Mornin' All,
The question of deafness in ferrets crops up periodically.  I've been doing
a little research into a test commonly referred to as the BAER test.  This
is a test that is done routinely by reputable Dalmation breeders to
determine the extent of hearing loss or deafness in their breeding stock.
Based on what I've found so far, this is a test that might possibly be
valuable to ferret owners/breeders.
 
This is what I found at http://www.dalmatians.com/dca/strain-baer.htm:
 
"The hearing test known as the brainstem auditory evoked response (BAER) or
brainstem auditory evoked potential (BAEP) detects electrical activity in
the cochlea and auditory pathways in the brain in much the same way that an
antenna detects radio or TV signals or an EKG detects electrical activity of
the heart.  The response waveform consists of a series of peaks numbered
with Roman numerals: peak I is produced by the cochlea and later peaks are
produced within the brain.  The response from an ear that is deaf is an
essentially flat line."
 
"Because the response amplitude is so small it is necessary to average the
responses to multiple stimuli (clicks) to unmask them from the other
unrelated electrical activity that is also present on the scalp (EEG, muscle
activity, etc).  The response is collected with a special computer through
extremely small electrodes placed under the skin of the scalp: one in front
of each ear, one at the top of the head, and one between and behind the
eyes.  It is rare for a dog to show any evidence of pain from the placement
of the electrodes - if anything the dog objects to the gentle restraint and
the irritation of wires hanging in front of its face.  The stimulus click
produced by the computer is directed into the ear with a foam insert
earphone.  Each ear is tested individually, and the test usually is complete
in 10-15 minutes.  Sedation or anesthesia are usually not necessary unless
the dog becomes extremely agitated, which can usually be avoided with
patient and gentle handling.  A printout of the test results, showing the
actual recorded waveform, is provided at the end of the procedure.  Test
results are confidential, but anonymous details will be used in Dr. Strain's
ongoing deafness research for later publication and education of veterinary
practitioners."
 
Dr. George M. Strain
Louisiana State University
School of Veterinary Medicine
Baton Rouge, Louisiana 70803
Phone: 504-346-3268
Fax: 504-346-5736
E-mail: [log in to unmask]
 
I have e-mailed Dr. Strain for more info & will forward anything I get to
the list.
 
Jan M. Lovell - Secretary
Georgia Domestic Ferret Association, Inc. - Founded in 1989
Dedicated to a Better Life for Domestic Ferrets Through Knowledge and
Understanding
770-442-5917
 
[Moderator's note: Please be sure to get Dr. Strain's permission to forward
his mail to the list.  BIG]
[Posted in FML issue 2132]