Psychometric function of jittered rate pitch discrimination

Area of Science:

• Auditory Neuroscience
• Biomedical Engineering
• Speech Processing

Background:

• The effect of pulse rate jitter on rate pitch discrimination (JRPD) remains debated.
• Previous studies on JRPD used limited participant numbers and specific cochlear implant devices.
• The psychometric function of rate jitter, crucial for adaptive procedures, has not been investigated.

Purpose of the Study:

• To determine psychometric functions for JRPD using a fixed stimulus paradigm.
• To investigate the impact of varying temporal jitter standard deviations (0-4 ms) on JRPD.
• To examine the influence of different jitter probability density functions (Gaussian and uniform) on JRPD.

Main Methods:

• Seven cochlear implant (CI) users (8 ears) with high-level speech perception participated.
• JRPD was measured using a two-stage forced-choice procedure.
• Electrical pulse patterns with temporal, Gaussian-distributed jitter (0-4 ms SD) and uniform jitter were applied.

Main Results:

• Rate pitch discrimination decreased as the amount of pulse rate jitter increased.
• This effect was observed regardless of whether Gaussian or uniform jitter distributions were used.
• The study successfully characterized JRPD psychometric functions under fixed stimulus conditions.

Conclusions:

• Pulse rate jitter significantly affects JRPD in CI users.
• Current CI coding strategies should account for pulse rate jitter.
• Further research into the psychometric functions of jitter is warranted.