
Djordje PopovicAdvanced Brain Monitoring
Djordje Popovic
MD, PhD
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54
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Introduction
Skills and Expertise
Additional affiliations
January 2005 - September 2007
Publications
Publications (54)
INTRODUCTION: The capacity for case‐control epidemiological investigations into the relationship between sleep duration, structure and continuity, and memory consolidation, metabolic syndromes, neurodegenerative disorders and hospital stays might be expanded by using non‐traditional sleep measurement, if the results were accurate. This is the first...
Mental workload is difficult to quantify because it results from an interplay of the objective task load, ambient and internal distractions, capacity of mental resources, and strategy of their utilization. Furthermore, different types of mental resources are mobilized to a different degree in different tasks even if their perceived difficulty is th...
Sleep mask for reducing sleep inertia. In an embodiment, the sleep mask comprises a foam layer having a shape that covers both of a human subject's eyes so as to attenuate ambient light. Visual stimulation element(s), configured to emit light, are positioned between the foam layer and the subject's eyes. In addition, a plurality of sensors position...
Sleep deprivation and inefficiency can have a crucial impact on performance. One potential method for ameliorating the impact of bad sleep, or eliminating it all-together, is with sleep stage-dependent sensory stimulation. The effect of superficial facial heating on sleep architecture was studied in 10 subjects. A 20% decrease in sleep onset latenc...
Photoplethysmography (PPG) is obtained using one red (e.g., 660 nm) and one infrared (e.g., 880 to 940 nm) light emitting diode with a single photo diode in combination with a pressure transducer thereby allowing both CVP and SpO2 to be measured simultaneously. The system also includes sensors capable of measuring position, angle and/or movement of...
Study Objectives:
A majority of patients diagnosed with obstructive sleep apnea are position dependent whereby they are at least twice as severe when sleeping supine (POSA). This study evaluated the accuracy and efficacy of a neck-worn device designed to limit supine sleep. The study included nightly measurements of snoring, sleep/wake, time supine...
Systems and methods for assessment of sleep quality in adults and children are provided. These techniques include an apparatus worn above the forehead containing the circuitry for collecting and storing physiological signals. The apparatus integrates with a sensor strip and a nasal mask to obtain the physiological signals for the user. The form fac...
Accuracy and limitations of automatic scoring of sleep stages and electroencephalogram arousals from a single derivation (Fp1 -Fp2 ) were studied in 29 healthy adults using a portable wireless polysomnographic recorder. All recordings were scored five times: twice by a referent scorer who viewed the standard polysomnographic montage and observed th...
In this paper we introduce a novel workload assessment tool (called PHYSIOPRINT) that is based on the combination of two types of physiological signals: electroencephalography (EEG) and electrocardiography (ECG). The tool is inspired by a theoretical workload model developed by the US Army that covers a large number of different workload types rele...
Electroencephalography (EEG) assessment in research and clinical studies is limited by the patient burden of multiple electrodes and the time needed to manually score records. The objective of our study was to investigate the accuracy of an automated sleep-staging algorithm which is based on a single bipolar EEG signal.
Three raters each manually s...
Over the last decade, numerous papers have presented the use of dry electrodes capable of acquiring electroencephalogram (EEG) signals through hair. A few of these dry electrode prototypes have even progressed from lab-based EEG acquisition to commercial sales. While the field has improved rapidly as of late, most dry electrodes share a number of s...
The ability of cerebral vasculature to regulate cerebral blood flow
(CBF) in the face of changes in arterial blood pressure (SAP) or
intracranial pressure (ICP) is an important guard against secondary
ischemia in acute brain injuries, and official guidelines recommend that
therapeutic decisions be guided by continuous monitoring of CBF
autoregulati...
In contrast to numerous reports on long-term psychological consequences of disasters, the literature addressing the acute impact of intentional collective disaster is limited.
This research aimed to examine the impact of the bombing campaign on the behavior of people living in Belgrade during the air attacks in 1999.
The questionnaire was designed...
Alterations of sleep duration and architecture have been associated with increased morbidity and mortality, and specifically linked to chronic cardiovascular disease and psychiatric disorders, such as type 2 diabetes or depression. Measurement of sleep quality to assist in the diagnosis or treatment of these diseases is not routinely performed due...
INTRODUCTION : Self-applicable devices with electrodes below the hairline (e.g. ZEO, ARES) represent a promising tool for assessment of sleep quality in long-term or large-scale applications where the use of PSG is cost-prohibitive, while the information provided by actigraphs or sleep diaries does not suffice. As part of our efforts towards develo...
