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63 Results for: "Sleep"

Statistical modeling of circadian rhythms of physical activity

  • Published on Jun 21, 2017

Purpose: The proposed symposium will introduce novel and intuitive statistical methods for modeling the human circadian rhythm based on data collected using body-worn physical activity monitors. All methods are motivated by and applied to large observational studies. Rationale: Biological rhythms have been under intense methodological development across all disciplines of ...


Sleep pattern detection using raw tri-axial wrist and hip actigraphy in the Raine Study

  • Published on Jun 21, 2017

Sleep disorders occur in around 20% of the population and are associated with a multitude of serious health implications. Whilst polysomnography is considered the 'gold standard' in assessing sleep patterns, it is intrusive and costly hence actigraphy is increasingly being considered as a viable alternative. Current actigraphic sleep pattern detection algorithms ...


Automated sleep scoring algorithms for activity monitors – a comparison to polysomnography in the Raine Study.

  • Published on Jun 21, 2017

Introduction: Wrist-activity monitors are widely used to assess sleep and activity. Accurate measurement of time at 'lights out' (LO) is essential for calculation of several activity-derived measures including sleep latency (SL), sleep duration (SD), wake after sleep onset (WASO) and sleep efficiency (SE). To determine LO some devices use subjective ...


Accuracy of an automated algorithm to detect nocturnal sleep in adults using 24-h waist accelerometry

  • Published on Jun 21, 2017

Purpose: We previously developed and tested the accuracy of an automated algorithm implemented using SAS to detect bed time, wake time, and sleep period time (SPT) in a sample of children. The purpose of this study was to test the accuracy of the algorithm in an adult sample. Methods: 104 adults ...


Utility of ActiGraph wear sensor in assessing wear-time in 24-hour wrist measurement

  • Published on Jun 21, 2017

There are no standard procedures for identifying wake wear, sleep wear and non-wear time from the 24-h accelerometer recordings. Participant diaries increase participant burden and frequently have missing values. The Choi algorithm identifies 90-min consecutive zero counts as non-wear time, allowing for 2 minutes of non-zero counts, thus possibly ignoring short ...


Physical Activity, Mind Wandering, Affect, and Sleep: An Ecological Momentary Assessment

  • Published on Jul 2016

Background: A considerable portion of daily thought is spent in mind wandering. This behavior has been related to positive (eg, future planning, problem solving) and negative (eg, unhappiness, impaired cognitive performance) outcomes. Objective: Based on previous research suggesting future-oriented (ie, prospective) mind wandering may support autobiographical planning and self-regulation, this ...


Physical Activity, Sedentary Time, and Sleep and the Association With Inflammatory Markers and Adiponectin in 8- to 11-Year-Old Danish Children

  • Published on Jul 2016

Background: Inflammatory markers, adiponectin, and movement/nonmovement behaviors have all been linked to risk factors for cardiovascular disease; however, the association between childhood movement/nonmovement behaviors and inflammatory markers and adiponectin is unknown. Methods: We explored the association between accelerometer determined moderate-to-vigorous physical activity (MVPA), sedentary time, and sleep (7 days/8 ...


Nocturnal sleep-related variables from 24-h free-living waist-worn accelerometry: International Study of Childhood Obesity, Lifestyle and the Environment

  • Published on Dec. 2015

Objectives: We describe the process of identifying and defining nocturnal sleep-related variables (for example, movement/non-movement indicators of sleep efficiency, waking episodes, midpoint and so on) using the unique 24-h waist-worn free-living accelerometer data collected in the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE). Methods: Seven consecutive ...


24 Hours of Sleep, Sedentary Behavior, and Physical Activity with Nine Wearable Devices.

  • Published on Oct. 17, 2015

Background: Getting enough sleep, exercising and limiting sedentary activities can greatly contribute to disease prevention and overall health and longevity. Measuring the full 24-hour activity cycle - sleep, sedentary behavior (SED), light intensity physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) - may now be feasible using small wearable devices. ...


Isolating out-of-bed wear from non-wear and in-bed wear periods in young adults hip-worn accelerometer data (continuous wear protocol)

  • Presented on 2015

Background: The published literature shows no automated method valid for isolating adults out-of-bed wear in continuously worn (24h/day) accelerometer data. We developed an automated algorithm (AA) for continuous hip-worn protocol Actigraph (GT3X+) data that separates out-of-bed wear from in-bed wear and non-wear periods. Methods: In 95 participants of the ...