27-Year Study Confirms Brain Implant Safety

A 27-year study involving five patients has confirmed that brain implants used to restore touch in paralyzed individuals are safe and effective for up to 10 years. The research, published by a team of 22 authors from UPMC and the University of Chicago, represents the first long-term experiment specifically focused on the safety of these neural devices.

Robert Gaunt, the lead researcher and an associate professor in the Department of Physical Medicine and Rehabilitation at UPMC, explained that the implants are placed in brain regions responsible for arm and hand movement and sensation. The team uses MRI imaging to locate these specific areas. Once implanted, the devices use small electrical pulses to stimulate the brain, allowing patients to feel sensations.

"We implant devices into the parts of the brain involved in moving the arm and hand and feeling things with the arm and hand. We find those areas using MRI," Gaunt said. "We can also inject our own patterns into the brain using very small pulses of electricity. If we do that in the right way, people can feel things."

The study relied on cumulative data collected over nearly three decades. One participant has worn the device for more than 11 years. Gaunt noted that the duration was necessary because there is no shortcut to understanding long-term biological responses to implanted hardware. The process involved significant trial and error, where researchers would adjust stimulation patterns based on patient feedback regarding what they felt.

The devices function by listening to patterns of activity from individual neurons. Gaunt compared this signal to Morse code. Researchers decode these patterns to create commands that can control external tools, such as robotic arms. The primary goal of this specific study was to document safety over an extended period, rather than just immediate functionality.

Charles Greenspon, an assistant professor at the University of Chicago and co-author, emphasized that previous research focused on what the technology could do, such as improved control. This study shifts the focus to how long the devices remain safe. "Every other study to date is about functionality of the technology," Greenspon said. "Does it allow improved control? What can patients do with the technology? This is about long term safety."

Gaunt stated that the devices are expected to eventually fail, but 10 years appears to be a reliable benchmark for their operational lifespan. The findings provide a standard for future neurotechnology companies to validate their own devices without spending a decade on independent safety testing, provided they adhere to the parameter ranges established in this study.