Common Data Element for Disorders of Consciousness: Recommendations from the Working Group on Therapeutic Interventions.

BACKGROUND: Over the past 30 years, there have been significant advances in the understanding of the mechanisms associated with loss and recovery of consciousness following severe brain injury. This work has provided a strong grounding for the development of novel restorative therapeutic interventions. Although all interventions are aimed at modulating and thereby restoring brain function, the landscape of existing interventions encompasses a very wide scope of techniques and protocols. Despite vigorous research efforts, few approaches have been assessed with rigorous, high-quality randomized controlled trials. As a growing number of exploratory interventions emerge, it is paramount to develop standardized approaches to reporting results. The successful evaluation of novel interventions depends on implementation of shared nomenclature and infrastructure. To address this gap, the Neurocritical Care Society's Curing Coma Campaign convened nine working groups and charged them with developing common data elements (CDEs). Here, we report the work of the Therapeutic Interventions Working Group. METHODS: The working group reviewed existing CDEs relevant to therapeutic interventions within the National Institutes of Health National Institute of Neurological Disorders and Stroke database and reviewed the literature for assessing key areas of research in the intervention space. CDEs were then proposed, iteratively discussed and reviewed, classified, and organized in a case report form (CRF). RESULTS: We developed a unified CRF, including CDEs and key design elements (i.e., methodological or protocol parameters), divided into five sections: (1) patient information, (2) general study information, (3) behavioral interventions, (4) pharmacological interventions, and (5) device interventions. CONCLUSIONS: The newly created CRF enhances systematization of future work by proposing a portfolio of measures that should be collected in the development and implementation of studies assessing novel interventions intended to increase the level of consciousness or rate of recovery of consciousness in patients with disorders of consciousness.

Neural oscillations track recovery of consciousness in acute traumatic brain injury patients.

Electroencephalography (EEG), easily deployed at the bedside, is an attractive modality for deriving quantitative biomarkers of prognosis and differential diagnosis in severe brain injury and disorders of consciousness (DOC). Prior work by Schiff has identified four dynamic regimes of progressive recovery of consciousness defined by the presence or absence of thalamically-driven EEG oscillations. These four predefined categories (ABCD model) relate, on a theoretical level, to thalamocortical integrity and, on an empirical level, to behavioral outcome in patients with cardiac arrest coma etiologies. However, whether this theory-based stratification of patients might be useful as a diagnostic biomarker in DOC and measurably linked to thalamocortical dysfunction remains unknown. In this work, we relate the reemergence of thalamically-driven EEG oscillations to behavioral recovery from traumatic brain injury (TBI) in a cohort of N = 38 acute patients with moderate-to-severe TBI and an average of 1 week of EEG recorded per patient. We analyzed an average of 3.4 hr of EEG per patient, sampled to coincide with 30-min periods of maximal behavioral arousal. Our work tests and supports the ABCD model, showing that it outperforms a data-driven clustering approach and may perform equally well compared to a more parsimonious categorization. Additionally, in a subset of patients (N = 11), we correlated EEG findings with functional magnetic resonance imaging (fMRI) connectivity between nodes in the mesocircuit-which has been theoretically implicated by Schiff in DOC-and report a trend-level relationship that warrants further investigation in larger studies.

What is a minimal clinically important difference for clinical trials in patients with disorders of consciousness? a novel probabilistic approach.

Over the last 30 years, there has been a growing trend in clinical trials towards assessing novel interventions not only against the benchmark of statistical significance, but also with respect to whether they lead to clinically meaningful changes for patients. In the context of Disorders of Consciousness (DOC), despite a growing landscape of experimental interventions, there is no agreed standard as to what counts as a minimal clinically important difference (MCID). In part, this issue springs from the fact that, by definition, DOC patients are either unresponsive (i.e., in a Vegetative State; VS) or non-communicative (i.e., in a Minimally Conscious State; MCS), which renders it impossible to assess any subjective perception of benefit, one of the two core aspects of MCIDs. Here, we develop a novel approach that leverages published, international diagnostic guidelines to establish a probability-based minimal clinically important difference (pMCID), and we apply it to the most validated and frequently used scale in DOC: the Coma Recovery Scale-Revised (CRS-R). This novel method is objective (i.e., based on published criteria for patient diagnosis) and easy to recalculate as the field refines its agreed-upon criteria for diagnosis. We believe this new approach can help clinicians determine whether observed changes in patients' behavior are clinically important, even when patients cannot communicate their experiences, and can align the landscape of clinical trials in DOC with the practices in other medical fields.

