This SBIR Phase I application addresses the development of an integrated, multi-purpose Sleep and Physical Activity Recording and Technical Analysis (SPARTA) system that can be used to independently assess both sleep (duration, quality, and timing) and physical activity (duration, frequency, intensity, and timing). As an objective monitor for the study of sleep, physical activity, and/or their interrelationship, the SPARTA system has great potential. Sleep disordered breathing and short sleep duration are linked to greater risk of various diseases, such as high blood pressure, obesity, cardiovascular disease, and diabetes. Insufficient and poor quality (i.e., fragmented) sleep are also associated with excessive daytime sleepiness, which has behavioral, cognitive, and psychophysiological consequences. Despite its importance, accurate and objective assessment of sleep duration and quality has not been practical in large clinical research studies. Additionally, physical activity is a known lifestyle and behavioral factor that plays a role in the etiology and prevention of many chronic diseases, such as cancer and coronary heart disease. Accurate measurement of physical activity energy expenditure and intensity levels in children and adults is a challenging problem that is important to epidemiologists, exercise scientists, clinicians, and behavioral researchers. Although there are a number of indirect and direct methods for assessing physical activity and energy expenditure, all current methods have well-documented shortcomings. The proposed Phase I SBIR effort will focus on developing the prototype SPARTA monitor and testing it in sleep studies;concept feasibility for the physical activity monitoring component of the SPARTA monitor has already been demonstrated by Barron Associates and is documented herein. The performance of the SPARTA monitor will be rigorously assessed in terms of the accuracy of its sleep/awake discrimination algorithms and sleep quality measures in comparison with both polysomnography (the criterion measure) and wrist actigraphy (a commonly-used, low-cost alternative to polysomnography). The Phase I effort will involve one-night sleep studies conducted in both child and adult subjects that will include a mix of both relatively healthy individuals and individuals with sleep-related breathing disorders so that algorithm sensitivity and specificity can be assessed. The SPARTA integrated ECG and triaxial accelerometry monitor will provide an ergonomic ambulatory measurement capability suitable for the accurate and objective assessment of sleep and physical activity in free-living individuals. As a 24/7 """"""""wear-and-forget"""""""" monitor, it will offer ease of use and convenience to both the wearer and the clinician/researcher. The SPARTA monitor will occupy the middle ground between high- cost, high-accuracy, dedicated clinical/research instruments and solutions for assessing both sleep and physical activity, and low-cost, low-accuracy activity and sleep monitors (e.g., actigraphs). Its small (12 cm W 2.5 cm W 1 cm), lightweight (10 g), consolidated, untethered design will make it less vulnerable to movement artifact than conventional (tethered) ECG monitoring systems.
The SPARTA system has huge potential as a relatively low-cost ergonomic monitor for the objective assessment of physical activity and/or sleep duration/quality in free-living individuals. The system will enable accurate and objective data to be collected in both clinical and research studies where such measurements have not been practicable. The SPARTA system will improve the convenience of obtaining such data from the perspectives of both the wearer and the clinician/researcher.
