Keywords

1 The Importance of Sleep Environment

Sleep environment is usually the place in which people sleep but at this time there is no clear definition. According to the book “Cognitive Behavioral Therapy for Insomnia” , there is a sleep environment checklist to show that a sleep environment would contains six physical elements such as light, noise from external environment, interior temperature, humidity and air circulation, and settings (including bedding and pillows) and 1 psychological element, safety [1]. Moreover, Kim et al. [2] mentioned that people’s sleep would be affected by changes in air temperature, relative humidity, indoor air quality (IAQ), illumination, and noise [2]. They investigated the sleep environment and sleep quality in certain individual’s own bedroom in Korea and found out that air temperature, humidity, and CO2 concentrations were connected to people’s sleep problems. Therefore, we will introduce several elements, such as light, noise, and air temperature, in the bedroom to better illustrate the importance of these factors as they relate to our sleep.

Light might be the most influential environmental element over our sleep, because it has been seen as a zeitgeber, an external time cue which could regulate the individual’s sleep-wake circadian rhythm. Meijer et al. [3] had found that the suprachiasmatic nuclei (SCN) is the primary pacemaker of the mammalian circadian system which contain cells to sense environmental light intensity to alter their level of activities [3]. The timing and physical characteristics of the light stimulus will indeed influence the individual’s sleep-wake circadian rhythm. Previous studies have shown that bright light exposure later in the day delays the sleep-wake circadian and earlier in the day may advance the circadian rhythm [4, 5]. The shorter wavelength (e.g. blue and green) is more effective in phase advance than longer wavelength (eg. red light) [6, 7]. However, the function of individual sensitivity to light could also affect the circadian effect of light exposure.

Noise is defined as unwanted sounds and this affects everyone every day and every night [8]. It has two main sources, one is from outside bedrooms such as transportation(/traffic) noise, and the other one is from inside buildings including mechanical devices (e.g. elevators, ventilation, pumps, and water pipes) or domestic noises (e.g. neighbour’s voices, TV set, pets, and musical instruments). Noise has been proven to have adverse effects on individuals’ sleep, such as, shortening the sleep length due to prolonging sleep latency, increasing the number of awakenings and modifying sleep-stage. Carter [9] reported that slow-wave sleep (SWS) could be reduced due to intermittent traffic noises. REM sleep rhythmicity could also be affected by environmental noise exposure. As previous studies have already shown, SWS is related to an energy restoration state of the sleeping body and REM sleep is related to mental and memory processes. Therefore, noise can also cause daytime dysfunction, such as excessive daytime sleepiness. However, the noise sensitivity of the sleepers depends on their personal characteristics such as age, sex, personality characteristics and self-estimated sensitivity to noise. Muzet [8] had mentioned that elderly people complain much more than younger adults about environmental noise.

Sleep environments that are too hot or cold will also negatively affect individuals’ sleep quality, and the amount of sleep stages. Ohayon and Zulley [10] investigated the predictive factors for global sleep dissatisfaction (GSD) in a population of 4,115 Germans and found that bedrooms which are too hot is one of the most predictive factors. Individuals would remain more awake (sleep less), and have more sleep stage 1, stage 2 and Rapid Eye Movement (REM) sleep in a cold environment than in natural or hot environments [11].

Notably, the physical elements of sleep environment were related to individual’s sleep disturbances. A previous study has shown that dissatisfication with sleep environment was an important predictor for long-term insomnia in a population of 6,277 Japanese subjects [12]. As we know, insomnia is a highly prevalent complaint among the general population in modern society. About one-third of the adult population exhibit at least one symptom of insomnia [13]. Furthermore, in this population, an estimated 6% of adult’s symptoms meet the diagnosis criteria of insomnia. Insomnia can adversely affect different aspects of an individual, such as health, quality of life and occupational or academic performance. Furthermore, the risks of traffic or work-site accidents and psychiatric disorders may increase. Therefore, we should pay more attention to how to design our sleep environment to decrease the opportunity to develop insomnia symptoms. As for those who have been diagnosed with sleep disorders, such as insomnia, sleep disordered breathing, sleep walking, sleep eating, REM behavioral disorder and so on, a sophisticated modification of the sleep environment is indispensable to help improve such diseases and for prevention of further complications. The term “Environmental Sleep Disorders” is also used to emphasized the importance of the sleep environment. Therefore, Perlis et al. [1] suggested that the clinical assessment of insomnia should include information regarding an individual’s sleep environment.

