Download Characteristics of Auditory Neuropathy and Central Auditory

Characteristics of Auditory Neuropathy and Central Auditory Processing Disorder
Prepared by Charles Berlin, Ph.D.
July 2011
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Auditory
Neuropathy
(ANSD)
Central Auditory
Behavioral Result
Processing Disorder
Birth History
About 30% are very
premature. About 35%
have histories of jaundice
and transfusion.
40% of NICU babies have
this but they make up
about 15% of the total of
ANSD patients. About
10% do NOT need
intervention because they
have very mild cases
Twelve genes now known,
the most prevalent of
which are Otoferlin,
Pejvakin, and Connexins
(26 and 30) and MohrTranebjaerg, an x-linked
late-onset disorder that
includes blindness
Anywhere from mildly
impaired to totally deaf.
Generally unremarkable, but
sometimes prematurity
ANSD children need to have age-corrected
studies of speech and language. CAPD kids are
hard if not impossible to diagnose correctly
until they can use language and take complex
listening tasks. Children with no usable hearing
CANNOT BE DIAGNOSED WITH BEHAVIORAL
TESTS SUCH AS S.C.A.N. ETC. Electrophysiology
is necessary along with MRIs and CAT scans.
No known genetic causes.
Genetic ANSD patients will not “get better” the
way NICU babies or other birth damaged infants
might. Again in cases like USHER 1, 2, etc., pure
tone audiometry which confirms deafness
makes it nearly impossible to make a behavioral
diagnosis properly.
Almost always normal
CAPD children rarely if ever behave as if they
are totally deaf unless they have demonstrable
Genetics
Audiogram
Tympanometry
Generally Normal
Generally normal
Middle Ear Muscle
Reflexes
Almost always absent or
elevated
Auditory
brainstem
responses
Speech in Noise
Never normal
Virtually always normal. IF A
CHILD IS DIAGNOSED AS
HAVING CAPD IN ISOLATION,
HE/SHE must have NORMAL
REFLEXES.
Virtually always normal
Very poor
Very poor
Management
Cochlear implants, FM
systems, hearing aids
(least effective in our
sample, Berlin et al. 2010)
Fast ForWord, Earobics, and
other training programs that
modify the speech signal.
Difficult to employ if the
peripheral audiogram is very
poor.
temporal lobe lesions.
Children with middle ear disease will have
abnormal tympanograms that require medical
or surgical attention.
The reflexes assess the lower brainstem’s
integrity along with inner hair cells. CAPD
patients should not have elevated middle ear
muscle reflex thresholds and should always be
between 75 and 95 dB.
The site of lesion in ANSD starts at the inner
hair cells (Amatuzzi et al. ) can extend to the
primary nerve fibers (Starr et al.)
This is often why people are (mis-)diagnosed as
having CAPD. At worst, CAPD is a diagnosis by
exclusion, or hunch; at best, one must always
rule out ANSD because the behavioral
symptoms are so similar when it comes to
haring in noise and educational impact.
The literature is quite muddy with respect to
CAPD and deaf-blindness.