Hearing Loss Associated with Neurologic Disorders

Question 1

What is ANSD operationally defined as?

Answer 1

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

Question 2

Are OHCs intact in ANSD?

Answer 2

Yes

Question 3

Is neural synchrony affected in ANSD?

Answer 3

Yes
Therefore, you will see intact emissions (OHCs are fine) and ABR and reflexes abnormal

Question 4

Will anything that has to do with the 8th nerve be abnormal for ANSD?

Answer 4

Yes
ABR generated by neural structures
Neural integrity of VIII and lower brainstem pathways affected
ARTs also abnormal/absent because of VIII nerve involvement

Question 5

Is there typically severe impairment of speech perception especially in noise because of disruption of synchronous 8th nerve firing in ANSD?

Answer 5

Yes

Question 6

What percent of the deaf population has ANSD?

Answer 6

10% to 15%

Question 7

How many babies in the NICU have ANSD?

Answer 7

Around 40%

Question 8

Do the majority of NICU babies with ANSD have a bilateral loss?

Answer 8

Yes
Some unilateral

Question 9

Are OAEs for ANSD babies normal?

Answer 9

Yes
Because they are coming from the OHCs

Question 10

Can ANSD be genetic or environmental?

Answer 10

Yes

Question 11

What are characteristics of genetic-based ANSD nonsyndromic?

Answer 11

Observed in families or
No other family member may be affected
Autosomal recessive mode of inheritance
Synapsis of IHC and 8th nerve fibers affected

Question 12

What are some characteristics of genetic based ANSD syndromic?

Answer 12

Often associated with peripheral neuropathies (nerve function abnormal)
Charcot-Marie-Tooth syndrome and Friedreich’s ataxia

Question 13

What are some characteristics of genetic based mitochondrial ANSD?

Answer 13

Mitochondrial inheritance indicates that affected females will have affected off-spring but affected males will not

Question 14

What are some characteristics of environmental based ANSD?

Answer 14

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

Question 15

Are thresholds variable for ANSD?

Answer 15

Yes
They don’t give you a lot of information

Question 16

Can people with ANSD benefit from hearing aids?

Answer 16

They can provide limited benefits, but current recommendations include trial amplification if there is residual hearing

Question 17

Is it usually recommended for people with ANSD to trial an FM device?

Answer 17

Yes
To reduce effects of noise distance, and reverberation especially in the classroom

Question 18

Could manual communication also be helpful for someone with ANSD?

Answer 18

Yes
Cued speech or ASL

Question 19

What is the current most successful treatment for ANSD?

Answer 19

CIs

Question 20

Is charcot marie tooth common?

Answer 20

Yes
It is one of the most common inherited neurological disorders

Question 21

What is the most common form of charcot marie tooth?

Answer 21

Type 1A
Deletion or point mutation

Question 22

What is the transmission of charcot marie tooth?

Answer 22

Variable
Inherited as AD, AR, or X-linked recessive

Question 23

What is charcot marie tooth?

Answer 23

A progressive neurodegenerative disease characterized by polyneuropathy

Question 24

What are some characteristics of charcot marie tooth?

Answer 24

It affects both motor and sensory nerves
Absent limb reflexes
Chronic degeneration of peripheral nerves causing muscular atrophy
Muscle wasting seldom seen above elbows or mid-thighs

Question 25

What is the typical onset of charcot marie tooth?

Answer 25

12 to 20 years Full blown condition by 30 years

Question 26

Is charcot marie tooth life threatening?

Answer 26

No

Question 27

Does charcot marie tooth have 100% penetrance?

Answer 27

Yes

Question 28

What are the audiological findings of charcot marie tooth?

Answer 28

SNHL with onset either in childhood or adulthood Hearing loss is slowly progressive Hearing loss maybe caused by auditory neuropathy due to demyelination of CN VIII

Question 29

What is ataxia?

