Medical alarm

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A medical alarm is an alarm system designed to signal the presence of a hazard requiring urgent attention and to summon emergency medical personnel. Other terms for a medical alarm are Personal Emergency Response System (PERS) or medical alert.

Typical systems have a wireless pendant or transmitter that can be activated in an emergency. When the medical alarm is activated, the signal is transmitted to an alarm monitoring company's central station, other emergency agency or other programmed phone numbers. Medical personnel are then dispatched to the site where the alarm was activated.

Elderly people and disabled people who live alone commonly use/require medical alarms.


Home alert systems were conceived and developed in Germany in the early 1970s by Wilhelm Hormann with the aim of developing new comprehensive structures for ambulatory and non-ambulatory care for the sick, the elderly, those who live alone, and people with disabilities.

Hormann's concept of "home alert" (Hausnotruf) is thus to be seen as fairly broad, including the communication of biomedical data and social communication, and not limited to use as an "elder alarm". This has been set forth extensively in the research literature on PERS.[citation needed]

The technical implementation succeeded with the help of AEG-Telefunken Backnang GmbH and was presented to the international public early in 1980. In 1982 the Hausnotruf PERS system was distinguished with the Frankfurt Innovation Prize of the German Economy by the Wirtschaftsclub Rhein Main e.V. (Rhein-Main Business Club) in Frankfurt-am-Main.

In 1975 American International Telephone Company offered an emergency home phone system similar to Hormann's. The user wore a medallion around the neck that when pushed delivered a preprogrammed message to several phone numbers.[1]

In Switzerland, estimates assume that around 50,000 emergency call devices are in use.[2]

Types of providers[edit]

There are several different types of medical alarm providers:

  • Hospital programs which are operated by volunteers.
  • Companies that provide for seniors in their homes.
  • Full service companies that provide installation, ongoing education and periodic testing programs.
  • Individually coordinated services that rely on a smart phone app to communicate alerts to a list of personal contacts.
  • Closed systems which are run by an organization such as a university or CCRC

Types of devices[edit]

There are a number of different devices that can be used to trigger an alarm.

  • Pendant worn around the neck[3]
  • Small device worn on the belt[4]
  • Wristband[5]
  • Installed motion detectors in a home
  • Radar based detectors in a room[6]
  • A smart phone[7]

Active devices require the user to take some action to trigger an alarm condition; passive systems monitor the user and raise an alarm based on an algorithm - a fall, lack of activity, etc. A weakness of active devices is that the user must be conscious to trigger the alarm. Both passive and active devices require that the user wear the device. Installed systems can be expensive and difficult to deploy.


Medical alarm device with GSM support

A medical alarm system may consist of

  • Personal Device
    • a wireless transmitter, which is worn around the neck, on a belt, or on a wrist
    • an application running on a smart phone and carried in a pocket
    • the device may contain a speaker and microphone
  • Sensor(s)
    • fall detection sensors
    • movement sensors
    • door open/close sensors
    • usage sensor on a device such as a microwave oven
  • Communication
    • cellular data access for operation anywhere there is cell phone coverage
    • an in-home base station that is either connected to a regular telephone, or to a WiFi network, an ISDN line, or to a cellular data network. The base station may contain a speaker and microphone
  • Data
    • some systems will transmit the GPS location of the alarming device
    • some systems can be configured to transmit additional personal information when an alarm is triggered (such as age, medical history, etc.)
  • Responders
    • Class-B EMT Operators
    • local 911 service
    • friend(s) or family

In addition there are various other types of accessories (emergency buttons, fall sensors, smoke detectors, carbon monoxide detectors, flood detectors, motion detectors) that can be placed around the home and integrated with the base station.

Many base stations are available that can be connected over analog or digital ISDN connections. In the event of a power failure, these devices can operate on batteries, thus adding an extra degree of safety.

In case of emergency the user can set off a call for help by the press of an alert button on his personal device, without needing to reach the telephone. Systems with passive alerts may set off a call for help if no movement has been detected over some period of time, or if a fall is detected.

If a base station shares a phone line, it is able to terminate an in-progress call so that a call for help can be initiated over the telephone.

With some systems, an alert arrives in the offices of the alert system operator (which may be a public rescue service or a private security company) and the data of the affected person (address, medical condition, family contacts) are displayed. With others, there is no system operator, and the user simply programs the numbers of family members, neighbors, or local emergency responders.

If present, a responder can speak with the user through the microphone/speaker in order to clarify the type and severity of the emergency and discuss further measures.

Depending on the organization of the service and the type of emergency help required, relatives or neighbors can be informed. If necessary, health care services or personal physicians can be notified or emergency medical services can be alarmed. Some monitoring services also provide the client with a USB medical alert device so that arriving emergency personnel can have immediate access to vital medical information.

