Aerospace medicine and biology: A continuing bibliography with indexes, supplement 203

This bibliography lists 150 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 199

This bibliography lists 82 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1979

ATTENTIONAL BIAS TO ALCOHOL IN AN IN VIVO SETTING

The phenomenon of attentional bias to alcohol, where drinkers demonstrate a preference in allocating visual attention towards alcohol-related stimuli rather than neutral stimuli, is well-established. Studies detecting this phenomenon typically utilize computer-administered stimulus presentation tasks such as the visual dot probe task. Despite their frequency of use, these tasks do not represent the ways in which individuals typically encounter alcohol outside of the laboratory. Typical environments where alcohol is present allow individuals to move about freely and encounter alcohol while also being exposed to many other stimuli. This dissertation sought to implement a novel approach to assessing attentional bias in vivo, and identify how alcohol consumption might influence such in vivo attentional bias. This two-study dissertation utilized an in vivo task where participants looked freely around a room representing a recreational setting containing numerous objects while portable eye-tracking glasses monitored what an individual looked at and for how long. Target items of alcohol and neutral beverages were placed throughout the environment and fixation time spent on these objects was recorded. The first study of this dissertation examined attentional bias to alcohol-related objects across two identical testing sessions to understand the impact of novelty on allocation of in vivo attention. The second study tested individuals using the same in vivo assessment following a 0.30 g/kg dose of alcohol, a 0.65 g/kg dose of alcohol and a placebo. Participants also completed the visual dot probe task in order to measure and compare their attentional bias in a more traditionally implemented task to the novel in vivo approach. Results from the first study indicate that as the novelty of stimuli begins to wane and habituation to neutral stimuli occurs, attentional bias to alcohol-related objects emerges. This attentional bias was shown to be related to drinking habits, where heavier drinkers demonstrated increased attentional bias. The second study in this research found no discernible effect of alcohol consumption on in vivo attentional bias, but did identify a satiating effect of consumption on bias as measured by the visual dot probe task. Additional visual dot probe findings suggest the specificity of the effect of alcohol consumption on attentional bias. Together, these findings help inform whether there is benefit in utilizing an ecological model of measuring attentional bias and how the phenomenon might be measured in laboratory settings in the future

Development of a practical and mobile brain-computer communication device for profoundly paralyzed individuals

Thesis (Ph.D.)--Boston UniversityBrain-computer interface (BCI) technology has seen tremendous growth over the past several decades, with numerous groundbreaking research studies demonstrating technical viability (Sellers et al., 2010; Silvoni et al., 2011). Despite this progress, BCIs have remained primarily in controlled laboratory settings. This dissertation proffers a blueprint for translating research-grade BCI systems into real-world applications that are noninvasive and fully portable, and that employ intelligent user interfaces for communication. The proposed architecture is designed to be used by severely motor-impaired individuals, such as those with locked-in syndrome, while reducing the effort and cognitive load needed to communicate. Such a system requires the merging of two primary research fields: 1) electroencephalography (EEG)-based BCIs and 2) intelligent user interface design. The EEG-based BCI portion of this dissertation provides a history of the field, details of our software and hardware implementation, and results from an experimental study aimed at verifying the utility of a BCI based on the steady-state visual evoked potential (SSVEP), a robust brain response to visual stimulation at controlled frequencies. The visual stimulation, feature extraction, and classification algorithms for the BCI were specially designed to achieve successful real-time performance on a laptop computer. Also, the BCI was developed in Python, an open-source programming language that combines programming ease with effective handling of hardware and software requirements. The result of this work was The Unlock Project app software for BCI development. Using it, a four-choice SSVEP BCI setup was implemented and tested with five severely motor-impaired and fourteen control participants. The system showed a wide range of usability across participants, with classification rates ranging from 25-95%. The second portion of the dissertation discusses the viability of intelligent user interface design as a method for obtaining a more user-focused vocal output communication aid tailored to motor-impaired individuals. A proposed blueprint of this communication "app" was developed in this dissertation. It would make use of readily available laptop sensors to perform facial recognition, speech-to-text decoding, and geo-location. The ultimate goal is to couple sensor information with natural language processing to construct an intelligent user interface that shapes communication in a practical SSVEP-based BCI

