Evaluation of Automatic Directional Processing with Cochlear Implant Recipients

Manual switching between programs intended for specific real-life listening environments by adult cochlear implant users: do they use the intended program?

OBJECTIVE

The aim of the current study was to investigate the use of manually and automatically switching programs in everyday day life by adult cochlear implant (CI) users.

DESIGN

Participants were fitted with an automatically switching sound processor setting and 2 manual programs for 3-week study periods. They received an extensive counselling session. Datalog information was used to analyse the listening environments identified by the sound processor, the program used and the number of program switches.

STUDY SAMPLES

Fifteen adult Cochlear CI users. Average age 69 years (range: 57-85 years).

RESULTS

Speech recognition in noise was significantly better with the "noise" program than with the "quiet" program. On average, participants correctly classified 4 out of 5 listening environments in a laboratory setting. Participants switched, on average, less than once a day between the 2 manual programs and the sound processor was in the intended program 60% of the time.

CONCLUSION

Adult CI users switch rarely between two manual programs and leave the sound processor often in a program not intended for the specific listening environment. A program that switches automatically between settings, therefore, seems to be a more appropriate option to optimise speech recognition performance in daily listening environments.

Speech Understanding and Subjective Listening Effort in Noise With Different OTEs and Sound Processing Technologies

OBJECTIVE

To determine speech reception thresholds (SRTs) in noise and subjective listening effort (LE) in cochlear implant (CI) recipients for application of three sound processing (SP) technologies with two off-the-ear (OTE) CI sound processors, a fixed moderately directional microphone (Standard), an adaptive directional microphone (Beam), and the spatial noise-reduction setting ForwardFocus, with the Kanso 2 (OTE2), and Beam with the Kanso (OTE1).

STUDY DESIGN

Prospective repeated measures, within-subject design.

SETTING

Single tertiary-referral center.

PATIENTS

Twenty CI recipients with bilateral severe-to-profound sensorineural hearing loss.

MAIN OUTCOME MEASURES

SRTs were assessed in two spatial configurations with frontal speech and noise from 90-180-270 degrees (S0N90-180-270) or from the CI side (S0NCI). SRTs were obtained for sentences of the Oldenburg sentence test presented in International Collegium of Rehabilitative Audiology (ICRA) noise ICRA5-250. LE for speech understanding in noise was evaluated in S0N90-180-270 and assessed in effort scale categorical units (ESCUs) by using Adaptive Categorical Listening Effort Scaling (ACALES). LEs at 5-dB signal-to-noise ratio (SNR) were calculated from fitted psychometric curves.

RESULTS

With OTE2 in S0N90-180-270, SRT with ForwardFocus (-4.28 dB SNR) was better than with Beam (-3.13 dB SNR) and Standard (0.43 dB SNR). ForwardFocus showed lower LE5dB (2.61 ESCU) compared with Beam (4.60 ESCU) and Standard (5.32 ESCU). In a comparison of both OTEs in S0N90-180-270 regarding best-performing SP technology, ForwardFocus with OTE2 yielded a better SRT and better LE5dB than Beam with OTE1 (SRT: -1.70 dB SNR; LE5dB: 4.00 ESCU). With OTE2 in S0NCI, SRT was improved with ForwardFocus (-2.78 dB SNR) compared with Beam (-1.23 dB SNR) and Standard (1.83 dB SNR).

CONCLUSION

With respect to SP technology and OTE, CI recipients experience best SRT and lowest LE in S0N90-180-270 when using ForwardFocus with OTE2. ACALES is feasible for assessing subjective LE in CI recipients.