Measuring implanted patient response to tone pips

Electrical Cochlear Response Consistency from different Cochlear Implant Users

The Electrical Cochlear Response (ECR) is a scalp potential recently described in the literature which offers an alternative approach for objective adaptation of Cochlear Implant (CI) to individual patient requirements. Thus it is necessary to know about the consistency of this response across implanted patients using devices with different design criteria. This work shows that the ECR wave shape morphology is not affected by CI manufacture design differences. For this purpose and to contend with the sensibility to electric stimulation change along the cochlea, six contiguous intracochlear electrodes located at the apical end of the cochlea were studied. According to the CI manufacturer, the population of twelve implanted pediatric patients was divided into three groups. Artifacts due to the CI stimulation pip tone and operation during ECR acquisition were canceled using the Empirical Mode Decomposition method. For wave shape morphology comparison among electrodes, ECR amplitude was normalized, and the average intra- and inter-user group ECR Correlations were calculated. Intra and inter-group Correlation coefficient goes from 0.58 to 0.9 and from 0.63 to 0.85, respectively. For the same patient and group Correlation coefficient between ECR of the electrode located at the apical end of the cochlea and adjacent electrodes decreases from apex to base. These results support the consistency of the ECR waveshape morphology across users of different CI types.Clinical Relevance- ECR offers a new objective methodology for the initial programming and later readjustment of electrical stimulation provided by the cochlear implant. The patient uses the device in daily operation mode; the scenery is quite impossible with the current resources for evaluating CI performance. This methodology is compatible with all current CIs without special hardware or software requirements due to different devices type. It can be applied any time after initial device programming, regardless of patient age or previous training. Therefore, it is important to know that ECR wave shape morphology is not affected by the differences in design and operation of current cochlear stimulation systems.

Calibrated Ling Sounds Test for Cochlear Implant fitting in children

The Implanted children audiometric evaluation inaccuracies may lead to an extended period of the time to achieve proper cochlear implant (CI) electric stimulation. In this work we hypothesized that the relationship between implanted patient hearing thresholds estimation based on the Electrical Cochlear Response (ECR) and detection thresholds to Ling Sounds intensity calibrated according to higher energy spectral component allow electrical current stimulation adjustment of intracochlear electrodes. ECR is an objective test which is performed while patient is asleep and using the CI in everyday operation mode. Stimulus are variable intensity pip tones whose frequency is coincident with the central frequency of the band frequencies in which incoming sound is divided. The ECR Hearing Threshold is determinate by initial ECR detection and is defined as the minimum intensity level which auditory nerve portion involved with test electrode responds to electric stimulation hence producing an auditive experience to subject. Correlation observed between ECR Hearing Thresholds and Calibrated Ling Sounds detection thresholds is high enough (r²= 0.99) for electrodes electric current adjustment based on patient detection thresholds obtained in a Calibrated Ling Sound Test.