Abstract
Background The acceptable noise level (ANL) is a measure of willingness to listen to speech
in the presence of background noise and is thought to be related to success with amplification.
To date, ANLs have only been assessed over short periods of time, including within
a session and over a 3-week and 3-month time period. ANL stability over longer periods
of time has not been assessed.
Purpose The purpose was to examine the stability of ANL over a 1-year time period.
Research Design A repeated-measures, longitudinal study was completed.
Study Sample Thirty young adults with normal hearing served as participants. The participants
were tested at two different sites.
Data Collection and Analysis Two trials of most comfortable listening levels (MCLs), background noise levels (BNLs),
and ANLs were assessed for each participant during three experimental sessions: at
0 months, 6 months, and 1 year.
Results Two-way repeated-measures analysis of variances revealed no significant change in
MCLs, BNLs, or ANLs within a session or over a 1-year time period. These results indicate
that ANLs remain stable for 1 year in listeners with normal hearing.
Conclusions The finding that the ANL is stable over a longer period of time supports the theory
that the ANL is an inherent trait of the listener and mediated at in the central auditory
nervous system.
Keywords
acceptable noise level - background noise acceptance - stability