Usefulness of Artificial Neural Networks in the Diagnosis and Treatment of Sleep Apnea-Hypopnea Syndrome

Sleep apnea-hypopnea syndrome (SAHS) is a chronic and highly prevalent disease considered a major health problem in industrialized countries. The gold standard diagnostic methodology is in-laboratory nocturnal polysomnography (PSG), which is complex, costly, and time consuming. In order to overcome these limitations, novel and simplified diagnostic alternatives are demanded. Sleep scientists carried out an exhaustive research during the last decades focused on the design of automated expert systems derived from artificial intelligence able to help sleep specialists in their daily practice. Among automated pattern recognition techniques, artificial neural networks (ANNs) have demonstrated to be efficient and accurate algorithms in order to implement computer-aided diagnosis systems aimed at assisting physicians in the management of SAHS. In this regard, several applications of ANNs have been developed, such as classification of patients suspected of suffering from SAHS, apnea-hypopnea index (AHI) prediction, detection and quantification of respiratory events, apneic events classification, automated sleep staging and arousal detection, alertness monitoring systems, and airflow pressure optimization in positive airway pressure (PAP) devices to fit patients’ needs. In the present research, current applications of ANNs in the framework of SAHS management are thoroughly reviewed

Light, activity and sleep in my daily life: : Design of an online intervention targeting changes to routines and the home

Background: Older adults spend more time at home after retirement, and the home becomes a central place for activity. While research indicates that indoor lighting, exposure to daylight, physical activity and sleep interact to influence functioning, mood and daily rhythm, strategies are needed to promote behavioural changes to optimise these factors in daily life. The objective is to design an intervention delivered as a web-based course to encourage behaviour change related to outdoor physical activity, sleep patterns and changes to the home environment. The behaviour changes are intended to promote mental wellbeing and improve lighting and darkness conditions. The intervention strategy departs from the Information-Motivation-Behavioural Skills Model. Intervention components build on goal implementation theory. The Technology Acceptance Model is used as a framework to evaluate usability aspects of the course content and the learning management system. Method: Using a mixed-methods approach, qualitative and quantitative data were collected through video observations, semi-structured interviews and a 10-item Likert scale questionnaire (The System Usability Scale). Scores were averaged for each participant and converted into a usability score out of 100 (a score of 68 or above is considered above average). In a first round, three experts on pedagogy, design for older people and/or interaction design were invited to independently assess the usability of the course content on their laptops in a full-scale model of an apartment. The setting enabled manipulations of the lighting conditions (daylight mode and night mode, change of luminaires), contextual interviews and video observation to identify any problems when participants experimented with the test kit included in the course material. They participated on three occasions lasting 2 hours each. Six healthy adults (aged 70+) participated in a similar usability trial in a second round. Findings: Experts’ average usability score was 78.3, indicating “Good” usability. However, the interviews did reveal some issues (e.g. difficult or inconsistent terms, unclear instructions). Results were used to refine the course before the second usability trial with six participants. Based on the interviews and usability ratings, the participants were positive about the course, and the instructions were easy to follow. All six participants rated the overall user-friendliness of the course as 6 out of 7. The average usability score was 86.7, indicating “Excellent” usability. Based on the participants’ feedback and interactions in the apartment, changes to the course content included, e.g. clarifying terms, the different types of text links and instructions. Unexpected issues with online enrolment in the course appeared before the second trial because standard instructions developed by the university were not tailored to the participants.Conclusions: A two-step usability evaluation by experts in the first round and target users in the second proved valuable. It enabled refinement of the course content and significantly reduced the number of identified usability issues in the second trial. A learning management system seems promising for use in behaviour-change interventions. However, the time-limited lab trials restricted a complete evaluation. Therefore, the next step is to pilot the course and evaluate the feasibility in real-world homes

Physiological Approach To Characterize Drowsiness In Simulated Flight Operations During Window Of Circadian Low

Drowsiness is a psycho-physiological transition from awake towards falling sleep and its detection is crucial in aviation industries. It is a common cause for pilot’s error due to unpredictable work hours, longer flight periods, circadian disruption, and insufficient sleep. The pilots’ are prone towards higher level of drowsiness during window of circadian low (2:00 am- 6:00 am). Airplanes require complex operations and lack of alertness increases accidents. Aviation accidents are much disastrous and early drowsiness detection helps to reduce such accidents. This thesis studied physiological signals during drowsiness from 18 commercially-rated pilots in flight simulator. The major aim of the study was to observe the feasibility of physiological signals to predict drowsiness. In chapter 3, the spectral behavior of electroencephalogram (EEG) was studied via power spectral density and coherence. The delta power reduced and alpha power increased significantly (

