOLIC/SYSTEMIC-—–HYPERLIPIDEMIA, THYROID ABNL, DM, AUTOIMMUNE Dz, HEART Dz, HTN, SICKLE CELL ANEMIA, MS IDIOPATHIC
 PMHx CURRRENT MEDS PERINATAL Hx SCREENING SCREEN 0-29 DAYS—-KERNICTERUS, LBW, LOW APGARS, RECURRENT INFXNS, FH, MALFORMATIONS, MENINGITIS, OTOTOXIC MEDS, CMV INFXN, TORCHES, WHITE FORELOCK—–WOULD BE CAREFUL IN RECOMMENDING UNIVERSAL SCREENING IN THAT BOTH ITS EFFICACY AND UTILITY LACK EVIDENCE (IT HARDLY PICKS ANYONE UP WHO WOULDN’T GET SCREENED FOR HIGH RISK AND THERE IS NO EVIDENCE THAT PICKING THEM UP EARLY HELPS THEM) SCREEN 29 DAYS-2YRS IF PARENTERAL CONCERN, NF II 1/500 INCIDENCE OF HL AFTER THE AGE OF 6 MILESTONES 12 MO—-BABBLING 18 MO—-ONE WORD 24 MO—-10 WORDS 30 MO—-100 WORDS AND 2 WORD COMBOS 36 MO—-200 WORDS AND TELEGRAPHIC SENTENCES 48 MO—-80% CLARITY PE SKIN CHANGES—NF WHITE FORELOCK OF WAARDENBERG’S (AUTO D) VISUAL EXAM—VISUAL ACUITY, PERRL, EOMI, NYSTAGMUS (THE ONLY OBJECTIVE SIGN OF VERTIGO) DYNAMIC VISUAL ACUITY “ILLEGIBLE E” TEST AND HEADSHAKE QUALITATIVE TESTING OF THE VOR—-(ENG AND ROTARY CHAIR QUANTITATIVELY TEST THE VESTIBULO-OCULAR REFLEX ARC AND TONE) ABDUCENS PAULSEY—MOBIUS (AUTO D –MIXED LOSS, FACIAL AND HYPOGLOSSAL DIPLEGIA) INTERSTITIAL KERATITIS–SYPHILIS AND COGAN’S ABNL PIGMENT—OI, WAARDENBERG’S, PIEBALDNESS CATARACTS—ALPORTS, STICKLER, RUBELLA RP (FUNDOSCOPIC EXAM)—USHERS, HALLGRENS, REFSUMS, LAWRENCE-MOON-BIEDLE ABNL AURICLE—-BOR, MOBIUS, GOLDENHAR, TREACHER-COLLINS GOITER—PENDRED’S NEURO EXAM—-HEADSHAKE, GAZE EVOKED AND SPONT NYSTAGMUS, HALLPIKE, FISTULA TEST STRENGTH, REFLEXES, GAIT, TANDEM GAIT, A, A, AND ORIENTED X 3 RHOMBERG, TANDEM OR ACCENTUATED RHOMBERG, UNTERBERGER (FAKUDA), AND FOAM AND DOME (POOR MAN’S POSTUROGRAPHY) GIVE YOU QUALITATIVE INFORMATION ON THE VESTIBULO-SPINAL REFLEX ARC AND TONE DYSMETRIA, DYSDIADOCHOKINESIA OTOLOGIC EXAM TUNING FORKS–WEBER CAN DETECT 3 DB DIFFERENCE BETWEEN EARS A NULL POINT EXISTS 45 DEGREES FORM THE HEAD WHERE THE FORK CANNOT BE OPTIMALLY HEARD RHINNE—512=BEST 256=MOST SENSITIVE—CAN DETECT A 15 DB CHL 512=25 DB CHL 1024=35DC CHL GELLE=OCCLUDE EAC WITH FORK ON MASTOID AND GET NO CHANGE=CHL SCHWABACH=COMPARES PT AND EXAMINERS HEARING WITH FORK ON MASTOID—EXAMINER HEARS IN LONGER=DIMINISHED—SNHL, PT HEARS IT LONGER=PROLONGED—CHL(UNMASKED) BING CONFIRMATORY TEST—PLUG EAC–WEBER LOCALIZES THERE AUSCULTATE AROUND THE EAR FISTULA TEST CONSIDER GENETICS CONSULT LAB CBC MHATP FASTING BLOOD SUGAT–GTT ESR THYROID FUNCTION TESTS INNER EAR AG (68OOKD PROTIEN)—-70% + IN SSNHL (A WESTERN BLOT ASSAY THAT YOU MUST SEND OUT) SERUM CORTISOL FANA, ANA—–RAJI CELL ASSAY AND LTT (LYMPHOCYTE TRANSFORMATION AND MIGRATION INHIBITION TEST) RF TORCH VIRAL TITERS LIPID PROFILE UA EKG OTHERS: CRP, C-ANCA, COMPLEMENT–CIq BINDING PROTIEN AUDIO 0-6 MONTHS = BOA
