ES2203332A1 - Portable system for monitoring the movement, postural state and physical activity of a person throughout the 24 hours of the day - Google Patents

Abstract

The invention relates to a portable system for monitoring the movement, postural state and physical activity of a person throughout the 24 hours of the day. The inventive system consists of a device (1) which is fixed to the body of the person (2) to be monitored, said device comprising an intelligent accelerometer (4), a combined router (3) and mobile telephone and a network server (5). The aforementioned device (1) is connected to a control centre (7) from the router (3) via a mobile telephone link (9) or from the network server (5) which is wirelessly connected to a fixed unit (6). Said fixed unit also connects the device (1) with the control centre (7) via a basic telephone connection (8) (switched telephone network or PSTN).

Description

Portable system for motion monitoring, status postural and physical activity of humans during the 24 hours of day.

Object of the invention

The present invention aims at a system that allows the online monitoring and 24 hours a day movement and postural state of the subject who carries it, as well as of your physical activity These capabilities serve as support for other added values, such as the detection of falls and impacts and the subsequent generation of events and alarms. The system is constituted by a wireless personal area network, carried by the subject, which integrates at least one unit of accelerometry Smart and a server from that network. The latter has capacity for the processing of the signals coming from the unit of smart accelerometry The wireless personal area network maintains wireless communication, through the network server, with a central data storage and management system incidents

Background of the invention

The study of balance and human motility is an area of I have been studying for a long time in the field of kinesiology The ability to measure human movement through autonomous and discrete systems are currently charging a large importance for both medical research and improvement of health care for two population groups especially important: older people and people with chronic pathologies

A major problem that people face older, as a result of both loss of strength and flexibility, such as motor and sensory capacity, are the falls These have a proven relationship with morbidity and mortality in this population group. They also represent a burden important within public health spending, which is going to be seen markedly increased in the coming years, due to the inversion of the population pyramid. There is also an aspect psychological, fear of falling, which accelerates the loss of strength and the deterioration of the motor control of these people, increased the frequency of falls and deteriorating their autonomy and quality of lifetime.

Chronic pathologies, such as diabetes or insufficiency chronic kidney, increasingly affect a greater percentage of the population. The causes are diverse and are not the object of the present report, however it is interesting to note that a significant percentage of patients with chronic pathologies such as the named are people with more than 65 years and therefore form Part of the previous group. The measurement of movement during daily activities in this second group, allows the calculation of metabolic activity indices that can be used in conjunction with physiological models or other algorithms as an aid to insulin prescription, in the case of diabetic patients, or to estimate the generation of urea nitrogen, creatinine, and others metabolic products causing uremic syndrome, in the case of patients with chronic renal failure.

From the assistance point of view, the postural and movement, allows to detect falls and other minor impacts, and it helps in the prescription of insulin (diabetics) and doses of dialysis (kidney patients). But it is also an important instrument of help in the investigation of the etiology of falls and in the knowledge of glucose dynamics and uremic toxins

In order to enable movement measurement, without disturbances or restrictions, in recent years they have developed different portable devices, within the field of home telecare. Some of those developments have reached the commercial phase and are currently available in the market. However, they all suffer from a clear lack interoperability and have important limitations in their functionality, as described below.

Synthesizing, the autonomous devices developed until the Moments can be classified into three groups. The simplest group is based on the detection of the inclination of the subject, usually by electronic devices of not much precision. These devices only detect that the individual lies in position horizontal. The sum of that information along with the knowledge of the daily habits of the subject, allows the estimation of Possible falls The second group of devices adds a sensor of impact, which used in conjunction with the tilt sensor  Increase the reliability of fall detection. Despite its obvious limitations, these modern devices can perform the online monitoring of the subject for a large part of the day, provided that this is maintained in reduced environments, such as home. They are small and can be attached to the belt.

Taking advantage of recent advances in systems micro-electromechanical (MEMS) and capacity increase and microcontroller size reduction, very recently it is beginning to investigate new devices with capacity to monitor the movement of the carrier subject in real time, calculating postural and kinematic coefficients. Nevertheless, these devices continue to work in reduced environments, and also exclude periods of demonstrated high supervision risk, when the subject is not wearing a belt or is undressed, such as the bathroom or the bedroom.

An additional problem with these devices is the incompatibility between two functional specifications important: the easy accessibility of the device and the measurement of accelerations in the right body place. In relation to this Last specification, different studies have shown that it is possible to detect transitions between postural states and parameters metabolic or kinetic from acceleration records acquired through a sensor placed on the waist or chest. However, the quality of the information and therefore the accuracy of these parameters and the necessary process capacity, can be optimized if the sensor is placed near the center of gravity of the subject, that is to say in the back, in the medium plane, at the height of the sacrum. On the other hand, the accelerations measured by the current devices have dynamic components linked to relative movement of the apparatus with respect to the body. This complicates signal processing algorithms, which in turn require many more computational resources, making time analysis difficult real.