Microbiome in Anxiety and Other Psychiatric Disorders.

Initial studies suggested that the fluctuations in the quantity, variety, and composition of the gut microbiota can significantly affect disease processes. This change in the gut microbiota causing negative health benefits was coined dysbiosis. Initial research focused on gastrointestinal illnesses. However, the gut microbiome was found to affect more than just gastrointestinal diseases. Numerous studies have proven that the gut microbiome can influence neuropsychiatric diseases such as Parkinson's disease, Alzheimer's disease, and multiple sclerosis.

Transcranial focused ultrasound selectively increases perfusion and modulates functional connectivity of deep brain regions in humans.

Background: Low intensity, transcranial focused ultrasound (tFUS) is a re-emerging brain stimulation technique with the unique capability of reaching deep brain structures non-invasively. Objective/Hypothesis: We sought to demonstrate that tFUS can selectively and accurately target and modulate deep brain structures in humans important for emotional functioning as well as learning and memory. We hypothesized that tFUS would result in significant longitudinal changes in perfusion in the targeted brain region as well as selective modulation of BOLD activity and BOLD-based functional connectivity of the target region. Methods: In this study, we collected MRI before, simultaneously during, and after tFUS of two deep brain structures on different days in sixteen healthy adults each serving as their own control. Using longitudinal arterial spin labeling (ASL) MRI and simultaneous blood oxygen level dependent (BOLD) functional MRI, we found changes in cerebral perfusion, regional brain activity and functional connectivity specific to the targeted regions of the amygdala and entorhinal cortex (ErC). Results: tFUS selectively increased perfusion in the targeted brain region and not in the contralateral homolog or either bilateral control region. Additionally, tFUS directly affected BOLD activity in a target specific fashion without engaging auditory cortex in any analysis. Finally, tFUS resulted in selective modulation of the targeted functional network connectivity. Conclusion: We demonstrate that tFUS can selectively modulate perfusion, neural activity and connectivity in deep brain structures and connected networks. Lack of auditory cortex findings suggests that the mechanism of tFUS action is not due to auditory or acoustic startle response but rather a direct neuromodulatory process. Our findings suggest that tFUS has the potential for future application as a novel therapy in a wide range of neurological and psychiatric disorders associated with subcortical pathology.

A Systematic Approach to Neuropsychiatric Intervention: Functional Neuroanatomy Underlying Symptom Domains as Targets for Treatment.

An ever-growing population experiences a wide range of psychopathologies, and there is now more than ever a need for clear differential diagnoses between disorders. Furthering this need is the fact that many psychological, psychiatric, and neurological disorders have overlapping features. Functional neuroimaging has been shown to differentiate not only between the function of different brain structures but also between the roles of these structures in functional networks. The aim of this article is to aid in the goal of parsing out disorders on the basis of specific symptom domains by utilizing the most recent literature on functional networks. Current literature on the role of brain networks in relation to different psychopathological symptom domains is examined and corresponding circuit-based therapies that have been or may be used to treat them are discussed. Research on depression, obsession and compulsions, addiction, anxiety, and psychosis is reviewed. An understanding of networks and their specific dysfunctions opens the possibility of a new form of psychopathological treatment.

Focusing in on the Future of Focused Ultrasound as a Translational Tool.

This article summarizes the field of focused ultrasound for use in neuromodulation and discusses different ways of targeting, delivering, and validating focused ultrasound. A discussion is focused on parameter space and different ongoing theories of ultrasonic neuromodulation. Current and future applications of the technique are discussed.

