An active electronic, high-density epidural paddle array for chronic spinal cord neuromodulation

Journal of Neural Engineering, 2025 · DOI: https://doi.org/10.1088/1741-2552/adba8b · Published: March 19, 2025

Simple Explanation

This research introduces a new type of electronic device that can be placed on the spinal cord to deliver electrical stimulation. This device, called HD64, has a large number of electrodes that can be programmed to stimulate specific areas of the spinal cord. The HD64 device was tested in sheep for over a year, and it worked well without any problems. The device allowed researchers to control the muscles in the sheep's legs and record electrical signals from the spinal cord with high precision. This new technology could lead to better treatments for people with spinal cord injuries or other neurological conditions by allowing doctors to stimulate the spinal cord in a more targeted and effective way.

Study Duration

15 months

Participants

Two sheep

Evidence Level

Level 5, Animal Study

Key Findings

1
The active paddle array (HD64) performed nominally when implanted in sheep for over 15 months, and no device-related malfunctions were observed.
2
The onboard multiplexer enabled bespoke electrode arrangements across, and within, experimental sessions, allowing for tailored stimulation patterns.
3
Spatial electrode encoding enabled machine learning models to accurately perform EES parameter inference for unseen stimulation electrodes, reducing the need for extensive training data.

Research Summary

This paper introduces the HD64, a novel high-density active electronic epidural paddle for spinal cord neuromodulation. The device integrates a 60-electrode programmable array with an active electronic multiplexer, all sealed in a hermetic package. The HD64 was chronically implanted in sheep for 15 months, demonstrating stable performance and enabling precise control of motor responses and high-resolution spinal recordings. The study highlights the potential of active electronics in neural interfaces for improved stimulation targeting, recording resolution, and machine learning-driven parameter optimization in EES.

Practical Implications

Improved Spinal Cord Stimulation Therapies

The high-density and programmable nature of the HD64 could lead to more effective and personalized spinal cord stimulation therapies for conditions such as spinal cord injury and chronic pain.

Advanced Neural Interface Design

The integration of active electronics into implantable neural interfaces opens new avenues for incorporating advanced computation, signal processing, and closed-loop control directly at the neural interface.

Efficient Machine Learning-Based Optimization

The spatial encoding of electrodes enables the development of more efficient machine learning models for optimizing stimulation parameters, reducing the need for extensive training data and accelerating the translation of EES to clinical use.

Study Limitations

1
The study was conducted on sheep, and the results may not be directly generalizable to human anatomy and physiology.
2
The lack of existing implantable pulse generators (IPGs) capable of generating the power and communication signals necessary to control the onboard multiplexer.
3
The neural network parameter inference is limited to monopolar stimulation patterns, and therefore, cannot take advantage of the improved selectivity identified by bipolar stimulation.

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