Alternative pulse shapes in electrical hearing

Autor: Astrid Van Wieringen, John M. Deeks, Robert P. Carlyon, Olivier Macherey, Jan Wouters
Přispěvatelé: Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)
Rok vydání: 2008
Předmět:
MESH: Microelectrodes
medicine.medical_specialty
Biomedical Research
Materials science
Acoustics
medicine.medical_treatment
MESH: Neurophysiology
Neurophysiology
Audiology
Stimulus (physiology)
MESH: Cochlear Implants
01 natural sciences
Loudness
03 medical and health sciences
0302 clinical medicine
Cochlear implant
0103 physical sciences
medicine
Animals
Humans
Waveform
MESH: Animals
Cochlear Nerve
010301 acoustics
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph]
MESH: Cochlear Nerve
MESH: Humans
Dynamic range
MESH: Biomedical Research
MESH: Electric Stimulation
Electric Stimulation
Sensory Systems
[PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Cochlear Implants
Amplitude
Power consumption
[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]
Microelectrodes
030217 neurology & neurosurgery
Excitation
Zdroj: Hearing Research
Hearing Research, Elsevier, 2008, 242 (1-2), pp.154-63. ⟨10.1016/j.heares.2008.03.005⟩
ISSN: 0378-5955
DOI: 10.1016/j.heares.2008.03.005
Popis: International audience; Cochlear implants (CIs) stimulate the auditory nerve with trains of symmetric biphasic (BI) pulses. We review studies showing that more efficient stimulation can be achieved by modifying these pulses by (1) increasing the inter-phase gap (IPG) between the two phases of each pulse, thereby delaying the recovery of charge, (2) increasing the duration and decreasing the amplitude of one phase - so-called "pseudomonophasic (PS)" waveforms, and (3) combining the pseudomonophasic stimulus with an IPG in a "delayed pseudomonophasic" waveform (PS_IPG). These efficiency gains, measured using changes in threshold and loudness, occur at a wide range of pulse rates, including those commonly used in current CI systems. In monopolar mode, dynamic ranges are larger for PS and for long-IPG pulse shapes than for BI pulses, but this increase in DR is not accompanied by a higher number of discriminable loudness steps, and hence, in a better coding of loudness. Moreover, waveforms with relatively short and long interphase gaps do not yield different patterns of excitation despite the relatively large differences in threshold. Two important findings are that, contrary to data obtained in animal experiments, anodic currents are more effective than cathodic stimulation for human CI patients and that the thresholds decrease with increases in IPG over a much longer time course (more than 3 ms) than for animals. In this review it is discussed how these alternative pulse shapes may be beneficial in terms of reducing power consumption and channel interactions, which issues remain to be addressed, and how models contribute to guiding our research.
Databáze: OpenAIRE
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