ASSR

Question 1

Generator sites

Answer 1

1. Starts at the cochlear level (IHC) - crucial for processing the sounds on the basilar membrane
2. Neurons of the 8th nerve, cochlear nucleus, inferior colliculus and primary cortex

Question 2

What are the different stimulus used in ASSR?

Answer 2

1. Amplitude Modulated Pulses
2. Frequency Modulated Pulses
3. Mixed Modulated Pulses

Question 3

What are amplitude modulated (AM) pulses

Answer 3

AM pulses are centred around a characteristic frequency and alternate amplitudes (max-min and max-half max)

Question 4

What are maximum and minimum pulses

Answer 4

The maximum and minimum amplitudes of the AM pulses

Question 5

What is the generation site

Answer 5

IHC create nanovolts (1000 x smaller than the potentials created by abr)

Question 6

How good is it at estimating hearing thresholds

Answer 6

IDK

Question 7

What are the advantages of ASSR

Answer 7

1. Good at providing a rough estimate of hearing thresholds
2. faster than abr
3. testing both ears at the same time
4. time locked to the stimulus

Question 8

What are the disadvantages of ASSR

Answer 8

1. It is not able to detect retrocochlear pathologies - results could be absent or incorrect
2. Can test both ears at the same time
3. It is faster than ABR tone bursts

Question 9

What is frequency modulated (FM) pulses

Answer 9

1. Is the number of pulses per second (82 Hz means 82 pulses per sec)
2. There is not change to the amplitude but change to the frequency

Question 10

What is mixed modulation pulses

Answer 10

A combination of frequency and amplitude modulation

Question 11

What are the affects of of frequency (4)

Answer 11

1. <20 Hz - ALR generator sites
2. 20-60 Hz - MLR sites
3. > 60 Hz - ABR sites
4. > 70 Hz - ASSR not affected by sleep