 6-24 MONTHS = VRA 24-36 MONTHS = TROCA (TANGIBLE REINFORCEMENT OPERATANT CONDITIONING AUDIO) 3-5 YEARS = PLAY AUDIOMETRY > 5 CONVENTI0NAL AUDIO PTA=AVG OF AIR CONDUCTION AT 500, 1000, 2000 HZ BC SCORES—-USED TO BE THOUGHT THAT THE FOCNFIGURATION OF THE PURE TONES HAD DIAGNOSTIC VALUE—-COOKIE BITE OR “U” SHAPED AUDIO REALLY DOES NOT CORRELATE WELL WITH A NONSYDROMIC HEREDITARY LOSS AS PREVIOUSLY THOUGHT MASKING ALL MASKING IS VIA AC MAXIMAL MASKING IS ABOUT 110 DB MUST MASK ALL BC IF THE CONTRA(NONTEST) EAR IS ABOUT THE SAME OR BETTER MUST MASK ALL AC IF THE NONTEST EAR AC OR BC IS 40 DB BETTER—–MASK AT PTA(SRT) + 15 DB + THE A-B GAP OF THE NON TEST EAR USE INSERT EAR PHONES WHENEVER POSSIBLE (VS CIRCUMAURAL HEAD PHONES) SDT/SAT=SPEECH DETECTION THRESHOLD / SPEECH AWARENESS THRESHOLD= THE LOWEST THRESHOLD WHICH AN INDIVIDUAL CAN DETECT SPEECH—-USED IN CHILDREN, LANGUAGE BARRIER, MR SHOULD BE 8-9 DB BETTER THAN THE SRT—-AGAIN VALIDATES THE PTA’S SRT=SPONDEES(BISYLLABIC WORDSEACH WITH EQUAL STRESS)—SHOULD BE WITHIN 6 DB OF PTA’S AT 5, 10, AND 20 KHZ ABNL VARIATION OF THE SDT OR SRT FROM THE PTA’S SUGGEST PSEUDOHYPACUSIS SDSWRS(WORD RECOGNITION SCORE)=MONOSYLLABIC PHONETICALLY BALLANCE WORDS-CONSTANANT-VOWEL-CONSTANANT (PRESENTED ANT 40 DB SL)—–VOWELS ARE LOW FREQ—-CONSTANANTS ARE HIGH FREQ 90-100 = nl 75-90 = mild 60-75 = moderate 50-60 = poor < 50 = severe——THINK RETROCOCHLEAR PATHOLOGY GLYCEROL TEST : 1.2 ML OF 95% SOL/KG—AUDIO 1, 2, AND 3 HOURS POST INGESTION—Sx IMPROVE IN 1 HOUR WITH MAX IMPROVEMENT IN 2-3 HOURS (>60% HYDROPIC PTS IMPROVE > 10 db PURE TONES BETWEEN 250-1000 DB AND 12 – 16 % IN IMMITANCE AUDIOMETRY—- BATTERY CONSITING OF TYMPANOMETRY, EAC VOLUME, ACOUSTIC REFLEXES (THRESHOLDS AND DECAY) IMMITENCE=A MEASURE OF HOW EASILY A SYSTEM CAN BE SET INTO MOTION ADMITANCE=EASE WITH WHICH ENERGY FLOWS (COMPLIANCE) IMPEDENCE=RESISTANCE (ADMITANCE = 1/IMPEDENCE DYNAMIC TYMPANOMETRY= A NL COMPLIANCE OR ADMITANCE GIVES YOU A TYPE “A” CURVE NEG PRESSURE WITHOUT FLUID=TYPE “C” CURVE FLUID=FLAT TYMP-TYPE “B” CURVE NL EAC VOLUMES: NEONATE=<0.5CC CHILD=0.3-1.0CC ADULT=0.75-1.75CC STATIC TYMPANOMETRY=ACOUSTIC REFLEXES—–BEST FOR PSEUDOHYPOCUSIS STIMULUS IS A SOUND—-TAKES 70-100 DB HL TO GENERATE A BILAT RESPONSE—THE RESPONSE IS PRIMARILY THE STAPEDIUS MUSCLE CONTRACTING (VERY LITTLE V3—TENSOR TYMPANI)—-THUS YOU REALLY DO NOT GET MUCH OF ANYTHING IN LATE OTOSCLEROSIS—AS YOU THINK YOU WOULD IF THE TENSOR PULLED THE MALLEUS REGARDLESS OF FOOTPLATE FIXATION GET A POORLY EXPLAINED “ON-OFF’ EFFECT THOUGHT TO BE DUE TO EARLY PARTIAL “STICKY” FOOT PLATE FIXATION COCHLEAR (PERIPHERAL) AUDITORY DAMAGE LEADS TO EARLY REFLEXES—ANY THING LESS THAN 70 dB=RECRUITMENT OAE–OTOACOUSTIC EMISSIONS—(-MECHANICAL) SOUND GENERATED WITHIN THE COCHLEA--NEED TO HAVE A NL FUNCTIONING MIDDLE EAR-—THOUGHT TO BE GENERATED BY MOVEMENT (CONTRACTURE AND LENGTHENING) OF THE OUTER HAIR CELLS—-THUS MOVING THE BASILAR MEMBRANE—PERILYMPH OF THE SCALA TYMPANI—-OW—-OSSICULAR CHAIN—AND TM LIKE A SPEAKER HEAD 2 TYPES: SPONTANEOUS—–50% PTS(FEMALES>MALES)–NOT CLINICALLY USEFUL-—NOT RELATED TO TINNITUS!!! DETECTED IN THE 1-2 KHZ RANGE EVOKED:-–THREE TYPES OF EVOKED (EVOKING STIMULUS IS AUDITORY AS IS THE DETECTED RESPONSE)—SEDATION IS NOT A FACTOR!!! TRANSIENT (MOST USEFUL)—PRESENT IN OVER 90% OF NL EARS—MAY BE ABLE TO DETECT 30-40 DB SNHL—(STIMULUS IS A CLICK)—–
