Low Intensity Focused Ultrasound for Posttraumatic Stress Disorder

PTSD is highly prevalent in Veterans and is associated with significant psychiatric and medical comorbidity and healthcare utilization. Most importantly, PTSD prevents Veterans from reintegrating into society and is associated with significant disability and psychosocial dysfunction. Despite its prevalence and devastating impact, even the most efficacious treatments have modest success in improving either symptoms or functioning in Veterans with PTSD. One reason for this limited efficacy is the inability for current treatments to directly target and engage deep brain regions which are directly involved in PTSD psychopathology. However, recent advances in the areas of neuroscience, psychiatry and technology allow, for the first time, development of new technologies that can non-invasively and reversibly modulate deep brain structures through the use of low intensity focused ultrasound (FUS). This application is targeting the amygdala, which is a core region involved in PTSD and many other psychiatric disorders.

To date, cleared uses of focused ultrasound are high-intensity sonication to irreversibly ablate tissue, therapeutically for movement disorders and cancer-related pain. Effects are highly focal (i.e., millimeter-scale), and occur without adjacent tissue damage. In contrast, FUS as it is proposed here uses acoustic energy at the same precision but within safety limits for diagnostic ultrasound. Although therapeutic use of FUS remains largely unexplored, several groups demonstrated that FUS can safely modulates neural activity in mice, rabbit, swine, and non-human primates. Even more recent data indicates FUS can safely modulate human cortical activity, including that of somatosensory and motor cortex as well as the thalamus in healthy individuals.

Our group has been leading the effort to evaluate the use of FUS, by delivering a single dose of FUS inside the bore of an MRI scanner to a group of depressed Veterans. However, FUS has not yet been developed for PTSD, and before rigorous clinical trials of FUS for PTSD can be initiated, several key questions remain and are the focus of this study.

Using a phase II-style proof of concept/dose-finding study, investigators will characterize the effects of sham-controlled FUS administrations. Veterans with chronic PTSD first receive an MRI scan to facilitate high-precision targeting using out-of-scanner stereotactic neuronavigation. After targeting, Veterans are randomized to receive sham FUS, or one, two, or three FUS administrations per week over a month, and then Veterans will be followed for up to three months to evaluate longer-term effects. Neuroimaging MRI will be obtained prior to and following completion of FUS to explore neural effects. Thus, this study will evaluate the short-term durability of any effects on symptoms and function, and the design will provide important insight into the potential use for repeated administrations over time. The significance of this project lies in the potential to develop non-invasive deep brain stimulation for PTSD, with lessons learned that will be applicable for broader implementation; this goal can be realized through this careful and programmatic phase II study.