The results revealed that speech understanding in noise improved when using asymmetric directional microphones compared to binaural omnidirectional microphone fittings and was not significantly hindered compared to binaural directional microphone fittings. The results also revealed that listeners accepted more background noise when fitted with asymmetric directional microphones as compared to binaural omnidirectional microphones. Lastly, the results revealed that the acceptance of noise was further increased for the binaural directional microphones when compared to the asymmetric directional microphones, maximizing listeners' willingness to accept background noise in the presence of noise. Clinical implications will be discussed.

Background: The acceptable noise level (ANL) is a measure of willingness to listen to speech in thepresence of background noise and is thought to be related to success with amplification. To date, ANLshave only been assessed over short periods of time, including within a session and over a three-week andthree-month time period. ANL stability over longer periods of time has not been assessed.<br />Purpose: The purpose was to examine the stability of ANL over a one-year time period.<br />Research Design: A repeated-measures, longitudinal study was completed.<br />Study Sample: Thirty young adults with normal hearing served as participants. The participants weretested at two different sites.<br />Data Collection and Analysis: Two trials of most comfortable listening levels (MCLs), background noiselevels (BNLs), and ANLs were assessed for each participant during three experimental sessions: at0 months, six months, and one year.<br />Results: Two-way repeated-measures analysis of variances revealed no significant change in MCLs,BNLs, or ANLs within a session or over a one-year time period. These results indicate that ANLs remainstable for one year in listeners with normal hearing.<br />Conclusions: The finding that the ANL is stable over a longer period of time supports the theory that theANL is an inherent trait of the listener and mediated at in the central auditory nervous system.<br />

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