Answer 29

An inability to coordinate voluntary muscular movements

Question 30

Is friedreichs ataxia common?

Answer 30

Yes One of the most common forms of AR ataxia

Question 31

Is friedreichs ataxia AR?

Answer 31

Yes

Question 32

When does friedreichs ataxia manifest?

Answer 32

Before adolescence

Question 33

What is friedreichs ataxia characterized by?

Answer 33

Incoordination of limb movements Dysarthria Nystagmus Diminished or absent tendon reflexes and Babinski sign Impairment of position and vibratory senses Scoliosis, pes cavus (abnormally high foot arch), and hammertoe Cardiomyopathy Abnormalities in motor and sensory nerve conduction, including CN VIII and CN II, which cause hearing loss and visual impairment

Question 34

What triad of clinical manifestations is commonly regarded as sufficient for diagnosis of friedreichs ataxia?

Answer 34

Hypoactive knee and ankle reflex Progressive cerebellar dysfunction Preadolescent onset

Question 35

What kind of transmission does Hereditary Sensory and Autonomic Neuropathy type 1 have?

Answer 35

AD

Question 36

Is Hereditary Sensory and Autonomic Neuropathy type 1 rare?

Answer 36

Yes

Question 37

What is Hereditary Sensory and Autonomic Neuropathy type 1 characterized by?

Answer 37

Adult-onset (~ 37 yrs.) of progressive SNHL progressing to deafness Early-onset dementia Sensory neuropathy by 20 to 35 years resulting in lack of feelings in toes and ulceration, in some cases requiring amputation Generally, an early death by the 4th to 5th decade, is reported

Question 38

What transmission does neurofibromatosis (NF) have?

Answer 38

AD

Question 39

Does NF have high penetrance and variable expressivity?

Answer 39

Yes Because it's AD

Question 40

What is NF 1 known as?

Answer 40

The peripheral form

Question 41

What is NF 2 known as?

Answer 41

The central form

Question 42

Is NF1 or NF2 more common?

Answer 42

NF1

Question 43

What are characteristic features of NF1?

Answer 43

Cafe-au-lait spots Cutaneous & subcutaneous fibromatous tumors Lisch nodules in the eye About 5% have VIII nerve tumors

Question 44

How many tumors do people with NF1 typically have?

Answer 44

Increase in number throughout life Usually first appear around puberty

Question 45

What are lisch nodules around the eye in NF1?

Answer 45

Looks like spots in iris

Question 46

What is the transmission of NF2?

Answer 46

50% AD and 50% spontaneous mutation

Question 47

Does NF2 have complete penetrance?

Answer 47

Yes

Question 48

When is the disease onset of NF2?

Answer 48

Young adulthood

Question 49

What is NF2 characterized by?

Answer 49

Characterized by a progressive disabling/disfiguring course Bilateral vestibular schwannomas

Question 50

Does NF2 typically have audiological symptoms and not NF1?

Answer 50

Yes

Question 51

Do NF2 patients also have café au lait spots?

Answer 51

No Less than half have them

Question 52

What other symptoms does NF2 have besides bilateral vestibular schwannomas?

Answer 52

Progressive visual loss is common Intelligence is not impaired Emotional consequences and devastating communication disorder

Question 53

How is NF2 diagnosed?

Answer 53

CT scans and MRI with contrast

Question 54

What is the differential diagnosis for NF2?

Answer 54

NF1 and vestibular schwannoma

Question 56

How do you treat NF2?

Answer 56

Surgery to remove the tumors Destroy VIII nerve, which results in deafness in both ears Tumors can come back

Question 57

Are cochlear implants an option for NF2 patients?

Answer 57

No No nerve to stimulate

Question 58

What is the current device option for someone with NF2?

Answer 58

Auditory brainstem implant (ABI) An ABI bypasses the damaged auditory nerve and connects directly to the brainstem to detect sound Provides sound awareness and very limited speech understanding