Cristina Ornelas Peralta

Neural response thresholds in the Nucleus Contour cochlear implant before and after stylet removal

Conclusion. The study shows that there are differences in the measurement of the action potentials with and without the stylet in the Nucleus Freedom Contour Advance that are higher in the apex than in the base of the cochlea. Objectives. To determine if there are differences in the intraoperative impedances and in the neural response telemetry threshold values in the Nucleus Freedom Contour Advance before and after stylet removal. Subjects and methods. This was a prospective clinical study. Intraoperative impedances and neural response telemetry in users of the Freedom Contour Advance Cochlear Implant were measured before and after stylet removal. Results. There was a significant reduction in the impedance values of an average 1.5 kΩ±2.3 in common ground mode and 1.3 kΩ±2.3 for all monopolar modes after the stylet removal (p < 0.001). When analyzing the apical, medium, and basal electrodes, there was a statistically significant reduction in the neural response thresholds after stylet removal only in the apical electrodes (p = 0.001).

Neural response telemetry in patients with the double-array cochlear implant

This study aimed to evaluate the neural response in double-array cochlear implant as well as to describe the refractory recovery and the spread of excitation functions. In a prospective study 11 patients were implanted with the double-array cochlear implant. Neural response telemetry (NRT) was performed intra-operatively. NRT threshold could be registered in 6 of the 11 patients, at least in one electrode. The remaining five patients did not show measurable neural response intra-operatively. It was noted that although recovery and spread of excitation functions could be recorded in all the tested electrodes with measurable neural responses, the responses were shown to be different from the usual register in patients with other etiologies.

Psychoacoustic dynamic range and cochlear implant speech-perception performance in nucleus 22 users.

Abstract Background Cochlear implant speech processors compress a wide acoustical dynamic range of sounds into a smaller electrical dynamic range. Some patients show wider electrical dynamic ranges than others and most of them have good speech perception performance. The knowledge of the average psychoacoustical dynamic range in adults will help the audiologist program children who do not give reliable responses. Aim This study was conducted to analyse the dynamic ranges of experienced Nucleus 22 cochlear implant users with good speech-perception and patients with poor speech-perception performances. Method Thirty-one maps of adult subjects with Nucleus 22 cochlear implants using the SPEAK processing strategy, in bipolar stimulation were analysed. By the time of this study, all of them had used a cochlear implant for over a year. They were divided into two groups: group 1, composed of those with good speech perception for sentences (better than 80%), and group 2, composed of those with speech perception results for sentences worse than 70%. Results Results showed that both dynamic ranges were wide in the two groups (average 50 units). Conclusion Although dynamic ranges vary among subjects and electrodes, a lower variability was observed within the group of patients with better speech perception.