 DISTORTION PRODUCT—-STIMULOUS IS 2 DIFFERENT FREQUENCIES AND RESPONSE IS SOMETHING INBETWEEN—DETECTS UP TO A 50 DB SNHL—IS MORE FREQUENCY SPECIFIC THAN TRANSIENT EVOKED THUS CAN GIVE YOU MORE INFO AND BE CLINICALLY USEFUL STIMULOUS FREQUENCY—-MOST FREQUENCY SPECIFIC AND LEAST CLINICALLY APPLICABLE –STIMULOUS AND RESPONSE ARE OF SIMILAR FREQUENCY —-OAE MAY BE IMPORTANT IN DEFINING THE ENTITY OF AUDITORY NEUROPATHY( VS THE USUAL CAUSE OF SNHL WHICH IS HAIR CELL DAMAGE)—AUDITORY NEUROPATHY MAY PRECLUDE COCHLEAR IMPLANTATION!!! ELECTRICAL RESPONSE AUDIOMETRY ECOG MEASURED THE ELECTRICAL RESPONE OF THE COCHLEA AND EIGHTH NERVE ECOG(ECOCHG)=ELECTROCOCHLEOGRAPHY—CM = THE COCHLEAR MICROPHONIC = THE IMMEDIATE RESPONSE FROM THE HAIRBEARING SURFACE OF THE TYPE I OHC ECOG-–STIMULUS IS AUDITORY CLICKS—SENSE ELECTRIC POTENTIALS VIA AN ELECTRODE IN THE CANAL OR VIA A TRANSTYMPANIC ELECTRODE ON THE PROMONTORY—GET DETECTION ELECTODE AS CLOSE TO RW AS POSSIBLE, AP FORM THE TYPE I OCH, SP FORM THE BASILAR MEMBRANE DEFLECTING INTO THE SCALA TYMPANI GET AN SP/AP RATIO—-HIGH IS CONSISTENT WITH RELATIVE ENDOLYMPH/PERILYMPH HYDROPS—THE SP CAN BE SEPARATED FROM THE 1ST WAVE OF THE ABR BY INCREASING THE CLICK FREQUENCY—THE SP HAS NO REFRACTORY PERIOD ECOG DEMONSTRATES ENHANCEMENT OF THE SP/AP RATIO GREATER THAN O.33- O.4, ALSO AN INCREASED AP DIFFERENCE (95% SENSITIVE FOR EARLY MENIERS) ECOG CAN BE USED INTRAOP FOR MONITORING, PRE OP FOR COCHLEAR IMPLANT!!! ABR=BAEP—TESTS THE NERVE—-BRAINSTEM AUDITORY EVOKED POTENTIAL TESTING—POST MENINGIC CHILD, INFANTS WITH RECURRENT AOM, MR, DIFFICULT TO TEST PTS—-PICKS UP 7 DISTINCT WAVES—-1ST (SUPERIMPOSED ON THE ECOG), 3RD, AND 5TH I=EIGHTH NERVE (ONLY WAVE PRESENT AFTER A NERVE SECTION) II=COCHLEAR NUCLEUS III=OLIVARY NUCLEUS(SUP) IV=LATERAL LEMNISCUS V=INF. COLLICULUS (MIDBRAIN) NOT FREQ SPECIFIC—STIM = A CLICK AT AROUND 3000-4000HZ—-OVERESTIMATES THE HL BY ABOUT 10-20DB INTERAURAL WAVE V LATENCY DIFFERENCE (ITV) = 0.2MSEC MAX—–LONGER IN NEONATES CER—TESTS THE CNS ENG—-REALLY THE ONLY IMPORTANT VESTIBULAR TEST—DISTINGUISHES BETWEEN VESTIBULAR AND NONVESTIBULAR—-HOWEVER, REALLY ONLY TESTS AT A VERY LOW FREQUENCY—-THUS YOU CANNOT DIAGNOSE A TOTAL LOSS OF VESTIBULAR FUNCTION AN EXCELLENT TEST TO GIVE YOUR PTS A TRUE REFERENCE TO TRUE VERTIGO!!!!! UTILIZES THE BULBAR DIPOLE—DOES NOT WORK IN BLIND PEOPLE–HAVE TO USE INFRARED DETECTORS TESTS II AND III EVALUATE THE CENTRAL VOC (VESTIBULAR OCULAR CONTROL) SYSTEM I—CALIBRATES THE EYE MOVEMENTS—10-15 DEGREES II—SACCADES, LATENCY, VELOCITY, AND ACCURACY—-ABNL POINT TO A CENTRAL DEFECT SLOW OR ABNL —PARAPONTINE GAZE CENTERS DYSCONGUGATE—-MLF DYSMETRIA—-CEREBELLAR III—SMOOTH PURSUIT—SINUSOIDAL/PERPENDICULAR PATTERN)—GAIN, PHASE, ACCELERATION—-ABNL=CENTRAL PROBLEM IV—-OPTOKINETIC NYSTAGMUS (FORM/SYMMETRY) V—-GAZE OR FIXATION VI—POSITIONAL VII—POSITIONING TEST VIII (THE CALORICS) ARE THE MOST VALUABLE EVEN THOUGH THEY ARE USING A NONPHYSIOLOGIC STIMULUS, EXAMINING ONLY THE VERY LOW FREQUENCIES, AND TESTING ONLY THE HORIZONTAL SCC AND SUP VESTIBULAR NERVE VIII—CALORICS——30 DEGREES = COLD, 44 DEGREES = HOT—-ICE H2O IN THE PRONE POSITION IS THE MOST STIMULATORY TO THE VESTIBULAR NERVE (4 X GREATER THAN SUPINE)—CAN HAVE UP TO A 44% DIFFERENCE BETWEEN PTS AND ONLY A 25% DIFFERENCE BETWEEN EARS CAVEATES–CONGENITAL NYSTAGMUS “MINER’S NYSTAGMUS” (OFTEN PENDULAR WITH NO DIRECTIONAL PREPONDERANCE) APPEARS IN PTS WITH MACULAR DEGENERATION AS THEY ARE TRYKING UNSUCCESSFULLY TO “FOVEATE”—SEE THIS IN NEONATES WHERE