Degenerative Consequences of Congenital Deafness

In this study, the investigators will study one of the basic biophysical properties of the auditory nerve, charge integration, behaviorally (detection threshold versus phase duration functions). The investigators will compare charge integration in two subject groups: congenitally deafened and deafened at a later age in life. The investigators will then examine if behaviorally estimated neural excitation patterns differ between short phase duration and long phase duration stimulation. Lastly, The investigators will measure if speech recognition improves with using long phase duration stimulation, relative to using the standard default short phase duration stimulation. The primary endpoint of the study is speech recognition, and the secondary endpoints are the steepness of the detection threshold versus phase duration functions, and the width of psychophysically estimated neural excitation.