(Clinical Applications) Sasan Dabiri, M.D. Assistant Professor Department of Otorhinolaryngology Head & Neck Surgery Amir A lam hospital Tehran University of Medical Sciences Last Updated in February 2015
Auricle (pinna) Sound gathering & localization External Ear Canal Resonance (specific frequencies) Tympanic Membrane & Middle Ear Cochlea Impedance matching (air fluid) Mechanical energy Electrical energy Cochlear nerve Conduction to CNS
Primary Audiologic Evaluation Audiometry (subjective) Pure Tone Audiometry Speech Audiometry Acuostic Immittance (objective) Tympanometry Acoustic Reflex Advanced Audiologic Evaluation Otoacoustic Emissions Auditory Brainstem Response Electrocochleography
Audiometry Pure Tone Audiometry (PTA) Sound Characteristics: Intensity (SPL, HL) : decibel (db) Frequency : Hertz (Hz) Sound Threshold: lowest signal intensity detected at 50% of presentations Air conduction vs. Bone conduction Air Bone Gap (ABG)
Audiometry Pure Tone Audiometry (PTA)
Audiometry Pure Tone Audiometry (PTA) Normal
Audiometry Pure Tone Audiometry (PTA) Conductive
Audiometry Pure Tone Audiometry (PTA) Sensorineural
Audiometry Pure Tone Audiometry (PTA) Mixed
Audiometry Pure Tone Audiometry (PTA) 0 10 20 30 40 50 60 70 80 90 250 500 1000 2000 4000 6000 8000 Down to 25 db Hearing Level = Normal 26 40 db Hearing Level = Mild Hearing Loss 41 55 db Hearing Level = Moderate Hearing Loss 56 70 db Hearing Level =Moderately Severe Hearing Loss 71 90 db Hearing Level =Severe Hearing Loss Lower than 90 db Hearing Level = Profound Hearing Loss
Audiometry Pure Tone Audiometry (PTA) Average of hearing =.5 + 1 + 2 + 4 KHz 4
Audiometry Bone Conduction Air Conduction Right Ear Left Ear Unmasked < > Masked [ ] Unmasked x Masked
Audiometry Pure Tone Audiometry (PTA) Speech Audiometry Speech Reception Threshold (SRT) Word Recognition Score (WRS) (Previously named SDS)
Audiometry Pure Tone Audiometry (PTA) Speech Audiometry Prevention of errors in Audiometry Comparison of mean PTA & SRT Appropriate follow up in asymmetry Attention to technical errors Compatibility to examination Masking
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Tympanic membrane movement Applications: Middle ear function External canal volume
Acoustic Immittance Immitance = Impedance + Admittance
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type A N
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type A S Ossicular fixation
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type A D Atrophic TM Ossicular discontinuity
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type B Glue in middle ear Mass in middle ear Perforation
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type C Eustachian dysfunction
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Type D Scarred TM Hypermobile TM
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Stapedial reflex Reflex threshold & Reflex decay Cochlear Nerve Cochlear Nucleus Facial Nerve Facial Nucleus Superior Olivary Nucleus Facial Nucleus Facial Nerve
Acoustic Immittance Immitance = Impedance + Admittance Tympanometry Stapedial reflex Reflex threshold & Reflex decay Appications: Evaluation of Auditory pathway Localization of Facial nerve lesion
Advanced Audiology Otoacoustic Emissions (OAE) Evaluation of cochlear function Applications: Neonatal hearing screening Auditory neuropathy
Advanced Audiology Otoacoustic Emissions (OAE) Evaluation of cochlear function
Advanced Audiology Otoacoustic Emissions (OAE) Auditory Brainstem Response (ABR) Evaluation of synchronized response of lower auditory pathway neurons 5 waves in diagram (I, II, III, IV, V) Applications: Evaluation of hearing sensitivity Otoneurologic evaluation
Advanced Audiology Otoacoustic Emissions (OAE) Auditory Brainstem Response (ABR)
Advanced Audiology Otoacoustic Emissions (OAE) Auditory Brainstem Response (ABR) Electrocochleography (ECoG) Evaluation of cochlear function Applications: Ménière s disease Enhancing wave I in ABR
Advanced Audiology Otoacoustic Emissions (OAE) Auditory Brainstem Response (ABR) Electrocochleography (ECoG) Evaluation of cochlear function
Electronystagmography Videonystagmography Caloric Test Vestibular Evoked Myogenic P. Test Rotatory Chair Test Posturography
Tinnitus - Definition The perception of sound in the absence of external stimuli (tinnire means ringing in latin)
Tinnitus - Neurophysiology
Tinnitus - Subjective Tinnitus: sound is only perceived by the patient (most common) Non-pulsatile Tinnitus: Perceived sound is continuous (most common) Objective Tinnitus: sound produced by para-auditory structures which may be heard by an examiner Pulsatile Tinnitus: Perceived sound has cyclic non-continuous course that may be vascular or muscular
Tinnitus - Differential Diagnosis Subjective Tinnitus Pulsatile Tinnitus Presbycusis Noise exposure Meniere s disease Otosclerosis Head trauma Acoustic neuroma Cerumen impaction Drugs Middle ear effusion TMJ problems Depression Hyperlipidemia Venous Hum Benign Intracranial Hypertension Glomus Jugulare Glomus Tympanicum Arteriovenous Malformation Palatal Myoclonus
Tinnitus - Evaluation History Taking Thorough and Complete Hx Physical Examination Head & Neck Examination (including Otologic Examination) Paraclinic Evaluation Audiometry Imaging
Tinnitus - Management Medical Non-pharmacologic Behavioral Therapy (Retraining, Biofeedback) Masking & Hearing aid Electromagnetically Pharmacologic Antidepressants Benzodiazepines Surgical (just for apparent otologic pathology)
Thanks for Your Attention