Ultra low power wearable sleep diagnostic systems

Sleep disorders are studied using sleep study systems called Polysomnography that records several biophysical parameters during sleep. However, these are bulky and are typically located in a medical facility where patient monitoring is costly and quite inefficient. Home-based portable systems solve these problems to an extent but they record only a minimal number of channels due to limited battery life. To surmount this, wearable sleep system are desired which need to be unobtrusive and have long battery life. In this thesis, a novel sleep system architecture is presented that enables the design of an ultra low power sleep diagnostic system. This architecture is capable of extending the recording time to 120 hours in a wearable system which is an order of magnitude improvement over commercial wearable systems that record for about 12 hours. This architecture has in effect reduced the average power consumption of 5-6 mW per channel to less than 500 uW per channel. This has been achieved by eliminating sampled data architecture, reducing the wireless transmission rate and by moving the sleep scoring to the sensors. Further, ultra low power instrumentation amplifiers have been designed to operate in weak inversion region to support this architecture. A 40 dB chopper-stabilised low power instrumentation amplifiers to process EEG were designed and tested to operate from 1.0 V consuming just 3.1 uW for peak mode operation with DC servo loop. A 50 dB non-EEG amplifier continuous-time bandpass amplifier with a consumption of 400 nW was also fabricated and tested. Both the amplifiers achieved a high CMRR and impedance that are critical for wearable systems. Combining these amplifiers with the novel architecture enables the design of an ultra low power sleep recording system. This reduces the size of the battery required and hence enables a truly wearable system.Open Acces

Hyperbaric Medicine

Hyperbaric oxygen is a known therapeutic agent, and treatments using this agent remain a matter of discussion and research. This Special Issue collection will add new knowledge and also offer some not so usual approaches to foster contemporary understanding and potential benefit for patients and scholars

