The amygdala is a region of the brain known for its connections to emotional responses and fear memories, and hyperreactivity of the amygdala is associated with symptoms of PTSD (post-traumatic stress disorder). That said, it’s quite a leap to design neurosurgical ablation of the amygdala to address someone’s PTSD. This type of irreversible intervention could only be considered because of the presence of another brain disorder: epilepsy.
In a case series published in Neurosurgery, Emory investigators describe how for their first patient with both refractory epilepsy and PTSD, observations of PTSD symptom reduction were fortuitous. However, in a second patient, before-and-after studies could be planned. In both, neurosurgical ablation of the amygdala significantly reduced PTSD symptoms as well as reducing seizure frequency.
Since the two surgeries were completed, some of the talented researchers involved have moved to other universities – neuroscientists Kelly Bijanki and Cory Inman to Baylor College of Medicine and University of Utah, and neurosurgeon Jon Willie to Washington University St. Louis. Still, longstanding interest in both PTSD and epilepsy continues at Emory, which has one of the leading epilepsy surgery practices in the country, as well as the Grady Trauma Project.
More recently, the researchers report, they have evaluated amygdala ablation in a third patient, and they have been studying its neurocognitive effects in other epilepsy patients who did not meet the clinical criteria for PTSD. Emory neuroscientist Sanne van Rooij, who is co-first author of the case series with Bijanki, is presenting additional data on the effects of amygdala ablation at the International Society for Traumatic Stress Studies meeting on November 13.
Aside from directly confirming that the amygdala plays a critical role in driving PTSD, studying these surgeries may help researchers refine non-ablative or non-invasive interventions for PTSD, such as deep brain stimulation or transcranial magnetic stimulation.
In the Neurosurgery paper, the patients’ cases sound harrowing; in both, PTSD resulted from trauma first, but epilepsy developed years later. Patient 1 was a 62-year old Vietnam War veteran who had experienced a blast injury in 1972, in which fellow soldiers were killed. He had a more than 30 year history of PTSD symptoms, refractory to medication, and was unable to tolerate cognitive behavioral therapy. Patient 2 was a 42-year old woman with a 19-year history of civilian PTSD symptoms, coming from multiple instances of fatal violence against family members. Her PTSD was refractory to psychotherapy and antidepressant medications.
Willie says that the third patient’s story was more complicated – she had pre-existing epilepsy and had already undergone surgery, before having a car crash and traumatic brain injury, which led to PTSD.
In the people described in the Neurosurgery paper, the right hemisphere was nondominant, in terms of normal cognition. However, seizures and the disease process in the patients’ PTSD were dominated by the amygdala on the right side of the brain – so only the right amygdala and hippocampus were ablated. The amygdala on the left side of the brain was retained, so it could continue providing its important functions. In fact, neuropsychological evaluations revealed that some aspects of cognition (language and verbal memory) in both people improved after surgery, while measures of visual memory and pattern recognition declined slightly.
Patient 2 told the researchers that after her ablation she was re-training herself now that the excessive fear responses were gone (which are documented in the paper). She had developed the habit of going to the window and looking out and worrying about things going on outside, and after the ablation procedure, she noticed she was still going to the window but not feeling scared or worried anymore.