The Relationship Between EAP and EABR Thresholds and Levels Used to Program the Nucleus 24 Speech Processor: Data from Adults

Abstract

Either EAP or EABR thresholds can be used in combination with a limited amount of behavioral information to predict MAP T- and C-levels with reasonable accuracy.

Acoustic–electric interactions in the guinea pig auditory nerve: Simultaneous and forward masking of the electrically evoked compound action potential

“…The probe pulses elicited ECAPs with amplitudes corresponding to at least 40% of saturation amplitude, i.e., well above ECAP thresholds. In CI users, ECAP thresholds are consistently higher than behavioral thresholds, and are often comparable to maximum comfortable stimulation levels (Brown et al, 1998(Brown et al, ,2000Eisen & Franck, 2004). This difference may limit the potential clinical relevance of the present study.…”

The Development of the Nucleus® Freedom™ Cochlear Implant System

“…Telemetry also supported the world's first recording of the ECAP using the intracochlear electrodes via NRT. 21 Neural response telemetry can be used to assist in device fitting [22][23][24] and can be very helpful in fitting young children 25 and others who do not give reliable behavioral responses. It has been shown that NRT-based fitting procedures are quicker than behaviorally based methods in young children, with similar aided thresholds and speech detection scores for the 2 methods.…”

The Intra-Cochlear Impedance-Matrix (IIM) test for the Nucleus® cochlear implant

“…The second is the ability of the neural elements of the implanted cochlea to respond to the electrical stimuli of the ICS so that meaningful auditory information can be relayed to the higher auditory centres. The interface between these two factors is the programming or "fitting" of the CI sound processor, whereby stimulation current limits are set for each electrode, usually using behavioural estimates of threshold and maximum comfort level from the CI user, but sometimes using a variety of objective measures [6,22].…”

“…In the latter case the activity detected is generated by multiple fibres and constitutes the electrically-evoked compound action potential (eCAP) of the auditory nerve, and this procedure is known as neural response telemetry (NRT) in Cochlear's Nucleus systems [14]. In this way, verification of an auditory response is obtained as well as some level of confirmation of device function, and response characteristics can be useful in the setting of processor fitting parameters, particularly in young children who are unable to provide reliable behavioural responses [6,16]. Because of the evolved state of this method and its automatic determination of the neural responses [18], the method has gained broad clinical application in this patient group.…”