Otoscopy, hearing screening (AC) and pure tone testing with AC and BC Lecture 5

Screening and Assessment Screening Options Case Hx HHIE Otoscopy Pure tone AC screening Pure tone audiometric assessment Air Conduction or Soundfield if unable to tolerate headphones Bone Conduction Procedures for PT testing Variables affecting results Cross hearing in pure tone testing

Hearing Screening Options OptionsConditionFail /Criteria Case History QuestionsSelf Report background None Questionnaire HHI-E/ HHI-A Perception of Handicap Pass < 10 Refer>10 Pure tone hearing screen Detection of soundPass 20 dB, children Pass 25 dB HL, adult OtoscopyCondition of ear canal and middle ear Varies Drainage, wax, foreign body, asymmetry, redness

Case History Hearing History Do you have a hearing loss in one or both of your ears? Was your HL sudden in onset? Do you have any ringing or noises in your ears? Medical History, History of Noise Exposure Have you had a recent illness that could have caused your HL such as sudden noise exposure, viral illness, meningitis, mumps, syphilis, aminoglycoside use, high fever, diuretic use or head trauma? Do you have any recent discharge or drainage? Do you have any pain, fullness, or discomfort in your ears? Family History Determine time of onset of HL

Hearing Handicap Inventory Elderly (HHIE: Ventry & Weinstein, 1983) 10 item, yes, no, sometimes; Paper/pencil format Perceived psychosocial effects of hearing loss Psychometric Properties Strong internal consistency Strong test retest reliability (.84) High correlation with degree of hearing loss Pass/Fail Criteria Total Score < 10: Pass Total Scores > 10: Refer Total Scores > 18: Benefit from HA

When to screen, what to expect Clinical Indications Adults Screen as needed, requested or when they have conditions that place them at risk for HL (i.e. recreational noise exposure, family hx, concerned family member) See ASHA guidelines Expected Outcomes Identification of those persons most likely to have HL that requires referral Does not differentiate between types of HL (conductive, sensorineural etc)

Normal TM Color: grayish, translucent appearance. Structures behind TM: Handle of malleus touches TM- actually draped over bone and is visible. Manubrium is closest to the drum and is most prominent. The tip at the bottom-most aspect is the umbo. The light reflex: Light originating from scope reflects off the surface of the drum, making a triangle that is visible below the malleus. Annulus: ring surrounding TM

Otoscopy

Otoscopy/Video Otoscopy Pull up on pinna and away for adults Pull downward on ear lobe for children Carefully place speculum in ear canal Rotate otoscope anteriorly towards the nose and attempt to ID landmarks

Non Diagnostic Otoscopy Wax Fluid in middle ear Perforated eardrum Presence of foreign body

Landmarks Annulus Manubrium Umbo Cone of Light Incus (shadow) Pars Tensa Pars Flaccida

Setting/Equipment/Specifications Conduct hearing screening in a clinical or natural environment conducive to obtaining reliable screening results Determine ambient noise levels Be sure equipment is calibrated annually Perform listening check prior to administering pure tone test

Clinical Process (Hall and Mueller, 1997) Briefly inspect each ear for evidence of abnormality (ear canal collapse, drainage etc) Seat patient comfortably with profile toward you Instruct patient to respond when they just barely hear the stimulus or even if they just think they heard a sound Use appropriate language level Response mode: Press a button Raise hand Give verbal response

Clinical Process- ASHA Guidelines Protocol – Adults Tones Frequencies  Present at 1000, 2000 and 4000 Hz Level  25 dB HL Ear  Right and left ear individually Protocol – Kids Tones Frequencies  Present at 500, 1000, 2000 and 4000 Hz Level  20 dB HL Ear  Right and left ear individually Subjective Procedure

Tips in conducting hearing screening Position client in chair Adults – facing away from examiner (only after giving instructions) Child – varies If they can follow directions w/o difficulty – face away If they can’t follow directions – face towards examiner and give more feedback visually Provide instructions – pg 94 Position headphones Familiarize with task and then test

Tips in conducting hearing screening Present a pure tone signal to the better ear (50 dB HL) If patient responds, then drop down by 10 dB steps until you obtain a response at desired screening level (20 dB HL – children, 25 dB HL for adults) Use pure tone signals of 1-2 seconds duration If NR from patient, increase in 5 dB steps until the patient responds, and then drop down in 10 dB steps Stop presenting tones once you obtain a response at the desired screening level