Some units can call user selected numbers, so relatives or neighbors can be called directly, avoiding the expense of a monitoring service.[9]

With some systems, it is common practice for the user to leave a house key with a neighbor or at the system office so that emergency personnel can enter the house even if the resident cannot open the door. Keys are kept in a safe and marked only with numbers so that improper use is precluded.

In addition to this "active alarm" there is also the option of a "passive alarm" (sometimes called a "safety clock"), on the principle of a so-called dead man's switch. On some device is a button that the user is to activate several times a day; this confirms that the user is well. If this confirmation goes lacking for a longer period (usually around 12 hours), a telephone call is placed or someone is sent to check whether everything is in order at the residence.

Depending on the company offering it, the system may provide for more than emergency use. Some solutions will periodically call to converse with the user.


In the event of an alarm, some systems will place a phone call to a community emergency service such as 911. Others will place a call to the configured number of a friend or family member. Some systems will send an SMS message to configured contacts.[10]

Some systems provide 24x7x365 professional monitoring. The monitoring service for medical alarms (central station) is a call center facility that is staffed by trained professionals. These professionals are available at all times to receive calls from the medical alarm system. Monitoring service centers that are approved by Underwriters Laboratories (UL) have internal backup systems to add redundancy. Some monitoring services employ trained medical operators enabling them to better evaluate the severity of medical requests. In most less developed countries however, response to medical alarms are slow.

Current and future trends[edit]

A Florida State University research team is currently working on an Android device to be worn by the user that not only can be used as a typical medical alert monitoring system but has fall detection software built into it.[11] The system is designed to monitor the user's location, position, and movement in the event a fall occurs. New fall detection technologies are being integrated into watches, pendants, hearing aids, and wall mounted devices that do not need to be worn by an individual.[12]

Medical alarms in pop culture[edit]

"I've fallen and I can't get up!" was a catchphrase from a 1989 LifeCall Medical Alert System television commercial. In this commercial, an elderly actor is seen fallen and distraught and uses the medical alert system to summon help. The unintentional humor in the commercial made it a frequent punchline for many comedic acts. Due to the trademark changing hands between competing companies, the trademark currently belongs to LifeCall's direct competitor, Life Alert Emergency Response, and is used in all channels of Life Alert's advertising.

See also[edit]


  1. ^ "Emergency Dialer" Popular Science, October 1975, p. 104.
  2. ^ "Gesundheit - Nottelefone teils untauglich und überteuert", Schweizer Radio und Fernsehen (SRF), 2012-03-06, retrieved 2012-03-06
  3. ^ Regterschot, G. Ruben H.; Wahle, Fabian; Geraedts, Hilde; Baldus, Heribert; Zijlstra, Wiebren (August 2014). "Chair rise transfer detection and analysis using a pendant sensor: An algorithm for fall risk assessment in older people". 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society: 1830–1834. doi:10.1109/EMBC.2014.6943965.
  4. ^ Desai, Kimaya; Mane, Pritam; Dsilva, Manish; Zare, Amogh; Shingala, Parth; Ambawade, Dayanand (2 October 2020). "A Novel Machine Learning Based Wearable Belt For Fall Detection". 2020 IEEE International Conference on Computing, Power and Communication Technologies (GUCON): 502–505. doi:10.1109/GUCON48875.2020.9231114.
  5. ^ Zhang, Hongtao; Alrifaai, Muhannand; Zhou, Keming; Hu, Huosheng (February 2020). "A novel fuzzy logic algorithm for accurate fall detection of smart wristband". Transactions of the Institute of Measurement and Control. 42 (4): 786–794. doi:10.1177/0142331219881578.
  6. ^ Amin, Moeness G.; Zhang, Yimin D.; Ahmad, Fauzia; Ho, K.C. Dominic (March 2016). "Radar Signal Processing for Elderly Fall Detection: The future for in-home monitoring". IEEE Signal Processing Magazine. 33 (2): 71–80. doi:10.1109/MSP.2015.2502784.
  7. ^ IMedicalApps Article, September 2009
  8. ^ Bird, Jordan J. (29 June 2022). "EEG Wavelet Classification for Fall Detection with Genetic Programming". The15th International Conference on PErvasive Technologies Related to Assistive Environments: 376–382. doi:10.1145/3529190.3535339.
  9. ^ "How Do Medical Alerts Work - Contact Lists and Custom Protocols". Retrieved 29 April 2020.
  10. ^ "AtGuardianAngel Provides Integrated Connected Health Service for Seniors". Retrieved 18 December 2015.
  11. ^ "Florida State University team studying android app that could save lives Comments Feed". Retrieved 18 December 2015.
  12. ^ "Best Fall Detection Systems for Older Adults".{{cite web}}: CS1 maint: url-status (link)

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