In addition to the above limitations, current devices They are not clearly interoperable. In many cases, they haven't even been designed to be integrated into a modular architecture and open

Description of the invention

The invention proposes a new system that allows subject monitoring 24 hours a day and resolves all Problems that have been cited. The invention is based on the current state of information technologies and communications, new micro-electromechanical systems and electronic technology, and supposes an innovative contribution in the application of these to solve certain current needs and future in the area of health care.

The system devised is characterized by allowing monitoring real-time movement and postural state of the subject carrier, automatically detecting possible falls and calculating the metabolic activity index, during the 24 hours of the day, through a constituted personal wireless network, of according to claim 1, by a server device, and at minus a smart acceleration sensor unit bodily

According to the above, the system is constituted by a server, a set of smart sensing units of Acceleration and a router. All these elements are carried by the monitored person, and are connected to each other in a way wireless, creating what is called a personal network wireless The server acts as a network server, is responsible for the real-time processing of the signals measured by intelligent units and manages communication between the network and an external center for data management and monitored signals. The management center refers to a capable computer system to properly store and treat the monitored signals of any subject, providing notices to emergency centers sanitary As such, it is part of the current concept of telecare, and is external to the system here describe.

Communication between the network and the management center is carried out in different way depending on the location of the patient. In the home, or equivalent residence, the server communicates in a manner wireless with a fixed unit, in turn connected to a phone permanent. The fixed unit is an element also external to the present invention. In open environments, when the fixed unit is not detected, the communication is carried out through a device portable, which we call router, connected to the local port of a subject's mobile phone. The router size is similar (very small) to the smart unit, with a very internal architecture similar to this one, replacing the sensors, with a buffer of additional memory, in order to reduce the number of connections per unit of time with the management center. The scheme of presented connectivity aims to ensure access universal to the management center, even for subjects residing in rural means, at a very economical cost.

Both the network and its own elements are identified by numbers (IDs) recorded in erasable memory, not volatile. This feature allows you to increase or modify the acceleration monitoring of a certain subject, attending to the needs of the medical team, to carry out certain diagnoses and research studies, being able to then reuse the corresponding smart drive in Another patient or subject.

Finally, the communications scheme used in the own network is an open aspect of the present system, existing currently different protocols and standards, as well as solutions commercials that can be implemented. However, in the description of a preferred embodiment a solution is presented concrete, but not exclusive, for this system.

Each smart unit consists of at least one microcontroller with code (ROM) and volatile data (RAM) on the chip itself, one or more accelerometers with acceleration measurement capability static and dynamic, controlled by the microcontroller, a non-volatile storage memory, an integrated transceiver, a PCB antenna and a button or similar size battery or battery, for the feeding.

The system is also characterized, according to the claim 3, because a sensor unit is carried attached to the skin as a transdermal patch. This has been achieved thanks to small size that current technology has achieved in micro-electromechanical devices (MEMS) and in microprocessors and programmable devices To ensure that the sensor unit can be carried in any situation and continuously, this It is covered by a waterproof material and hypoallergenic, so it doesn't need to be detached neither in the bathroom nor at night.

The system is also characterized, according to the claim 4, for its ability to measure accelerations bodily in places of difficult access by the subject himself who holder. This feature is of great importance, since the This system is aimed at population groups with increased mobility difficulties, and as described in the background section, different studies have shown the feasibility of measuring postural and kinetic parameters that clearly represent the type of movement and posture of the subject, through the dynamic and static accelerations of the center of the subject's severity. An optimal point for measurement would be in the back at the height of the sacrum, within the median plane body (parallel to the sagittal).

An additional feature of the present system, linked to the way of fixing the sensor unit, is the absence of dynamic components of acceleration associated with movement relative of the sensor with respect to the subject's body. The elimination of these components represents another important advantage of this system compared to those currently existing, by simplifying the processing of signal and facilitate the execution of algorithms on the server, in addition of eliminating false impact events.

According to claims 2 and 5, the system devised is characterized by the high autonomy time of the units smart sensors. This feature is achieved thanks to the reduced consumption of current MEMS devices, at low necessary transmission powers, and finally thanks to the mode of operation established in the design. All the elements of a sensor unit is turned off or in SLEEP mode (microcontroller) for most of the time, except of the transceiver, which is in reception mode (minimum consumption) almost always. Reestablishment time is used of the sensors and the measurement, in each sampling period, to perform the corresponding signal processing instantly previous.

