A recent research study has pinpointed a specific neural activity pattern that can predict and track the clinical condition of individuals with obsessive-compulsive disorder (OCD) undergoing deep brain stimulation (DBS). This innovative approach is becoming increasingly popular for treating severe psychiatric disorders. The study, conducted by experts from Baylor College of Medicine and Texas Children’s Hospital, including Drs. Sameer Sheth, Wayne Goodman, Nicole Provenza, Sandy Reddy, and Anthony Allam, was recently published in Nature Medicine.
“Recent advancements in surgical neuromodulation have enabled the continuous monitoring of brain activity in OCD patients during their daily lives,” explained Dr. Nicole Provenza, an assistant professor at Baylor College of Medicine and McNair Scholar. “We leveraged this opportunity to identify key neural patterns that can predict the clinical state of twelve individuals with treatment-resistant OCD undergoing DBS therapy.”
DBS as an Effective Treatment for Severe OCD
OCD is a prevalent and debilitating mental health condition affecting 2-3% of the global population, with around two million sufferers in the US alone. In severe cases, individuals dedicate significant time to performing repetitive, seemingly irrational actions and fixating on intrusive thoughts. OCD takes a considerable toll on patients’ well-being, impacting their quality of life, relationships, and work. While traditional therapies like psychotherapy and medication are successful for most, 20-40% of severe cases do not respond to these treatments.
Since the early 2000s, DBS therapy has been utilized to regulate neural activity in brain regions associated with OCD symptoms. Many patients who qualify for this treatment have not experienced substantial benefits from standard therapies. In this group, about two-thirds witness significant improvement in OCD symptoms following DBS.
Similar to how pacemakers regulate heart activity, DBS devices manage brain electrical signals. These devices transmit electrical impulses from a generator, usually implanted in the chest, through thin wires to specific brain regions. Precise adjustment of the stimulation parameters enables the electrical pulses to restore dysfunctional brain circuits to a healthy state.
DBS is an FDA-approved procedure commonly used for movement disorders like essential tremors and Parkinson’s disease and is now increasingly employed for severe OCD cases.
Dr. John Ngai, Director of the Brain Research Through Advancing Innovative Neurotechnologies® Initiative at the National Institutes of Health, which partly funded this study, remarked, “The advancements in DBS research are remarkable, a technology established for decades in treating movement disorders. This recent progress is just one success story among others supported by the BRAIN Initiative, bringing treatments for conditions such as OCD closer to reality.”
Importance of a Clinical Marker for Monitoring OCD Patients Undergoing DBS
Determining the proper dosage is more challenging for psychiatric disorders like OCD compared to movement disorders. Dr. Sheth, professor at Baylor College of Medicine, highlighted this issue, “For movement disorders patients, the effects of stimulation adjustment are promptly noticeable as abnormal movements decrease. However, achieving precise DBS programming for OCD and similar disorders is more complex due to the delayed improvement following stimulation initiation. Identifying which adjustment led to an improvement months later is challenging. Our objective in this study was to identify a dependable neural indicator to guide us through DBS management and remotely monitor our patients’ symptoms, which is crucial given that many patients travel long distances to receive DBS treatment available only in specialized centers.”
Targeting the Core of the OCD Challenge
The research team focused on the typical behavior seen in OCD, characterized by pathological avoidance. Individuals with OCD often struggle with uncontrollable avoidance of perceived harm or distress, leading to intrusive thoughts and irrational fears which result in rigid routines and repetitive actions.
The team aimed to explore how brain oscillations in the theta (4-8 Hz) to alpha (8-12 Hz) range, known for their role in cognitive processes, were altered in severe, treatment-resistant OCD cases. They utilized modern DBS devices’ ability to record brain activity in addition to delivering stimulation.
Unlike standard studies that monitor brain activity during specific cognitive tasks, this study continuously monitored brain activity in the background of daily activities using the DBS system. By recording activity from the implantation of the DBS system, the team captured neural patterns in the severely symptomatic state before stimulation initiation, finding a fluctuation in 9 Hz ventral striatum neural activity that followed a circadian rhythm over the day.
Dr. Goodman, a professor at Baylor College of Medicine, noted, “Before DBS activation, we observed a predictable neural pattern in all participants. Following DBS, as individuals began to respond and show improvement, this pattern broke down. Individuals with OCD often exhibit repetitive behaviors due to a limited range of responses. After DBS activation, their behavior diversified, reflecting a more varied brain activity pattern. This shift in neural activity indicates reduced engagement in repetitive and compulsive OCD behaviors.”
Dr. Sheth, a McNair Scholar and Cullen Foundation Endowed Chair at Baylor College of Medicine, added, “We have identified a neurophysiological marker that indicates improvements in mood and behaviors in OCD patients post-DBS treatment. These discoveries are set to revolutionize patient monitoring during DBS therapy.”
“Incorporating this knowledge into a clinician-oriented dashboard could enhance therapy delivery, simplifying the DBS programming process for OCD and making treatment more accessible to both clinicians and patients. Furthermore, the possibility of these neural activity patterns serving as biomarkers for other neuropsychiatric disorders is promising,” concluded Dr. Provenza.
