SoundTrak: A Data Acquisition and Analysis System for OSDB

描述（由申请人提供）：阻塞性睡眠呼吸障碍（OSDB）在儿童中很常见，现在被认为具有严重的神经认知、神经行为和心血管后果。在儿童中诊断OSDB有很大的局限性，他们通常没有离散性呼吸暂停或呼吸不足，可以通过测量气流来诊断。相反，儿童通常有长时间的高阻力呼吸，在气道狭窄的情况下，他们产生非常低的食管压力波动来维持气流。食管压（Pes）记录是诊断OSDB的权威方法，但这种测量是有创的，并没有广泛应用。即使没有pe，实验室多导睡眠描记术（PSG）也是一个复杂、繁琐和昂贵的程序。两位弗吉尼亚大学（UVA）医生的研究表明：(1)频率在2- 10khz范围内的高频吸气声（HFIS）是儿童发生OSDB的标志；(2)儿童在睡眠中上呼吸道变窄时产生HFIS，此时上呼吸道充当共振腔，完全符合圆柱形管道中声音共振的物理原理。需要强调的是，这些HFIS不同于描述成人打鼾的低频（< 2 kHz）声音。Barron Associates和UVA提议开发SoundTrak系统，这是一种低成本的睡眠监视器，用于个人家庭环境，以无创和符合人体工程学的方式获取和分析与OSDB相关的HFIS数据。SoundTrak系统将通过一个麦克风和一个小型便携式PC基站收集低频和高频声音数据。呼吸运动将使用无线胸带进行测量，从而可以检测到吸气，并将患者的睡眠声音与其他来源（例如，兄弟姐妹在同一房间睡觉，暖气、通风和空调系统的噪音等）区分开来。此外，商用无线腕戴式手指血氧仪系统将被纳入I期研究，以调查HFIS事件期间通气是否充足的问题，这可能发生在有或没有血红蛋白去饱和的情况下。当HFIS事件发生时没有去饱和，它们通常不会被PSG检测到，因为在这种情况下，气流足以维持通风和氧合；这通常被称为上呼吸道阻力综合征（UARS）。能够区分有无去饱和的HFIS事件将提供一种简单的无创方法来研究这些事件是否会导致OSDB的发病率。先前关于OSDB结果的研究在不使用pe的情况下无法检测到UARS。该小组最近的工作证明了在睡眠实验室使用HFIS和胸部监测作为诊断OSDB的替代方法的可行性。这项工作的中心目标是证明在疑似患有OSDB的儿童中进行家庭HFIS研究的可行性。特别是，传统的夜间实验室多导睡眠图，包括食管测压和/或脉冲传递时间测量，将与基于易于使用的原型SoundTrak系统的多夜家庭睡眠研究进行比较，并评估其在OSDB诊断方面的一致性。公共卫生相关性：这项研究产生的产品具有强大的潜力，可以为世界各地睡眠实验室进行的传统多导睡眠图研究提供更准确和更具成本效益的替代方案。多导睡眠描记术也可能无法再现患者通常的睡眠习惯，因为患者处于一个新的环境中，并且高度仪器化；因此，使用SoundTrak系统的家庭研究可能会被发现为诊断OSDB提供更有代表性的数据。医疗保险最近宣布，它将涵盖家庭睡眠诊断，包括那些使用呼吸暂停/低呼吸指数作为主要标准的诊断。这个决定强调了项目的相关性和市场的可行性。

DESCRIPTION (provided by applicant): Obstructive sleep-disordered breathing (OSDB) is common in children and is now recognized as having substantial neurocognitive, neurobehavioral, and cardiovascular consequences. There are major limitations in diagnosing OSDB in children, who often do not have discrete apneas or hypopneas that can be diagnosed by measurement of airflow. Instead, children often have long periods with high-resistance breathing where they generate very-low esophageal pressure swings to maintain airflow in the presence of a narrowed airway. Esophageal pressure (Pes) recording is the definitive method to diagnose OSDB, but this measurement is invasive and not widely available. Even without Pes, laboratory polysomnography (PSG) is a complex, burdensome, and costly procedure. Work by two University of Virginia (UVA) physicians, who are part of the proposing team, demonstrated that: (1) high-frequency inspiratory sounds (HFIS) in the frequency range of 2-10 kHz are a marker for the occurrence of OSDB in children; and (2) children generate HFIS when they have a narrowed upper airway during sleep, in which case their upper airway acts as a resonating chamber, completely in agreement with the physics of sound resonance in a cylindrical pipe. It is important to emphasize that these HFIS are different from the low-frequency (< 2 kHz) sounds that describe snoring in adults. Barron Associates and UVA propose to develop the SoundTrak system, a low-cost sleep monitor for use in individuals' home environments to noninvasively and ergonomically acquire and analyze HFIS data pertaining to OSDB. The SoundTrak system will unobtrusively collect low- and high-frequency sound data via a microphone and a small portable PC base station. Breathing movements will be measured using a wireless thoracic band, enabling inspirations to be detected and the patient's sleep sounds to be discriminated from other sources (e.g., a sibling sleeping in the same room, noise from heating, ventilation, and air conditioning systems, etc). Additionally, a commercial wireless wrist-worn finger oximetry system will be included in the Phase I study to investigate the issue of adequacy of ventilation during HFIS events, which can occur with or without oxyhemoglobin desaturation. When HFIS events occur without desaturation, they are frequently not detected by PSG since, in this case, airflow is adequate to maintain ventilation and oxygenation; this is often referred to as the upper airway resistance syndrome (UARS). Being able to distinguish HFIS events with and without desaturation will provide a simple noninvasive method to study whether these events contribute to morbidity in OSDB. Prior studies looking at outcomes for OSDB have been unable to detect the UARS without use of Pes. Recent work by the proposing team demonstrated the feasibility of using HFIS and thoracic monitoring in the sleep laboratory as an alternative to polysomnography for diagnosing OSDB. The central goal of the proposed effort is to demonstrate the viability of in-home HFIS studies in children who are suspected of having OSDB. In particular, traditional overnight laboratory polysomnography, augmented to include esophageal manometry and/or pulse transit time measurement, will be compared with multi-night in-home sleep studies based on an easy-to-use prototype SoundTrak system, and their agreement with respect to a diagnosis of OSDB assessed. PUBLIC HEALTH RELEVANCE: Products resulting from this research have strong potential to provide a more accurate and cost-effective alternative to traditional polysomnography studies performed in sleep laboratories worldwide. Polysomnography may also fail to reproduce patients' usual sleep habits, since the patient is in a new environment and is highly instrumented; as such, home studies using the SoundTrak system are likely to be found to provide more representative data for diagnosing OSDB. Medicare recently announced that it will cover in-home sleep diagnostics, including those using the apnea/hypopnea index as their main criterion. This decision underscores the relevance of the project and the viability of the marketplace.