Hearing Tests: Rinne Test and Weber Test

00:01 Now it's time for you to think about some auditory tests.

00:06 There are two tests that can be performed to determine how intact the auditory pathway is.

00:13 One, is the Rinne test.

00:16 And the other test for you to remember, is the Weber test.

00:24 First, I want you to understand the Rinne test as an auditory test.

00:32 Here a tuning fork is going to be used to assess bone conduction and air conduction of sound.

00:41 First, the tuning fork would be placed at the mastoid process.

00:45 And that this will help you evaluate bone conduction as a practicing clinician.

00:52 From here the tuning fork would be placed near the external acoustic meatus, or the ear canal to evaluate the conduction of audition through the air.

01:07 If this is normal, air conduction time will be twice as long as bone conduction time.

01:15 When sound waves are produced by a tuning fork that is placed next to a normal ear, they travel through the air causing the tympanic membrane to vibrate and the ossicles to move.

01:25 The movement of the ossicles causes the cochlear fluid to move.

01:28 This action transforms the sound vibrations into electrical signals that are then relayed via the auditory nerve to the auditory brainstem, and the auditory cortex.

01:38 A normal ear will continue to hear the sound because air conduction is normally greater than bone conduction.

01:44 If the patient cannot hear the tuning fork after it is moved, this means that bone conduction is greater than air conduction due to something interfering the conductive component.

01:53 This is called conductive hearing loss.

01:56 Sensorineural hearing loss is due to any impairment of the auditory electrical signals from the cochlea to the auditory cortex.

02:04 In sensorineural hearing loss, both bone and air conduction are equally diminished.

02:08 So the perceived sound will disappear much earlier than usual.

02:12 Although air conduction may normally remain greater than bone conduction.

02:16 Mixed forms of hearing loss also exist.

02:19 However, if someone has conduction hearing loss, bone conduction will be greater or equal to air conduction.

02:35 If the loss is attributable to damage to the neural pathway, and this would be sensorineural loss.

02:46 And if this is the case, air conduction is going to be greater than bone conduction, but less than twice as long.

02:56 The normal would be twice as long if you have sensorineural loss.

03:01 Air conduction still going to be greater than bone conduction but will be less than twice as long.

03:09 The Weber test is another auditory test that can be performed.

03:14 Here the tuning fork once it's vibrating will be placed on the top of the middle skull.

03:24 You'll ask the patient, "Where is the sound coming from?" If everything's working normally, the patient will respond that they can hear in both ears.

03:38 If there is some pathology at play, such as conduction hearing loss, if it's unilateral, the vibration will be louder in the affected ear.

03:50 So if there is conduction hearing loss in the left ear, the vibration will be louder in the left ear because that's the one that's affected.

04:00 If there is unilateral sensorineural loss, the vibration is going to be louder in the normal ear because of the impairment in the affected ear.

04:15 This table on auditory tests allows you to make sense of the Weber test versus the Rinne test.

04:25 Normal versus abnormal.

04:28 And so if we take a look here, normal evaluation in the Rinne test which show that air conduction is greater than bone conduction bilaterally.

04:41 There should be about twice as long.

04:44 In the Weber test, the individual should be able to hear and localize the sound in both ears.

04:53 With conductive hearing loss, the Rinne test will demonstrate the bone conduction is going to be greater than air conduction in the affected ear.

05:07 Whereas, air conduction will be greater than bone conduction in the unaffected ear.

05:13 With the Weber test, conductive hearing loss will be characterized by the lateralization to the affected ear.

05:25 And then lastly, with sensorineural hearing loss with the Rinne test, air conduction is going to be greater than bone conduction in both ears.

05:36 And then the Weber test will demonstrate lateralization to the unaffected ear away from the affected ear.