Summary: Researchers have discovered a pattern of neural activity that can accurately predict and monitor the clinical status of OCD patients undergoing deep brain stimulation (DBS). The study highlights how this biomarker can guide DBS therapy, improving treatment outcomes for people with severe, treatment-resistant OCD.
The identification of a reliable neural signature represents a significant advance in DBS technology, making therapy more accessible and effective. These results could potentially extend to other neuropsychiatric disorders, offering new perspectives for diagnosis and treatment.
Highlights:
- New biomarker identified: A specific neural activity pattern predicts and monitors the clinical status of OCD in patients receiving DBS.
- Enhanced DBS Therapy: This biomarker can guide DBS programming, thereby improving treatment outcomes for patients with severe, treatment-resistant OCD.
- Wider consequences: The findings could extend to other neuropsychiatric disorders, providing new diagnostic and treatment opportunities.
Source: Baylor College of Medicine
A recent study from Baylor College of Medicine and Texas Children’s Hospital has identified a specific pattern of neural activity as a novel biomarker to accurately predict and monitor the clinical status of people with obsessive-compulsive disorder (OCD) who underwent deep brain stimulation (DBS), an emerging treatment approach for serious psychiatric disorders.
The study, led by Drs Sameer Sheth and Wayne Goodman with co-lead authors Drs Nicole Provenza, Sandy Reddy and Anthony Allam, was published in Natural medicine.
“Recent advances in surgical neuromodulation have enabled long-term, continuous monitoring of brain activity in OCD patients as they go about their daily lives,” said Nicole Provenza, M.D., assistant professor at Baylor College of Medicine and McNair Scholar. “We used this new opportunity to identify key neural signatures that may serve as predictors of clinical status in twelve individuals with treatment-resistant OCD who were receiving DBS therapy.”
DBS emerges as an effective treatment for severe and treatment-resistant OCD
OCD is a common and disabling mental disorder that affects 2 to 3 percent of the world’s population. Approximately two million people in the United States suffer from OCD. In severe cases, patients spend an inordinate amount of time performing repetitive, seemingly senseless compulsions and persisting with intrusive thoughts.
OCD has a significant impact on the well-being and quality of life of patients and their caregivers and can interfere with the ability to hold down employment and maintain relationships. Although psychotherapy and medication are effective for the majority of people affected, approximately 20–40% of people with severe OCD are resistant to these conventional treatments.
Since the early 2000s, DBS therapy has been used to modulate neural activity in specific brain regions linked to OCD symptoms. Many patients eligible for this therapy have not benefited adequately from conventional therapies. In this treatment-resistant population, approximately two-thirds of patients experience significant improvement in OCD symptoms after DBS.
Just as pacemakers regulate the electrical activity of the heart, DBS devices regulate the electrical activity of the brain.
DBS devices transmit electrical impulses from the generator, usually implanted in the upper chest, through a pair of thin wires to specific target areas of the brain. By fine-tuning the stimulation parameters, the electrical impulses can restore a dysfunctional brain circuit to a healthy state.
DBS is an FDA-approved procedure commonly used to treat movement disorders such as essential tremor and Parkinson’s disease and is increasingly being used to treat severe OCD.
“We have seen remarkable progress in DBS research, a technology that has been used for decades to treat movement disorders,” said Dr. John Ngai, director of the Brain Research Through Advancing Innovative Neurotechnologies Initiative (The BRAIN Initiative) at the National Institutes of Health.
“The breakthrough reported here represents just one of many successes in which the BRAIN Initiative has helped develop a new generation of DBS technologies, bringing treatments for conditions like OCD closer to the clinic.”
Need for a clinical biomarker to monitor the response of OCD patients to deep brain stimulation
Determining the correct dose is often more difficult for psychiatric disorders like OCD than for movement disorders.
“In patients with movement disorders, it is more evident that the stimulation and tuning are correct because abnormal movements such as tremors or stiffness immediately diminish,” said Dr. Sheth, professor and vice chair of research in the department of neurosurgery at Baylor College of Medicine, director of the Gordon and Mary Cain Pediatric Neurology Research Foundation laboratories, and investigator at the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital.