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 298)

This bibliography lists 173 reports, articles, and other documents introduced into the NASA scientific and technical information system in May, 1987

Beyond illumination: An interactive simulation framework for non-visual and perceptual aspects of daylighting performance

This paper presents a proof-of-concept for a goal-based simulation structure that could offer design support for daylighting performance aspects beyond conventional ones such as illumination, glare or solar gains. The framework uses a previously established visualization platform that simultaneously and interactively displays time-based daylighting performance alongside renderings, and relies on a goal-based approach. Two novel performance aspects are investigated in the present paper: health and delight. For the first aspect, drawing from the latest findings in photobiology in terms of effects on sleep, health and well-being, the goal is to integrate time-dependencies of non-visual responses to light into a dynamic light-response model for the non-visual system that can be part of a design process. For the second, the goal is to deepen our understanding of the perceptual qualities of daylight through a dynamic analysis of spatial contrast and its variability over time. The two approaches discussed in this paper introduce a new framework for the Lightsolve simulation environment that includes a Radiance calculation engine combined with an interactive visualization platform for temporal and spatial ‘distribution’ of performance

Measuring attention using Microsoft Kinect

The transfer of knowledge between individuals has increasingly become achieved with the aid of interfaces or computerized training applications. However, computer based training currently lacks the ability to monitor human behavioral changes and respond to them accordingly. This study examines the ability to predict user attention using features of body posture and head pose. Predictive abilities are assessed by an analysis of the relationship between the measured posture features and common objective measures of attention, such as reaction time and reaction time variance. Subjects were asked to participate in a series of sustained attention tasks while aspects of body movement and positioning were recorded using a Microsoft Kinect. Results showed support for identifiable patterns of behavior associated with attention while also suggesting the complex inter-relationship of measured features and susceptibility of these features to environmental conditions

Investigation of possible causes for human-performance degradation during microgravity flight

The results of the first year of a three year study of the effects of microgravity on human performance are given. Test results show support for the hypothesis that the effects of microgravity can be studied indirectly on Earth by measuring performance in an altered gravitational field. The hypothesis was that an altered gravitational field could disrupt performance on previously automated behaviors if gravity was a critical part of the stimulus complex controlling those behaviors. In addition, it was proposed that performance on secondary cognitive tasks would also degrade, especially if the subject was provided feedback about degradation on the previously automated task. In the initial experimental test of these hypotheses, there was little statistical support. However, when subjects were categorized as high or low in automated behavior, results for the former group supported the hypotheses. The predicted interaction between body orientation and level of workload in their joint effect on performance in the secondary cognitive task was significant for the group high in automatized behavior and receiving feedback, but no such interventions were found for the group high in automatized behavior but not receiving feedback, or the group low in automatized behavior

Effects of circadian rhythm phase alteration on physiological and psychological variables: Implications to pilot performance (including a partially annotated bibliography)

The effects of environmental synchronizers upon circadian rhythmic stability in man and the deleterious alterations in performance and which result from changes in this stability are points of interest in a review of selected literature published between 1972 and 1980. A total of 2,084 references relevant to pilot performance and circadian phase alteration are cited and arranged in the following categories: (1) human performance, with focus on the effects of sleep loss or disturbance and fatigue; (2) phase shift in which ground based light/dark alteration and transmeridian flight studies are discussed; (3) shiftwork; (4)internal desynchronization which includes the effect of evironmental factors on rhythmic stability, and of rhythm disturbances on sleep and psychopathology; (5) chronotherapy, the application of methods to ameliorate desynchronization symptomatology; and (6) biorythm theory, in which the birthdate based biorythm method for predicting aircraft accident susceptability is critically analyzed. Annotations are provided for most citations

Habitability and Performance Issues for Long Duration Space Flights

Advancing technology, coupled with the desire to explore space has resulted in increasingly longer manned space missions. Although the Long Duration Space Flights (LDSF) have provided a considerable amount of scientific research on human ability to function in extreme environments, findings indicate long duration missions take a toll on the individual, both physiologically and psychologically. These physiological and psychological issues manifest themselves in performance decrements; and could lead to serious errors endangering the mission, spacecraft and crew. The purpose of this paper is to document existing knowledge of the effects of LDSF on performance, habitability, and workload and to identify and assess potential tools designed to address these decrements as well as propose an implementation plan to address the habitability, performance and workload issues