A sleep environment is indeed related to how well we sleep. Hence, how to help individuals adjust their sleep environment could be a predisposing factor to having better sleep quantity and quality. Utilizing a new technology might be one of the solutions, so we will introduce three types of sleep technologies which aim to control our sleep environment in the following paragraphs.

2 Existing Technologies for Sleep Environment Control

As technology advances, more and more devices or products have been developed to help users to adjust to their sleep environments. Overall, there are basically three kinds of sleep environment control technologies, proactive controller, knowledge-enhanced controller, and sensor-enhanced controller, and we will introduce each controller in following paragraphs and illustrate the last one in more detail with a case study.

2.1 Proactive Controller

Users adjust their sleep environment by themselves based on how comfortable they feel. Sometimes they will adopt an expert’s suggestions if they believe that they will help them to achieve better sleep (shown in Fig. 10.1). Most of the time, the behavior of adjusting their sleep environments are related to how much users can detect their physiological status. Light switches, air conditioners, and dehumidifiers are examples that belong to this kind of controller.

Fig. 10.1
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Proactive controller

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2.2 Knowledge-Enhanced Controller

Nowadays some sleep technologies have been developed with sleep medicine knowledge to adjust the users’ sleep environment. These new sleep technologies will integrate professional suggestions from the experts or physicians to help the users (shown in Fig. 10.2).

Fig. 10.2
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Knowledge-enhanced controller

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“Sleep Light Wizard” is one example of knowledge-enhanced controller to help user create a better illumination of sleep environment based on the know-how from light therapy and the knowledge related to human sleep-wake circadian rhythm. It has three major components, an interactive control panel, the ceiling which is equipped different wavelength and intensity of Light Emitting Diode (LED) lights, and individual reminding device. Sleep Light Wizard has three main functions, spatial atmosphere simulation, light sleep-helper, and light clock. The user can use the interactive control panel to adjust the characteristics of illumination, such as location, intensity and wavelength, to simulate different spatial atmospheres, such as a party in the living room or sleep time in a bedroom. The aim of individual reminding devices is to awake each person who sleeps in the same space at a different time by using directional light and acoustic sounds [14]. The algorithm of the light clock comes from the concept of light therapy. If there is a couple, husband needs to get up at 7:30 a.m. and the wife needs to get up at 9:00 a.m., they could set the clock time separately. At 7:00 a.m. the next morning, the acoustic source and the light source begin to emit prompts toward the husband. Next, between 7:00 a.m. and 7:30 a.m., the strength of light source would get stronger step by step until the husband is woken up. At 8:45 a.m., the acoustic source and the light source begin to emit prompts toward the wife and then the intensity will become more stronger when the time is close to 9:00 a.m. The components of the Sleep Light Wizard are shown in Fig. 10.3.

Fig. 10.3
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The components of sleep light wizard

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2.3 Sensor-Enhanced Controller

There are some controllers which change elements automatically via the users’ personal data. Most of the time, the data is collected from the sensors which are equipped in the controllers (Shown in Fig. 10.4).