“However, achieving this level of precise programming of deep brain stimulation for OCD and other psychiatric disorders is much more difficult because there is a long delay between the start of stimulation and improvement in symptoms. It is difficult to know which particular adjustment led to a particular change months later.
“Our goal in undertaking this study was therefore to find a reliable neuronal biomarker to guide us in the management of DBS and to remotely monitor the evolution of our patients’ symptoms.
“This is particularly important because many of our patients travel long distances across the country or the world to receive DBS treatment, which for OCD is currently offered in very few specialty centers.”
Targeting the Root of the OCD Problem
To identify an optimal target for biomarker development, the team focused on one of the most characteristic behaviors of OCD: pathological avoidance. People with OCD often suffer from a difficult-to-control tendency to avoid potential danger or distress.
In trying to avoid such perceived threats in daily life, they often become prey to intrusive internal thoughts and irrational fears (obsessions), which lead to rigid routines and repetitive behaviors (compulsions).
The team’s goal was to understand how low-frequency brain oscillations in the theta (4-8 Hz) to alpha (8-12 Hz) range, which a large body of literature suggests play an important role in cognitive processes, were altered in people with severe, treatment-resistant OCD.
To do this, they took advantage of a new feature of modern DBS devices: the ability not only to provide stimulation but also to record brain activity.
Typically, studies that monitor brain activity patterns are designed to be brief episodes conducted while participants perform a specific cognitive task.
This study is unique, however, in that the researchers were able to use the DBS system to continuously monitor brain activity patterns in the background of daily activities. This feature of the study allowed the research to be embedded in the natural lives of the study participants rather than confined to artificial laboratory environments.
Recordings began as soon as the DBS system was implanted. Because stimulation is typically initiated several days or weeks later, the team was able to measure patterns of neural activity in a severely symptomatic state.
Interestingly, they found that neuronal activity in the ventral striatum at 9 Hz (theta-alpha border) demonstrated a significant circadian rhythm that fluctuated over the 24-hour cycle.
“Before DBS, we observed a highly predictable and periodic pattern of neural activity across all participants,” said Dr. Goodman, Professor and DC and Irene Ellwood Chair of Psychiatry in the Menninger Department of Psychiatry and Behavioral Sciences at Baylor College of Medicine.
“However, after the deep brain stimulation was activated, when people started to respond and improve their symptoms, we saw a breakdown in this predictable pattern. This is a very interesting phenomenon and we have a theory to explain it. People with OCD have a limited repertoire of responses to a given situation.
“They often perform the same rituals repeatedly and rarely vary their routines or engage in new activities, which can lead to high predictability of activity in this brain region.
“However, after DBS activation, their behavioral repertoire expands; they can respond more flexibly to situations and are not simply motivated by a strong desire to avoid OCD triggers.
“This expanded repertoire could reflect more diverse brain activity. So we think that this loss of highly predictable neural activity indicates that participants engaged in fewer repetitive and compulsive OCD behaviors.”
“In summary, we have identified a neurophysiological biomarker that can serve as a reliable indicator of mood and behavioral improvements in OCD patients following DBS treatment.
“We anticipate that these results will transform the way patients are monitored throughout DBS treatment,” added Dr. Sheth, who is also a McNair Scholar and Cullen Foundation Chair at Baylor College of Medicine.
“Integrating this information into a clinician-facing dashboard, for example, could help guide therapy implementation, demystifying the DBS programming process for OCD and making therapy more accessible to more clinicians and patients.”
“Additionally, we are excited by the potential possibility that similar neural activity signatures may underlie other neuropsychiatric disorders and could serve as biomarkers to diagnose, predict and monitor these conditions,” Dr. Provenza concluded.
About this OCD and DBS research news
Author: Graciela Gutierrez
Source: Baylor College of Medicine
Contact: Graciela…
News Source : neurosciencenews.com
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