2A_MCL&UCL

Question 1

Suprathreshold abilities will vary in terms of what?

Answer 1

Sound clarity

Speech recognition in quiet and noise

Question 2

Suprathreshold abilities will vary depending on acoustic signal encoding associated with what?

Answer 2

Frequency (range, resolution, discrimination)
Temporal processing (across different time scales)
Loudness perception (comfort and discomfort)

Question 3

What populations might we test for MCL and LDL?

Answer 3

• normal hearing with loudness intolerance complaints
• hearing impaired with:
  
  • conductive component
  • SNHL with complaints of loudness intolerance
• hearing aid evaluations

Question 4

How does OHC loss affect basilar membrane displacement?

Answer 4

Displacement becomes more linear

• loss of frequency selectivity, especially for low level stimuli
• greater spread of excitation for louder sounds, especially with lower frequencies

Question 5

________ and _____ are associated with abnormal loudness perception and can occur with SNHL

Answer 5

Recruitment and Hyperacusis

Question 6

What is LDL?

Answer 6

Loudness Discomfort Level

• reflection of tolerance to loud sound
• can be measured with any signal (typically PTs)

Question 7

What do we know about hyperacusis?

Answer 7

Hyperacusis is hypersensitivity to sound (any level)

• normal or near-normal hearing thresholds
• may co-occur with tinnitus
• cause unknown

Question 8

Why do we measure LDLs?

Answer 8

• if intolerance to loud sounds is a reported concern

- may cause HA rejection if power output set beyond LDLs

Question 9

Describe the scale used to measure LDLs

Answer 9

It is a validated procedure that uses a simple 2 dB step ascending method that includes a list of descriptors, such as “very soft”, “loud but ok”, and “painfully loud”

• stimuli: warble tones (0.5 - 4 kHz)
• LDL = lowest intensity (-1) that evokes a judgement of “uncomfortably loud” in 2/3 trials

Question 10

Can LDL be predicted based on detection thresholds from audiogram?

Answer 10

No

Question 11

What is MCL?

Answer 11

The most comfortable level - a level or range of levels designated by an individual as the most comfortable for listening
- no standardized, universally accepted clinical method (e.g. ascending, descending, pre-recorded, live voice, PT)

Question 12

Describe the ascending MCL procedure (Martin & Clark)

Answer 12

• instructions: to determine the level most comfortable for listening
• begin slightly above SRT/SDT
• increase in 5 dB steps
• determine “comfortable” range
• repeat

Question 13

Do MCL measurements have long-term reliability?

Answer 13

No: 8 - 12 dB on individual test-retest

Question 14

Why do we measure MCL?

Answer 14

• indication of preferred listening level
• insight into potential problem fittings in HAE
• estimate word recognition testing (max recognition at PBmax) BUT DO NOT ASSUME MCL = PBmax FOR WRS TESTING

Question 15

Why would individuals with SNHL exhibit variable MCL results?

Answer 15

• slope of hearing loss
• variable degrees of recruitment
• difference in signals used for assessment
• differences in underlying pathophysiology

Question 16

What are some recommendations by Punch et al to obtain reliable MCL measurements?

Answer 16

• MCL before UCL

- Ascending MCL before descending MCL if both are used