Assessment of the relationship between speech discrimination in noise abilities and spectral resolution, temporal resolution and melodic contour identification abilities in adult cochlear implant users

Which deficiencies in auditory skills are more related to cochlear implant users performance in speech understanding in noise is not clarified. In this study, speech discrimination in noise performance of cochlear implant users have been associated with their temporal resolution, spectral resolution and melodic contour identification skills; and the differences in performance of these skills were investigated by dividing the users into two groups based on their success in speech discrimination in noise. For this purpose, 24 adult unilateral cochlear implant users between the ages of 18-55 were included in the study. Firstly, word identification test in silent and Turkish Matrix Test were applied to the participants. Participants who were divided into groups based on adaptive Matrix speech reception threshold were applied with Spectral-Temporally Modulated Ripple Test (for spectral resolution), Gap Detection Test (for temporal resolution), Melodic Contour Identification Test (for tracking the auditory regularities and the direction of change in pitch contours). In the result of the study, it was observed that both temporal resolution and spectral resolution were associated with speech understanding performance evaluated with +8 dB SNR, which is accepted as the SNR level exposed in daily life. The skill associated with Matrix adaptive evaluation performance was found to be spectral resolution. Groups that showed top and bottom performance in discrimination speech in noise significantly differed from each other in all speech tests and spectral resolution skills. Results have showed that the skills associated with distinguishing speech in noise are primarily spectral resolution and secondly temporal resolution. The results were compared with previous studies, suggestions were made for future studies. Keywords: speech discrimination in noise, cochlear implant, melodic contour identification, spectral resolution, temporal resolution