October is National Fire Prevention Month-a good time to ask the question: If there is a fire, will your patients wake up in time? Consider these facts:

• Roughly half of all home fire deaths result from incidents reported overnight (between 11 p.m. and 7 a.m.)-the hours when people are typically sleeping;

• During a fire, an individual often has fewer than 2 minutes to safely evacuate;

• In a recent study, 44 percent of people with hearing loss did not wake up to the sound of a typical smoke alarm, which uses a 3100 Hz pure tone signal.

Put these facts together and you have a critical safety issue for your patients: They are not likely to wake up to their smoke alarm-and if they don't wake up, they can't escape a burning building.

What's more concerning, your patients probably don't know this. People with hearing loss may still be able to hear their smoke alarm when they are awake, but that does not mean it will wake them up from sleep. Audiology professionals have the opportunity to help patients by making them aware of the safety gap and encouraging them to be sure their fire alarm is right for their needs.

Research Tells the Story

Even though most people with hearing loss have more trouble hearing high frequencies than low ones, the typical smoke alarm uses a high frequency-a 3100 Hz pure tone signal. In the "Waking Effectiveness Study" by Dorothy Bruck and Ian Thomas of Victoria University, nearly half of the subjects with mild to moderately severe hearing loss slept through code-mandated levels (75 dBA) of the 3100 Hz smoke alarm signal.¹In that same study, researchers found there was a tone highly effective at waking participants with mild to moderately severe hearing loss: the 520 Hz square-wave tone. In fact, 92 percent of the people in the study woke up from deep sleep at 75 dBA of the low frequency alarm, while only 56 percent woke up at 75dBA for the standard alarm's 3100 Hz pure tone. The 520 Hz square-wave tone also was more effective in waking participants than strobe lights or tactile devices. Strobe lights alone woke less than 30 percent of participants, while bed shakers and pillow shakers woke 80 to 83 percent.

The report also indicated that people may respond differently to different types of signals and suggested that a bedroom alarm "kit" that combined two types of sensory signals, such as an auditory signal and a tactile signal, may be more effective than one signal.

Perhaps most disturbing is that many people who are affected by hearing loss indicated they do not act on their need for specialized alerting devices. This may be due to cost or a sense of denial around their needs.

A New Standard for Safety

Because of this research and related studies, the 2010 edition of NFPA 72® National Fire Alarm Code includes a provision that will require use of a low-frequency (520 Hz) square-wave signal for fire alarms installed in residential bedrooms of those with mild to severe hearing loss by January 2010 and in all commercial sleeping rooms by January 2014. This is a significant step by the fire safety community to address this safety issue, but it's just one part of the solution. It is up to individuals to take action in their homes.

As healthcare professionals, you are a critical resource and advocate for your patients. It is important to educate them not only about health issues specific to their hearing loss, but about safety issues as well. In particular, it is important to make patients aware of safety issues that come as a result of their hearing loss and to encourage them to use devices that are right for their needs. In terms of fire alarms, the most effective alerting technology is a 520Hz square-wave signal. A bed shaker, while less effective than the low-frequency alarm for people with mild to moderately severe hearing loss, is more effective than strobe light alarms and is most effective for waking those who are deaf.

Help your patients heed this wake-up call.

References

1. Bruck, D, Thomas, I, and Kritikos, A. (2006). Investigation of auditory arousal with different alarm signals in sleeping older adults. Project Report. Fire Protection Research Foundation, Victoria, Australia. Accessed online at www.nfpa.org/assets/files/PDF/Research/Investigation_of_Auditory_Arousal.pdf

David Albert, MD, is chief scientific officer and chairman of the board of Lifetone Technology, www.lifetonesafety.com.

Residential Fires:

In 2007, there were 414,000 fires in residential structures. These fires resulted in 2,895 deaths and 14,000 injuries and caused $7,546 million in damage.

Cooking is the biggest cause of fires in the home. Other causes are heating, incendiary/suspicious, open flame/ember/torch, other heat/flame/spark, exposure, smoking, appliances/air conditioning, natural causes, electrical distribution, other equipment, and children playing.

Source: U.S. Fire Administration, www.usfa.dhs.gov/statistics/national/residential.shtm