Hearing disorders

Question 1

hearing loss

Answer 1

-common chronic impairment (older adults)
-10% people in US
-about 1/800 t0 1/1000 newborns are born with severe to profound hearing loss
-2-3x as many born with lesser hearing loss
-nerves age
-during childhood another 2-3/1000 children acquire moderate to severe hearing loss
-infections -> rubella
-adolescents
-older adults

Question 2

3 segments of ear

Answer 2

-outer ear- auricle and canal
-middle ear- TM, ossicles, middle airspace
-inner ear- cochlea, semicircular canals, internal auditory canals

Question 3

3 classes of hearing loss

Answer 3

-sensorineural- often high frequency, affects inner ear, usually permanent
-conductive- usually low frequency or flat, affects outer and/or middle ear, usually temporary, or at least medically or surgically treatable
-mixed loss- usually affects both high and low frequencies, both conductive and sensory neural components but only conductive portion treatable

Question 4

sound levels

Answer 4

-0-180
-0- ex. faintest sound heard by human ear
-180- rocket launching pad
-protection required for sounds 90 or greater when exposed 8h/day (lawnmower, shop tools, truck traffic)

Question 5

screening

Answer 5

-begins at birth- ring bell and look for eye movements
-newborn- within the 1st week of life
-infants and young children
-sudden losses
-progressive losses

Question 6

children screening

Answer 6

-any child with delays in speech or difficulty in school should undergo evaluation for hearing loss
-mental retardation, aphasia, autism also must be considered
-delayed motor development may signal vestibular deficit -> often associated with sensorineural hearing loss

Question 7

ask for the following history

Answer 7

-neurologic signs and symptoms
-dizziness, vertigo, nystagmus (rapid eye movement), headache, facial palsy
-history of CNS or ear infection
-ototoxic drug- gentamicin + glycosides -> deafness
-exposure to loud noise
-head trauma
-sudden loss of hearing
-otalgia
-family history of hearing loss

Question 8

physical exam

Answer 8

-external ear for:
-obstruction- wax (cerumen)
-infection- cerumen infection -> most common cause of conductive hearing loss
-congenital malformations
-perforation of TM
-otitis media
-cholesteatoma- abnormal collection of skin cells deep inside your ear
-neurologic exam- cranial nerve function -> balance, facial weakness, and taste functions

Question 9

webers test

Answer 9

-use for pts with unilateral hearing loss -> differentiates
-travels through bone- that is why is can travel past wax or fluid
-stem of vibrating 512 Hz or 1024 Hz tuning fork placed on midline of head
-pt indicates in which ear the tone is louder
-if sound lateralizes (louder on one side than the other) -> pt may have either ipsilateral conductive hearing loss or contralateral sensorineural hearing loss
-unilateral conductive hearing loss- tone is louder in ear with hearing loss
-unilateral sensorineural hearing loss- tone is louder in normal ear

Question 10

whisper test

Answer 10

-rib finger tips next to hear to see if they can hear it
-initial test

Question 11

rinne test

Answer 11

-hearing by bone and by air conduction is compared
-bone conduction bypasses the external and middle ear and tests inner ear, 8th cranial nerve, central auditory pathways
-stem of vibrating tuning fork is held against mastoid process(for bone conduction)
-when sound is no longer perceived the fork is removed from mastoid and the still vibrating tines are held close to the pinna (for air conduction)
-normally AC > BC
-conductive hearing loss- BC > AC
-sensorineural hearing loss- both air and bone are reduced AC > BC remains

Question 12

conductive hearing loss

Answer 12

-occurs from a dysfunction of the outer or middle ear
-usually can be treated with medicine or surgery
-deficit of loudness only
-maintains soft speaking voice
-excellent speech discrimination when speech is loud enough
-typically either low frequency or flat hearing loss (equal at all frequencies)

Question 13

causes of conductive hearing loss

Answer 13

-cerumen- most common cause of treatable hearing loss, especially elderly
-foreign bodies
-otitis media- temporary (mild to moderate) or permanent via destruction of ossicles
-cholesteatoma- benign tumor / untreated otitis media
-residual middle ear fluid (secretory otitis media)- commonly causes temporary hearing loss
-occlusion/foreign body
-congenital atresia
-external otitis
-TM perforation
-ossicular fixation- otosclerosis- stiff joints
-ossicular disarticulation