Fig. 10.4
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Sensor-enhanced controller

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Gajjar [15] had proposed a concept of an “Environmental Control System”, which is related to an interior environmental controlling system. This system involves multiple sensors and control systems to modify the internal temperature and humidity. “iWakeUp” is another example [16] which is an intelligent alarm clock driven by video-based monitoring. The aim of this new technique is to wake the user up when they are having light sleep which may result in a better mental status. It will determine the sleep status and then find out the optimal wakeup time to wake the user up via analysing the amount of movement from video recordings. They also found that the subjects using iWakeUp reported a lower level of sleepiness and higher level of vigour than subjects who did not use it. Figure 10.5 shows that the conceptual model of iWakeUp system.

Fig. 10.5
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Conceptual model of iWakeUp system

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3 Case Study – Sleep Coach

The remainder of this chapter presents a new environmental control sleep system, Sleep Coach, which integrates the characteristics of three types of environmental controllers. Sleep Coach is essentially the result of multidisciplinary research including input from those with industrial design, medicine, psychology and engineering backgrounds. It is not only a bedroom environmental control device or a sleeper to set up their own sleep environment, but also contains a sleep-promotion program in it. This sleep-promotion program was designed based on the concept of “Cognitive Behavioral Therapy for Insomnia CBT-I” and therefore, Sleep Coach is especially suitable for people with insomnia symptoms.

Insomnia is a highly prevalent complaint among the general population in modern society. According to one epidemiological study [13], approximately one-third of the adult population exhibit at least one symptom of insomnia. Furthermore, among this population, an estimated 6% of adult’s symptoms meet the diagnosis criteria of insomnia. Insomnia is defined as repeated sleep difficulties, such as difficulty with sleep initiation, maintenance or quality that occurs during adequate sleep time and opportunity which typically leads to some forms of daytime impairment, such as daytime sleepiness [17]. Moreover, insomnia also has adverse effects on different aspects of an individual, such as health, quality of life and occupational or academic performance. Furthermore, the incidence of traffic, work-site accidents or psychiatric disorders may increase if someone suffers from insomnia symptoms. It has been shown that pharmacotherapy is efficacious on situational insomnia which is often caused by acute stress. However, it is not suitable for chronic insomnia and may cause several side-effects, such as increasing tolerance and dependence when medications are used over a long period. Therefore, some researchers have suggested that the CBT could be an alternative therapy for insomnia and its efficacy has been proven in many studies [18–20]. One study showed that CBT treatment can help improve the sleep difficulties of 70–80% of insomnia sufferers [21]. The most frequently used CBT therapies for chronic insomnia are stimulus control, sleep restriction, sleep hygiene, relaxation training, and cognitive therapy. The basic idea of CBT is to take the maladaptive sleep habits, autonomic and cognitive arousal, dysfunctional beliefs and attitudes about sleep as risk factors to suffering from chronic insomnia. Therefore, if we can remove these factors, the severity of the insomnia will decrease. Edinger et al. [22] showed that the CBT is useful to reduce dysfunction beliefs about sleep rather than using progressive muscle relaxation training only or a sham behavioral intervention. However, when attempting to use CBT, it really requires a great deal of cooperation between the patients and physicians. In addition, it takes time to teach the idea or concept of CBT to patients. The average duration of CBT for one section is between 6 and 10 weeks. Moreover, the patient has to apply these techniques thus proving its efficacy, so the patient will lose patience with the process and will not continue to follow the instructions of their physicians. Moreover, CBT combines several instructions together, thus the patients may become easily confused and then might be frustrated when applying these instructions. For example, they might forget how to practice certain relaxation techniques, even though they had learned them in the hospital and may be frustrated when they were trying to practice them again at home. Moreover, it combines several instructions which may change a little bit for each individual, thus these characteristics of CBT may result in a lower compliance of patient. On the other hand, clinical professionals do not have viable instruments to monitor the patient’s compliance and practicing performance. All they can do is to trust their patient based on their self-reports and these reports might not represent the real situation. Therefore, the Sleep Coach is not simply a environmental controller, but also a therapy-assistance device.

