Impact of signal preprocessing algorithms on speech perception and listening effort in complex listening environments

Introduction Speech perception in noise in cochlear implant (CI) users is often significantly reduced compared to subjects with normal hearing (NH). Furthermore, increased listening effort is reported. In the present study, the impact of different signal preprocessing algorithms in CI systems on speech perception and listening effort in noise was investigated.

Methods 15 bilateral CI users fitted with the CP1000 speech processor (Cochlear) participated in the study. While performing the OLSA test in noise, subjective listening effort was recorded in parallel with a categorical scaling procedure (ACALES). Testing was performed with standard microphone sensitivity as well as with an adaptive directional microphone (BEAM) and a spatial noise reduction algorithm (Forward Focus, FF).

Results There was a significant improvement in speech reception threshold (SRT) when using BEAM (3 dB) and FF (5.9 dB) compared to the standard microphone. The lowest (i.e. best) SRT was achieved with FF. Listening effort with FF was reduced by 2 to 2.6 category units compared with the standard microphone and was also up to 1.4 category units lower than with BEAM.

Conclusion Signal preprocessing strategies in CI systems can both improve speech perception in noise and reduce listening effort. However, the effect is highly dependent on the individual noise condition.

Cochlear Deutschland GmbH und Co. KG

Publication History

Article published online:
24 May 2022