Characteristics of the Summating Potential Measured Across a Cochlear Implant Array as an Indicator of Cochlear Function.

Objectives: The underlying state of cochlear and neural tissue function is known to affect postoperative speech perception following cochlear implantation. The ability to assess these tissues in patients can be performed using intracochlear electrocochleography (IC ECochG). One component of ECochG is the summating potential (SP) that appears to be generated by multiple cochlear tissues.

Intracochlear tPA infusion may reduce fibrosis caused by cochlear implantation surgery.

Background: Experiments show that the extent of ongoing fibrotic change within the cochlea can be determined by the volume and pattern of bleeding within the first 24 h following cochlear implantation. Tissue-type plasminogen activator (tPA) is effective at reducing thrombus volume when administered both within and external to the systemic circulation.

Aims/objectives: To determine if tPA delivered into the scala tympani immediately following implantation will reduce thrombus volume within the lower basal turn of the cochlea.

The Early Postoperative Effects of Cochlear Implantation on Horizontal Semicircular Canal Function.

Objectives: To use video head impulse testing to examine the effect of cochlear implantation (CI) on horizontal SCC vestibulo-ocular reflex (VOR) gain early after surgery, and to relate outcomes to subjective imbalance.

Study Design: Prospective cohort study.

Setting: Academic tertiary referral center.

Defining the Hook Region Anatomy of the Guinea Pig Cochlea for Modeling of Inner Ear Surgery.

Hypothesis: The aim of this study was to describe the hook region anatomy of the guinea pig cochlea to identify the optimal surgical approach for cochlear implantation and to determine what anatomical structures are at risk.

Background: Animal studies investigating hearing loss after cochlear implantation surgery are currently constrained by the lack of a reproducible implantation model.

Methods: Guinea pig cochleae were imaged using thin-sheet laser imaging microscopy.

Outcomes After Cochlear Implantation in the Very Elderly.

Objective: To evaluate the outcomes after cochlear implantation (CI) in the elderly population, with a particular emphasis on perioperative complications, dizziness, and speech perception outcomes.

Study Design: A retrospective cohort study of elderly cochlear implant patients.

Setting: Tertiary referral center (Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne).

Early cochlear response and ICAM-1 expression to cochlear implantation.

Aim: To examine the early cochlear response and intercellular cell adhesion molecule-1 (ICAM-1) expression to implantation of a cochlear electrode into the scala tympani.

Background: Understanding the early response of the cochlea to implantation may inform the duration which drug therapies should be delivered to protect hearing.

Methods: Guinea pigs were implanted with a cochlear electrode and survived 1, 2, or 7 days before they were euthanized, cochleae harvested, processed, and cryosectioned for light microscopy or ICAM-1 immunohistochemistry.

Systemic immunity influences hearing preservation in cochlear implantation.

Hypothesis: To determine whether a systemic immune response influences hearing thresholds and tissue response after cochlear implantation of hearing guinea pigs.

Methods: Guinea pigs were inoculated with sterile antigen (Keyhole limpet hemocyanin) 3 weeks before cochlear implantation. Pure-tone auditory brainstem response thresholds were performed before implantation and 1 and 4 weeks later.

Prediction and control of neural responses to pulsatile electrical stimulation.

This paper aims to predict and control the probability of firing of a neuron in response to pulsatile electrical stimulation of the type delivered by neural prostheses such as the cochlear implant, bionic eye or in deep brain stimulation. Using the cochlear implant as a model, we developed an efficient computational model that predicts the responses of auditory nerve fibers to electrical stimulation and evaluated the model's accuracy by comparing the model output with pooled responses from a group of guinea pig auditory nerve fibers. It was found that the model accurately predicted the changes in neural firing probability over time to constant and variable amplitude electrical pulse trains, including speech-derived signals, delivered at rates up to 889 pulses s(-1).