Sleep Coach has two versions for two main users, one part is called Sleep Coach for user, which is used by the sleeper, and the other part is called Sleep Coach-Doc which is used by the physicians or professionals. The reason why Sleep Coach has different versions will be illustrated later. There are five modules in Sleep Coach, including Environmental Control and other modules for CBT treatment, includes Screening, Diary, Training and Advice. Sleep Coach-Doc, which is used by physicians, has four corresponding modules which are Diagnosis, Training, Advice, and Environmental Controller (shown in Fig. 10.6).

Fig. 10.6
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Modules of sleep coach and Sleep Coach-Doc

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The environmental controller module plays the role of environment control, and the other modules serve as a part of a sleep-promotion program. The Environmental Controller Module (Fig. 10.7) is used to adjust the environmental elements of the bedroom to remove external affective factors on sleep. There are two elements, light and air temperature, which we had mentioned earlier. Moreover, curtains are commonly seen in the bedroom, so the user also can control the curtains through the Sleep Coach. Except in cases where the user changes the elements on their own, the Sleep Coach is equipped with biosensors which can detect the changes in the user’s physiological status and then make adjustments to the environment automatically.

Fig. 10.7
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The conceptual interface of environmental controller module

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Now we’re going to introduce the remaining modules which serve as the sleep promotion program in the Sleep Coach. Screening Module and Diary Module are used to portray an individual’s personal sleep situation. The main content of the screening module is a Brief Insomnia Screening Scale (BISS-C) which was developed according to International Classification of Sleep Disorder [17], the newest version of diagnosis criteria for sleep disorders. This scale provides the user with a chance to analyze his/her sleep problems in a short time by using only 31 items. The items are related in to four categories, including sleep environment (SE), sleep opportunity (SO), insomnia symptoms (IS), and daytime symptoms (DS). Chiang et al. [23] have shown that BISS-C is a reliable and valid instrument to evaluate the insomniac symptoms of individuals. The Diary Module is used to overview the user’s sleep conditions and it is the most basic and useful instrument for assessing insomnia in clinics. However, it has some disadvantages when it is used, for example, it’s hard to keep the user to using it on an ongoing basis. Therefore, diary modules in Sleep Coach attempted to resolve this issue by using an interactive interface and passive fill-out reminders, where users can record valuable sleep events following instructions and can be reminded to record this with a dim light from the Sleep Coach screen.

Training Module (shown in Fig. 10.8) consists of new relaxation Chinese-version tasks which are designed with the concept of eastern culture and related relaxation techniques, such as breathing relaxation techniques, autogenic training and guided imaging. When users are practicing tasks, they should do so with biosensors to record their physiological status and then they can compare their recent status with the prior status. Users can get real-time feedback and do regular training activities while at home. Screening, Dairy and Training Modules can be used as a database to understand the user’s sleep condition.

Fig. 10.8
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Training modules of Sleep Coach

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Fig. 10.9
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Scenario of Sleep Coach

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The last two modules are Advice Module and Diagnosis Module. The goal of having an advice module was to help users record all of their prescriptions at home. Physicians might conduct several treatments at the same time and each of them has their own related details. For example, when the physician asks the user to practice sleep limitation treatment, the patient has to remember the time he/she has to perform. If he/she forgets the correct time, all he/she has to do is to check the advice module instead of calling the physicians. The aim of diagnosis module is to help physicians make a more accurate diagnosis and give the patients more useful advice through summarizing data from the screening and diary modules in Sleep Coach, as well as additional items for screening some physiological and psychological disorders that might be the main reason behind the insomnia. This module is used through the Sleep Coach-Doc interface. The rest of the modules in Sleep Coach-Doc correspond to Sleep Coach and they are used by the physicians to set up Sleep Coach.

