Clinical Metrics for Assessing Audibility, Comfort and Performance of Cochlear Implant Recipient MAPs

Optimising the clinical fitting of a cochlear implant to an individual listener is an important aspect of post-operative clinical care. The level of success experienced by any individual with a cochlear implant can be influenced, to a significant extent, by the quality of the clinical programming by the audiologist. During clinical programming the audiologist typically measures the amount of electrical charge required to elicit first hearing (the T-level) and to provide a loud but comfortable percept (the C-level) on each of the 22 electrodes. The amount of electrical stimulation required for a threshold and a comfortably loud percept varies across the electrodes of the array and also across individual users. Appropriately set lower and upper electrical stimulation levels are vital for ensuring that the listener is able to detect reasonably soft sounds whilst loud sounds are perceived as loud while remaining comfortable. Achieving this result across the relevant frequency range is a prime aim of programming.

There are a number of challenges in achieving optimal fitting of cochlear implant recipients in the clinical setting. First, there are varying skill levels and experience level of health professionals and allied workers involved in programming devices for cochlear implant recipients, often resulting in variability in the quality of the program (or MAP) provided to an individual. Second, there are varying levels of access to specialized equipment such as sound booths which are required for some types of audiometric measures to be reliably obtained. Finally, there are increasing demands on clinical capacity, with the specialized centres typically treating recipients having limited resources and ability to effectively manage the rapidly increasing population.

As a result, there is an increased need for effective, quality-controlled but streamlined management of implanted recipients.

The aim of the current study is to investigate the potential use of specific metrics in assessing the quality and optimizing an individual's cochlear implant fitting. Assessment of the sensitivity and specificity of specific metrics that are potential predictors of inaccurate T-levels and C-levels is important to determining best methods for streamlined high quality fitting, as well as automated adjustments for optimizing. One of the key objectives is to integrate a new technological advance in the form of in-situ audiometry, which removes the need for a sound booth to conduct audibility checks of the program. Other planned investigations relate to identifying the metrics which best identify maps that are not optimized, and to development and assessment of a range of techniques which may be able to be effectively applied in the clinical setting.