Audiometric Test Battery OptionsPurposeResults Pure tone AC thresholdDetermines degree of HL dB HL Pure tone BC thresholdDetermines type of HL dB HL, but compares AC and BC to yield CHL, SNHL or MHL Acoustic ImmitanceDetermines condition of ME and AR Pressure units and type of tympanogram Speech AudiometryDetermines extent of speech understanding Percent of words correct

Pure tone audiometry – threshold testing Cornerstone audiometric assessment tool Several researchers involved in development of technique for hearing testing (Carhart & Jerger, Hughson & Westlake) Purpose: to quantify the amount, type and configuration of hearing loss Results recorded on audiogram Not screening Scope of Practice: Limited to audiology

Air and Bone Degree of Hearing Loss Determined by pure tone air results Type of Hearing loss Determined by comparing pure tone bone results with pure tone air results Configuration of Hearing loss Determined by pattern of pure tone air results

Current Procedure (modified Hughson Westlake Method) Begin in better ear Use warbled, pulsed or conventional pure tones Begin at 1000 Hz Assess mid octaves if gap of more than 20 dB Familiarize with task Signal duration: ____ seconds Present a pure tone signal to the better ear at a level comfortably ________the patient’s presumed threshold Usually 40 dB above threshold (typically at 50 dB HL) for normal hearing

Determining Threshold After demonstrating familiarization, then begin threshold search with down 10, up 5 rule… Increase the intensity level in ____ dB steps until the patient responds Go back down another ____dB and present the stimulus once more Increase the intensity again in ___ dB increments, seeking a response

The patient’s threshold for the stimulus is the lowest level obtained in at least half of a series of presentations Record threshold level on audiogram Go on to the next frequency using same method until all frequencies are obtained (250, 500, 1,2,4,&8 K) Go to other ear after the first ear is completed.

Variables affecting results Cognitive ability Adults Children May have to do an alternative assessment

Alternate assessments VRA and Conditioned Play Audiometry Conditioned Play Audiometry Visual Reinforcement audiometry aKOZeea8s1mSpbCMijDu&index=37 aKOZeea8s1mSpbCMijDu&index=37

Variables affecting results Environment Ambient noise levels cannot exceed an allowable value (ASHA guidelines) Distractors Visual Proprioception

Variables affecting results Stimulus Starting level – must provide familiarization Duration of stimulus Type of tone Presentation pattern

Pitfalls and Fixes False Positives and False Negatives Collapsing ear canals Standing waves Tactile response

Pure Tone Average (PTA)- pg 98 PTA - simple summary of degree of HL Conventional formula: Average of 500, 1000, 2000 Hz / 3 Alternative 4 frequency formula Average of 500, 1000, 2000, 4000 Hz / 4

Audiogram Calculate Pure tone average

Cross-over Hearing Cross over can occur through Air Conduction or Bone conduction The sound presented to the test ear crosses through the skull and stimulates the hair cells of the opposite cochlea The ear that is actually responding to the tone is not the test ear Conditions When one ear hears much better than the other When there are large differences between the ears If assessing at very high intensity levels

Cross-over Hearing AC When values >/= 40 dB consider using masking to re- evaluate thresholds in which ear?

Interaural attenuation (IA) Amount of reduction in intensity that occurs when a signal crosses the head from one ear to the other Sound can cross via AC or BC Typical IA value = 40 dB HL for AC Typical IA value = 0 dB HL for BC Varies by individual, HL and frequency

Cross-Over Hearing in Air Conduction Is AC (test ear) – 40 dB > AC (non test ear)? Examples:

BC Complex phenomenon that involves interaction of 3 different ways to stimulate the cochlea. *Distortional BC – of bony cochlear labyrinth Inertial BC – inertial response of middle ear ossicles and inner ear fluids Osseotympanic BC – radiation of sound energy into external ear canal Each contributes differently to the BC response

Set-up BC testing completed with test ear uncovered Non test ear can be covered when using masking If the ear is covered, then a BC signal sounds louder Increase in sound pressure in the ear canal

Air vs Bone Results AC can be the same as BC AC can be worse than BC = Air Bone Gap BC should not be worse than AC – slight variations can be obtained

Occlusion Effect (OE) Demonstration Occurs for frequencies </= 500 Hz Occurs in normal hearing or SNHL if ear occluded Does not occur in CHL

Interaural attenuation (IA) for BC Amount of reduction in intensity that occurs when a signal crosses the head from one ear to the other Sound also crosses via BC IA values for BC Compare AC and BC threshold of the test ear IA = 10 dB HL

Cross Hearing in BC Only a concern when there is an ABG in the test ear Is AC (test ear) – BC (test ear) > 10 dB? Air-Bone-Gap in Test Ear > 10 dB