Ramped pulse shapes are more efficient for cochlear implant stimulation in an animal model

Area of Science:

• Biomedical Engineering
• Neuroscience
• Auditory Neuroscience

Background:

• Commercial cochlear implant (CI) devices utilize rectangular electrical pulses for stimulation.
• Current CI stimulation strategies are based on the efficacy of rectangular pulse shapes.

Purpose of the Study:

• To investigate a novel stimulation paradigm using biophysically-inspired electrical ramped pulses for cochlear implants.
• To evaluate the charge efficiency and physiological responses to ramped pulse shapes compared to rectangular pulses.

Main Methods:

• Electrically-evoked auditory brainstem response (eABR) recordings were performed in mice.
• Ramped and rectangular electrical pulse shapes were used to stimulate the auditory system.
• Charge consumption and response amplitude were measured and compared.

Main Results:

• Ramped pulse shapes required less charge, but higher current amplitude, to achieve similar response amplitudes compared to rectangular pulses.
• The most charge-efficient ramped pulse featured a rising ramp across both phases.
• These findings were consistent across longer phase durations.

Conclusions:

• This study provides the first physiological data on CI stimulation using ramped pulse shapes.
• Ramped pulses demonstrate potential for reducing charge consumption, leading to more battery-efficient cochlear implants.
• The findings may inform the design of other efficient neural implants.