Hearing Aid Dispensers Written Exam | Questions with Verified Answers

Hearing Aid Dispensers Written Exam | Questions with Verified Answers db loss of a perforation of TM - ANSWER -10-15db loss procedure done to fix perforation - ANSWER -tympanoplasty or myringoplasty monomeric spots - ANSWER -looks like a hole in TM, but reflects light like a mirror. holes that have healed. aka "mirror membranes" average dimentions of an adult eardrum - ANSWER -2.3-2.9cm in length, .7cm in diameters pars tensa - ANSWER -lower 4/5 of TM and tight pars flaccida - ANSWER -upper 1/5 of TM and flaccid otis externa - ANSWER -"swimmers ear" - inflammation of the walls of the EAM. will not cause loss unless swelling blocks canal. treat: warm salt water, drying it, topical antibiotics polyps - ANSWER -masses of tissue that grow outward from a surface cholesteatoma - ANSWER -non-cancerous tumor in the middle ear. oderous discharge. sometimes perforates upper TM. invasions of skin into the middle ear - sac of concentric rings of protein. causes conductive loss. most dangerous pathology. enlarged canal - ANSWER -result of ear surgery. often have no ear drum or ossicular chain. need approval of physician before fitting tympanosclerosis - ANSWER -white, chalky calcium deposits caused by degeneration of tissue on eardrum, thicking and scarring from peforations and infections epitympanic cavity - ANSWER -attic of middle ear. allows air into mastoid cells of temporal bone. branches several nerves incudotapedial junction - ANSWER -top of incus to head of stapes annular ligament - ANSWER -footplate of stapes that is held in the oval window speed of sound - ANSWER -700mph or 340 m/s (4x as fast through water, 14x as fast through steel) reflection - ANSWER -is an echo or a reverberation reverberation - ANSWER -often in a small room, 17m or less, reverbs can mask high frequencies echo - ANSWER -heard and perceived later than original sound (more than 1/10s after) absorption - ANSWER -aborbs sound. can improve environments w/ reflection or reverb. better in warmth and moist diffraction - ANSWER -sharpness in the change in direction of sound, bending. high diffraction=bigger wavelengths (low freq) refraction - ANSWER -sound passes through one medium to another, change in speed and wavelength infrasound - ANSWER -below audible range of 20 Hz ultrasound - ANSWER -above audible range of 20K Hz octave - ANSWER -anytime the frequency doubles. f(2) = on octave; f(3)= two octaves faintest sound a human can hear - ANSWER -10 ^ -16 watts/cm^2 and pressure of .0002 dynes/cm^2 threshold of pain - ANSWER -1000 dynes/cm^2 when SPL levels double how many db levels increase? - ANSWER -6 db db HL expresses: - ANSWER -threshold levels db SPL expresses: - ANSWER -voices or environmental sounds pinna function: - ANSWER -gather sound, aid in localization, enahnce high freq bw 2k-5k hz aperture - ANSWER -entrance to canal, first bend isthmus - ANSWER -narrowing of canal resonance frequency - ANSWER -between 3k-4k (or 2k-5k in other studies) range, natural boost of 10db, when combined w/ high freq enhancement of the pinna - 15-20 db increase around 2700 hz stenosis - ANSWER -narrowing of ear canal atresia - ANSWER -absense of an ear canal microtia - ANSWER -smaller than normal pinna anotia - ANSWER -absence of one or both external ears oval window - ANSWER -at footplate of stapes round window - ANSWER -hydraulic energy discharging membrane - pressure release window for cochlea acoustic reflex - ANSWER -tensor tympani (muscle on malleus) and the stapedius muscle contract to prevent damaging intensities of loud sounds otitis media aka OM - ANSWER -fluid in middle ear space, most common, fluid can be infected non-supportive OM - ANSWER -w/ no infection suppurative OM -3 classifications - ANSWER -1. acute - more severe w/ short duration and onset. 2. chronic - recurring infection. 