THE FOVEAL REGION IS INCOMPLETELY DEVELOPED POSITIONAL TESTING—–NO MOVEMENT—THE PT IS IN 1 PARTICULAR (OFTEN PECULIAR) STATIC POSITION! POSITIONING TESTING—-LIKE HALLPIKE/DIX -OTOLARYNGOLOGY (BARANY/NYLEN-NEUROLOGY) ROTATIONAL TESTING (ROTARY CHAIR) ACTIVE—HEADSHAKE = HIGHEST FREQUENCY PASSIVE—-ROTARY CHAIR TEST = SINUSOIDAL OSCILLATION TEST—ABLE TO TEST THE VESTIB SYSTEM AT MULT FREQUENCIES (LIKE AN AUDIO) “COMPARE THE VELOCITY OF THE SLOW EYE MOVEMENTS TO THE VELOCITY OF THE CHAIR” GAIN—THE RATIO BETWEEN THE MAX EYE VELOCITY AND THE MAX CHAIR VELOCITY PHASE = SYMMETRY NOT EAR SPECIFIC
 CAN TEST CHILDREN EASIER MOST USEFUL FOR BILAT VESTIBULOPATHY (OTOTOXICITY) MOST SENSITIVE, FREQ SPECIFIC—ENG ONLY TESTS THE VESTIB SYSTEM AT A VERY LOW FREQ PLATFORM POSTUROGRAPHY—CAN GIVE QUANTITATIVE TESTING OF THE VESTIBULO-SPINAL RELFEX SYSTEM CT (HIGH RESOLUTION WITH THIN CUTS) MRI (T-1 GADOLINIUM ENHANCED AND OR T2 FAST SPIN ECHO) DIFF Dx TEMPORAL PATTERN OF VERTIGO SECONDS BPPV VS TIA VS DYSAUTONOMIA MINUTES-HOURS HYDROPS VS TIA VERTIGO LASTING A DAY OR LONGER VESTIBULAR (VIRAL) NEURONITIS OR NEUROLABYRINTHITIS—VS MS VS VBI VESTIBULAR NEURONITIS OR NEUROLABYRINTHITIS IS ONLY ASSOC WITH PRECEEDING URTI IN ABOUT 30% OF CASES CONSTANT METABOLIC, PSYCOGENIC, PHARMICOLOGIC, OR TOXIC—?CHRONIC VESTIBULAR NEURONITIS?   VESTIBULOPATHY—-ANATOMIC LOCATION PERIPHERAL (LABYRINTIAN)—–HYDROPS, PLF, COGAN’S, MAL DE BARQUEMENT–MOTION SICKNESS—-THE ONLY REASON TO PRESCRIBE ANTIVERT OR SCOPOLAMINE—ALSO THE MOST COMMON FORM OF PERIPHERAL VERTIGO, SYPHILIS, OTHER VIRAL OR BACTERIAL LAYRINTHITIS OR VESTIBULAR NEURITIS, BPPV, ETOH, OTOTOXICITY, ALTERNOBARIC VERTIGO, ETD,OME, AOM, LABYRINTHIAN CONCUSSION OR ISCHEMIA CENTRAL EIGHT NERVE—-MICROVASCULAR (LOOP) COMPRESSION SYNDROME., CPA TUMOR, TRUAMA, INFXN CENTRAL BRAINSTEM—-VBI, WERNICKES, MS, CERVICAL VERTIGO, INFXN (PRION, MENINGITIS), TRAUMA, CVA, NEOPLASM—-Sx = CROSSED FINDINGS—IPSI CN’S AND CONTRA BODY CENTRAL CEREBELLAR FINDINGS—-DYSDIADOKOKINESIA, DYSMETRIA, ATAXIA (FALL IPSI), PENDULAR DTR’S CENTRAL CORTICAL—SIEZURES, PARALYSIS, ANESTHESIA, APHASIA, APROSODIA, ANOSOGNOSIA, ASTERIOGENESIS, AGRAPHESTHESIA CENTRAL SUBCORTICAL—-MOTOT ABBERATION, RESTINT TREMOR, CHOREA, DYSTONIA, HEMIBALLISMUS, VISUAL FIELD DEFICITS, HYPESTHESIAS   ACUTE VESTIBULAR SYNDROME A SYNDROME OF SEVERE VERTIGO, NAUSEA, VOMITING, SPONTANEOUS NYSTAGMUS, AND POSTURAL INSTABILITY MUST DIFFERENTIATE A PERIPHERAL (VESTIBULAR) INSULT FROM A CENTRAL (INF. CEREBALLAR) INSULT THE DIFFERENTIAL IS BASED ON CHRONOLOGY OF SYMPTOMS, PT RISK FACTORS FOR STROKE, ABILITY TO SUPPRESS WITH VISUAL FIXATION, CHARACTERISTICS OF NYSTAGMUS (VERTICLE, DIRECTION CHANGING), ASSOC SYMPTOMS (OTOLOGIC), ACCOMPANYING NEUROLOGIC SIGNS (DYSPHASIA, WEAKNESS ECT..). NEW LITERATURE SHOWING SOME VESTIBULAR TESTS CAN PICK THESE PTS UP AS WELL: TOROK MONOTHERMAL CALORIC TESTING SHOWS VESTIBULAR DECRUITMENT AND HYPERACTIVE CALORIC RESPONSES WERE OF PARTICULAR VALUE PAST NEUROLOGY DOGMA LEADS ONE TO BELIEVE THAT VERTIGO, DIZZINESS, WOOZINESS AND GIDDINESS ARE NOT INDICATIVE OF CVDz THIS DOGMA HOWEVER IS CHANGING—THESE PTS OFTEN PROGRESS ON TO A MAJOR STROKE IT HAS BEEN SAID THAT ANYONE >45 YEARS OF AGE PRESENTING WITH ACUTE VERTIGO WITH NO ASSOC OTOLOGIC SYMPTOMS SHOULD BE IMAGED FO R/O A CVA —-THIS IS OF COURSE CONTROVERSIAL—-BUT AT LEAST THINK OF IT CHRONIC VESTIBULAR NEURONITIS?