Ambient assisted living (AAL) for the elderly and patients with chronic diseases

The concept of a smart home or smart environment consists of a network of smart sensors, wearables, and automated mechanisms in the Internet of Things (IoT). It gives the ability to monitor indoor environmental conditions, including noise levels, air quality, lighting quality, and control home appliances, windows, air conditioning systems, doors, etc., substantially helping the inhabitants improve their life quality.

There are a wide variety of useful and personalized services that classify smart homes differently and provide different kinds of assistance to the users in their daily life activities and actions. Assistive services, in particular, are specifically tailored to the unique needs of the user and are part of an assisted living environment. These services are mainly focused on acquiring high-level information about the users by monitoring their physical condition, activities, and indoor localization.

Ambient assisted living (AAL) systems are built on top of those smart home services to support the elderly and people with chronic diseases. The goal is to improve their life quality and enable them to live independently in their preferred environment as part of telehealth and telemedicine.

These systems consist of an ecosystem of interconnected wearable and non-wearable medical sensors, wireless sensor and actuator networks (WSANs), and applications that provide a complete overview of the patient’s health status and a provision of the required healthcare services.

The information, collected from the sensor network, is sent to a coordinator node/gateway and then to any healthcare entity (caregivers, doctors, and physiotherapists) via cloud centers, where data is processed by data analysis algorithms.

This real-time monitoring can prevent many medical emergencies, such as heart failure, asthma attacks, among others. Besides, the medical diagnostics, taken directly from the patient’s home using sensors, can significantly reduce hospital costs and allow a better treatment, specifically tailored for the patient.

For the last decade, companies come up with a variety of AAL based smart home projects, providing efficient solutions such as indoor environmental quality (IEQ) monitoring solutions, particularly of indoor air quality (IAQ) and indoor lighting quality (ILQ) that can play a major role in human health and well-being. This post will explore some of the components for the implementation of an efficient AAL environment.

1. Health status monitoring systems

Health status monitoring systems in an AAL environment monitor the daily activities and the physiological parameters and of patients, such as temperature, heart rate (HR), blood pressure, respiratory rate (RR), and blood oxygen saturation (SpO2), using wearable biomedical sensors.

• Cardiovascular monitoring – There are several methods to record and monitor cardiac activity using non-invasive techniques. The most popular technique is the electrocardiogram (ECG), using Ag-AgCl electrodes (wet electrodes), which have potential drawbacks such as irritant effects on the skin and deterioration of signal quality associated with long-term use. This makes ECG monitoring based on wet electrodes less reliable for AAL. To replace these traditional electrodes, several companies have come up with many alternatives, namely wearables and textile electrodes that can be embedded in custom clothes.
• Body temperature monitoring – Body temperature is one of the key vital signs to determine an individual’s general health condition. There are several wearable systems available today to provide both skin and core temperature measurements in real-time.

2. Body motion and daily activities monitoring

In addition to monitoring physiological signs, there is another equally important aspect in AAL, i.e., the monitoring of gait parameters that characterize a person’s locomotion and activities of daily living (ADL).

Monitoring an individual’s walking patterns, for instance, can provide important data about their health conditions. Gait disorders may be caused by neurological conditions, orthopedic problems, and medical conditions. Vision-based systems and cameras are very useful to monitor gait activities and detect physical impairment.

Despite the accuracy, these systems have some constraints, limiting their use. They include privacy issues and the fact that the user must always remain in sight or within the range of the camera. This can somehow prevent continuous monitoring of gait activity.

Alternatively, wearable motion sensors, based on gyroscopes and accelerometers, are a great solution to understand gait dynamics. Several key features can also be extracted from the sensors based on the linear and angular motion measurements obtained from body kinematics.

The most used indoor tracking and localization technologies use mechanical, magnetic, acoustic, radiofrequency, and light-based methods in the form of pressure sensors, proximity sensors, vibration sensors, accelerometers, and gyroscopes.

3. Indoor environmental quality monitoring

Indoor environmental quality (IEQ) is an important indicator of the general quality conditions of indoor environments being remotely monitored in real-time to prevent dangerous and adverse situations. It consists of multiple subdomains, including air quality, lighting quality, noise levels, thermal comfort, among others.

• Indoor air quality (IAQ) – Air pollution is one of the greatest risks for human health and can potentially cause numerous respiratory problems like asthma, chronic obstructive pulmonary disease (COPD), allergies, and, in a more extreme case, lung cancer. Particulate matter (PM), ozone (O3), sulfur dioxide (SO2), nitrogen oxides (NOx), and carbon monoxide (CO) are the most common air pollutants that can form from both outdoor and indoor sources. Different IAQ monitoring systems are available today with different distributed sensing solutions. Automatic adjustment of IAQ based on actuators is one of the great benefits of home automation systems.
• Indoor lighting and noise – Indoor lighting quality (ILQ) and indoor noise levels also have a great impact on human health, in terms of an individual’s visual ability and several positive biological effects. Adequate lighting during the day and night can regulate sleep-wake rhythms and vastly improve an individual’s health, productivity, and comfort. Today, we can get many smart lighting systems capable of changing its light temperature, color, and intensity to support human health and regulate sleep-wake rhythms.