3. adhesive - fluid becomes thick and sticky procedure to treat OM - ANSWER -PE tube otosclerosis - ANSWER -spongy growth on stapes, causing fixation and progressive loss. Audiometrically will have a notch at 2k hz called Carharts Notch (cond component across board except at 2k). procedure: stapedectomy to remove and replace w/ prosthesis barotrauma - ANSWER -caused by sudden change in air pressure (eustachian tube dysfunction). may result in fistula fistula - ANSWER -abnormal opening b/w middle and inner ear. can cause SN loss if hair cells damaged by loss of fluid mastoiditis - ANSWER -infection of mastoid bone. risk of meningitis. procedure: mastoidectomy or antibiotics stiffness effect - ANSWER -conductive component in low freq * eustachian tube dysfunction mass effect - ANSWER -conductive component in high freq * otitis media perilymph - ANSWER -same as cerebral-spinal fluid. found in scala vestibula and scala tympani endolymph - ANSWER -manufactured in cochlea, slightly diff polarity than perilymph. found in scala media inner hair cells - ANSWER -about 3k-4k / ear. they are afferent - SEND info TO the brain outer hair cells - ANSWER -3-4 rows, about 12k-15k /ear (12k was answer on the practice test). they are efferent - RECEIVE info FROM the brain. they amplify soft sounds in the cochlea base of cochlea respond to: - ANSWER -high freq sounds apex of cochlea respond to: - ANSWER -low freq sounds hyperacusis - ANSWER -abnormally acute hearing due to heightened irritability of the sensory and/or neural mechanisms. bothered by moderate or even soft sounds acoustic neuroma - ANSWER -tumor on auditory nerve. can be life-threatening. symptoms: large, unexpected AN asymmetries, WR poorer than expected, recent onset of unilateral tinnitus, dizziness. tests for acoustic neuroma - ANSWER -PIPB (rollover test), acoustic reflex delay, tone decay, ABR, MRI labyrinthitis - ANSWER -inflammation of the inner ear, involving both vestibular & auditory portions meniere's disease aka endolymphatic hydrops - ANSWER -build up of fluids in the scala media, too much production of endolymph or absorbed too slowly resulting in pressure that damages the organ of corti. most apparent symptom: vertigo auditory neuropathy - ANSWER -distorted speech. aud deprivation telephone-type electronic h.a - ANSWER -1k-1800 hz, 10-15 db gain w/ carbon granule microphone (heavy static). 1892 vacuume tube - ANSWER -crystal microphone (high impedence, failed at humidity and temp increases; fragile). 1907, emerged in the 20s-30s miniature vacuum tube - ANSWER -wearing h.a. 1938-50s Year of first, 1-piece aid: - ANSWER -1944 transitor eva - ANSWER -on head via glasses or post auricle aids. 1947-50s ITE custom - ANSWER -transitor using magnetic microphones (sufficient in speech freq and durable) 1964, omnidirectional ceramic microphone - ANSWER -improves crystal but had very high impedence, omnidirectional FET microphone - ANSWER -transformed the impedence and improved sensitivity, extended the freq range in the lows to 10 hz, withstood heat and humidity better electret microphone - ANSWER -used in almost all aids today! integrated circuit aka IC - ANSWER -various components all populated into a tiny wafer of silicone. helps miniaturize. electrical energy from microphone is amplified and modified by the IC microphone function: - ANSWER -takes acoustical energy (waves) and transduces it to electrical energy receiver function: - ANSWER -tranduces the electrical energy from the microphone and IC and transduces it back to acoustical energy conductors - ANSWER -allow flow of electrons (current). the greater the flow of the current in HA, the greater the vol or strength. (the battery is a conductor. measured in V) semi-conductors - ANSWER -act as a conductor under certain conditions. when heat, light or an electric field is applied to the outer shell, the electrons start flowing resistors / insulators - ANSWER -limits the flow of electrons. measured in ohms (ex: tubing). insulators = high resistors current - ANSWER -voltage/resistance OR sound/pressure capacitor - ANSWER -impede low freq and pass the highs (like resistors, also measure in ohms) inductor - ANSWER -impede the high freq and pass the lows EX: telecoil (like resistors, also measure in ohms) transitor - ANSWER -amplifier. also a semi-conductor. acts like a spring board for current flow.