Wk11-27-CI Challenges w/ Diff Pop'ns

Question 1

Where in the body does the auditory input from both ears first come together?

Answer 1

Isilateral and contralateral superior olivary complex

- most of the signal crosses to the contralateral side

Question 2

Auditory activity in the cortex is dominated by the (ipsi/contra)-lateral pathway

Answer 2

Contra

Question 3

What type of recordings can we use to measure auditory activity at each level of the pathway?

Answer 3

EEG recordings (electroencephalography)

Question 4

Hemispheric specialization for _____ and ______ information develops with maturation

Answer 4

Temporal and spectral

Question 5

True/False: One study found more temporal information is seen on the left side and more spectral information on the right side

Answer 5

True

Question 6

Match the following numbers and levels:

a) ABR
b) Late latency response
c) Middle latency response

I. Brainstem
II. Thalamus
II. Cortex

Answer 6

ABR - Brainstem
Middle latency response - Thalamus
Late Latency response - Cortex

Question 7

What can we deduce from deviations from normal of the peak amplitude or latency?

Answer 7

Based on when the deviations occur (e.g. ABR vs Middle latency vs late latency responses), we can infer where in the auditory pathway the problem is
- can also help us determine if children have a delay in auditory development

Question 8

ABR can be used to help identify ______ in the cochlea

Answer 8

Lesions

- also, acoustic tumours in the AN or brainstem

Question 9

At what age do we begin to see the adult-like P1N1P2 complex?

Answer 9

Over 12 years of age

Question 10

What is the primary difference between the auditory cortical response of children older and younger than 7 years of age?

Answer 10

Younger than 7 years old = P1/P2 complex (No N1) with an amplitude ~6microVolts
7-12 years old = P1/P2 of ~ 3 microVolts, with shallow N1

Question 11

What happens to the auditory activity and development of the auditory system in individuals who are deaf?

Answer 11

Early auditory deprivation causes reorganization in the auditory system

• visual input becomes processed in the auditory cortex
• Lee et al found that by 20.3 years of age, the auditory system is completely taken over

Question 12

True/False: Children who are implanted with CI’s during the sensitive period perform better than their peers that are implanted later, after longer periods of deafness

Answer 12

True

Question 13

How do we measure early auditory development? What do we find post-implantation?

Answer 13

eABRs

Auditory brainstem function becomes faster and more efficient over the first year after implantation

Question 14

Examining unilateral cochlear implant use, researchers have found that auditory brainstem development improves mostly during the first ____ (1, 5, 10) year(s) of use

Answer 14

1 year; largely no change in wave eV absolute latency from 1 year to 10 years

Question 15

How did researchers show that unilateral CI use promotes maturation of auditory midbrain function?

Answer 15

By comparing middle latency responses of CI users with responses of normal hearing peers
- shape is very similar, and no significant differences were found between latencies and amplitudes of the 2 groups

Question 16

Based on middle latency response, does early CI implantation allow for normal-like auditory development?

Answer 16

Yes; normal-like cortical responses are seen over the long-term, but differences from normal remain in LATER LATENCIES
(CI users’ P2 shows a higher amplitude than normal hearing listeners)

Question 17

How was increased perceptual processing was found to influence P2?

Answer 17

Increased amplitude

- found during an experiment which involved auditory training; the P2 wave was higher post training

Question 18

One study found that CI users rely more on _____ cues compared to normal hearing listeners, to identify emotion

Answer 18

Visual; CI users also take more time to decide which reaction it was, compared to normal hearing listeners.

Question 19

What is one concern of sequential CI implantation compared to simultaneous?

Answer 19

It may create a mismatch between the development of the left and right auditory pathways

Question 20

Mismatched ABRs persist in children with more than __ years of unilateral hearing, despite time after bilateral implantation

Answer 20

2 years
- children who receive both implants during the time of brainstem development (simultaneously or within 6-12 months) do not show this mismatch after 2 years.

Question 21

Does unilateral implant use lead to mismatched auditory CORTICAL responses at bilateral implantation also?

Answer 21

Yes

Question 22

_______ imaging is used to localize areas of the brain that respond to sound (measures activity and localizes the activity under each peak in different hemispheres)

Answer 22

Beamformer

- the measurements are referred to as dipole moments

Question 23

Gordon et al found that cortical activity is abnormally (small/large) in the contralateral cortex after more than 1.5 years of unilateral implant use

Answer 23

Large

• this reflects an abnormal strengthening of pathways from that ear
• we protect the brain from these changes by providing children with bilateral implants simultaneously