Clinical Tests for Hearing

8/13/2019 Clinical Tests for Hearing

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Clinical Tests

for Hearing

Dr. Vishal Sharma



Tuning Fork

(Gardiner Brown)

Parts:

1. Prongs or tines

2. Shoulder

3. Stem or handle

4. Base or footplate





Tuning Forks

Frequencies used in E.N.T.:

256, 512, 1024 Hz

128 Hz → produces more of vibration sense

more than 1024 → short sound decay time



Striking Surfaces

Hard: Olecranon, radial styloid process, patella

Soft: Thenar & hypothenar eminences,

thick rubber strip

Tuning fork is allowed to fall by its own weight

Impact area is b/w proximal two-thirds & distal

one-thirds of its prongs



Rinne Test



Rinne Test

Duration comparison technique: Vibrating tuning fork kept on pt's mastoid Pt

signals when sound ceases → Move vibrating

tuning fork over opening of ear canal (2 cm

away & axis parallel to it) → Patient indicates if

sound is still heard



Rinne Test

Loudness comparison technique (better):

Vibrating tuning fork kept on pt's mastoid Pt

signals if sound is heard → Move vibrating

tuning fork immediately over opening of ear

canal → If sound is heard → patient asked

which sound is louder



Results of Rinne Test

Better response:

sound heard longer or louder

A.C. > B.C. (positive test):

Normal hearing or Sensorineural deafness

B.C. > A.C. (negative test):

Conductive deafness



Rinne Negative

256 Hz = 15 - 30 dB HL

= mild conductive deafness

512 Hz = 31 - 45 dB HL

= moderate conductive deafness

1024 Hz = 46 - 60 dB HL

= severe conductive deafness





Results of Weber test

Sound heard equally (central):

Normal hearing or B/L equal deafness

Sound lateralizes to deafer ear:

Conductive deafness

Sound lateralizes to better hearing ear:

Sensorineural deafness



Why Weber lateralizes to deafer

ear in Conductive HL ?1. Lack of masking effect of surrounding noise

on tuning fork sound, as air conduction is

reduced in conductive deafness

2. Lack of dispersion of sound energy due to

ossicular break





Absolute Bone Conduction Test

Pt's B.C. compared vs. examiner's normal B.C.

Vibrating tuning fork kept on pt's mastoid with

pt’s E.A.C. occluded (to prevent A.C.) → pt

signals when sound ceases → vibrating tuning

fork kept on examiner's mastoid with

examiner's E.A.C. occluded



Results of Absolute Bone

Conduction Test

Pt stops hearing before examiner:

sensorineural deafness

Both hear for same duration:

normal hearing / conductive deafness



Schwabach Test



Schwabach Test

Same as A.B.C. but E.A.C. is not occluded

Pt stops hearing before examiner:

sensorineural deafness

Both hear for same duration:

normal hearingPt hears longer than examiner:

conductive deafness



False Negative Rinne

Etiology: U/L severe Sensorineural deafness

Detection: Rinne negative, Weber lateralized to

better hearing ear

Confirmation: A.B.C. reduced in deaf ear

Correction: Repeat Rinne test with masking of

better ear with Barany's noise box



False Negative Rinne

Mechanism:

In deaf ear, air conduction & bone conduction are

absent. Trans-cranial transmission of sound to

opposite cochlea is perceived as I/L bone

conduction. Reported as bone conduction > air

conduction in deaf ear (Rinne Negative)



Gelle Test

Vibrating tuning fork placed on pt's

mastoid & examiner increases pt's E.A.C.

pressure with Siegel's speculum

Softer sound:

normal hearing or sensorineural deafness

No change in sound:

conductive deafness



Bing Test

Vibrating tuning fork placed on pt's

mastoid & examiner blocks pt's E.A.C.

Louder sound:

normal hearing or sensorineural deafness

No change in sound:

conductive deafness



Thank You

Documents

Clinical Tests for Hearing