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SOUND. INTENSITY is the measure of power in terms of dynes/cm2 or on logarithmic scale in terms of bels and decibels. The perception of intensity is loudness.. SOUND. FREQUENCY is the number of waves passing at a particular point in one second. This reflects the wavy pattern. The perception of frequ
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2. SOUND Sound is energy comprising of compressional waves. Each wave of compression is followed by a rarefaction.
3. SOUND INTENSITY is the measure of power in terms of dynes/cm2 or on logarithmic scale in terms of bels and decibels. The perception of intensity is loudness.
4. SOUND FREQUENCY is the number of waves passing at a particular point in one second. This reflects the wavy pattern. The perception of frequency is the pitch. The higher is the frequency, the higher is the pitch and more shrill is the sound. The lower is the pitch, the more bass is the sound.
5. PATHWAY OF SOUND Air
Pinna
EAM
Tymp. Membrane
Ossicles
Footplate of stapes
Scala vestibuli and tympani
Hair cells.
Cochlear nerve.
Cochlear N. nucleus
Superior olivary complex.
Lateral lemniscus
Inferior colliculus
Auditory area of cerebral cortex.
10. TRANSMISSION OF SOUND Pinna, external auditory meatus
condution only.
Middle ear conduction and
impedance matching.
Internal ear Dampening and
Conversion into electrical signals.
Cochlear nerve and beyond
Transmission as electrical signals.
12. HEARING TESTING AIR CONDUCTION
BONE CONDUCTION
13. HEARING IMPAIRMENT CONDUCTIVE DEAFNESS
SENSORINEURAL DEAFNESS
14. FACTS IN T.F. TESTS Air conduction is normally better than the bone conduction
In conductive deafness bone conduction not only relatively improves than the air conduction but absolutely improves as compared to the bone conduction of a normal ear.
In S.N.Deafness both the air and bone conduction decrease but air conduction is still better than the bone conduction
15. RINNIE TEST In rinnie test we compare the air conduction with the bone conduction
16. RINNIE TEST LOUDNESS COMPARISON METHOD
Patient is asked to compare the loudness of Air conduction with bone conduction
LOUDNESS DECAY METHOD
Patient is asked to assess the sound after complete decay
20. RINNIE TEST FINDINGS RESULT INFERENCE
AC>BC R+VE 1)Ear is normal
2)Ear is having S.N. Deafness
BC>AC R-VE Ear is having Conductive deafness
21. WEBER TEST In Weber test we compare the bone conduction of the two ears simultaneously.
22. WEBER TEST The tuning fork is struck and placed in the midline of skull e.g. vertex, forehead, teeth, chin. The patient is asked to indicate whether he hears the sound in the centre, in right ear or left ear
26. WEBER TEST FINDINGS RESULT INFERENCE
Patient hears W-central Both the ears
Better in centre are normal
Both the ears are diseased to
the same extent
Patient hears better W-RE 1-Right ear is having
In Right Ear conductive deafness
2- Left ear is having
S.N. Deafness or both
Patient hears better W-LE 1-Left ear is having
In Left Ear conductive deafness
2- Right ear is having
S.N. Deafness or both
27. ABC TEST In ABC test we compare the absolute bone conduction of the patient's ear with that of a normal ear.
28. ABC TEST The tuning fork is struck and placed on the mastoid process of the patient's ear and the ear is blocked. Patient is asked to indicate when the sound is completely abolished. The tuning fork is then shifted to the examiner's mastoid and the ear is blocked.
30. ABC TEST FINDINGS RESULT INFERENCE
Examiner hears ABC-Shortened Patient is
the sound on patient having S.N.D
Examiner does ABC-Equal Patient is not
Not hear the Having S.N.D
sound