Previous electroencephalography (EEG)-based fatigue-related research primarily focused on the association between concurrent cognitive performance and time-locked physiology. The goal of this study was to investigate the capability of EEG to assess the impact of fatigue on both present and future cognitive performance during a 20-min sustained atte...
INTRODUCTION Wrist actigraphy is often used in conjunction with unattended cardio-respiratory monitoring to provide an estimate of the total sleep time. Head movements have rarely been used for this purpose; however, head-worn sleep recorders (e.g.NightCap, ARES, ZEO) have been introduced with some success, and further advances in the miniaturizati...
A great deal of research over the last century has focused on drowsiness/alertness detection, as fatigue-related physical and cognitive impairments pose a serious risk to public health and safety. Available drowsiness/alertness detection solutions are unsatisfactory for a number of reasons: (1) lack of generalizability, (2) failure to address indiv...
INTRODUCTION: Several recent studies have reported the sleep-promoting effects of mild warming of hands and/or feet either prior to or during the process of falling asleep. Anecdotal reports have implied a similar effect of facial warming but the objective evidence was lacking. This study examined the effects of mild facial warming on sleep latenci...
INTRODUCTION: Cognitive impairments caused by chronic sleep deprivation can be ameliorated by brief naps, but the effect depends on accumulated sleep debt and timing, duration and sleep architecture of the naps. Naps would likely be more effective if their timing and duration could be tailored with respect to the accumulated sleep debt and previous...
Increased intracranial pressure (ICP) is one of the major causes of secondary brain ischemia that accompanies a variety of pathological conditions, most notably, traumatic brain injury (TBI), stroke, and intracranial hemorrhages. However, aside from a few Level I trauma centers, ICP monitoring is rarely a part of the clinical management of patients...
The learning of a novel task currently rely heavily on conventional classroom instruction with qualitative assessment and observation. Introduction of individualized tutorials with integrated neuroscience-based evaluation techniques could significantly accelerate skill acquisition and provide quantitative evidence of successful training. We have cr...
This paper presents a theoretical framework for the development of non-invasive methods for detection and discrimination between
mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD). Growing use of IEDs and increased pace of multiple
deployment cycles in current conflicts has lead to significant increases in exposure to risk...
One of the major deficiencies with the EEG-based classifiers used in today’s laboratory settings is that they are often ill
suited for the real world. In many cases the classifiers that were painstakingly developed in the controlled laboratory environment
become unreliable with increased mobility of the user. In addition to increased mobility, many...
Sleep deprivation-induced deficiencies in performance can be associated with high financial and human costs. Napping is an
effective countermeasure, but the effects depend on previously accumulated sleep debt and timing, duration and sleep architecture
of the naps. Long-term assessment of sleep architecture of nap/sleep episodes could yield an esti...
INTRODUCTION: Brief naps dispersed throughout the day can ameliorate cognitive impairments caused by chronic sleep deprivation but the effect depends upon their timing, duration, sleep architecture, accumulated sleep debt and susceptibility to sleep deprivation. More efficient mitigation of cognitive deficits could be achieved by tailoring timing a...
INTRODUCTION: Cognitive impairments caused by chronic sleep deprivation can be ameliorated by frequent brief naps, but the effect depends on accumulated sleep debt and timing, duration and sleep architecture of the naps. Naps would likely be more effective if their sleep architecture, timing and duration could be tailored with respect to the accumu...
INTRODUCTION: A limited number of studies have measured changes in sleep-disordered-breathing subsequent to treatment with mandibular repositioning devices (MRD). This pilot study assesses changes in ef- ficacy and/or need for routine adjustment to optimize outcomes.
METHODS: Seven females and eight males underwent in-home sleep stud- ies (ARES Med...
The aim of the study was to validate the measurement of Forehead Venous Pressure derived from a single site on the forehead as an alternative to esophageal manometry and respiratory effort bands in the differential diagnosis of sleep apnea.
Fourteen subjects underwent a laboratory polysomnography concurrently with ARES Unicorder at Walter Reed Army...
When conducting a treatment intervention, it is assumed that variability associated with measurement of the disease can be controlled sufficiently to reasonably assess the outcome. In this study we investigate the variability of Apnea-Hypopnea Index obtained by polysomnography and by in-home portable recording in untreated mild to moderate obstruct...