The system is also characterized by taking advantage of design low maintenance systems with the ability to detect own failures, to ensure the minimum need for maintenance of the smart drive, and capturing any possible error automatically, notifying the management center if this happen. For this, the architecture of the unit has two surveillance systems The first detects and recovers blockages in the firmware (watch-dog module). The second is a system of hardware monitoring, which automatically performs the off- on of the complete sensor unit, when it detects Some physical problem in the unit. Any error, permanent or of the unit, it is communicated to the server, which analyzes it and send if necessary to the management center. This architecture automates the process of detecting breakdowns or deterioration of sensor units, including failure and loss of accuracy of Accelerometers If the error disables the communication of the unit with the server, this last element is responsible for warning from the event to the management center.

The system is also characterized, according to the claim 6, for providing a very complete interface of Easy access to the subject. The interface is supported by the server of the personal wireless network, which is worn on the wrist. East It has a push button to make emergency calls to health care center, along with an optical subsystem and acoustic, consisting of a small speaker and an indicator bright. One of the most important functions of this subsystem is the information to the subject about the status of the request for a request for help, in case there has been a fall. It also informs the user of the correct status of all sensors that configure the system. The information is presented duplicated acoustically and optically, in order to meet possible auditory and visual deficits of the monitored subject.

The server unit is constituted by a processor digital signal (DSP) with embedded logic modules (e.g. timers) and  Erasable memory for the code, the interface module described in the previous paragraph, an integrated transceiver, a PCB antenna and battery The unit firmware can be updated by a local port, to meet the possible addition or removal of network elements, and the design of new processing algorithms signal This feature allows you to customize the system presented, to adjust it to the needs of the subject that leads, and those of the medical or research team. Although the devised system leaves open the choice of technology more suitable for erasable memory, however a concrete solution, but not exclusive, in the preferred embodiment described below.

The system is also characterized by its ability to perform, in real time and autonomously, the signal analysis of the  accelerometers, computing the different kinematic parameters, postural and activity indices, and sending them to the center of management. It is also characterized by its distributed character, of so that the sensor units perform an initial analysis of the signal, by sampling at a frequency higher than the necessary for the calculation of kinematic parameters and postural, and send the signal with a lower sampling rate to the server, for full analysis. This scheme reduces the computational load of the processor belonging to the server and improves the detection of possible fall or impact events, characterized by frequencies and amplitudes greater than measures during normal activities of the subject. When a possible impact event is captured, the smart unit sends this data to the server, which analyzes the temporal environment in more detail surrounding that impact. The unit set information Smart is periodically sent to the server. The period of update is about a second.

Based on the functional and architectural design that has been described, the system is also characterized, by guaranteeing the subject supervision 24 hours a day, both inside and out of home.

The open and modular system design also facilitates the adding new biosensors to the personal wireless network. This it is possible thanks to the distribution in the consumption of resources leave the processor free time to attend to the capture of others signs, provided they do not require excessive treatment. exist many signs of clinical interest and that comply with these requirements, such as blood pressure, temperature, level of blood oxygen saturation, etc. The system guarantees the interoperability with possible new sensors, through the server firmware reload, which allows setting the number and the identifiers of the new elements in the network, as well as The processing program itself.

Description of the drawings

To complement the description that is being made and with in order to help a better understanding of the characteristics of the invention, according to a preferred embodiment practice thereof, is accompanied as an integral part of said description, a set of drawings where illustrative and not limiting, the following has been represented:

Figure 1.- Shows a schematic representation of the system portable for movement monitoring, postural state and physical activity of a person 24 hours a day, which It constitutes the object of the present invention.

Figure 2.- Shows a simplified block diagram corresponding to the intelligent accelerometry unit.

Figure 3.- Shows a diagram similar to that of the figure previous but corresponding to the router.

Figure 4.- Shows, finally, a block diagram corresponding to the network server.

Preferred Embodiment of the Invention

In view of the figures outlined, and more specifically of the Figure 1, can be seen as in the system that the invention proposes a device (1) to be carried by the subject (2), device in which a wireless network of personal area (3), connected to the outside through a unit fixed (6). In the simplest embodiment of the system it incorporates a single unit (4) of intelligent accelerometry, with its corresponding network server (5), while the fixed unit external to the device (1) has been referenced with (6) and is connected to the management center (7) through a connection basic telephony (8). The management center (7) is in turn connected to the router (3) through the mobile phone link (9).

The intelligent accelerometer unit (4) is represented in the block diagram of figure 2 and is embodied in a 8-bit microcontroller (10) powered with 3 volts from of a battery (11), like the rest of the elements of this smart sensor unit, with adequate clock frequency For this application.

With the microcontroller (10) collaborate an erasable memory (12),  a transceiver (13), an antenna (14) and two accelerometers (15) and (16).

