It is 2:00 am. I am searching through my house to find the smoke alarm that is running out of battery. Why does it always seem to go off at 2:00 am?! This sound is familiar to many of us; however, most alerting devices (alarm clocks, smoke alarms, carbon monoxide detectors, weather monitors, etc.) have one thing in common: alerting users with a high-pitch auditory signal. This raises a significant concern. Patients who are deaf or are hard of hearing may not be able to hear an alerting signal unaided, which puts their lives at risk and can make them less independent.
In 2015, 1,345,500 fires were reported in the United States, causing 3,280 civilian deaths, and 15,700 civilian injuries. These numbers mean that in 2015, a house fire was reported every 86 seconds (National Fire Protection Association, 2017). Hopefully the call was not to a home with a hearing-impaired individual who did not hear the smoke alarm.
According to the National Fire Protection Association, from 1980 to 2011, the percentage of fatal home fire victims 65 years of age or older increased from 19 percent to 31 percent (Ahrens, 2014). In 2010, the beginning of the “baby boomer” generation started turning 65. One in three adults age 65–74 years have presbycusis, putting them in the high-risk category for not hearing fire safety devices, but many are also at higher risk due to vision impairment and mobility issues. Alerting devices are not top of mind for patients, but should be a recommendation for patients of any age with hearing loss whether they are ready to aid their hearing loss or not.
Smoke alarms are used to provide early warning of fire, allowing for a better opportunity to escape a burning building. In homes with no or non-working smoke alarm, the death rate per 100 reported fires was more than twice as high (1.18 deaths per 100 fires) compared to homes with working smoke alarms (0.53 deaths per 100 fires) (Ahrens, 2015). Not being able to hear a working smoke alarm is as beneficial as a non-working system; this is the reality for individuals who are deaf or hard of hearing. Residential smoke alarms typically have a frequency output between 3500–4000 Hz, with a required sound pressure level of at least 85 dB when measured at a distance of 10 feet from the source. Adults with presbycusis typically have a sloping hearing loss; even if the smoke alarm is in working condition, it is unlikely they will hear the alarm or wake to it while sleeping. This is the dangerous reality many patients unknowingly live in.
The smoke alarm is just one example of an alerting device, but shows the dangers of not hearing alerting devices. There are three different stimulants for alerting devices—auditory, visual (lights), and tactile (bed/pillow shakers). Some manufactures make alerting devices with a combination of stimulants (i.e., devices with an auditory signal and strobe lights). It is also important to understand the differences available for each device. For example, alerting devices are available with lower frequency tones, amplified tones (greater than 85 dB), strobe lights of different intensity and frequency, and bed shakers with various vibration patterns and intensity of vibration.
In a study by Bruck and Thomas (2007), where individuals were tested on their ability to wake to a variety of smoke alarms, the following conclusions were drawn:
The low frequency 520 Hz tone presented at 75 dBA awoke 92 percent of hard-of-hearing participants, while the same tone presented at 95 dBA awoke 100 percent of participants, which was significantly more effective than the 3100 Hz tone presented at 75 dBA, which awoke only 56 percent of participants.
When presented alone, the bed shaker and pillow shaker devices awoke 80–83 percent of the participants. Of important note is that participants age 60 or over were less likely to awaken to the bed shaker than those younger than age 60.
The strobe light, when presented alone, only awoke 27 percent of participants.
Safety and Independence
While I did eventually find the beeping alarm and changed the battery, I now have a new concern that keeps me up at night—will my patients awake if the alarm goes off at their house? As audiologists, our role is to help others hear and communicate, therefore, it is important to remember how our patients live their daily lives, which includes times without their devices. It is important to remind our patients of the dangers of not being able to hear an alerting device such as a smoke or carbon monoxide alarm.
Equally important is our responsibility to help patients lead independent lives, this includes being able to live safely in their homes. Patients should be encouraged to have alerting devices that can alert them unaided in each room of the house, and an alerting device with two different stimulant types that can wake them from sleep in the bedroom. Armed with this information, I hope all audiologists will sleep well knowing their patients are safe both awake and asleep.
Ahrens M. (2014) Characteristics of home fire victims. National fire protections association fire analysis and research division. Quincy, MA.
Ahrens M. (2015) Smoke alarms in U.S. home fires. National fire protections association fire analysis and research division. Quincy, MA.
Bruck D, Thomas I. (2007) Optimizing fire alarm notification for high risk groups research project: Waking effectiveness of alarms (auditory, visual and tactile) for adults who are hard of hearing. The fire protection research foundation.
National Fire Protection Association. (2017) An overview of the U.S. fire problem.