Loudness discomfort level and reliability as a function of instructional set

Area of Science:

• Audiology
• Hearing Science
• Speech and Hearing Sciences

Background:

• Loudness discomfort levels (LDLs) are crucial for fitting hearing aids.
• Standardizing LDL measurement protocols is essential for accurate hearing aid settings.
• Previous research has not fully explored the impact of instructional sets on LDL measurement reliability in sound field conditions.

Purpose of the Study:

• To compare loudness discomfort levels (LDLs) obtained using two distinct instructional sets.
• To assess the reliability of LDL measurements under different listening criteria.
• To determine the optimal instructional set for reliable LDL measurement in a sound field environment.

Main Methods:

• Twenty subjects with normal hearing sensitivity participated.
• Loudness discomfort levels (LDLs) were measured using a 12-speaker babble in a sound field.
• An up-down adaptive procedure measured LDLs under two conditions: 'not to listen for any period' and 'not to listen for 15 minutes or longer'.
• Measurements were repeated four times over 1-3 weeks for reliability assessment.

Main Results:

• Average LDLs were 9 dB higher when participants were instructed to stop listening immediately compared to a 15-minute threshold.
• High reliability was observed for both instructional sets (correlations 0.90-0.97 and 0.62-0.89).
• The 'not to listen for any period' criterion yielded slightly more reliable LDL measures.

Conclusions:

• The instructional set significantly influences measured loudness discomfort levels (LDLs).
• Using the 'not to listen for any period' criterion may provide more reliable LDL measurements for hearing aid fitting.
• Reliable LDLs can be measured in sound field conditions with appropriate methodologies.