Data-driven approach to optimum wavelength selection for diffuse optical imaging

The production of accurate and independent images of the changes in concentration of oxyhemoglobin and deoxyhemoglobin by diffuse optical imaging is heavily dependent on which wavelengths of near-infrared light are chosen to interrogate the target tissue. Although wavelengths can be selected by theoretical methods, in practice the accuracy of reconstructed images will be affected by wavelength-specific and system-specific factors such as laser source power and detector sensitivity. We describe the application of a data-driven approach to optimum wavelength selection for the second generation of University College London's multichannel, time-domain optical tomography system (MONSTIR II). By performing a functional activation experiment using 12 different wavelengths between 690 and 870 nm, we were able to identify the combinations of 2, 3, and 4 wavelengths which most accurately reproduced the results obtained using all 12 wavelengths via an imaging approach. Our results show that the set of 2, 3, and 4 wavelengths which produce the most accurate images of functional activation are [770, 810], [770, 790, 850], and [730, 770, 810, 850] respectively, but also that the system is relatively robust to wavelength selection within certain limits. Although these results are specific to MONSTIR II, the approach we developed can be applied to other multispectral near-infrared spectroscopy and optical imaging systems

Diffuse optical tomography for the detection of perinatal stroke at the cot side: a pilot study

BACKGROUND: Perinatal stroke is a potentially debilitating injury, often under-diagnosed in the neonatal period. We conducted a pilot study investigating the role of the portable, non-invasive brain monitoring technique, diffuse optical tomography (DOT), as an early detection tool for infants with perinatal stroke. METHODS: Four stroke-affected infants were scanned with a DOT system within the first 3 days of life and compared to four healthy control subjects. Spectral power, correlation, and phase lag between interhemispheric low frequency (0.0055–0.3 Hz) hemoglobin signals were assessed. Optical data analyses were conducted with and without magnetic resonance imaging (MRI)- guided stroke localization to assess the efficacy of DOT when used without stroke anatomical information. RESULTS: Interhemispheric correlations of both oxyhemoglobin and deoxyhemoglobin concentration were significantly reduced in the stroke-affected group within the very low (0.0055–0.0095 Hz) and resting state (0.01–0.08 Hz) frequencies (p < 0.003). There were no interhemispheric differences for spectral power. These results were observed even without MRI stroke localization. CONCLUSION: This suggests that DOT and correlation-based analyses in the low-frequency range can potentially aid the early detection of perinatal stroke, prior to MRI acquisition. Additional methodological advances are required to increase the sensitivity and specificity of this technique

A conceptual classification of parents’ attributions of the role of food advertising in children’s diets

Background: High levels of child obesity are triggering growing concerns about the prevalence and effects of food advertising targeted at children. Efforts to address this advertising are confounded by the expanding repertoire of media and promotional techniques used to reach and attract children. The present study explored parents’ views on food marketing and the strategies parents employ when attempting to ameliorate its effects. As part of an online survey of Australian parents’ attitudes towards a range of food advertisements, respondents were invited to provide additional comment in an open-ended question. The question was optional and asked “Are there any other comments you would like to make?”. One in five of the survey respondents (18%; n = 235) elected to answer this question by discussing their views on food advertising and children’s diets. The responses were imported into NVivo10 for coding and analysis. A grounded approach was used to draw meaning from the data and develop a proposed conceptual classification of parents’ attributions relating to food advertising and its consequences.Results: The majority of responses related to the negative perceived effects of unhealthy food advertising on children’s diets, with few respondents considering such advertisements to be innocuous. The responses were classified into four conceptual categories reflecting differing attitudes to advertising (negative to neutral) and varying levels of locus of control (low to high). The typical characteristics of parents allocated to the four categories exhibited variation according to weight status, television viewing habits, education level, and family size. The largest number of responses was coded to the category characterized by a negative attitude toward food advertising and a low locus of control. Parents in this category were more likely than others to be overweight/obese and heavy television viewers. Parents in the negative attitude to advertising and high locus of control category nominated a variety of parenting practices that could form the basis of parent education interventions. Conclusions: The results suggest that many Australian parents may feel disempowered in the face of high levels of advertising for unhealthy foods. The current voluntary regulatory code appears to be inadequate in scope and coverage to address this situation

Advertising of fast-food to children on Australian television: Impact of industry self-regulation.

