Reports say chronic pain affects 51.6 million Americans, and the effects are considered “high-impact” for about 17 million of them, influencing their life or work. Traditional methods of pain relief, such as opioid medications, carry the risk of addiction among other side effects. Current spinal cord stimulators are alternatives, but are expensive and require invasive surgery with a need for regular battery replacement. Researchers at USC’s Zhou Lab, collaborating with UCLA, have developed a new device called the UIWI (Ultrasound-Induced Wireless Implantable) stimulator.
This device is a wireless and flexible solution that’s powered externally using a wearable ultrasound transmitter (WUT). The stimulator makes use of a piezoelectric element made of a material called lead zirconate titanate (PZT) to convert ultrasound waves into electrical energy. A neural network model called ResNet-18 is used to analyze EEG (electroencephalogram) brain signals to determine the level of pain that’s experienced by the user. The use of machine learning here allows the device to detect pain level and instantly adjust the intensity of stimulation appropriately.
In lab tests performed on rodents, the device effectively reduced the pain caused by mechanical (e.g., pin prick) and thermal (e.g., heat) stimuli. While the device was active, the animals showed a preference for the environment. Future versions might be even smaller to the extent that they can be injected through a syringe, with smartphone controls and integrated imaging with stimulation. A personalized, smart, and non-addictive alternative to existing options of pain management is the ultimate goal.
