When combined in a single system, neurostimulation devices form what is known as closed-loop neuromodulation—technologies that can sense neural activity and adjust stimulation in real time. While these concepts may seem like science fiction, some next-generation devices are already transforming lives, with their impact expected to grow significantly over the next decade.
At its core, the nervous system functions by transmitting electrical signals between the brain, spinal cord, and nerves. Closed-loop neuromodulation technologies are designed to interact with these signals, offering new possibilities for medical treatment.
Understanding Neurostimulation
Neurostimulation involves sending carefully controlled electrical impulses into specific parts of the nervous system to restore or regulate function. This approach, used clinically for decades, is now being applied in increasingly sophisticated ways. According to Associate Professor Mohit Shivdasani, chair of the upcoming Australasian Bioelectronics, Neurosensing, and Neuromodulation Symposium hosted by UNSW, “All functions of the body are controlled by the brain, spinal cord, and the nerves.”
Unfortunately, sometimes these nerves or the brain fail to send the correct messages due to disease or trauma. Decades of research and real-world devices have shown that sending artificial inputs to these nerves can either restore function in specific body areas or treat underlying conditions. “In some cases, these devices can work almost like flipping a switch, where symptoms caused by the underlying condition are dramatically reduced as soon as stimulation begins,” Shivdasani explains.
The Role of Neurosensing
Neurosensing, on the other hand, focuses on recording signals from the nervous system. These signals can reveal information about movement, pain, inflammation, or even speech intentions. Together, sensing and stimulation form the foundation of modern closed-loop neuromodulation, enabling the targeted control of neural activity.
How Do These Technologies Work?
Neurons communicate using tiny electrical pulses. Closed-loop devices employ in-built electrodes to detect these signals while delivering electrical currents to influence them, typically through the same electrodes. Precision is critical; for example, deep brain stimulation targets areas just a few millimeters wide, located several centimeters beneath the brain’s surface.
Many neurotechnologies are already well established. Cochlear implants, which stimulate the auditory nerve, allow people who are profoundly deaf to perceive sound. They are now approved for use in infants as young as six months, dramatically improving language development.
Applications and Advancements
- Deep brain stimulation for Parkinson’s disease, reducing tremor and movement difficulties, as well as other neurological conditions.
- Spinal cord stimulation for chronic neuropathic (nerve-related) pain.
- Vagus nerve stimulation for epilepsy and inflammatory conditions.
Of these, deep brain stimulation and spinal cord stimulation devices have already become closed-loop, where they both sense and stimulate, marking an important step toward a new generation of smarter, more responsive implants. The continued miniaturization of electronics and improvements in materials science are expected to make implants ever-smaller, longer-lasting, and more compatible with the body.
The Future of Neurostimulation
For the general public, this could mean more effective treatments with fewer side effects, longer device lifespans, and less invasive procedures. In many cases, the results can be immediate. People with severe tremors or pain may experience relief as soon as the device is switched on. For people with Parkinson’s disease, deep brain stimulation can instantly and dramatically reduce tremors, stiffness, and movement freezing.
“It’s never a cure for the underlying condition, but it can give back significant quality of living for most implant recipients,” says A/Prof. Shivdasani from UNSW’s School of Biomedical Engineering.
These technologies offer something few other treatments can: restored independence. In many ways, the future of neurostimulation is less about reinventing the technology and more about refining it—making it more precise, more adaptive, and more closely aligned with each patient’s needs.
Advancements in Neurosensing
Neurosensing is also advancing through brain-computer interfaces (BCIs), which record neural signals to allow people with paralysis to control computers or communicate. While most BCIs are still in clinical trials, early studies show they can decode intended movement or speech directly from the brain. For people with paralysis or severe motor impairment, this could allow direct interaction with computers, smartphones, or communication devices via their thoughts alone.
Non-invasive versions, using external sensors to record brain activity, already exist. More invasive systems, where electrodes are implanted near specific brain regions, are still in clinical trials. Beyond treatment, neurosensing is deepening scientific understanding of how the brain works. Each improvement in sensing accuracy helps researchers decode how neural circuits process information, paving the way for better therapies.
Challenges and Considerations
Given the way the technologies interact with complex areas of the body, the technical challenges are unsurprisingly demanding. For instance, the brain is extraordinarily complicated and does not tolerate foreign objects easily. Preventing immune reactions, filtering out neural “noise,” and ensuring precise targeting are all ongoing areas of research.
As these technologies continue to evolve, the potential to improve the quality of life for countless individuals is immense. The journey from science fiction to reality in neurostimulation is well underway, promising a future where the boundaries of medical treatment are constantly being redefined.