Marksmanship training involves a combination of classroom instructional learning and field practice involving the instantiation of a well-defined set of sensory, motor and cognitive skills. Current training procedures rely heavily on conventional classroom instruction often with qualitative assessment based on observation (i.e. coaching). We have d...
The increasing demands of the global economy for 24-hour, 7-day operations is affecting the health and performance of workers worldwide. The deleterious effects of chronic sleep deprivation and associated stress have potentially dangerous and expensive consequences as a result of impaired alertness, attention, memory and decision-making for individ...
INTRODUCTION: Increased activity of the sympathetic nervous system (SNS) as measured by catecholamine blood levels, muscle sympathetic nerve activity or heart rate variability (HRV) has been reported in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) therapy reduces the activity of the SNS but its use in trea...
INTRODUCTION: Measurement of respiratory effort is important in differ- entiating central from obstructive breathing during sleep and distinguish- ing sleep disorder breathing (SDB) from normal changes in ventilation.
METHODS: Thirteen patients underwent a laboratory-PSG which in- cluded an esophageal catheter and chest-wall and abdomen piezoelec-...
INTRODUCTION: Portable devices have been increasingly used for the di- agnosis of obstructive sleep apnea (OSA) but are limited by the inability to measure and stage sleep. This is a preliminary report on the accuracy of automated algorithm for staging sleep using a forehead portable re- corder (ARES™ Unicorder).
METHODS: Five healthy subjects and...
Our research objective is to use neuroscience-based assessments to accelerate military skill acquisition and provide quantitative evidence of successful training by detecting, in real-time, cognitive and physiological states of the trainee under various conditions.
The research focuses on: (a) integrating brain monitoring capabilities into rifle ma...
The ability to track salient targets is common to contemporary work environments ranging from airport security to imagery analysis. A neurotechnology platform was implemented for real-time EEG to monitor operator state during review of complex satellite imagery. Consistent, quantifiable stimulus-locked ERP signatures for targets/non-targets were id...
Restoration of motor function to paralyzed limbs by functional electrical stimulation (FES) has been hampered by the lack of precise and gradual control over muscle recruitment. A suitable interface should provide selective stimulation of individual muscles with graded recruitment of force. The BION was developed to enable neuromuscular stimulation...
There is increasing evidence that mandibular advancement devices (MADs) can be an effective treatment for some patients with obstructive sleep apnea, a highly prevalent chronic disease. In this study, the objectives were to objectively assess the effectiveness of MAD therapy using a limited channel recorder, and to develop a model for identifying p...
We are developing a novel, robust tactile sensor array that mimics the human fingertip and its distributed set of touch receptors. The mechanical components are similar to a fingertip, with a rigid core surrounded by a weakly conductive fluid contained within an elastomeric skin. It uses the deformable properties of the finger pad as part of the tr...
INTRODUCTION: This restrospective analysis of an existing database of sleep studies acquired with an ARES Unicorder investigates the nightto-night variability to assess the utility of multi-night studies.
METHODS: A total of 477 subjects with >4-hours of recording time on each of two-nights were analyzed. Auto-scoring rules identified apneas (10-s...
Background: The prevalence of obstructive sleep apnea/hypop-nea (OSA) in commercial truck drivers is substantially greater than in the general population and undiagnosed OSA in transportation workers is a concern. We describe the validation of a simple, inexpensive and easy to use screening tool to identify individuals with a significant probabilit...
This study has been carried out to examine whether the Suchey-Brooks (S&B) methods could be successfully applied in age assessment of populations from the Balkans. The known-age sample consists of 33 females and 52 males pairs of pubic bones collected from the autopsy cases. Age estimation by S&B method showed an accuracy of 89.74% in males and 72....
The performance of prosthetic hands and robotic manipulators is severely limited by their having little or no tactile information compared to the human hand. Technologies such as MEMS, microfluidics, and nanoparticles have been used to produce arrays of force sensors, but these are generally not robust enough to mount on curved, deformable finger p...
This paper analyzes the reliability of the Işcan’s sternal rib-ends phase method for the assessment of individual age at the time of death in the Balkan population. The method is based on the morphological age changes of the sternal rib ends. The tested samples consisted of 65 ribs from autopsy cases in the Institute for Forensic Medicine, Universi...
Marksmanship training involves a combination of classroom instructional learning and field practice involving the instantiation
of a well-defined set of sensory, motor and cognitive skills. Current training procedures rely heavily on conventional classroom
instruction often with qualitative assessment based on observation (i.e. coaching). We have d...