Hearing Loss Associated with Neurologic Disorders Flashcards
What is ANSD operationally defined as?
Intact otoacoustic emissions (although sometimes they may disappear later in the condition) because OAEs measure OHC function
Or present cochlear microphonic (CM) with absent emissions
Grossly abnormal/absent ARTs, electrocochleography (ECochG), and ABR responses
Are OHCs intact in ANSD?
Yes
Is neural synchrony affected in ANSD?
Yes
Therefore, you will see intact emissions (OHCs are fine) and ABR and reflexes abnormal
Will anything that has to do with the 8th nerve be abnormal for ANSD?
Yes
ABR generated by neural structures
Neural integrity of VIII and lower brainstem pathways affected
ARTs also abnormal/absent because of VIII nerve involvement
Is there typically severe impairment of speech perception especially in noise because of disruption of synchronous 8th nerve firing in ANSD?
Yes
What percent of the deaf population has ANSD?
10% to 15%
How many babies in the NICU have ANSD?
Around 40%
Do the majority of NICU babies with ANSD have a bilateral loss?
Yes
Some unilateral
Are OAEs for ANSD babies normal?
Yes
Because they are coming from the OHCs
Can ANSD be genetic or environmental?
Yes
What are characteristics of genetic-based ANSD nonsyndromic?
Observed in families or
No other family member may be affected
Autosomal recessive mode of inheritance
Synapsis of IHC and 8th nerve fibers affected
What are some characteristics of genetic based ANSD syndromic?
Often associated with peripheral neuropathies (nerve function abnormal)
Charcot-Marie-Tooth syndrome and Friedreich’s ataxia
What are some characteristics of genetic based mitochondrial ANSD?
Mitochondrial inheritance indicates that affected females will have affected off-spring but affected males will not
What are some characteristics of environmental based ANSD?
Infectious disorder due to viral involvement
E.g., mumps and measles (can be unilateral)
Immune disorders can be accompanied by deafness typical to ANSD
For example, Guillian-Barre syndrome
Affects proximal nerve roots and proximal portions of VIII N
Deafness and paralysis with a lengthy period of recovery
If arterial blood supply affected, OHCs will be affected
Are thresholds variable for ANSD?
Yes
They don’t give you a lot of information
Can people with ANSD benefit from hearing aids?
They can provide limited benefits, but current recommendations include trial amplification if there is residual hearing
Is it usually recommended for people with ANSD to trial an FM device?
Yes
To reduce effects of noise distance, and reverberation especially in the classroom
Could manual communication also be helpful for someone with ANSD?
Yes
Cued speech or ASL
What is the current most successful treatment for ANSD?
CIs
Is charcot marie tooth common?
Yes
It is one of the most common inherited neurological disorders
What is the most common form of charcot marie tooth?
Type 1A
Deletion or point mutation
What is the transmission of charcot marie tooth?
Variable
Inherited as AD, AR, or X-linked recessive
What is charcot marie tooth?
A progressive neurodegenerative disease characterized by polyneuropathy