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Pitch SIPI, Experiments for Rate Pitch Perception in Cochlear-Implant Listeners with Short-Interpulse-Interval (SIPI) Stimulation

Authors Lindenbeck, M.
Year 2017
Thesis Type Audio Engineering project
Topic Psychoacoustics
Abstract Despite ongoing research, cochlear-implant (CI) listeners still show large deficits in pitch perception. In essence, current CIs produce amplitude modulated pulse trains as electrode signals. Here the modulation contains the entire acoustic information, the pulse trains remain periodic. The Acoustics Research Institute (ARI) investigates a new method of stimulation: In order to increase ITD (interaural time difference) sensitivity while maintaining speech intelligibility, the temporal fine structure is modified by adding additional pulses with short-interpulse-intervals (SIPI). Ongoing experiments with pseudo-syllabic signals already showed improvements in ITD sensitivity. Within the project, an ARI software (ExpSuite) is extended to include experiments that allow to test the hypothesis that the introduction of SIPI pulses improves the pitch perception of CI listeners. Besides, potentially confounding factors such as loudness differences are addressed. To validate the software functionality, a pilot study is conducted. Furthermore, insight into the principal effectiveness of the SIPI pulses shall be gained to find out, what extent and which setting a subsequent, comprehensive study should have.
Supervisors Majdak, P., Höldrich, R.