Low-cost future for sensor alarms in falls prevention

The University of Adelaide is developing a low-cost movement sensor alarm system to aid falls prevention in the acute care setting with plans to trial the technology in residential aged care.

Using radio-frequency identification (RFID) technology, the researchers from the university's Auto-ID Lab in association with the Adelaide Geriatrics Training and Research with Aged Care (G-TRAC) Centre are developing a system using very low-cost, wearable sensors allied to a customisable alarm system based on individual falls risk, along with a more intuitive, discreet alarm system that can be integrated with common nurse call systems.

Auto-ID Lab director Damith Ranasinghe told the Health Informatics Conference (HIC 2013) last week that there are a number of movement sensors currently being used to study and prevent falls, particularly in hospitals, but many of them are only able to detect when a person gets out of bed and many are too expensive for widespread use.

Dr Ranasinghe said there were two different methods commonly used: “instrument the person” or “instrument the environment”. The latter involves placing movement sensors near hospital beds, video cameras for monitoring or using pressure mats attached to the actual bed that are able to alert nurses that a person has got out. These methods often have drawbacks such as false alarms, privacy concerns, high cost and susceptibility to damage.

“Instrumenting the person” using wearable sensors is an area of real interest for researchers. The Irish company Shimmer, for example, manufactures and markets a range of wearable credit card-sized sensors both for research and for commercial use that are based on wireless technology and are particularly good for biofeedback and athletic training, but also for healthcare applications.

Shimmer sensors can be rather expensive, however, with the company's kinematic sensor platform costing upwards of 200 euros. What the Auto-ID Lab is working on is very low-cost technology using the Wireless Identification and Sensing Platform (WISP), developed by Intel Research and the University of Washington in the US.

The sensors are designed to be very low-cost – between $3 and $4, Dr Ranasinghe said – and are maintenance free as they don't use batteries. As they are so cheap, they are disposable, important in a hospital or residential aged care for hygiene and infection control.

Wireless sensors require an antenna, which in a hospital setting can be placed unobtrusively on the ceiling, but Dr Ranasinghe's team is also investigating the use of conductive fabrics made from silver thread and plastics, These can be sewn into clothing, can produce a barrier between the antenna and the body and can also be laundered. The team is also investigating snap-on tags that can be sterilised and reused.

Of even more practical application is the ability to use the sensors to produce a customised alarm system based on the individual, following a falls risk assessment that most elderly people are given when entering hospital.

“With most of these [alternative] devices, you can't really customise them based on personal needs,” Dr Ranasinghe said. “But we can individualise alarms so we can say if Mrs Jones isn't supposed to get off the bed but she can get off a chair, we can customise the alarm for that person.

“With our technology we can uniquely identify each patient with RFID. We now have the ability to customise alarms individually based on falls risk.”

Dr Ranasinghe said most alarm systems concentrated on monitoring bed exits, which is where most falls in hospitals occur. However, the technology his team is developing also aims to monitor people when they are sitting in or rising from a chair, walking around the room, leaving the room or moving without the use of their walking aids.

Dr Ranasinghe is currently working on a project with the university's Associate Professor Michael Sheng, a specialist in developing context-aware computer algorithms for inference engines, which can interpret what a person is doing automatically.

“Traditionally, if you look at algorithms that are in practice in terms of deciding whether a person is on or off the bed, they are almost all pressure mat-based,” Dr Ranasinghe said. “If the pressure is below [a certain level] or above it, you are in or out of bed. We have a different approach … we train the computer to recognise patterns and the computer can learn what the person is doing based on these patterns.”

What the team is now developing is a monitoring application that will allow hospitals to customise an alarm system for that individual, which can send a discreet alert telling a nurse that a patient is active, and when and where they are doing it.

“What we are proposing is to send an alert signal to a pager that is carried by nurses – pager systems that are already in use in hospitals, so we don't have to add anything on and we can use the existing infrastructure – and now it will be who, where, what and when,” he said.

“No longer will it simply be a buzz. We can send a discreet message that is more directed to clinicians. Who is the patient? Where? Room 2. What is she trying to do? Get off the bed. And at what time.”

