Bioresorbable silicon electronics for transient spatiotemporal mapping of electrical activity from the cerebral cortex.

Bioresorbable silicon electronics technology offers unprecedented opportunities to deploy advanced implantable monitoring systems that eliminate risks, cost and discomfort associated with surgical extraction. Applications include postoperative monitoring and transient physiologic recording after percutaneous or minimally invasive placement of vascular, cardiac, orthopaedic, neural or other devices. We present an embodiment of these materials in both passive and actively addressed arrays of bioresorbable silicon electrodes with multiplexing capabilities, which record in vivo electrophysiological signals from the cortical surface and the subgaleal space. The devices detect normal physiologic and epileptiform activity, both in acute and chronic recordings. Comparative studies show sensor performance comparable to standard clinical systems and reduced tissue reactivity relative to conventional clinical electrocorticography (ECoG) electrodes. This technology offers general applicability in neural interfaces, with additional potential utility in treatment of disorders where transient monitoring and modulation of physiologic function, implant integrity and tissue recovery or regeneration are required

The physiologic correlates of learning in the classroom environment

This study served to further investigate learning and memory, and to offer a potential tool to support educational interventions. More specifically, this was accomplished by an investigation of the physiologic changes in the brain that occurred while students learned medical anatomy. A group of 29 students taking the Gross Anatomy course at Boston University School of Medicine participated in the study. Testing occurred in two sessions: prior to the course and at the completion of the course. For each session, scalp EEG was recorded while participants were shown 176 anatomical terms (132 relevant to the course and 44 obscure) and asked to respond with "Can Define", "Familiar", or "Don't Know". Behavioral results indicated a positive correlation between participants' course grades and performance on the experimental tasks. EEG results were analyzed for event-related potential (ERP) components related to two memory components: familiarity and recollection. Results had a number of indications. For Don't Know responses, a stronger early frontal, late parietal, and late frontal effect occurred more so for terms of Session 1 compared to Session 2. For an analysis of just Session 2 data, results indicated increased activity of the early frontal, late parietal, and late frontal effects for Can Define responses only. Session 2 Can Define responses elicited a stronger early frontal ERP, occurring between 300 and 500 milliseconds yet, the most post-retrieval processing and monitoring appeared for Can Define terms of Session 2. Ultimately, we focused on investigating two points: 1) the effect of classroom learning on memory, and 2) the examination of ERPs as a tool to guide education interventions. Specifically, ERPs would potentially indicate markers to predict whether students would retain materials long before behavioral measures indicate these results. This has potential to determine whether long-lasting or transient learning will occur; as well as the potential to support early intervention strategies for not just students, but also individuals with learning disabilities or memory impairments

Prognostic value of pulmonary dead space in patients with the acute respiratory distress syndrome.

A study published in the previous issue of Critical Care demonstrates that measurement of the pulmonary dead-space fraction is superior to hypoxemia as an indicator of a favorable physiologic response to prone positioning in patients with severe acute respiratory distress syndrome. These results add to the growing evidence supporting the clinical and research value of measuring pulmonary dead space in patients with acute respiratory distress syndrome and using this pulmonary physiologic end-point as one indicator of a favorable response to therapy

Determining predictors of underlying etiology and clinical deterioration in patients with physiologic instability in the emergency department

Thesis (M.A.)--Boston UniversityShock is a critical state defined by inadequate oxygen delivery to tissues. It is well known in the critical care community that early diagnosis and treatment of shock are crucial to improving patient outcomes. However, in many cases, when a state of circulatory shock has been reached, irreversible damage already occurred. In the present study, we broadened our patient cohort from those with shock to those with physiologic instability with the intent of finding predictive factors that allow us to recognize when a patient is at risk for deterioration or when it is already occurring. These patients included patients with pre-shock, shock, and other forms of dysfunction. The purpose of this study was to determine the predictors of underlying etiology of physiologic instability as well as the likelihood of clinical deterioration in these various states, using elements from the physical exam, history, laboratory values, and vital sign measurements. This study was a prospective observational study of patients, from November 15, 2012 to March 1, 2013, found to have physiologic instability in the emergency department at an urban, academic tertiary-care hospital with 55,000 annual visits. Physiologic instability was defined as any one of the following abnormalities: heart rate (HR) > 130, respiratory rate (RR>24), shock index (SI) > 1, systolic blood pressure (SBP) 4.0 mmol/L, for a time period of more than five minutes. We identified 540 patients, 74.8% of which were included. Data describing epidemiology, and elements from the patient history and physical exam were abstracted from physician charts and the final etiology of physiologic instability, defined as septic, cardiogenic, hypovolemic, hemorrhagic, or other, was adjudicated by a physician. Blood samples from a subset of our patient group were collected from the hospital hematology laboratory and sent to the Wyss Institute to be analyzed using a novel bacterial detection assay. All of the covariates that data was collected for were analyzed to determine their diagnostic and prognostic value. [TRUNCATED

Physiologic Status Monitoring via the Gastrointestinal Tract

Reliable, real-time heart and respiratory rates are key vital signs used in evaluating the physiological status in many clinical and non-clinical settings. Measuring these vital signs generally requires superficial attachment of physically or logistically obtrusive sensors to subjects that may result in skin irritation or adversely influence subject performance. Given the broad acceptance of ingestible electronics, we developed an approach that enables vital sign monitoring internally from the gastrointestinal tract. Here we report initial proof-of-concept large animal (porcine) experiments and a robust processing algorithm that demonstrates the feasibility of this approach. Implementing vital sign monitoring as a stand-alone technology or in conjunction with other ingestible devices has the capacity to significantly aid telemedicine, optimize performance monitoring of athletes, military service members, and first-responders, as well as provide a facile method for rapid clinical evaluation and triage.United States. Dept. of the Air Force (Air Force Contract FA8721-05-C-0002)United States. Dept. of Defense. Assistant Secretary of Defense for Research & EngineeringNational Institutes of Health (U.S.) (Grant EB000244)National Institutes of Health (U.S.) (Grant T32DK7191-38-S1