Question 14

conductive hearing loss management

Answer 14

-due to problems that occur in outer and middle ear
-usually temporary and/or treatable with antibiotics or surgery
-wax removal
-for the few people who have uncorrectable conductive hearing losses -> hearing aids
-hearing aids are significantly effective as sound remains clear if it is made loud enough

Question 15

sensory neural hearing loss (SNHL)

Answer 15

-dysfunction of inner ear or auditory nerve
-usually permanent and untreatable
-results in loudness deficit and distorted hearing

Question 16

characteristics of SNHL

Answer 16

-inappropriately loud voice
-tinnitus
-high frequency loss common
-speech sounds distorted
-background noise makes listening more difficult
-hearing aids may help

Question 17

causes of SNHL

Answer 17

-genetics/congenital
-disease- mumps, measles, meningitis, CMV
-ototoxic drugs
-head trauma
-presbycusis- old age
-meniere’s disease- vertigo, tinnitus
-acoustic neuroma- central hearing loss
-noise exposure- prolonged exposure to hazardous noise causes hearing loss by physical destruction of hair cells in cochlea

Question 18

characteristics of NIHL (noise induced hearing loss)

Answer 18

-loss can be sudden with acoustic trauma from an explosion
-more often gradual onset that may go unnoticed
-amount of loss varies from person to person
-risk of noise induced progression stops if no longer exposed to noise -> Aging invariably worsens loss
-for most -> Aging effects are not significant before 50

Question 19

4 P’s of noise induced hearing loss

Answer 19

-painless
-progressive
-permanent
-preventable

Question 20

noise induced hearing loss management

Answer 20

-sensory neural hearing loss is due to problems that occur in the inner ear and are almost always permanent and untreatable
-hearing aids will benefit most people with sensory neural loss but results can vary

Question 21

cochlear implants

Answer 21

-device provides electrical signals directly into the auditory nerve via multiple electrodes implanted in the cochlea

Question 22

mixed hearing loss

Answer 22

-combination of conductive (outer or middle ear) disorder and sensory neural hearing loss
-treatment may be available for conductive portion but sensory neural portion will remain
-causes can be unrelated (ex. NIHL plus TM rupture)
-causes can be related (ex. cochlear otosclerosis)

Question 23

non-organic hearing loss

Answer 23

-non-organic- no medical or physical reason for hearing loss, may be voluntary (malingering) or involuntary (psychological, health, think they cant hear)
-malingering- consciously faking or exaggerating a hearing impairment often for monetary or other personal gain to escape assignments or responsibilities

Question 24

symptoms that should alert you to malingering

Answer 24

-substantial equal hearing loss at all frequencies or no response to pure tones at all in one or both ears
-inconsistent results or marked different than prior results
-unilateral deafness without significant medical history unlikely
-exaggerated attention to test- may press on earphones, difficulty hearing you call them back for testing or to your directions (normal voice level is around 60 dB) but can hear you when your back is turned or when no visual cues
-unconscious development of a non-organic hearing loss - a compensatory protective device, psychogenic problem - the pt believes impairment is real

Question 25

central hearing loss

Answer 25

-occurring with central nervous system (cortex, brainstem, or ascending auditory pathways) as opposed to peripheral organs of hearing (cochlea and middle ear)
-vestibular schwannoma (acoustic neuroma)- 8th cranial nerve schwannomas (benign tumor of axon coverings) one of the most common intracranial tumors -> enhanced MRI
-always requires diagnostic work up by audiologist otologist and/or neurologist
-patient usually hears WNL for pure tones

Question 26

non-organic hearing loss vs central hearing loss

Answer 26

-non-organic hearing loss- typically display flat loss or total deafness in one ear but may exaggerate a trust loss, may (rarely) be involuntary but usually malingering involved (prior results your best clue)
-central hearing loss- hearing for pure tones often normal, problem is between cochlea and cortex (receptor cells are functional but problem is in transmission or processing)