Kolberg, Courtney

Background/Objectives: Speech perception is measured in quiet and in the presence of background noise, such as multi-talker babble (MTB), to establish cochlear implant (CI) candidacy and measure post-operative outcomes. Testing protocols often use interrupted noise that begins just before and ends shortly after the target sentence, providing insufficient time for the noise-reduction algorithms to activate in the hearing device and provide an improved signal-to-noise ratio (SNR). Furthermore, interrupted noise does not allow the hearing-impaired user to acclimatize to the abrupt onset of noise or to focus on the target sentence, a challenge related to auditory stream segregation. The present study compares speech perception in bimodal CI users across interrupted and continuous MTB noise conditions to highlight performance differences between these two distinct listening environments. Methods: Speech perception was evaluated for two different bimodal CI groups. Group 1: This group evaluated an automatic hearing aid program across three environments: quiet, continuous MTB, and interrupted MTB. Group 2: This group evaluated two manual hearing aid programs across the same three environments (quiet, continuous, and interrupted MTB). Results: For Group 1, scores in quiet reached 88%, significantly declined in interrupted MTB (38%), but improved in continuous MTB (67%). For Group 2, no significant mean differences were found between interrupted and continuous noise across the two manual programs, though individual variations persisted. Conclusions: Based on the findings of this study, continuous noise rather than interrupted noise should be utilized for establishing CI candidacy and evaluating post-implantation speech perception.

Objective: Auditory nerve monitoring through electrically evoked compound action potentials (eCAP) can be used to assess cochlear neural integrity during vestibular schwannoma (VS) resection. Herein, we report on 5 cochlear implant (CI) patients who underwent VS resection with present eCAP responses both intraoperatively and postoperatively. Patients either did not perceive any sound through their CI or rapidly adapted to electrical stimulation, suggesting that the presence of eCAP does not guarantee auditory nerve function in patients with VS resection. Patients: Five patients who underwent simultaneous VS translabyrinthine resection and cochlear implantation. Interventions: Simultaneous cochlear implantation and translabyrinthine microsurgical VS resection. Main outcome measure: Electrically evoked compound action potential. Results: All patients had eCAP responses present during their VS resection and for at least 50 days post-surgery. Three of the 5 patients did not perceive any sound with their cochlear implant. This shows that the presence of an eCAP alone does not guarantee a functional auditory nerve or auditory perception. The other 2 patients could hear non-speech sounds, but these sounds quickly became inaudible, indicating that their auditory nerve lacked the ability to integrate the electrical stimulus over time. Conclusions: The presence of an eCAP response does not guarantee auditory sensation through a CI. Although eCAP measurements provide insight into the function of the distal end of the nerve, it does not ascertain integrity or function of the larger auditory nerve pathway. Therefore, eCAPs should not be used in isolation to monitor auditory nerve function during VS resection.

Background/Objectives: Traditional hearing aid noise reduction algorithms offer no additional benefit in noisy situations for bimodal cochlear implant (CI) users with a CI in one ear and a hearing aid (HA) in the other. Recent breakthroughs in deep neural network (DNN)-based noise reduction have improved speech understanding for hearing aid users in noisy environments. These advancements could also boost speech perception in noise for bimodal CI users. This study investigated the effectiveness of DNN-based noise reduction in the HAs used by bimodal CI patients. Methods: Eleven bimodal CI patients, aged 71–89 years old, were fit with a Phonak Audéo Sphere Infinio 90 HA in their non-implanted ear and were provided with a Calm Situation program and Spheric Speech in Loud Noise program that uses DNN-based noise reduction. Sentence recognition scores were measured using AzBio sentences in quiet and in noise with the CI alone, hearing aid alone, and bimodally with both the Calm Situation and DNN HA programs. Results: The DNN program in the hearing aid significantly improved bimodal performance in noise, with sentence recognition scores reaching 79% compared to 60% with Calm Situation (a 19% average benefit, p < 0.001). When compared to the CI-alone condition in multi-talker babble, the DNN HA program offered a 40% bimodal benefit, significantly higher than the 21% score seen with the Calm Situation program. Conclusions: DNN-based noise reduction in HA significantly improves speech understanding in noise for bimodal CI users. Utilization of this technology is a promising option to address patients’ common complaint of speech understanding in noise.

Objectives To compare electrical stimulation and speech perception in vestibular schwannoma (VS) patients across treatment modalities and standard cochlear implant (CI) patients. Study Design Retrospective review. Setting Tertiary academic center. Patients Sixty-seven CI ears consisting of 23 standard CI controls and 44 VS patients with ipsilateral CI. VS patients were separated by treatment modality: 24 microsurgical resection, 15 radiation therapy, and 5 observation. Eleven VS patients with CI did not receive auditory sensation from electrical stimulation. Interventions VS microsurgical resection, radiation therapy, and observation. Main Outcome Measures Threshold (T-levels), comfort (C-levels), consonant-nucleus-consonant (CNC) word score, and AzBio sentence recognition scores. Results Patients who underwent microsurgical resection required significantly higher (p < 0.001) T-levels and C-levels compared with the standard CI group. Stimulation levels in the VS radiation therapy and observation groups were higher but not significantly different compared with standard CI controls. Overall rate of CI nonstimulation across all VS patients was 25%: 38% for microsurgery and 13% for radiation. Average CNC score for microsurgery group was 18% compared with 44% for radiation, 55% for observation, and 68.5% for standard CI controls. CNC word and AzBio scores were significantly lower (p < 0.001) for the microsurgery group compared with standard CI group. Conclusions Resection may negatively affect auditory nerve function, leading to higher stimulation levels, increased risk of nonstimulation, and poorer postoperative CI speech outcomes compared with observation or radiosurgery. When medically appropriate, nonsurgical VS management may be used to allow for optimization of CI programming and postoperative hearing outcomes.