—IS THIS AN ENTITY? TRY VALCYCLOVIR 1 PO TID X 10 DAYS—-SEEMS TO HELP SOMETIMES POST TRAUMATIC VERTIGO BLACKOUTS = LOC ALMOST NEVER RELATED TO A LABYRINTIAN ETIOLOGY T-BONE Fx & PLF—VERTIGO WOULD BE INSTANTANEOUS POST TRAUMATIC MENEIR’S SYNDROME (HYDROPS)—PROBABLY A REAL ENTITY CUPULOLITHIASIS/CANALOLITHIASIS—(BPPV) LABYRINTHIAN CONCUSSION—MAY BE PART OF A CEREBRAL (BRAIN) CONCUSSION—OFTEN Hx OF A BRIEF LOC—OFTEN PREDISPOSES TO A POST CONCUSSION SYNDROMEN (SERATONIN IMBALANCE) POST TRAUMATIC VASCULAR LOOPS CERVICAL VERTIGO—-CERVICOGENIC VERTIGO IS CERTAIANLY A REAL ENTITY! WHIPLASH——C/O DIZZINESS TYPICALLY BEGINS 1 WEEK OUT FROM INJURY   PROGRESSIVE NON-FLUCTUANT SNHL HYDROPS PLF METABOLIC(HYPOTHYROID)–FLAT B SNHL(PT USUALLY MYXEDEMATOUS, HOARSENESS, ETD—REVERSIBLE WITH TREATMENT (HYPERLIPIDEMIA)—(OTOTOXIC) AUTOIMMUNE INFXOUS(SYPHILIS) VASCULAR
 FLUCTUANT SNHL MORE LIKELY TO BE HYDROPIC, PLF—-BUT REALLY COULD BE ANY OF THE ABOVE ENTITIES POST TRAUMATIC SNHL–-GET SERIAL AUDIOS (Q.D.)—DO FISTULA, FRENZELS, ECT…. PLF—HEMOTYMPANUM ACTS AS A BLOOD PATCH COCHLEAR CONCUSSION POST TRAUMATIC HYDROPS POST TRAUMATIC VASCULAR LOOP POST TRAUMATIC (SHEARING) PHENOM TO BRAINSTEM—-EXPECT FELLOW TRAVELERS SUCH AS CONCOMMITANT CRANIAL NEUROPATHIES ***IF YOU HAVE ABSOLUTELY NO HEARING—YOU WILL NOT GET RETURN!—-A DEAD EAR NOT TO RECOVER! LOW FREQ LOSS RETURNS BEST HIGH FREQ LOSS RETURNS SOMEWHAT FLAT SNHL POST TRAUMA RARELY RETURNS UNILAT SNHL IDIOPATHIC, VIRAL(MUMPS), VASCULAR, MENIER’S, COCHLEAR OTOSCLEROSIS, CPA TUMOR, SYPHILIS, COGANS, PLF, (AUTOIMMUNE-USUALLY BILAT), MS, RELAPSING POLYCHONDRITIS, TEMPORAL ARTERITIS, WEGENERS, MUMPS INNER EAR CHL BASILAR MEMBRANE STIFFNESS(A POORLY DEFINED ENTITY)–SHOULD HAVE A + RW REFLEX OTHERWISE DO A STAPEDECTOMY Hx, SYMPTOMS, SIGNS, AND DATA INDICATIVE OF SITE OF LESION PERIPHERAL AUDITORY (COCHLEAR) DIPLACAUSIS BINAURIS DYSHARMONICA—HIGHER/ROUGHER PITCH GOOD SDS (40dB SL)-PHONETICALLY BALANCED WORDS RECRUITMENT +ABLB (WITH UNILAT HL)–ALTERNATE BINAURAL LOUDNESS BALANCE TEST—MUST HAVE NL HEARING IN 1 EAR AND MILD LOSS IN THE OTHER—PRESENT TONES AND INCREASE INTENSITY IN BOTH EARS AND PT COMPARES INCREASES +SISI (20 dB SL)-SHORT INCREMENT SENSITIVITY INDEX—TESTING IF PTS CAN DETECT 1 DB INCRESE IN INTENSITY AT 20 DB SL +EARLY ACOUSTIC REFLEXES = +ACOUSTIC REFLEXES AT 30 dB(ANY THING LESS THAN 70 dB=RECRUITMENT) TYPE II BEKESY TRACING (BEKESY AUDIOMETRY–CONTINUOUS VS PULSED TONES)–CAN ALWAYS HEAR THE PULSED TONES BETTER INCREASED LATENCY OF WAVE 1 AND 2 OF ABR ECOG (WAVE I ON ABR)–INCREASED SP/AP RATIO (>33-50%)=THE COCHLEAR MICROPHONIC FROM THE TYPE I OUTER HAIR CELLS +GLYCEROL TEST(REVERSIBILITY) ABNL OTOACOUSTIC EMMISSIONS VESTIBULAR—REALLY ONLY TEST LAT SCC! +FISTULA TEST/HENNEBERT’S SIGN TULLIOS PHENOM(GREATEST AT 500HZ) SYMPTOMS VERY SYMPTOMATIC–-N/V UNIDIRECTIONAL EPISODIC ASSOC. OTOLOGIC Sx–SNHL,TINNITUS,FULLNES, FACIAL PARESIS NYSTAGMUS—-”TO NY OR NOD” TYPE III NYLEN POSITIONAL NYSTAGMUS HORIZONTAL/ROTORY—-VERTICO-TORSIONAL DIRECTION FIXED—-HEAD SHAKE AND ETOH