UBIQUITOUS HEALTHCARE

The availability of ubiquitous remote monitoring is crucial for the medical and healthcare field of the future. Since a mobile phone has the basic functions for providing ubiquitous service, we investigated its application as a remote terminal. No other devices are required; simply replacing the mobile phone’s audio-microphone with a low-frequency microphone provides the functions required for the terminal. This paper describes how we designed a low-frequency microphone as the key device,how it is used to detect biosignals, and how it is applied to ubiquitous medical and healthcare monitoring.Microphones are widely used in everyday life, especially in relation to mobile phones. A microphone is an acoustic sensor, as well as a pressure sensor, with a very high gain of about 10 mV/Pa and an s/v ratio of about 68 dB for the frequency range of 20 Hz to 10 kHz. It is very sensitive and accurate for the audio-frequency range. Few pressure sensors have such high gain and accuracy.We considered the above superior characteristics in terms of a pressure sensor and expanded the lower frequency range from 20 to 0.1 Hz so that the microphone worked in the frequency range of 0.1 Hz to 10 kHz. We applied it to a security sensor to monitor the symptoms of fire, earthquake and break-ins[1]. The low-frequency microphone was easily realized just by closing the back chamber and reinforcing the pressure-sensitive film. However, this microphone was too large for installation in a mobile phone. When the microphone was placed in a thin air cushion under the bed mattress, it was able to detect the biosignals from the subject’s heartbeat, respiration, body movement and snoring.The micro-vibration generated from these vital functions acts on the pressure inside the air cushion even through the thick bed mattress. In an earlier paper, we proposed a pressure-based pneumatic bed sensing system using the large microphone. Furthermore, from the medical fact that the above biosignals,especially those pertaining to changes in the frequency of heartbeat and body movement occurrence, are deeply related to sleep depth, we presented frequency-based sleep depth indices for estimating sleep stages. The bed sensing system,which was a candidate ubiquitous health monitoring system with a function for sleep monitoring, was network-connected to 45 subjects for a year and a half to examine its validity.Unfortunately, the system was not sufficiently feasible. One serious problem was the high cost due to the bed sensing terminal device and specially designed network. Furthermore, the device was not portable. These two factors severely limited the market for the system. This paper describes a novel scheme to solve the problems above by designing and employing a compact low-frequency microphone for installation in mobile phones.

UBIQUITOUS HEALTHCARE

• Ubiquitous healthcare (u-Health) focus on prevention and early detection of diseases

• Extends traditional healthcare from Clinic or Hospital to the Patient home

• U-Health means healthcare services provided at anytime, at any place, for anyone

• It Comprises of sensing, monitoring, analyzing, and feedback process

* Sensing checks any physical or chemical changes in a body

* Monitoring measures bio-information or judges emergency state

* Analysis finds health index that presents health state and life pattern

* Feedback warns patients of their change of health state

IMPORTANCE OF THE UBIQUITOUS HEALTHCARE

The increasing aging population means that a larger population of some western countries will suffer from a wide range of age related illness’s ranging from dementia to physical disabilities. Supporting the needs of the elderly will mean additional costs on the public finances. To reduce costs, assisted independent living is an important goal. It has been proposed that ubiquitous and mobile services can beused to assist the elderly. However, the development and deployment of services customised to the needs of a patient group is a costly and difficult enterprise. The development of ubiquitous service is not an easy task and for a number of reasons. First, sensors are expensive and it is easy to deploy an expensive sensor network which is of eventual limited use. Second, even a user centric approach that focus on questioning the needs of the user group is not entirely reliable as a means for developing services because information is left out, or not as important as the user really thinks. Third, the most expensive part of a service is when faults or problems are discovered n the deployment phase. Not only is the final product delayed, but sub-optimum sensor networks and communication devices have already been deployed and oftware costs are considerably more expensive to correct at the end stage of development.

U-HEALTH

• Needs wearable sensors for continuous measurements of biological signals of a patient

• Wearable sensors could be

* ECG sensor for measuring pulse rate

* EMG sensor for muscle activity

* EEG sensor for brain electrical activity

Fig.1. Example of a U-Health system