Asymmetry in cochlear implant pulse shapes biases one polarity of stimulation to dominate.

Evidence

Stimuli were trains of electrical pulses delivered at a rate of 8 Hz. The four pulse shapes illustrated in Fig. 1 were tested, including symmetric biphasic (SYM), reversed pseudomonophasic (RPS), reversed pseudomonophasic with an interphase gap of 6.5 ms (RPS-IPG) and triphasic (TRI) pulses. The top pulse shapes are assumed to favor cathodic stimulation, hence the “C” at the end of their acronyms while the bottom pulse shapes are assumed to favor anodic stimulation, hence the “A”. The recordings were synchronized to the onset of the cathodic phase for the top pulse shapes and to the onset of the anodic phase for the bottom pulse shapes. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2272

Stimuli were trains of electrical pulses delivered at a rate of 8 Hz. The four pulse shapes illustrated in Fig. 1 were tested, including symmetric biphasic (SYM), reversed pseudomonophasic (RPS), reversed pseudomonophasic with an interphase gap of 6.5 ms (RPS-IPG) and triphasic (TRI) pulses. The top pulse shapes are assumed to favor cathodic stimulation, hence the “C” at the end of their acronyms while the bottom pulse shapes are assumed to favor anodic stimulation, hence the “A”. The recordings were synchronized to the onset of the cathodic phase for the top pulse shapes and to the onset of the anodic phase for the bottom pulse shapes. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2287

Categorization

• DEFINE: Establishes the pulse-shape/polarity naming scheme (SYM, RPS, RPS-IPG, TRI with C/A suffixes) used throughout the study.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 2272; Dijk, Pim van, Physiology, Psychoacoustics and…, 2287