MAY LEAD TO DIRECTION CHANGING NYSTAGMUS ASSYMETRIC SUPPRESSED BY VISUAL FIXATION > 50 % ENHANCED BY FRENZELS/EYES CLOSED OR DARKNESS INDUCED/POSITIONAL LATENCY(DELAYED ONSET—5-15 SECONDS) TEMPORARY—LASTS LESS THAN 1 MIN FATIGABLE REVERSIBLE—WHEN PT RESUMES PRETESTING POSITION OSCILLOPSIA ALEXANDER’S(BOTCHED RHINOPLASTY) LAW-–NYSTAGMUS PRESENT WHEN GAZING TOWARD THE FAST COMPONENT 1ST DEGREE GAZE EVOKED NYSTAGMUS(PRESENT WITH GAZE TOWARD FAST COMPONENT)—-IF YOU ARE FIGHTING THE “FLOW” THE NYSTAGMUS WILL BE MORE NOTICABLE THAN IF YOU GAZE WHERE THE EYES WANT TO GO! EWALD’S (WORKED ON PIGEONS) 1ST LAW—EYE MOVEMENT, HEAD MOVEMENT, AND PAST POINTING OCCUR IN THE SAME PLANE OS THE STIMULATED CANAL 85% OF PAST POINTING IS PERIPHERAL HSN(HEAD SHAKE NYSTAGMUS) +—–VELOCITY STORAGE THEN REVERSAL PHASE
 EWALD’S 2ND LAW—EXCITATION IS MORE EFFECTIVE THAN INHIBITION IN CHANGING LABYRINTHIAN ACTIVITY—IRRITATIVE PHENOM TEND TO RESIST CENTRAL COMPENSATION MORE THAN INHIBITORY ONES (HORIZONTAL CANAL(1) AMPULOPETAL FLOW CAUSES INCREASED RESPONSE) VERTICAL CANALS(2) AMPULOFUGAL FLOW CAUSES INCREASED RESPONSE) UNILAT WEAKNESS (25% JONKEES)=DIRECTIONAL PREPONDERANCE = SEEMS TO CORRELATE WITH SPONT NYSTAGMUS INSUFFICIENT GAIN ON ROTARY CHAIR–ESPECIALLY IN THE LOW FREQUENCIES—-PT MUST BE ALERT ABNL PHASE LAG ASYMMETRY POSTUROGRPHY–CLASSIC 5-6 PATTERN OF VESTIBULOPATHY CENTRALLESIONS AUDITORY-RETROCOCHLEAR/CENTRAL POOR SDS <50% +ROLLOVER +PIPB–PERFORMANCE INTENSITY FUNCTION FOR PHONETICALLY BALANCED WORDS—-(DECREASED SDS AT INCREASED DB INTENSITY) POOR BINAURAL FUSION RESULTS (STAGGERED SPONDIAC WORD TESTING) ABNL TONE DECAY—< 60 SECONDS–SHOULD HAVE > 60 SECONDS AT 20 DB SL(CARHART, OLSON-NOFFINGER,OWENS,ROSENBERG,GREEN, STAT) ABNL ACOUSTIC REFLEX TESTING—< 10 SECONDS AT 10 DB SL (SHOULD BE ABLE TO HOLD STAPEDIAL CONTRACTION FOR THIS LONG)—ACOUSTIC REFLEX ABSENT WITH ANY HL > 60 DB TYPE III OR IV BEKESTY TRACING ABNL LATENCY ON WAVES III – V ON ABR VESTIBULAR/CENTRAL (TRACKING/SLOW PURSUIT) ABNL SACCADES(FAST) AND GLISSADES(SLOW–CORRECTIVE EYE MOVEMENTS) MULTI-STEP SACCADES=CEREBELLAR HYPERMETRIC SACADESS=CEREBELLAR FLUTTER=BRAINSTEM INTERNUCLEAR OPHTHALMOPLEGIA=MLF(MS) SLOWING=CNS SPONTANEOUS—-NOT SUPPRESSED BY VISUAL FIXATION BRUN’S (BRAINSTEM COMPRESSION) NYSTAGMUS–ON SIDE OF LESION CONGENITAL NYSTAGMUS–INVERSION OF OKN SQUARE WAVE JERKS=CEREBELLAR PERIODIC ALTERNATING NYSTAGMUS=CNS REBOUND, UP OR DOWN BEATING=CEREBELLAR/BRAINSTEM SYMPTOMS—VIGOROUS NYSTAGMUS WITH A PAUSITY OF SYMPTOMS SUGGEST CENTRAL VERTIGO OCCASIONALLY ABSENT PROLONGED/STEADY ASSOC. WITH NEURO DEFICIT NYSTAGMUS VERTICAL AND IN ANY VARIABLE DIRECTION NOT POSITIONAL OR RELATED TO HEAD MOVEMENT NON-FATIGABLE—REPEATABLE GAZE PARETIC NYSTAGMUS—–INABILITY TO MAINTAIN LAT GAZE—-LATERAL GAZE CAUSES IPSI BEATING NYSTAGMUS PERIODIC ALTERNATING NYSTAGMUS SUPPRESSED BY FRENZELS OR CLOSING EYES–IN OTHER WORDS VISUALLY ENHANCED NO LATENCY LASTS >1 MIN(PROLONGED OR STEADY) DIRECTION CHANGING 2ND (1ST + STRAIGHT) GAZE EVOKED NYSTAGMUS TYPE II OR TYPE I NYLEN POSITIONAL NYSTAGMUS CALORIC INVERSION OR PERVERSION ON ENG POOR/WEAK UNI OR B RESPONSE ON OKN OKN INVERSION = CONG NYSTAGMUS ABNL PHASE LEADS ON ROTARY CHAIR TESTING CENTRAL PROCESSING ERRORS CNS—SYNTHETIC SENTENCE IDENIFICATION WITH CONTRALATERAL COMPETING MESSAGE / FILTERED SPEECH MAY BE A SPIN OFF OF ADHD AMPLIFICATION HEARING AIDS= BEST RESULTS—> COCHLEAR IMPLANT> TACTILE AIDS SSPL(SATURATION SOUND PRESSURE LEVEL) THE MAX AMOUNT OF SOUND PRESSURE(OUTPUT/POWER) THAT A HEARING AID CAN PRODUCE
