Benefits of directional microphone technologies for speech intelligibility and listening effort with two OTE CI sound processors

Introduction 

A method to improve speech intelligibility (SI) in noise of CI users is the use of directional microphone technologies (DMTs) in CI sound processors (SPs). Recently, the DMT ForwardFocus (FF) was implemented in the off-the-ear (OTE) SP Kanso 2. FF is a spatial post-filter technology designed to reduce distracting noise coming from behind. Our study investigates SI in noise of CI recipients using the Kanso 2 with FF, the DMT Beam and the Standard microphone directionality (SMD), and using the predecessor SP Kanso with Beam. Additionally, LE for SI in noise is investigated.

Material and Methods 

To date, 16 adult bilateral CI users were included. In each CI user and for each OTE and DMT condition, both the speech reception threshold (SRT) and LE are measured for unilateral listening with the SP on the better CI ear for frontal presentation of OLSA sentences in multi-talker babble simultaneously presented from three speakers (90°, 180°, -90°). For the assessment of LE, the Adaptive Categorical Listening Effort Scaling is used.

Results 

Using the Kanso 2, the CI users showed a lower SRT for OLSA sentences with FF compared to Beam (p<0,001), a lower SRT (p<0,001) and less LE (p<0,01) with FF compared to SMD as well as a lower SRT (p<0,001) and less LE (p<0,01) with Beam compared to SMD. Comparing both OTE SPs, SRT with Kanso 2 was lower than with Kanso (p<0,001).

Conclusion 

Compared to the SMD, the application of the DMTs FF and Beam with the Kanso 2 allows CI recipients to achieve better SI and lower LE, with FF associated with larger benefit in the spatial setup. Further, when using the current OTE Kanso 2 with the new DMT FF, CI recipients achieve better SI in noise than with the predecessor SP.

Conflict of Interest Der Erstautor weist auf folgenden Interessenkonflikt hin Grants und nicht-finanzielle Unterstützung von der Advanced Bionics AG (Stäfa, CH), der Cochlear Deutschland GmbH & Co. KG (Hannover, D) und der MED-EL Deutschland GmbH außerhalb der eingereichten Arbeit.

Publication History

Article published online:
24 May 2022