Ultrasound as a Neurotherapeutic: A Circuit- and System-Based Interrogation.

Focused ultrasound is a novel brain stimulation modality that combines the noninvasiveness of repetitive transcranial magnetic stimulation and the precision of deep brain stimulation. In this review, the authors examine low-intensity focused ultrasound for brain mapping and neuromodulation. They also discuss high-intensity focused ultrasound, which is used for incisionless surgeries, such as capsulotomies for obsessive-compulsive disorder. Future potential applications of focused ultrasound are also presented.

Ultrasonic Deep Brain Neuromodulation in Acute Disorders of Consciousness: A Proof-of-Concept.

The promotion of recovery in patients who have entered a disorder of consciousness (DOC; e.g., coma or vegetative states) following severe brain injury remains an enduring medical challenge despite an ever-growing scientific understanding of these conditions. Indeed, recent work has consistently implicated altered cortical modulation by deep brain structures (e.g., the thalamus and the basal ganglia) following brain damage in the arising of, and recovery from, DOCs. The (re)emergence of low-intensity focused ultrasound (LIFU) neuromodulation may provide a means to selectively modulate the activity of deep brain structures noninvasively for the study and treatment of DOCs. This technique is unique in its combination of relatively high spatial precision and noninvasive implementation. Given the consistent implication of the thalamus in DOCs and prior results inducing behavioral recovery through invasive thalamic stimulation, here we applied ultrasound to the central thalamus in 11 acute DOC patients, measured behavioral responsiveness before and after sonication, and applied functional MRI during sonication. With respect to behavioral responsiveness, we observed significant recovery in the week following thalamic LIFU compared with baseline. With respect to functional imaging, we found decreased BOLD signals in the frontal cortex and basal ganglia during LIFU compared with baseline. In addition, we also found a relationship between altered connectivity of the sonicated thalamus and the degree of recovery observed post-LIFU.

Design, Development, and Operation of a Low-Intensity Focused Ultrasound Pulsation (LIFUP) System for Clinical Use.

Noninvasive low-intensity focused ultrasound pulsation (LIFUP) neuromodulation provides a unique approach to both investigating and treating the brain. This work describes a well-calibrated, simple-to-use ultrasound stimulation system for neuromodulation studies. It provides a single-element 650-kHz transducer design and a straightforward control mechanism, with extensive calibration and internal electronic monitoring to prevent unwanted over or under treatment. One goal of this approach is to relieve researchers of many of the details associated with developing their own exposure equipment. A unique transducer positioning system and distinctive MRI fiducial targets simplify alignment and targeting. The system design, control software, calibration, and alignment techniques are described in detail. Examples of transducer targeting and neurostimulation using the system are provided.

Brain circuitry underlying the ABC model of anxiety.

Anxiety Disorders are prevalent and often chronic, recurrent conditions that reduce quality of life. The first-line treatments, such as serotonin reuptake inhibitors and cognitive behavioral therapy, leave a significant proportion of patients symptomatic. As psychiatry moves toward targeted circuit-based treatments, there is a need for a theory that unites the phenomenology of anxiety with its underlying neural circuits. The Alarm, Belief, Coping (ABC) theory of anxiety describes how the neural circuits associated with anxiety interact with each other and domains of the anxiety symptoms, both temporally and spatially. The latest advancements in neuroimaging techniques offer the ability to assess these circuits in vivo. Using Neurosynth, a large open-access meta-analytic imaging database, the association between terms related to specific neural circuits was explored within the ABC theory framework. Alarm-related terms were associated with the amygdala, anterior cingulum, insula, and bed nucleus of stria terminalis. Belief-related terms were associated with medial prefrontal cortex, precuneus, bilateral temporal poles, and hippocampus. Coping-related terms were associated with the ventrolateral and dorsolateral prefrontal cortices, basal ganglia, and anterior cingulate. Neural connections underlying the functional neuroanatomy of the ABC model were observed. Additionally, there was considerable interaction and overlap between circuits associated with the symptom domains. Further neuroimaging research is needed to explore the dynamic interaction between the functional domains of the ABC theory. This will pave the way for probing the neuroanatomical underpinnings of anxiety disorders and provide an evidence-based foundation for the development of targeted treatments, such as neuromodulation.