We envisage the scenario of Sleep Coach as shown in Fig. 10.9. The user always has Sleep Coach with them in their bedroom. The sleeper can either adjust the environment based on their own preferences or based on their bio-information to create a unique and ideally suitable sleep environment. Moreover, Sleep Coach could help users identify their sleep quality, remind them to type-up their sleep diary, offer home-based training programs and provide (or repeat) the advice of their physicians. If there is something wrong with the user’s sleep, he could go to the hospital with Sleep Coach. The user has already prepared the initial data to highlight his sleep issues for the physician. In the hospital, the physician could use the Sleep Coach-Doc to access the data in Sleep Coach. After reviewing the data in Sleep Coach-Doc, the physicians would have a snapshot of the patient’s sleep conditions and quickly grasp the reasons behind the sleep disturbance. With the data in the Sleep Coach-Doc, physicians have the confidence to design tailor-made treatment plans for these patients. They even can input prescription information and the detailed instructions into Sleep Coach via Sleep Coach-Doc interface. Furthermore, this device is portable and usable by patients anywhere and anytime. Sleep Coach integrates CBT and thus provides a complete solution for treating insomnia. With a thoughtful design and multiple user tests, the device and its interfaces are user-friendly and easy to use at home. The user can use Sleep Coach to follow the treatment schedule more regularly. Moreover, physicians can monitor how well the user has complied with the instructions. Sleep Coach shortens the distance between patients and physicians.

This new sleep technology proposes a new workflow for when Sleep Coach is introduced into the medical system. A comparison of the current workflow and the new workflow is shown in Fig. 10.10. There are three major advantages of the new workflow, it is time-saving, provides a precise treatment plan and offers compliance monitoring for professionals. Users can identify their sleep problems immediately and prepare personal data and a sleep diary before going to the hospital. Therefore, they can receive suggestions from their doctor at their first meeting and they do not need to waste their time with trying useless or unsuitable treatments. Once at the hospital, the physician can get the entire profile of the patient just by connecting Sleep Coach to Sleep Coach-Doc. With this useful data, the physician could immediately understand the users’ issues related to sleep and then make a more precise diagnosis. After seeing the physicians, the users would then carry out treatment plans with Sleep Coach and their compliance will also be recorded in this little device. This could help professionals to evaluate the efficiency of their various treatment plans.

Fig. 10.10
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Comparison between the current workflow and the new workflow with Sleep Coach

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Up to now, the hardware of Sleep Coach has three shapes, including a handheld device shaped, digital frame shaped, and one with a book-shaped (as shown in Fig. 10.11). The handheld device is equipped with three biosensors on the right side, which are used to gather users’ biological data, such as heart rate variability (HRV) and skin conductance level (SCL). It also includes a touch panel that allows users to interact with the system using their fingers. But there are three design issues with this format. First, the device is too small, so that it’s hard for people who have big hands to use its touch panel. Moreover, although the user could carry around this small device more easily, but it seems that there is no connection between it and sleep or bedroom. It might take time for users to get used to it. The last problem is that when users are trying to practice the training program, it’s hard for them to hold this device and try to relax at the same time. Consequently, the second format of Sleep Coach, digital frame, attempted to resolve some of the problems mentioned above. First, it is equipped with a screen that is similar to a 10-in. notebook. Therefore, even a person with big hand can use this device more conveniently. Second, the format is similar to an alarm clock which we would put beside our bed. Hence, this image could more easily fit in the bedroom. Third, the digital frame shaped Sleep Coach has a moving screen saver. The user would not forget to use it because of the eye-catching and interactive screen saver. Moreover, the user could conveniently put this device on the table to practice the training program. On the other hand, the book-shaped one is designed to function like an ordinary book. The design concept is based on an observation of users’ behavior and their bedroom environment. Most people would consider reading a book before they sleep, then the image of a book is easier to fit into a bedroom setting. There are two versions of this prototype, a pink version and blue version, for different users. The process of developing this prototype is shown in Fig. 10.12.

