Contra reflexes

Jae Utke jae1969 at hotmail.com
Mon Dec 7 10:05:04 EST 1998



>To: audiolog at net.bio.net
>From: Allan0001 at aol.com
>Subject: Contra reflexes

>
>
>What is the difference between Contra -reflex testing and Ispilateral 
>testing of the ears reflexes? 

I am an audiology student at the University of Sout Dakota.  Please 
forgive me if this sounds like it came from a lecture, because it 
probably did! :)

Ipsi:  same side.  The tone is presented and measured in the same ear.  
The pathway is as follows for Right Ipsi:  Outer ear, Middle ear, Inner 
ear, 8th Auditory Nerve, Cochlear Nucleus, Superior Olivary Complex, 
down the Right 7th Facial  Nerve.  

Left Contra:  Tone presented in right ear, measured in left.  Pathway is 
as follows:  Outer ear, Middle ear, Inner ear, Right 8th Auditory Nerve, 
Cochlear Nucleus, Superior Olivary Complex, down the Left 7th Facial  
Nerve.

Left Ipsi:  The tone is presented and measured in the Left ear.  The 
pathway is as follows for Left Ipsi:  Outer ear, Middle ear, Inner ear, 
Left 8th Auditory Nerve, Cochlear Nucleus, Superior Olivary Complex, 
down the Leftt 7th Facial  Nerve.

Right Contra:  Tone presented in left ear, measured in right.  Pathway 
is as follows:  Outer ear, Middle ear, Inner ear, Left 8th Auditory 
Nerve, Cochlear Nucleus, Superior Olivary Complex, down the Right 7th 
Facial  Nerve.

The possible results of a relex test:  

High Freq HL:  Lower freq's are present, Higher freq's absent

Lower Brainstem pathology:  Ipsilateral response, but no contralateral 
response.

Unilateral facial nerve pathology:  (My professor gave the example of a 
Right Facial nerve tumor:)  Left Ipsi and Right Contra responses, no 
Right Ipsi or Left contra response.

Unilateral pathology somewhere in the Ascending Pathway:  (Again, my 
professor gave the example of a lesion on the right side:)  Left Ipsi 
and Left Contra respond, Right Ipsi and Right Contra do not.

No Reflexes:  Normal reflexes, 
              signal may not be loud enough, 
              the degree of hearing loss is very high and the limits
                   of the machine have been reached, 
              there is a conductive HL, 
              or the patient could have MS.  
              (These examples are not totally inclusive; 
                   there could be other reasons out thre.)

The hearing thresholds as compared to reflex threshold:

85 dB SL:  Normal
55 dB SL and below:  Recruitment, possible Sensori-Neural HL
100 dB SL and above:  Possible retrocochlear pathologies

> Would both be done in a hearing evaluation or should be completed 
> by a audiologist if not done? 

      Yes.  If both ipsi and contras are not done, the results would be 
inconclusive.
    
>
>Thank you: 
>M. Allan

To verify that the information I have written is correct, I have 
forwarded this post to my audiology professor.  I will let you know if I 
have given any wrong or incomplete information.

Thank you,

Jae Utke, University of South Dakota, Department of Communication 
Disorders.


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