Trans 29 Assessment of Hearing Flashcards
(46 cards)
the distance between crest is ?
wavelength
we measure wavelength in? what unit?
frequency; hertz
is the height of the crest or the depth of the trough. This corresponds to the pressure measured in decibels. That pressure in layman’s term is called the loudness. How loud is sound.
amplitude
a unit used to express the ratio of two values of a physical quantity, often power or intensity.
decibels
Smallest audible sound in the decibel scale?
0db
Humans can hear what hertz
20 to 20,000 hz
How does the sound travel in the ear
Tympanic membrane → ossicles → oral window → inner ear
trace the ascending auditory pathway
EColi MA
Eigth cranial nerve > Cochlear nucleus > olivary nucleus > Lateral Lemniscus > inferior colliculus >MGB > Auditory cortex
Most commonly used tuning fork has a frequency of
512 Hz.
- Sounds delivered to the ear via AC will be attenuated
- If the sound is delivered to the ear via BC, bypassing the OE & ME, then the sound will be heard normally assuming there is no disorder
what hearing loss?
Conductive
• Sounds delivered to the ear via BC will be attenuated
what hearing loss?
SNHL
Findings in weber in normal, CHL, SNHL?
Normal hearing person: Sound is heard equally in both ears.
• Conductive hearing loss (CHL): Lateralized to worse ear.
• Sens
What test?
- AC is compared with BC.
- Vibrating tuning fork is places on patient’s mastoid and when he stops hearing, it is placed erect in line with the EAC, about 2cm from the orifice.
- If he still hears AC is more than BC. It is called positive when or those having sensorineural deafness.
RINNE
Negative Rinne (BC>AC) is seen in
Conductive deafness
3 instances when there is negative rinne?
- Patient has no hearing in test ear.
- BC stimulus may be perceived by contralateral ear.
- No hearing by AC the result is labeled is Rinne negative.
- This mistaken impression of function in a non-functioning ear is called false negative Rinne test.
What test?
- Compares the bone conduction of patient with that of a normal hearing person (examiner).
- Tuning fork is placed on the patient’s mastoid with the meatus blocked and when the patient no longer hears it, it is placed on the normal hearing person’s mastoid.
MODIFIED SCHWABACH TEST
FINDINGS IN SCHWABACH IN
Conductive, SNHL and Normal people?
- Conductive hearing loss + Normal hearing person: Patient and examiner hear the fork for the same duration
- Sensorineural hearing loss: Patient hears the fork for a shorter duration.
- Test of BC and examines the effect of occlusion of ear canal on hearing.
- Vibrating tuning fork is placed on the mastoid while the examiner alternately closes and opens the ear canal by pressing tragus inward.
what test?
BINGS
Bing positive? Bing negative?
- Normal person + SN hearing loss: Hears louder when ear canal is occluded and softer when canal is open (Bing +)
- Conductive hearing loss: No change appreciated (Bing -)
We use pure tones. The px is in a sound proof booth and wearing earphones where the sound is delivered. There’s also an oscillator in the mastoid to test for the conductive mechanism. Ideally, the px should not be seeing the examiner because there might be visual cues.
what test?
Pure tone audiometry
is an electronic device which produces pure tones, intensity of which can be increased or decreased in 5 dB steps.
• AC thresholds are measured for tones of 125, 250, 500, 1K, 2K, 4K, 8K Hz.
• BC thresholds are measures for tones of 250, 500, 1K, 2K, 4K Hz.
• It is charted in the form of a graph called the audiogram.
Audiometer
what ear is tested first in PTA?
Better ear
start at what hertz in PTA?
1000 Hz tone at a level above the threshold to allow easy identification of the tone. If the patient is suspected to be having a profound hearing loss then the testing should be started with 250Hz frequency. This is because of the fact that the individuals with profound hearing loss often have testable hearing only in the low frequency range.
is defined as the faintest tone that can be heard 50% or more of the time, and is established after several threshold crossings.
Threshold