Real time and delayed effects of subcortical low intensity focused ultrasound.

Deep brain nuclei are integral components of large-scale circuits mediating important cognitive and sensorimotor functions. However, because they fall outside the domain of conventional non-invasive neuromodulatory techniques, their study has been primarily based on neuropsychological models, limiting the ability to fully characterize their role and to develop interventions in cases where they are damaged. To address this gap, we used the emerging technology of non-invasive low-intensity focused ultrasound (LIFU) to directly modulate left lateralized basal ganglia structures in healthy volunteers. During sonication, we observed local and distal decreases in blood oxygenation level dependent (BOLD) signal in the targeted left globus pallidus (GP) and in large-scale cortical networks. We also observed a generalized decrease in relative perfusion throughout the cerebrum following sonication. These results show, for the first time using functional MRI data, the ability to modulate deep-brain nuclei using LIFU while measuring its local and global consequences, opening the door for future applications of subcortical LIFU.

Sedation-Induced Burst Suppression Predicts Positive Outcome Following Traumatic Brain Injury.

While electroencephalogram (EEG) burst-suppression is often induced therapeutically using sedatives in the intensive care unit (ICU), there is hitherto no evidence with respect to its association to outcome in moderate-to-severe neurological patients. We examined the relationship between sedation-induced burst-suppression (SIBS) and outcome at hospital discharge and at 6-month follow up in patients surviving moderate-to-severe traumatic brain injury (TBI). For each of 32 patients recovering from coma after moderate-to-severe TBI, we measured the EEG burst suppression ratio (BSR) during periods of low responsiveness as assessed with the Glasgow Coma Scale (GCS). The maximum BSR was then used to predict the Glasgow Outcome Scale extended (GOSe) at discharge and at 6 months post-injury. A multi-model inference approach was used to assess the combination of predictors that best fit the outcome data. We found that BSR was positively associated with outcomes at 6 months (P = 0.022) but did not predict outcomes at discharge. A mediation analysis found no evidence that BSR mediates the effects of barbiturates or propofol on outcomes. Our results provide initial observational evidence that burst suppression may be neuroprotective in acute patients with TBI etiologies. SIBS may thus be useful in the ICU as a prognostic biomarker.

Safety of focused ultrasound neuromodulation in humans with temporal lobe epilepsy.

OBJECTIVE: Transcranial Focused Ultrasound (tFUS) is a promising new potential neuromodulation tool. However, the safety of tFUS neuromodulation has not yet been assessed adequately. Patients with refractory temporal lobe epilepsy electing to undergo an anterior temporal lobe resection present a unique opportunity to evaluate the safety and efficacy of tFUS neuromodulation. Histological changes in tissue after tFUS can be examined after surgical resection, while further potential safety concerns can be assessed using neuropsychological testing. METHODS: Neuropsychological functions were assessed in eight patients before and after focused ultrasound sonication of the temporal lobe at intensities up to 5760 mW/cm2. Using the BrainSonix Pulsar 1002, tFUS was delivered under MR guidance, using the Siemens Magnetom 3T Prisma scanner. Neuropsychological changes were assessed using various batteries. Histological changes were assessed using hematoxylin and eosin staining, among others. RESULTS: With respect to safety, the histological analysis did not reveal any detectable damage to the tissue, except for one subject for whom the histology findings were inconclusive. In addition, neuropsychological testing did not show any statistically significant changes in any test, except for a slight decrease in performance on one of the tests after tFUS. SIGNIFICANCE: This study supports the hypothesis that low-intensity Transcranial Focused Ultrasound (tFUS) used for neuromodulation of brain circuits at intensities up to 5760 mW/cm2 may be safe for use in human research. However, due to methodological limitations in this study and inconclusive findings, more work is warranted to establish the safety. Future directions include greater number of sonications as well as longer exposure at higher intensity levels to further assess the safety of tFUS for modulation of neuronal circuits.