What does each wave represent?
I- Eighth nerve.
II- Cochlear nucleus.
III- Superior olivary complex. IV-Lateral lemniscus.
V- Inferior colliculus.
What disorders are associated with down-beating nystagmus?
- cerebellar degeneration
- multiple sclerosis
- brainstem infarction
- Lithium intoxication
- magnesium and thiamine deficiency.
What are the indications for hearing evaluation every 6 months until age 3?
- Family history of hereditary childhood hearing loss.
- In utero infection (TORCH). Neurodegenerative disorders.
What are the indications for performing hearing screening in neonates if universal screening is not available?
- Family history of hereditary childhood SNHL. Congenital perinatal infection (TORCH).
- Head or neck malformation. Birth weight
- Hyperbilirubinemia requiring an exchange transfusion (>20).
- Bacterial meningitis.
What are the indications for performing hearing screening in infants 29 days to 2 years?
- Parent concern.
- Developmental delay.
- Bacterial meningitis.
- Head trauma associated with loss of consciousness or skull fracture.
- Ototoxic medications.
- Recurrent or persistent otitis media with effusion for at least 3 months.
What are the three types of evoked OAEs?
- SFOAE (stimulus frequency).
- TEAOE (transient evoked).
- DPOAE (distortion product).
What are the neural pathways of the acoustic reflex?
- VIII to the ipsilateral ventral cochlear nucleus to the trapezoid body to the motor nucleus of VII to VII to the ipsilateral stapedius.
- VIII to the ipsilateral ventral cochlear nucleus to the trapezoid body to the ipsilateral medial superior olive to the motor nucleus of VII to VII to the ipsilateral stapedius.
- VIII to the ipsilateral ventral cochlear nucleus to the medial superior olive to the contralateral motor nucleus of VII to the contralateral VII to the contralateral stapedius.
What is the normal interaural attenuation value for bone conduction?
What are the clinical features of benign paroxysmal positional vertigo (BPPV)?
10-20-second attacks of rotational vertigo, precipitated by head movements, with spontaneous resolution after several weeks to months in So-go%.
A patient has a negative Rinne at 256 Hz AS. At 512 and 1024 Hz, it is positive as it is at all three frequencies AD. The Weber test lateralizes to the left at all three frequencies. He hears a soft whisper AD and a soft to medium whisper AS. What is his hearing loss?
15 dB CHLAS.
In patients with chronic otitis media but no cholesteatoma, what level of hearing loss is associated with ossicular chain disruption or fixation?
30 dB or more.
What is normal interaural attenuation of air-conducted tones?
40-80 dB depending on whether ear inserts or headphones are used and also on the frequency being tested.
What percent of the time will the Rinne test miss an air-bone gap
In the normal ear, contraction of middle ear muscles occurs at which pure tones?
65-95 dB HL.
What is a normal word recognition score?
What is rollover?
A decrease in speech discrimination scores when presented at higher intensities; suggestive of a retrocochlear lesion.
When comparing the summating to the compound action potential in electrocochleography, what value is considered abnormal?
A ratio 0-45.
How is stapedius reflex measured?
A signal is presented 10 dB above the acoustic reflex threshold for 10 seconds; if the response decreases to one half or less of the original amplitude within 5 seconds, the response is considered abnormal and suggestive of retrocochlear pathology.
What stimulus is used to evoke the ABR?
A simple acoustic click, between 2000 and 4000 Hz.
What is a spondee?
A two-syllable word spoken with equal stress on both syllables.
What is cryptotia?
Absence of the retroauricular helix.
What technique can be used to differentiate the SP from the nerve potential of VIII (AP)?
AP is a neural response that will respond to higher rates of stimulation. SP is a preneural response that is not affected by higher rates of stimulation. Therefore, increasing the click rate of the stimulus will affect the AP but not the SP.
Where are the recording electrodes for elctrocochleography placed?
As close as possible to the cochlea and auditory nerve (promontory, tympanic membrane, EAC).
What test can be use to exclude the absence of aidable hearing when the ABR is absent at maximum levels?
ASSEP (auditory steady-state evoked potentials).
What is the significance of a negative Rinne at 256 Hz, 512 Hz, and 1024 Hz?
At least a 15 dB conductive hearing loss (CHL), 25-30 dB CHL, and 35dB CHL, respectively.
What test should be used to assess auditory function in these patients?
Auditory brainstem response (ABR).
What disorders are associated with bidirectional gaze-fixation nystagmus?
Barbiturate, phenytoin, and alcohol intoxication.
What three audiometric test techniques are used to obtain behavioral response levels from a child?
Behavioral observation audiometry (BOA), visual reinforcement audiometry (VRA), and conditioned play audiometry (CPA).
Where is the peak pressure point in a normal tympanogram in an adult?
Between -100 and +40 daPa.