A New Route to Deep Brain Stimulation

Deep brain stimulation has transformed the treatment of certain neurological and psychiatric disorders. By delivering electrical pulses directly to specific brain circuits, implanted electrodes can relieve symptoms of Parkinson’s disease, epilepsy, and obsessive-compulsive disorder. Yet the procedure’s reliance on open neurosurgery has limited its use to the most severe cases.

In a new study, Carnegie Mellon University researchers introduce transnasal electrical stimulation, a technique that places electrodes at the base of the skull via the nasal cavity. By positioning electrodes in the olfactory cleft and the sphenoid sinus, air-filled spaces already accessed routinely in ear, nose and throat surgery, the researchers show that it may be possible to stimulate deep brain regions without traditional brain surgery. Their paper was recently published in IEEE Transactions on Biomedical Engineering.

“This radically different approach will allow more patients to explore deep brain stimulation therapies,” says Pulkit Grover, the senior author on the paper and a professor of electrical and computer engineering, biomedical engineering, and CMU’s Neuroscience Institute. “Current deep brain stimulations require brain surgery, which is risky, expensive, and something many patients do not want. Because of this, deep brain stimulation is usually only used in very severe cases. Our new non-invasive technique will give more people access to treatments for mental health conditions, such as severe depression, addiction, chronic pain, and schizophrenia.”

The compact, ultra-low-power implant is designed to fit inside the sphenoid sinus, a cavity located just below the brain and behind the nasal passages. The device, fabricated using flexible printed circuit technology and off-the-shelf electronic components, delivers brief electrical pulses to nearby electrodes.

“By going through the nose, we can place electrodes as close to the brain as possible without opening the skull,” explains Mats Forssell, an electrical and computer engineering research scientist and lead author on the study. “We gain access to structures on the bottom of the brain which are hard to reach in other ways. That’s what makes this technique so powerful.”

The implant can be used for both short and long term therapies. In an acute setting, electrodes could be temporarily inserted through the nose and connected to an external stimulator for short-term treatments or diagnostic testing. In a chronic setting, the fully implanted device would remain in the sphenoid sinus, avoiding external wires and enabling ongoing therapy. The implant can operate using a small rechargeable battery or be powered wirelessly via inductive coupling, with energy transmitted from a coil worn around the head. In both configurations, the system required only modest power, suggesting feasibility for longer-term use.

In tests using cadaveric tissue, the researchers demonstrated that the implant can generate electric fields in several deep and ventral brain regions, including the orbitofrontal cortex, amygdala, nucleus accumbens, and anterior hippocampus, areas strongly implicated in mood regulation and psychiatric disease.

“Given their potential impact on diagnosis and treatment, we’re working to bring these devices to patients as quickly as possible. While this process is typically slow, their minimally invasive nature gives us reason to believe we can accelerate that timeline, which gives a sense of urgency to our efforts,” Grover added.

The research team initially introduced the innovative technique, DeepFocus, in 2025 with support by grants from the Chuck Noll Foundation for Brain Injury Research and Congressionally Directed Medical Research Programs.