Cochlear Simulator

Overview

A cochlear implant (CI) is a neuroprosthetic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. Unlike hearing aids, which amplify sound, CIs bypass damaged parts of the ear to deliver sound signals directly to the auditory nerve. This web application provides a real-time, interactive simulation of how a CI processes sound. While professional audiological simulators are far more complex, this tool serves as an excellent educational introduction to the core principles of CI function, demonstrating how complex sounds are simplified into a pattern of electrical stimulation.

How to Use

After granting microphone access, speak or play sound to see the visualizations react. The key to understanding this simulation is to explore the controls:

• Array Type: Switches the right-hand view between a "Spiral" (a simplified representation of the cochlea's snail-like shape) and a "Linear" layout. The spiral is now rendered with approximately 2.5 turns to better represent the anatomy of a real human cochlea.
• Number of Electrodes: Adjusts the number of stimulation channels. A higher number provides more frequency detail, which generally leads to better speech and music perception.
• Color Scheme: Changes the color palette of the visualizations to your preference.
• Spectrogram Y-Axis: Changes how the left-hand frequency chart is scaled. "Auto Scale" adjusts to the current loudest sound, while "Fixed Scale" uses a constant maximum.
• Noise Gate & Threshold: This two-part control is essential for noisy environments. First, check "Enable" to activate the gate. Then, if you still see activity from background noise (like a fan), slowly increase the "Threshold" slider until the visualization is still. This ensures only intentional sounds are processed, providing a much cleaner simulation.

A Note on Microphone Noise: If you don't use the Noise Gate, you may see a constant bar at the far left of the spectrogram. This is a common artifact of built-in microphone hardware and not part of the sound in your room.

Future Directions

This simulator provides a foundational look at cochlear implant processing. Future enhancements could introduce more advanced concepts. For instance, simulating "current spread," where activating one electrode unintentionally stimulates adjacent neural tissue, could show how channel separation impacts clarity. Furthermore, while we've expanded the electrode count up to 40 to reflect experimental possibilities, some research trials have explored even higher-density arrays of up to 48 electrodes. Incorporating pre-loaded audio samples (like different vowels or musical notes) would also provide a powerful, consistent way to compare how distinct sounds are represented by the implant.