OBJECTIVE: To assess the impact of the quick-service restaurant industry (QSRI) self-regulatory initiative on fast-food advertising to children on Australian commercial television. DESIGN AND SETTING: Analysis of advertisements for foods on the three main free-to-air commercial television channels (channels 7, 9 and 10) in Sydney, Australia, over 4 days in both May 2009 and April 2010 in terms of: number of advertisements; types of food (coded core [healthy] foods, non-core [unhealthy] foods, miscellaneous foods; or fast foods); whether advertised meals were intended for children; whether advertisements were broadcast during children's peak viewing times; and whether the company in question was a signatory to the QSRI initiative. MAIN OUTCOME MEASURES: Change in the mean frequency and rate of food advertisements per hour from 2009 to 2010; change in the types of fast-food meals (healthier alternatives [at least one nutrient-dense, low-energy food considered part of a healthy diet for children], non-core [high in undesirable nutrients and not considered part of a healthy diet for children], and other) being advertised; and proportion of children's energy requirements provided by fast-food meals. RESULTS: From 2009 to 2010, the mean frequency of fast-food advertisements increased from 1.1 to 1.5 per hour. While non-core fast foods comprised a lesser share of fast-food advertising in 2010 than 2009, the mean frequency at which they were advertised during times when the largest numbers of children were watching television remained the same (1.3 per hour in both 2009 and 2010). Family meals advertised for children's consumption in 2010 provided energy far in excess of children's requirements. CONCLUSIONS: Children's exposure to unhealthy fast-food advertising has not changed following the introduction of self-regulation, and some fast foods advertised for children's consumption contain excessive energy. The limited impact of self-regulation suggests that governments should define the policy framework for regulating fast-food advertising to children

Hemodynamic response to burst-suppressed and discontinuous electroencephalography activity in infants with hypoxic ischemic encephalopathy

Burst suppression (BS) is an electroencephalographic state associated with a profound inactivation of the brain. BS and pathological discontinuous electroencephalography (EEG) are often observed in term-age infants with neurological injury and can be indicative of a poor outcome and lifelong disability. Little is known about the neurophysiological mechanisms of BS or how the condition relates to the functional state of the neonatal brain. We used simultaneous EEG and diffuse optical tomography (DOT) to investigate whether bursts of EEG activity in infants with hypoxic ischemic encephalopathy are associated with an observable cerebral hemodynamic response. We were able to identify significant changes in concentration of both oxy and deoxyhemoglobin that are temporally correlated with EEG bursts and present a relatively consistent morphology across six infants. Furthermore, DOT reveals patient-specific spatial distributions of this hemodynamic response that may be indicative of a complex pattern of cortical activation underlying discontinuous EEG activity that is not readily apparent in scalp EEG

Smart nutrition monitoring system using heterogeneous Internet of Things platform

Poor nutrition impairs the health and wellbeing of the population and increases the risk of chronic diseases such as obesity and type 2 diabetes. Chronic diseases that require dietary management can be better managed if food and nutrition intake is monitored. Existing methods for measurement are inaccurate and not scalable as they are based on a person’s ability to recall and self-report. In this paper, we propose a smart nutrition monitoring system based on Internet of Things (IoT) technologies to collect reliable nutrition intake data from heterogeneous sensors. The proposed method is non-invasive and consists of a combination of data sources from heterogeneous devices to increase accuracy. The system architecture is based on emerging Fog Computing concepts where data collection points are able to do the preprocessing and lightweight analytics before sending data to the Cloud. The system prototype is developed using various sensors including cameras to generate 3D images for food volume estimation