الفهرس 
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Abstract
Substantial improvements in postimplant performance is attributed to the introduction of multichannel cochlear implant devices, development of more complex speech processing strategies, and refinement of candidacy criteria. This was evidenced by improved open-set speech understanding in both children and adults.
Post operatively, speech processor programming and assessment of speech perception performance must be optimized to get the best results and to evaluate and determine the course of rehabilitation of cochlear implant patient .the major tests used to evaluate the postoperative performance are usually behaviorally-based. Obtaining reliable behavioral data from children or individuals with new implants, who may have little or no experience with normal sound stimulation, can be difficult. Therefore, it was extremely helpful to develop an objective measure for assessing those patients.
The aims of this study were to record ESRT and ECAP from cochlear implant users and investigate the relationship between electrophysiology and MAP psychophysics in cochlear implant users.
Twenty six pre-lingually deaf subjects implanted with Med-el multichannel cochlear implant were examined in the present study. All the subjects were implanted in Alexandria Main University hospital and attended the audiology clinic. Six subjects were rejected from the study because the ESRT couldn’t be recorded across all electrodes. They had an age range of 14-51 years; 16males and 2 males. The duration of implantation ranged from 5 to 8 years.
All subjects underwent the following:
• Behavioral measurements of threshold (T) and comfortable level (C).
• ESRT and ECAP threshold were measured across all available electrodes.
• aided free field testing with their implants based on the behavioral map.
• Speech perception testing was performed by using the phonetically balanced monosyllabic words.
ESRT response could be obtained from 20 subjects. Data were analyzed to find the relation between the ESRT and behavioral threshold (T) and comfortable (C) levels. Very high significant correlations were found between the ESRT and C levels across all electrodes. Moreover, computation formulae were done to predict C level from ESRT. As regards T levels, no correlations were found across all electrodes with ESRT.
As regard ECAP, it could be recorded from all cochlear implant subjects. There was correlation between ECAP thresholds and the T levels at all the electrodes. On other hand, no significant correlation was found between ECAP thresholds and C levels.
Warble tone aided response based on the behavioral map in all subjects revealed that good audibility of sound is achieved by all subjects. The aided thresholds for all patients lied within the average conversational levels of speech.
Speech discrimination scores of phonetically balanced monosyllabic words were performed in all subjects, however, performance in the discrimination task varied.