 ACOUSTIC GAIN=DB OUTPUT – DB INPUT AT A SPECIFIC FREQUENCY ANALOGUE= THE ELECTRICAL AND ACOUSTICAL SIGNALS ARE SIMILAR DIGITAL=ACOUSTIC ENERGY CONVERTED TO A SERIES OF SIGNALS CODED BY BINARY NUMBERS (0 & 1) WHICH CAN THEN BE PROGRAMMED MORE PRECISELY TO A PATIENTS NEEDS HALF GAIN RULE=COMFORTABLE GAIN YOU WANT OUT OF YOUR HA IS = TH ½ THE HEARING THRESHOLD BAHA CANNOT CORRECT ABOVE THE BC THRESHOLD! HEAD SHADOW EFFECT = 6 DB SIGNAL TO NOISE RATIO—LOSE 6 DB OF SOUND EACH TIME THE DISTANCE FROM THE SOURCE TO THE LISTENER DOUBLES OCCLUSION EFFECT=MUFFLED SENSATION DUE TO A SHIFT IN THE PEAK OF THE NATURAL RESONANCE OF THE EAC(NL=3000HZ) WITH A HA——CAUSES AN INCREASE IN LOW FREQUENCY AMPLIFICATION VENTED AID, NON-OCCLUDING EAR DEVICE(OPEN(IROS) OR SKELETON MOLD)—GOOD FOR HIGH FREQ (DOWN SLOPING) HL—ALLOWS THE LOW FREQ TO PASS THROUGH UNAIDED AND THEN CAN AID THE HIGH FREQUENCIES LIBBY HORN, OR ELECTRONIC FILTERING OF THE LOW FREQUENCIES COMBAT THE OCCLUSION EFFECT—–VENTED AIDS ARE MORE FOR PTS WITH HIGH FREQUENCY LOSS AND LOW FREQ PRESERVATION—–LETS THE LOW FREQ THROUGH FEEDBACK—COMBAT BY SEPARATING THE MICROPHONE AND RECIEVER —EITHER BY DISTANCE —BTE, BODY AID=BEST, EYEGLASS AID— OR CREATING A SEAL BETWEEN THE TWO—CIC AIDS CREATE A GOOD SEAL, OCCLUDING (NON-VENT EAR PEICES) WHEN YOU LOOSE THIS SEAL—THE PT TAKES OUT THE AID—-GET THE HIGH SQUEAL OF THE FEEDBACK ITE–UTILIZES THE PINNA FOR SOME GAIN CIC–RESOLVES THE OCCLSION EFFECT ALD(ASSISTED LISTENING DEVICES) FM = BEST—BEST FOR CHILDREN IN A CLASSROOM BODY AID IS PROBABLY THE BEST ALL AROUND FOR INFANTS AND CHILDREN WITH AURICULAR ATRESIA (SEVER CHL) OR SEVERE-PROFOUND SNHL INFARED—-LINE OF SITE GOLD MEDAL HEARING AID USERS—–OBTAIN AMPLIFICATION TO 40-50 DB SILVER 50-60 BRONZE FAIL TO OBTAIN 60 DB SILVER AND BRONZE MAY BENEFIT IN THE LONG RUN FROM A COCHLEAR IMPLANT IN FUTURE WILL CONSIDER IMPLANTING SDS < 30% AS 40-50% ABLE TO USE THE TELEPHONE -PSYCHOLOGICAL EVALUATION IMPORTANT   COCHLEAR IMPLANT COMPONENTS MICROPHONE – RECEIVES EXTERNAL STIMULUS AND SENDS TO PROCESSOR PROCESSOR – EXTERNAL DEVICE THAT TRANSDUCES MECHANICAL SIGNAL TO ELECTRICAL SIGNAL ELECTRODE – SENDS ELECTRICAL SIGNAL FROM PROCESSOR TO CN 8; VARY IN THAT THEY MAY BE SINGLE VS. MULTICHANNEL, UNIPOLAR VS. BIPOLAR, OR EXTRACOCHLEAR VS. INTRACOCHLEAR *ELECTRODE TYPE IS LIMITING FACTOR IN TYPE OF INFORMATION SENT TO CN 8 WITH SINGLE CHANNEL ELECTRODES ABLE TO SEND TEMPORAL RELATIONSHIP AND INTENSITY INFORMATION WHILE MULTICHANNEL ELECTRODES MAY ALSO SEND FREQUENCY INFORMATION IN ADDITION TO OTHER INFORMATION—IMPROVES SDS GRAETLY OVER SINGLE CHANNEL IMPLANT *SIGNAL MAY BE TRANSFERRED FROM EXTERNALLY TO INTERNALLY BY INDUCTION COILS OR THROUGH A PERCUTANEOUS PLUG PATIENTS: FORTUNATELY ALMOST ALL HEARING IMPAIREMENT IS A HAIRCELL PROBLEM—-THUS COCHLEAR IMPLANT IS ALMOST ALWAYS A VIABLE SOLUTION ADULTS —PREFER POST-LINGUALLY DEAF, BUT