Download hearing and equilibrium activities

HEARING AND EQUILIBRIUM ACTIVITIES
Directions: You will do a series of tests that involve both hearing and equilibrium. Two of the tests will be used
to determine if you have either conductive hearing loss or sensorineural hearing loss. Conductive hearing loss
means something is inhibiting the sound waves from reaching the inner ear whereas sensorineural hearing
loss indicates the malfunction of the inner ear in conducting the message to the brain.
On your own paper you should indicate your personal results. Copy the name of each of the tests you are
conducting and make the data tables to record your results. Answer the questions for each test on your own
paper.
A. SOUND LOCALIZATION
The ability to localize the source of a sound depends on two factors - the difference in the loudness of the
sound reaching each ear, and the time of arrival of the sound at each ear.
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Ask your partner to close both eyes. (No peeking!)
Snap your fingers at an audible distance from the ear (about 1 meter) and randomly move them to various
locations (front, back, sides, and above).
Have your partner locate the position by pointing in each instance.
Actual Location of Snapping
Reported Location
Front of head
Behind head
Above head
Right side of head
Left side of head
1.) Can the sound be localized equally well in all positions? If not, at what positions(s) was the sound most
difficult to locate? Explain why this is so.
B. RINNE TEST FOR COMPARING BONE AND AIR CONDUCTION HEARING
The Rinne test will be used to compare the perception of sound transmitted by air conduction and bone
conduction using the mastoid process found behind the ear. If your hearing is normal, air conduction should
be greater than bone conduction. You should be able to hear the tuning fork next to the pinna after you can no
longer hear it when held against the mastoid. If you are not able to hear the tuning fork after the mastoid test, it
means that bone conduction is greater than air conduction. This indicates there is something inhibiting the
passage of sound waves from the ear canal, through the middle ear apparatus and into the cochlea (i.e., there
is a conductive hearing loss).
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Tap a tuning fork sharply with the rubber mallet. Holding the base of the tuning fork (do not touch the
vibrating tongs), place its handle on your partner’s right mastoid process.
When your partner indicates that the sound is no longer audible, hold the still-vibrating prongs close to
the ear. Is your partner able to hear the sound again (by air conduction)?
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If your partner hears the fork again when it is moved to that position, hearing is not impaired.
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Repeat the test, but this time test air-conduction hearing first.
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After the tone is no longer heard by air conduction, hold the handle of the tuning fork on the mastoid
process. Is your partner able to hear the sound again (by bone conduction)?
If the subject hears the tone again by bone conduction after hearing by air conduction is lost, there is
some conductive deafness. Repeat the procedure for the left ear.
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Ear Tested
Rinne’s test results (normal or impaired)
Left
Right
C. WEBER TEST TO DETERMINE CONDUCTIVE AND SENSORINEURAL DEAFNESS
The Weber test will be used to determine if conductive and sensorineural hearing loss is present. In the Weber
test a vibrating tuning fork is placed in the middle of the forehead, equi-distant from the patient's ears on top of
thin skin in contact with the bone.
In a normal patient, the Weber tuning fork sound is heard equally loud in both ears with no one ear hearing the
sound louder than the other. In a patient with hearing loss, the Weber tuning fork sound is heard louder in one
ear (lateralization) versus the other. This clinical finding should be confirmed by repeating the procedure and
having the patient occlude one ear with a finger; the sound should be heard best in the occluded ear.
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Strike a tuning fork and place the handle of the tuning fork medially on your partner’s head.
1.) Is the tone equally loud in both ears, or is it louder in one ear?
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If it is equally loud in both ears, you have equal hearing, or equal loss of hearing in both ears. If
sensorineural deafness is present in one ear, the tone will be heard in the unaffected ear, but not in the
ear with sensorineural deafness. If conduction deafness is present, the sound will be heard more
strongly in the ear in which there is a hearing loss.
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Have your partner plug the left ear with a finger and repeat the test.
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Repeat by plugging the right ear. If you can hear the tone loudest in the blocked ear, you have
simulated what it is like to have conduction deafness.
Ear
Weber’s test results (normal or impaired)
Left
Right
D. BALANCE AND VISION
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Place your right foot firmly on the floor.
Lift your other foot and hold it behind you in the air. (Like a flamingo!)
Record the number of seconds you can stay in place in that position without moving while leaving your
eyes open.
Now record the number of seconds you can stay in place in that position with your eyes closed.
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Repeat the procedure with the left foot.
Foot
With Eyes open
(seconds)
With Eyes Closed
(seconds)
Left
Right
1.) How did closing your eyes affect the way you felt while balancing in the different positions?
2.) Explain the anatomy and physiology of equilibrium and the sensory organs involved.
(What sensory organs allow for the maintenance of equilibrium when your laboratory partner’s eyes are
open? Hint: there are three.)
3.) What sensory organs provide this information when his eyes are closed?
E. BARANY TEST - INDUCTION OF NYSTAGMUS AND VERTIGO (DIZZINESS)
 Make sure the subject is not inclined to nausea or extreme dizziness during rotational movements.
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Nystagmus is the involuntary rolling of the eyes in any direction or the trailing of the eyes slowly in one
direction, followed by their rapid movement in the opposite direction. It is normal after rotation,
abnormal otherwise. The direction of nystagmus is that of its quick phase on acceleration. Have the
subject walk a straight line, placing one foot directly in front of the other.
1.) Is the subject able to walk without undue wobbling from side to side?
2.) Did the subject experience nystagmus?____________
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The subject will stand and rotate 10 revolutions with their head tilted back (looking up) and a meter stick
on their forehead.
Once the revolutions are completed, make immediate note of the subject’s eyes as they stop and then
have them walk the line again.
3.) Did the subject experience nystagmus?_____________
4.) Was (s)he able to walk without undue wobbling from side to side? _____________
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Ask your partner to describe how (s)he felt during/ after spinning.
5.) Which apparatus in the inner ear was most effected?
6.) Is this a structure for dynamic or static equilibrium?
7.) Explain why the subject felt dizzy in terms of this structure.
H. STRUCTURES FOR EQUILIBRIUM
8.) Define crista ampularis, cupula, endolymph, and hair cells.
9.) Are the above structures for static or dynamic equilibrium?
10.) Where in the inner ear are these structures located?
11.) Define the hair cells and otoliths.
12.) Are the above structures for static or dynamic equilibrium?