The history of Cochlear™ Nucleus® sound processor upgrades: 30 years and counting

Speech understanding in noise for cochlear implant recipients using a spatial noise reduction setting in an off the ear sound processor with directional microphones

PURPOSE

Cochlear implant (CI) recipients struggle to hear in competing background noise. ForwardFocus is a spatial noise reduction setting from Cochlear Ltd. (Sydney) that can simultaneously attenuate noise from multiple sources behind the listener. This study assessed hearing performance with ForwardFocus in an off-the-ear (OTE) sound processor.

METHOD

Twenty-two experienced adult CI recipients participated. Speech reception data was collected in fixed noise acutely in the clinic. After three to five weeks take home experience, subjective impressions were recorded, and evaluations were conducted for speech reception in quiet and roving noise.

RESULTS

Group mean speech reception thresholds (SRT) were below 0 dB in two spatially-separated noise test conditions when using ForwardFocus in the OTE sound processor. SRT were -8.5 dB (SD 2.9) in 4-talker babble roving in a rear hemi-field (S0Nrearhemi) and -3.9 dB (SD 3.3) in 12-talker babble presented laterally and behind (S0N3). Results in S0N3 were significantly better with ForwardFocus On (p = 0.0018). Subjective ratings with the OTE were comparable to, or better than, with their walk-in BTE or OTE sound processor.

CONCLUSIONS

ForwardFocus provides significant benefits for speech recognition in competing background noise in an OTE sound processor. These results support clinicians in counselling CI recipients on potential sound processor options to consider.

Mechanical Energy Sensing and Harvesting in Micromachined Polymer-Based Piezoelectric Transducers for Fully Implanted Hearing Systems: A Review

The paper presents a comprehensive review of mechanical energy harvesters and microphone sensors for totally implanted hearing systems. The studies on hearing mechanisms, hearing losses and hearing solutions are first introduced to bring to light the necessity of creating and integrating the in vivo energy harvester and implantable microphone into a single chip. The in vivo energy harvester can continuously harness energy from the biomechanical motion of the internal organs. The implantable microphone executes mechanoelectrical transduction, and an array of such structures can filter sound frequency directly without an analogue-to-digital converter. The revision of the available transduction mechanisms, device configuration structures and piezoelectric material characteristics reveals the advantage of adopting the polymer-based piezoelectric transducers. A dual function of sensing the sound signal and simultaneously harvesting vibration energy to power up its system can be attained from a single transducer. Advanced process technology incorporates polymers into piezoelectric materials, initiating the invention of a self-powered and flexible transducer that is compatible with the human body, magnetic resonance imaging system (MRI) and the standard complementary metal-oxide-semiconductor (CMOS) processes. The polymer-based piezoelectric is a promising material that satisfies many of the requirements for obtaining high performance implantable microphones and in vivo piezoelectric energy harvesters.

Benefits of upgrading to the Nucleus® 6 sound processor for a wider clinical population

OBJECTIVES

To determine whether a large clinical group of cochlear implant (CI) recipients demonstrated a difference in sentence recognition in noise when using their pre-upgrade sound processor compared to when using the Nucleus 6 processor, and to examine the impact of the following factors: implant type, sound processor type, age, or onset of hearing loss.

METHODS

A file review of 154 CI recipients (aged 7-92 years old) who requested an upgrade to the Nucleus 6 sound processor at the Cochlear Care Centre Melbourne was conducted. 105 recipients had complete data collected according to the protocol. A repeated measures, single subject design was used. Performance of CI recipients was compared with their pre-upgrade sound processor versus the Nucleus 6 processor using the Australian Sentence Test in Noise.

RESULTS

Group performance of CI recipients improved by 4.7 dB with the Nucleus 6 compared with the pre-upgrade sound processor. The benefit was not affected by pre-upgrade sound processor type or implant type (including older implant types and sound processors), age or onset of hearing loss (pre-lingual versus post-lingual).

CONCLUSION

This study confirmed that a clinical group of CI recipients obtained a significant benefit when upgrading to the Nucleus 6 sound processor.

Impact of cognition and noise reduction on speech perception in adults with unilateral cochlear implants

OBJECTIVES

The purpose of this study was to investigate the impact of cognition and noise reduction (NR) technology in cochlear implants (CIs) on speech perception and listening effort.

METHODS

Thirteen adults fitted with unilateral CIs (Nucleus^® 6, CP900) participated in this study. Participants performed: (I) cognitive tests of working memory and processing speed, (II) speech perception in noise tests, and (III) an auditory-visual dual-task paradigm to quantify listening effort, as a part of the three-phase experimental study. Both the participant and the tester, performing the outcome measures, were blinded to the NR settings (ON/OFF) of the CI for phases II and III.

RESULTS

Speech intelligibility significantly improved with the NR activated, but was independent of individual differences in cognitive abilities. Listening effort did not significantly change with NR setting; however, there was a trend for participants with good working memory to have better speech perception scores with NR activated during the effortful listening task (dual-task paradigm).

CONCLUSION

Future studies are warranted to explore the interaction between cognition and CI NR algorithms during an effortful listening task.