Middle Latency Response

Question 1

What is the effect of level on the MLR?

Answer 1

Latency does not really shift in MLR

• Further you go along the auditory pathways, the less effects of level seen
• Level doesn’t change response at cortex

Question 2

What is the effect of filtering on the MLR?

Answer 2

Restrictive filter settings may result in false peaks

Question 3

How can you distinguish between postauricular (PAM) artifact and true responses?

Answer 3

PAM usually occurs around 20 ms

Question 4

What are the sleep effects on the MLR?

Answer 4

Get best response if subject is awake or in REM sleep

- Could get response in babies if they’re in REM sleep, but not a good idea to get recording if subject is sleeping

Question 5

How can you calculate ear effects?

Answer 5

Left ear C3 + Left ear C4/2

Right ear C3 + Right ear C4/2

Question 6

How can you calculate electrode effects?

Answer 6

C3 Left ear + C3 Right ear/2

C4 left ear + C4 Right ear/2

Question 7

What is the purpose of claculing ear effects?

Answer 7

Trying to determine that there’s not an asymmetry between the ears
- Get average amplitude when stimulating the R ear and compare it to the average amplitude when stimulating the L ear

50% reduction indicates something abnormal

Question 8

How can the MLR be compared to the ABR?

Answer 8

As a measure of low frequency hearing threshold, MLR is often superior to ABR

MLR is less dependent than ABR on synchrony

Question 9

How can the MLR be used to assess language-based learning impairment?

Answer 9

Pa latency is significantly delayed in children (8-12) with language disorder compared to children with normal learning