The microcontroller (10) manages the switching on and off of the accelerometers (15) and (16), capacitive, dual-axis, with output Digital modulated by pulse width and self-test function. The four channels corresponding to the total axes are demodulated by the microcontroller at each sampling point. The routine of demodulation is triggered by interruptions generated by flanks of the signals of each of the previous channels. The demodulation time is less than 0.5 ms. At this time you will add the accelerometer setting time (15) and (16), after switching on. The microcontroller (10) remains asleep, until the next sampling moment, unless you receive a command from the network server (5), in which case it is awakened by an interruption generated from the transceiver (13) that is operating in receiver mode.

The initial processing of the signal corresponding to the period of Previous sampling is performed taking advantage of the time intervals  corresponding to the ignition and demodulation of the measured signal during the current sampling instant.

The measuring axes are located so that three of them they belong to the medium plane of the subject (2), the fourth being perpendicular to it. The presence of three axes in the medium plane increases the sensitivity of the accelerometry unit intelligent (4) to the inclination of the subject in this plane, which It is of interest to more accurately capture the changes most frequent postures (upright position, sitting or horizontal).

The signal corresponding to the three orthogonal axes is sent to the network server (5) after a buffer re-sampling. Router (3) is structured, as seen in Figure 3, from of a microcontroller (17) assisted by an erasable memory (18), a transceiver (19) and its corresponding antenna (20), all of them powered by a battery (21), also collaborating with the microcontroller (17) a memory buffer (22) and transmitting the data through the local port (23) of the router with which in turn The mobile phone (24), external to the router, collaborates.

Finally, the network server (5), as seen in the  Figure 4, is structured based on a digital processor of signal (25), consisting of several embedded peripherals (26), the own processor (27) and an erasable memory (28) for code. The Signal processor (25) is assisted by a transceiver (29) with its corresponding antenna (30), which like the rest of the server is powered by a battery (31), also collaborating with the processor (25) a local port (32) and an interface (33), with a push-button (34) and an acoustic-optical alarm (35).

In a preferred embodiment and for the minimum configuration previously cited, a wireless transmission is used within of the free band for industrial, scientific and medical devices (ICM band), with self-correcting baseband coding. I know uses a master-slave protocol, being master the server of the wireless network of personal area and slaves the rest of the elements of the personal network. Communication between the network server (5) and the fixed external unit (6) of the device, inside the home, is performed by a peer-to-peer protocol. The assignment of Communications channel is managed by the cited elements, server (5) and fixed unit (6). Finally and in relation to the transport stage, wireless area network information personnel is sent through vectorized packages addressed to particular elements or the entire personal network (packages broadcast) Information security is guaranteed through the adequate encryption of the data. Also, all requests from the management center (7) to the device (1), and from the network server (5) to the rest of the network elements wireless, which may involve some technical risk or reduction of a patient's monitoring level, they are protected by key.

Claims (5)

1. Portable system for monitoring the movement, postural state and physical activity of humans 24 hours a day, which being constituted from a device (1), intended to be carried by the subject (2), and a center of management (7) that receives information from said device (1), is characterized in that said device participates in an intelligent accelerometer unit (4) with which a router (3) collaborates, complemented with a mobile phone, as well as a server network (5) connected to a fixed remote access unit (6), so that the router (3) and the fixed unit (6) establish communication with the management center (7), respectively through a link ( 9) mobile telephony and a basic telephony link (8). 2. Portable system for monitoring the movement, postural state and physical activity of humans 24 hours a day, according to claim 1, characterized in that the intelligent acceleration sensor (4) is structured based on a microcontroller (10) assisted by an erasable memory (12), a transceiver (13) with its antenna (14) and a battery (11) for supplying all these elements, said microcontroller (10) governing a set of accelerometers. 3. Portable system for monitoring the movement, postural state and physical activity of humans 24 hours a day, according to claim 1, characterized in that the router (3) is structured from a microcontroller (17), assisted by a memory Erasable (18), a transceiver (19) with its corresponding antenna (20) and a memory buffer (22), all of them powered by a battery (21), as well as a local port (23) associated with a mobile phone ( 24) outside the router. 4. Portable system for monitoring the movement, postural state and physical activity of humans 24 hours a day, according to claim 1, characterized in that the network server (5) is structured based on a digital signal processor (25) , with embedded peripheral modules (26) and an erasable memory (28) for code, the processor (25) being assisted by a transceiver (29) with its corresponding antenna, by a local port (32) and by an interface (33) , with a push button (34) and an acoustic-optical alarm (35), all of them powered by the corresponding battery (31). 5. Portable system for monitoring the movement, postural state and physical activity of humans 24 hours a day, according to previous claims, characterized in that the device (1), of very small dimensions, is capable of being placed in very bodily places of very difficult access, such as the subject's back (2), at the height of the sacrum, near its center of gravity.