Ear Disorders (Hansen) Flashcards
abnormal bone formation that causes stapes fixation that causes gradual conductive hearing loss; inner ear function may or may not be affected
otosclerosis
____ is the most common treatment for otosclerosis with >90% improvement in hearing.
stapedectomy; requires making a surgical incision and use of a prosthetic to bypass the stapes, and a rare adverse affect is significant hearing loss of the inner ear.
mutation of this gene accounts for ~50% of congenital, nonsyndromic, autosomal recessive, sensorineural hearing loss (aka, DFNB1).
GJB2; encodes connexin 26. can be treated quite successfully with chochlear implant.
otoecoustic emissions is the most common test of newborn screening, and detects the function of what cells?
outer hair cells; does NOT test hearing (ie, you could have normal hair cell function but damage to or absence of the auditory nerve and not hear anything)
*This is an important point*
test used for infants that fail the newborn screening, to assess hearing loss that may originate from the brainstem
auditory brainstem response; it is more expensive and difficult to perform than the otoacoustic emissions test (requires sedation), which is why it is not used for routine screening
this is diagnosed when there is a severely abnormal ABR but outer hair cell function is normal
auditory neuropathy
this gene mediates the Ca++ dependent release of neurotransmitters from the ribbon synapses on the presynaptic side of the hair cell, and its mutation causes DFNB9 (a nonsyndromic recessive auditory neuropathy that responds well to cochlear implant)
otoferlin
what is the main function of the vestibular reflex?
to maintain gaze stability
All of the following are charactersitics of Meniere’s disease EXCEPT:
A. usually only affects one ear
B. aural fullness or pressure with roaring tinnitus
C. endolymphatic hydrops
D. fluctuating low frequency SNHL
E. definitive diagnosis includes at least one episode of vertigo
E. For definitive diagnosis of Meniere’s, there must be at least 2 episodes of vertigo that last 20 minutes or longer, and other causes must be excluded.
Endolymphatic hydrops consists of abnormal fluctuations in the endolymph fluid, which fills the hearing and balance structures of the inner ear. These fluctuations cause an increase in pressure in the endolymphatic system (see picture). It is a non-specific finding in Meniere’s.
Which of the following statements regarding electronystagmogram is FALSE?
A. It employs caloric stimulation, which is a test of vestibular ocular reflex
B. It relies on irrigation of the ear canal with warm and cold water
C. Cold water irrigation produces inhibitory currents, which mimics head turning to the opposite side
D. Warm water elicits fast phase nystagmus to the contralateral side and slow phase to the ipsilateral side
E. Absent reactive eye movement suggests vestibular weakness of the horizontal semicircular canal of the side being stimulated
D. Warm water irrigation causes slow phase nystagmus away from the irrigated ear and fast phase nystagmus towards the irrigated ear.
Pneumonic for remembering the fast phase of nystagmus as it relates to cold or warm water irrigation:
COWS: Cold Opposite, Warm Same
hearing loss intervention that relies on the placement of electrodes within the cochlea to directly stimulate the auditory nerve, bypassing the mechanotransduction function of the hair cells
cochlear implants; they are used in children and adults with severe-profound SNHL and restore sound and speech perception
common and preventable hearing loss with initial damage that occurs at the post-synaptic structures and afferent fibers innervating inner hair cells; later there is loss of hair cells and auditory neurons and fibers
Noise induced hearing loss
Most common hearing test, that includes finding the hearing thresholds for a range of pure tones (250-8k Hz) and testing speech discrimination or word understanding in quiet. It is subjective, meaning a patient must report what they hear.
audiogram
which of the following regarding treatment of meniere’s disease is FALSE?
A. Treatment for Ménière’s disease initially involves a low sodium diet and diuretic and is successful in controlling vertigo in most patients
B. Due to its high ototoxicity, gentamicin should be conisdered only as a last resort in treating Meniere’s
C. Endolymphatic shunt is one treatment option for Meniere’s but is effective in about 70% of patients
D. Intratympanic injections, vestibular nerve section and labyrinthectomy ablate the vestibular function in the inner ear and require a period of vestibular rehab (typically around 3-4 weeks).
B. Gentamicin is highly ototoxic and is one of the prevailing methods for vestibular ablation and controlling vertigo caused by Meniere’s. It is cheaper and less invasive than the other surgical procedures and does not require anesthesia.
