Anatomia y Distintas Pruebas de Evaluacion

8/11/2019 Anatomia y Distintas Pruebas de Evaluacion

http://slidepdf.com/reader/full/anatomia-y-distintas-pruebas-de-evaluacion 1/28

SPHSC 461- Hearing ScienceLab 1 – The Conductive Apparatus

Spring 2011

Bonnie Lau

[email protected]



Introduction

1.The Conductive Apparatus

2.Otoacoustic Emissions3.Masking and the Critical Band

4.Audibility Curve and Loudness Scaling

5.Loudness and Temporal Integration6.Speech Perception



Introduction

Labs are graded high-pass/pass/fail:

High-pass - Attendance at lab, complete andaccurate lab assignment

Pass - Attendance at lab, complete and

adequate lab assignment (points deducted ifyou do not label graphs properly)

Fail - If not present at lab or if the lab

assignment was poorly done



Introduction

Labs can be handed in:

1. Day of lab

2. Beginning of lab the next week3. My mail box in Eagleson

• Labs cannot be made up

• Late labs will not be accepted

• It you are absent from a lab, you will receive a “fail”grade

• You must attend the lab that you are registered for



Lab 1 – The Conductive Apparatus

Part 1: Outer Ear

Work Station 1: OtoscopesWork Station 2: Transfer Function

Part 2: Middle Ear

Work Station 3: Tympanometry

Part 3: Inner Ear

Textbook



Outer and Middle Ear



External Ear



Pinna



Otoscopy

http://www.whnt.nhs.uk/UserFiles/Image/WUTH%20Website/Audiology/otoscopyweb2.jpg



How does it work?



Transfer Function

Frequency

A m p l i t u d e

Frequency

A m p l i t u d e

This goes in This comes out



Transfer Function

The transfer functionof the external ear

shows a boost in thefrequencies between2 and 5 KHz



Real Ear Measure

http://www.hearinglossweb.com/Medical/aud/img/real1.JPG



Transfer Function Information

Hz dB

Inside

dB

Outside

dB

Diff

250 6.0 5.5500 9.0 7.0

1000 5.0 4.4

2000 4.0 1.3

4000 5.5 2.5

6000 8.9 1.3

8000 5.5 1.9

Group Person Example

Hz dB

Inside

dB

Outside

dB

Diff

250 3.9 3.0500 8.0 8.0

1000 6.1 3.5

2000 5.0 1.9

4000 7.5 2.2

6000 2.5 1.9

8000 5.5 1.5

Graph the dB Difference (LABEL AXES)



How to Get the Gain in dB Data

Gain at 250 Hz is 0 dB



Middle Ear Function – Impedance

Mismatch



Tympanometry

SoundSource

Pressure

Microphone



Tympanometry – Basic Concepts

• The TM vibrates most efficiently when the pressure onboth sides is equal

• As the TM is displaced from its resting position by positiveor negative pressure in the external ear canal, thevibratory efficiency of the membrane is decreased

1. Load TM with air pressure equal to +200 daPa, measure

compliance

2. Measure compliance as pressure in the canal is decreased to 0

daPa (atmospheric pressure)

3. Negative pressure is created by the pump and compliance

measurements are made



Tympanometry

Purpose: determine the point and

magnitude of greatest compliance

Generally conducted with a lowfrequency probe tone (e.g. 226Hz)



Tympanometry

Middle-Ear Pressure-thepoint when pressureon both sides is equal

External-Ear CanalVolume - volume fromthe end of the probetip to the tympanicmembrane

Acoustic

Compliance/Mobilityof the TM-variouspoints at which thetympanic membranepasses or reflectssound



Tympanometer Output

1)Volume (ml)

2)Peak Pressure (daPa)

3)Compliance mmho (ml)



Acoustic Compliance

Reflects more sound Reflects more soundPasses more sound

Impedance Impedance

Admittance or compliance



Normative Values

A – normal ME function, greatest

compliance at 0 daPa

As – “stiffness/shallow”, peak at

0 daPa, but shallower – partiallyimmobilized stapes

Ad – “discontinuous/deep”,

abnormally high amplitude,

flaccidity of the TM or separation

of ME bones

B – flat, point of greatest

compliance cannot be found



Normative Values



Inner Ear



Inner Ear



Cochlea Stretched Out



Organ of Corti

Documents

Anatomia y Distintas Pruebas de Evaluacion