A team of experts from the University of California has done a study that has shown that personalized deep brain stimulation (DBS) can have a sustained antidepressant impact on patients who are suffering from severe depression. Scientists have said that deep brain stimulation targets a type of brain circuit that is linked to low mood. It is a prototype study that has enrolled a patient named Sarah who has been dealing with major depressive disorder since her childhood. Experts have inserted electrodes in her brain that has been able to evaluate various areas that are linked to mood swings. They have been able to detect a region in the brain that has been stimulated by impulses via electrodes, which has given major relief to Sarah from suicidal trends and low mood. Two scholars from the University of California, San Francisco, Dr. Katherine Scangos, and neurosurgeon DR. Edward Chang along with Sarah have presented the findings of the study in a press meet. Dr. Katherine Scangos is a professor of psychiatry. The patient has said that she has been benefitted from the life-changing effects of deep brain stimulation (DBS). She has said that before being enrolled in the study, she has tried a wide range of antidepressant drug combinations and electroconvulsive therapy to get some relief from severe depression but nothing has worked on her. Sarah has said that due to severe depression, her life has become limited and indigent each day. Experts have said that she has been trying hard to resist her suicidal thoughts that have overpowered her many times within an hour. The authors of the study have said that after the first targeted stimulation, the patient has experienced an incredible change. Sarah has said that after the first therapy, she has felt as if her disorder has vanished for a moment. The findings of the study have been reported in a journal called Nature Medicine.
In the first targeted stimulation, Dr. Edward Chang has inserted an arrangement of ten EEG electrodes into the patient’s brain. These electrodes have been dotted across areas of the brain that are connected to mood swings and emotions like the hippocampus and amygdala. For more than 10 days, the authors of the study have tracked the patient’s mood while the electrodes have been implanted in her brain. They have been able to detect a specific brain area that is known as the ventral striatum that has constantly induced mood lifts when experts have stimulated it. With the help of machine learning tools, they have found that brain waves that are generated in the amygdala have shot up whenever the patient has been feeling low. With the help of these findings, the authors of the study have planned a personalized stimulation for the brain networks of the patient. Experts have inserted a tiny, chronic neuromodulation device in her brain to track abnormal amygdala activities constantly. With the chronic neuromodulation device, they have been able to trigger a pulse of stimulation whenever any abnormal activity has been identified. This model has developed a closed-loop where stimulation is delivered only when the patient’s brain has informed the device that it is needed. This method is exactly opposite to earlier brain stimulation approaches that have been delivering a constant level of stimulation when they are switched on. Dr. Edward Chang and Dr. Scangos have said that the study has been able to achieve an exceptional level of personalized stimulation that works like a demand pacemaker for the brain. The authors of the study have said that once they have stimulated chronic implant, the momentary relief in the patient’s mood has turned into sustained progress that has changed the patient’s life. She has developed hobbies that she has used as only distractions from suicidal thoughts in the past. She has been able to derive joy from pursuing her hobbies.
Experts have used multiple questionnaires to assess Sarah’s symptoms of depression that have shown that her mood has drastically improved. Prior to therapy, she has been rated at 36 on the Montgomery-Asberg Depression Rating Scale (MADRS) that shows the patient is suffering from severe depression. However, many months after the device has been activated, the rating has reduced below 10 points that show remission of the disorder. It has been 15 months since Sarah has got the device implanted and she has said that she has been getting the benefits of the tool throughout this period. The authors of the study have titrated the signal to the brain of the patient to make sure stimulation is as effective as possible. Experts have said that the stimulation that is set free hundreds of times a day up to a limit of 30 minutes of stimulation is hardly noticeable to the patient. As per the report, the tool that has never been used in the treatment of depression in the past has been inspired by Edward Chang’s work towards treating epilepsy. Dr. Chang has used the technique of tracking electric currents inside the brain in his previous work as well. He has said that the battery and pulse generator that has been used in this device is around the size of a matchbox. Experts are planning to use this tool on more patients in the future. The technique should be personalized for each patient. The authors of the study have said that they hope one day this technique can be used in a non-invasive manner. Scientists who have been involved in the study have said that each electrode contact that has been used in the study has been able to record from around a millimeter to a millimeter and a half of the area of the brain. Experts have said that such kinds of details about the circuitries of depression will help experts find more targeted and non-invasive methods to treat depression in the future.