Macular pigment and percentage of body fat

PURPOSE. To investigate the relationship between percentage of body fat and macular pigment (MP) optical density. METHODS. One hundred healthy subjects of ages between 22 and 60 years volunteered to participate in this study. MP optical density was measured psychophysically, serum lutein and zeaxanthin were quantified by HPLC, and dietary intake of lutein and zeaxanthin was assessed using a validated food frequency questionnaire. Body fat was measured by dual energy x-ray absorptiometry (DEXA); body mass index (BMI) was also calculated for each subject. Clinical and personal details were recorded, with particular attention directed toward putative risk factors for AMD. RESULTS. There was a significant inverse relationship between the percentage of body fat and MP optical density in males (r ϭ Ϫ0.392, P Ͻ 0.01), and after correcting for age and dietary lutein and zeaxanthin, this inverse relationship remained significant (r ϭ Ϫ0.290, P Ͻ 0.05). The relationship between MP optical density and percentage of body fat in females was inverse, but not significant (r ϭ Ϫ0.197, P ϭ 0.149). A significant and inverse relationship between serum zeaxanthin and percentage of body fat was observed for females only (r ϭ Ϫ0.354, P Ͻ 0.01). Dietary intake of fat was inversely related to serum lutein and zeaxanthin, and significantly so for lutein (r ϭ Ϫ0.256, P Ͻ 0.05). However, dietary fat was unrelated to MP optical density (r ϭ 0.041, P ϭ 0.688). CONCLUSIONS. A relative lack of MP is associated with adiposity in men, and may underlie the association between body fat and risk for AMD progression in males. Further, the processes governing accumulation and/or stabilization of lutein and zeaxanthin in fat tissue appear to differ for males and females. (Invest Ophthalmol Vis Sci. 2004;45:3940 -3950) DOI: 10.1167/iovs.04-0273 A ge-related macular degeneration (AMD), which damages central vision, is the late stage of age-related maculopathy (ARM), and is the leading cause of blindness in elderly people in the Western World. 1 Under physiological conditions, lutein and zeaxanthin accumulate at the macula to the exclusion of all other carotenoids, and are collectively known as macular pigment (MP). The function of MP remains uncertain, but it is believed to reduce chromatic aberration as a result of its absorption spectrum which peaks at 460 nm (blue light). 2 These absorptive characteristics, alone or in combination with the capacity of the retinal carotenoids to quench reactive oxygen intermediates (ROIs), allow the MP to protect the retina from oxidative damage. Although the pathogenesis of AMD remains unclear, there is a growing body of evidence implicating oxidative stress, which refers to tissue damage arising from interaction between the constituent molecules of a tissue and ROIs. The retina is an ideal site for the generation of ROIs because of its high oxygen consumption, its wealth of chromophores, and its exposure to short wavelength visible light. Body fat is of particular interest, because adipose tissue is a major storage organ for carotenoids. 8 Of note, several large population-based studies have found an association between incidence and/or prevalence of AMD and BMI. 9 -13 BMI lends itself as a measure of obesity in epidemiologic studies, largely because it is quick and easy to record. However, the accuracy of BMI (a simple weight to height ratio) as a measure of fat mass, and consequently as a tool for investigating its relationship with carotenoid levels in the blood and retina, remains controversial. -17 The present study was designed to investigate the relationship between MP optical density and percentage of body fat as measured by dual energy x-ray absorptiometry (DEXA), which is the most available direct assessment of fat mass. The relationship between adiposity and serum concentrations of lutein and zeaxanthin was also evaluated. METHODS Subjects One hundred healthy subjects volunteered to participate in this study, which was approved by the Research Ethics Committee of Waterford Regional Hospital and the Ethics Committee of the Waterford Institute of Technology. Informed consent was obtained from each volunteer, and the experimental procedures adhered to the tenets of the Declaration of Helsinki. Subjects were recruited to this single-visit study at the Waterford Institute of Technology by a self-selected sample population who volunteered as a result of posters, newsletters, and word of mouth in the local community. Subjects had to be white between the ages of 20 and 60 years. Volunteers with ocular pathology were excluded. The following details were recorded for each volunteer: demographic data; general health status, with particular attention directed From th

Predicting cognitive fitness to drive with touchscreen DriveSafe DriveAware

Driving is a highly valued daily living activity easily disrupted by illness, injury, or age-related changes. General practitioners (GPs) are ultimately responsible for determining medical fitness to drive but lack valid and reliable tools. The desktop (original) version of DriveSafe DriveAware (DSDA) is a promising, valid and reliable test but it is not practical for medical practice. The concern of this thesis was the conversion of original DSDA into a touchscreen test of cognitive fitness to drive for GPs and occupational therapists to use in predicting patient driving performance without on-road testing. Because we were transitioning from a test administered and scored by a trained assessor to one where patient touch responses were scored in-app, we needed to develop an automatic data collection and scoring system that reflected the decision that would otherwise have been made by an expert-rater. We tested usability of the system with older adults then examined set scoring parameters to determine if these discriminated at-risk from comparison drivers. Results indicated the system we designed reflected the decisions that would have been made by a trained assessor. Next, we conducted a study to examine the internal validity, reliability, and predictive validity of data gathered with touchscreen DSDA. The criterion measure was outcome of a standardised occupational therapy on-road assessment. Rasch analysis provided evidence that touchscreen DSDA had retained the strong psychometric properties of original DSDA. However, results of a discontinued feasibility study indicated potential barriers to uptake of the test by physicians. Touchscreen DSDA may rather be a tool for occupational therapists to use in driver screening and addressing the community mobility need of their clients. Research indicates no there is no one best tool for screening fitness to drive. However, the thesis findings indicate touchscreen DSDA is one useful tool