By using RFID sensors attached to the nurse's name badge, alarms can also be automatically turned off. Pressure mat systems often require an alarm to be turned off manually, but if a nurse wearing an RFID tag is in the immediate vicinity of the patient, the alarm will automatically turn off, he said.

“That will reduce alarm frustrations and false alarms. It will also reduce disturbance and agitation because the alarm is not a buzz but a discreet message.

“An alternative approach is, if privacy can be worked out, we could install a video camera that can only be used when there is an alarm going off. So if a nurse knew that someone was trying to get off the bed, they could turn on the video link for just that moment to check if the person is all right. These are all alternative things that we can do.”

The team is also developing a hand-held falls risk management tool based on the commonly used traffic light system, in which high-risk patients are identified by using falls risk alert cards above their beds. By automating this process, the patient's falls risk information is then fed back into the system.

The Auto-ID Lab has been working with Adelaide's Queen Elizabeth Hospital and the Hospital Research Foundation on a number of trials of the new technology, and hopes to begin trialling it with residential aged care providers as well. Dr Ranasinghe said there was also great potential for the technology in keeping older people in their own homes for longer.

This research is only part of a wider effort into researching what has been dubbed the “Internet of Things”, or the ability to connect objects in the physical world to digital information on the internet. The Adelaide Auto-ID Lab is one of several labs worldwide leading research efforts this research. It also works closely with GS1 to help it develop global standards for RFID traceability networks.

Posted in Aged Care


0 # Cassandra 2013-07-24 13:33
My mother who passed away in a high care facility at age 80 was provided with a laser beam alarm beside her bed during the night. The bed was also lowered to the floor. My mother had Parkinson's Disease. The issue is not the lack of technology, it is the availability of a human staff member to attend to the patient. The alarms do not stop or prevent the actual fall. Even elderly people can fall quickly with or without a staff member beside the patient.
0 # Damith 2013-08-01 13:20
Yes I agree Cassandra.

But here is a bit of our thinking and our approach:

We also have a labour shortage and cost issues, this is also something we need to look at and that is why we are looking at other ways of responding such as: i) video links that can be used to check on the patient in the event of a high risk activity being performed so nurses are not rushing around from room to room for example; and ii) using robotic help (the first responders) to interact with the patient when we think that the patient is going to do something that might lead to a fall (so a more personalized approach to patients).

Also another key issue is that there is a lot of technology but, as I said in my presentation, they do NOT work well with older people and most have not even been tested on people per se. Clinical evidence says that pressure mats have false alarm rates of over 99%. So that is why we are conducting a pilot right now of our system at the Queen Elizabeth Hospital in South Australia to see how well our system works with frail older people.

Then, having a technology that gives a lot of false alarms means that eventually nursing staff gets frustrated and stops paying attention.

Finally I would add that in the event of a fall having a monitor would allow a clinician to get to the patient quickly and to follow protocol to check their health.

So in summary: i) we have to address the labour shortage issue and technology can help; and ii) along with technology we also need to demonstrate that the technology works through clinical trials.
0 # Cassandra 2013-08-01 13:30
Can you email me privately cassm.jo@hotmail.com
so I can offer a response 1:1??
0 # KarenG 2015-05-08 23:50
Very interested in the results of the pilot.
Mother is in residential care and at the moment a family stays with her 24hrs a day when she has an acute confusional episode. This may be 4 days and nights for one family member who ultimately has to sleep but is concerned they may not hear her get out of bed in the wee wee hours of the morning. Insufficient staff to offer this degree of surveillance and no way the family want chemical or physical restraint used for acute confusion.
0 # Cassandra 2015-05-09 14:51
I understand about family staying with their loved ones in aged care. Family involvement is paramount and often overlooked by managers in these facilities.
Video links sit in the privacy/confide ntiality space. Falls can occur in a split second with or without staff.
There will never be 1:1 ratio staff:patient.
Chemical restraining is shocking and one drug utilised for this purpose is banned in USA and UK but prescribed in Australia.
Due to my mother's Parkinson's Disease, she had a waist restraint when no 1:1 care with family and private carers/nurses during the day. If not, she would have had more falls than she had without it. If waist restraint care plans are not managed according to the law, the facility is negligent and patient is "assaulted".
The laser beam along the edge of her bed, lowered right to the floor once brilliant and not confronting at all.
Should be looked into by academics further and ask relatives.

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