Fig. 10.11
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Hardware prototype of Sleep Coach

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Fig. 10.12
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The developing process of book-shaped Sleep Coach

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A researcher conducted the first usability test of the handheld prototype in July 2008[24]. It recruited seven participants. Physicians had diagnosed all of them as insomniacs. Each testing session was approximately 2 h. They designed multiple tasks to observe whether they could complete the tasks using our prototypes. Some tasks focused on examining hardware design, such as the button locations or size of the device. The other tasks focused on the software design. For example, they designed a task to figure out whether the users could follow the instructions in Sleep Coach and complete the assigned tasks. Many usability problems were identified during the testing. Moreover, they also invited five participants to evaluate the validity of training tasks in Sleep Coach. All participants have to practice two tasks including a visualized signal breathing task (SB) and a hearing guide imaging task (GI) measuring their pulse rate at the same time. From the tests in the sleep lab, we found that users will naturally work with Sleep Coach, and that use of the training module can result in a significantly reduced pulse rate, which indicates better relaxation [25].

4 From Sleep Coach to Sleeper-Centered Bedroom

Since everyone spends around one third of their life at sleep, one’s quality of sleep is an absolutely important determinant of quality of life. In addition, the sleep disorders will negatively affect individuals during daytime, including both physiological and cognitive function. The creation of an ideal smart living space cannot exist without a well-designed sleep environment. It needs to integrate at least seven fields of knowledge, such as sensor technologies, architecture environment, sleep medicine, business, persuasive computing, user-centered design, and usability testing (Shown in Fig. 10.13).

Fig. 10.13
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The involved fields of a sleeper-centered bedroom

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Fig. 10.14
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The structure of sleeper-centered bedroom

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Sleep Coach is the first step to realize the concept of a sleeper-centered bedroom (Shown in Fig. 10.14). The starting point of building a sleeper-centered bedroom is to develop cheap and portable biosensor-monitoring techniques, which can be used to detect the sleeper’s physical condition, such as HRV, blood pressure, skin conductive level (SCL), and respiratory condition. For patients who suffer from sleep disorders, this information could become baseline data, which could help physicians to make a diagnosis or to evaluate the validity of certain treatments. Even more so such biosensor data with the use of other sensors in a smart living space could establish as a complete caring-network to establish the sleeper’s own sleep database. The second stage of building a sleeper-centered bedroom is to develop sleep-promotion program. This program would be equipped with a smart calculation module to analyzing the database based on physician’s diagnostic guidelines and knowledge of Sleep Medicine. At this stage the user could get the appropriate advice and could learn to develop proper sleep-promoting skills or activities. After gathering and analyzing the sleeper’s own profile, these suggestions would be presented through an interactive user interface helping the sleeper clearly understand a physician’s instructions. A smart living space for sleep can be established by integrating the elements mentioned above utilizing wireless-sensor techniques, environmental controllers and fuzzy calculation.

5 Conclusion

Sleep environment is critical for sleepers. From the related literature, we have found that lighting, noise and temperature significantly influence the sleep condition. We therefore focused on the improvement of the sleep environment. A new environmental controller, Sleep Coach, was introduced in this chapter. It integrates light sensors, biosensors and a microprocessor in the system. It is composed of three types of controllers: proactive controller, knowledge-enhanced controller, and sensor-enhanced controller to enable the automatic adjustments to the sleep environment according to the users’ unique needs. In fact, Sleep Coach promotes the concept of a sleeper-centered bedroom. Instead of fighting against an uncomfortable environment, Sleep Coach integrates existing technologies and knowledge with regards to sleep medicine to create a friendly environment for users. Sleep Coach can further become a bridge between the patient and the physicians. By collecting a sleepers’ physiological data, physicians can use this data and can more easily diagnose the reasons behind a patient’s sleep disorder and more effectively provide the treatment. In short, with the help such technologies, we can create an ambient environment which promotes the quality of sleep effectively.