MAY DO IN SELECTED PRELINGUALLY DEAF POST PUBESCENT (REALLY AFTER AGE 8) PRELINGUALLY DEAF EARS LACK THE CONNECTIONS OR PLASTICITY TO EVER ACHEIVE OPEN SET SPEECH RECOGNITION -MINIMAL TO NO RESIDUAL AIDABLE HEARING OR NO USEFUL SPEECH DISCRIMINATION, LOSS >95DB CHILDREN —SAME AS ABOVE—-MAY BE MORE APT TO IMPLANT PRELINGUALS ALTHOUGH CONG DEAFNESS OFTEN PARALLELS MANY OTHER PROBLEMS INCLUDING MR -MINIMUM AGE OF 2 -OTOLOGICALLY STABLE EAR—WOULD LIKE TO HAVE NL COCHLEA ON CT—R/O MONDINI OR MICHEL’S APLASIA CAN IMPLANT MONDINI —BUT MAY GET LESSER RESULTS AND HAVE MORE TENDENCY FOR A “GUSHER”—PATENT CHOCHLEAR AQUEDUCT—NOT THAT THAT MATTERS? NF2 CONTRAINDICATED—CONSIDER INSTEAD AN AUDITORY BRAINSTEM IMPLANT TEST FOR ADAPTATION—SOUND FADES AND PT CAN NO LONGER HEAR WANT TO HAVE GOOD SPIRAL GANGLION CELLS—–NORMAL INDIVIDUALS HAVE 30,000 FIRST ORDER COCHLEAR NEURONS PER EAR—–?DIAMETER OF THE COCHLEAR NERVE TRUNK ON HIGH RESOLUTION CT SCAN CORRELATE ? ALSO MUST R/O SEVERE LABYRINTHITIS OSSIFICANS—NEW BONE GROWTH IN THE LABYRINTH OFTEN DUE TO MENINGITIS——GANTZ PROCEDURE—DRILLING OUT THE COCHLEA MAY BE AN OPTION—90% POOR OUTCOMES—1 CASE OF ABILITY TO HAVE OPEN WET SPEECH DISCRIMINATION NEVER IMPLANT WITH RECURRENT AOM—PROBABLY BEST TO DO A RADICAL MASTOIDECTOMY FIRST LOOK FOR OBLITERATIVE OTOSCLEROSIS AS THIS WOULD BE DIFFICULT TO IMPLANT AS WELL WANT TO TEST THE AUDITORY NERVE TO ASSURE IT WORKS—-ECOG—COULD BE DEGENERATED FROM MENINGITIS, LABYRINTHITIS OSSIFICANS OR TRAUMATIZED (T-BONE Fx) MAY BE AN IDEAL TREATMENT FOR DEBILITATING TINNITUS?
 EVALUATION -OTOLOGIC —TRY TO IDENTIFY ETIOLOGY -EVEN IF UNIDENTIFIABLE MOST ETIOLOGIES ARE SUITABLE EXCEPT MICHEL’S APLASIA SECONDARY TO CN 8 ABSENCE -PE—EAR MUST BE FREE OF DZ -TM MUST BE INTACT
 -LOOK FOR CONGENITAL DEFECTS ASSOCIATED WITH 1ST AND 2ND BRANCHIAL CLEFTS -RADIOLOGY—NEED HIGH RESOLUTION CT OF THE TEMPORAL BONE -AUDIOLOGY—EXTENSIVE TESTING WITH BOTH AIDED AND UNAIDED EAR MAY BE COMPARED TO HISTORICAL CONTROLS TO PREDICT SUCCESS -IF CAN NOT HAVE HEARING LEVEL AIDABLE TO BETTER THAN 70 DB OR PATIENT HAS POOR SPEECH DISCRIMINATIONS, PATIENT IS A GOOD CANDIDATE MAY TRY TRANS TYMPANIC ELECTRICAL STIMULATION—-IMPLANT THE MOST REACTIVE EAR! MANAGEMENT -PREREQUISITE – UNINFECTED ME, NEED TO PRE-TREAT PREPLACEMENT EFFUSIONS (POST PLACEMENT EFFUSIONS DO NOT NEED TO BE TREATED IF NOT INFECTED) -SURGERY – CREATE A POST-AURICULAR POCKET TO COMPARTMENTALIZE COIL FROM SKIN INCISION – NEED LIMITED MASTOIDECTOMY WITH FACIAL RECESS – COCHLEOSTOMY ANTERIOR AND INFERIOR TO ROUND WINDOW NICHE – PLACE ELECTRODE INTO SCALA TYMPANI -COMPLICATIONS – MOST ARE ASSOCIATED WITH THE POST-AURICULAR SKIN FLAPS (INFECTION/BREAKDOWN) -COMPLICATIONS OTHERWISE SAME AS MASTOIDECTOMY -MENINGITIS-PERILYMPH GUSHER – ASSOCIATED WITH MONDINI APLASIA COMPLICATING FACTORS – LABYRINTHITIS OSSIFICANS OR SCLEROSISING LABYRINTHITIS MAY LIMIT ELECTRODE ADVANCEMENT AND REQUIRES THE USE OF A SINGLE CHANNEL OR SHORT INSERTION OF A MULTICHANNEL ELECTRODE USUALLY ACTIVATE AND ENCODE 1 MONTH POST OPERATIVELY

Ewald’s first law=stimulation of a certain semicircular canal leads to the stimulus of the EOM’s in that plane.

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