Smoke Alarms With Mother's Voice Wake Kids Faster

Traditional tonal alerts less effective at rousing children from deep sleep, study finds

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By Leslie Sabbagh
HealthDay Reporter

MONDAY, Oct. 2, 2006 (HealthDay News) -- "Johnny! Johnny! Wake up! Get out of bed! Leave the room!"

Smoke alarms equipped with this personalized recording of a worried mother's voice were significantly better at waking up children in a deep sleep and enabling them to perform a simulated escape procedure than standard residential tone alarms, a new study found.

"The bad news is that the study confirms early reports that children do not respond adequately to conventional residential smoke alarms," said study author Dr. Gary A. Smith, director of the Center for Injury Research and Policy at Children's Hospital, in Columbus, Ohio.

"The good news is that the study showed children do respond to their parent's voice smoke alarm," he added.

The study findings were published in the October issue of the journal Pediatrics.

For the study, the researchers attempted to wake 24 children, 6 to 12 years of age, from stage 4 (deep) sleep with two different smoke alarms. Only mothers' voices were recorded, and the tone of voice was urgent, Smith said. The voice recording was repeated over and over.

Twenty-three (96 percent) of the 24 children awoke to the parent voice alarm, compared with 14 (58 percent) of the children to the tone alarm. One child did not awaken to either alarm. Nine children awoke to their parent's voice but not to the tone, while none awakened to only the tone and not the voice. Twenty (83 percent) of the children in the parent voice alarm group successfully performed the escape procedure within five minutes of the alarm's first warning, compared with nine (38 percent) in the tone alarm group. The median time to awaken was 20 seconds in the voice alarm group, and three minutes in the tone alarm group, the study found.

"I was relieved to see this," Smith said, "because I expected biological variation and didn't expect [voice alarms] to work 100 percent of the time." The study also showed an age-dependent response that is "very apparent at six and seven. We purposely didn't go younger, because it's widely considered that kids 5 years and younger are considered too young to perform self-rescue."

The researchers also knew the children wouldn't awaken to traditional alarms, so "we bumped up the intensity of both alarms hoping that would give us a good comparison," Smith explained. Sure enough, some children slept through five minutes of the 100-decibel tone alarm, roughly four times the intensity of standard smoke alarms. "We stopped the tonal alarm after five minutes, but within seconds of hearing their mother's voice, the same children would bolt upright in bed."

What's important is that the researchers accounted for sleep stage and found there are still children who will not wake up to either signal, even at the 100-decibel level, said Judy Comoletti, assistant vice president of public education for the National Fire Protection Association.

Since the recordings were all performed by mothers, "we don't know if this has to be a mother's voice and if they have to use the child's first name," Smith said. "Going in, we did not expect to see a large response to either of the smoke alarms but were surprised and pleased to see such a dramatic response to the parent's voice."

Comoletti said the study confirms previous research that voice alarms are more effective than conventional alarms for some children. However, she added, "Recent research has shown that voice alarms are less effective for older adults. There needs to be more research to identify an alternative signal that could offer better waking effectiveness across the general population. In the meantime, NFPA strongly encourages families to have working smoke alarms and to develop and practice escape planning."

In June, the National Fire Protection Association revised the National Fire Alarm Code, and, for the first time, smoke alarms that use voice notification will meet code and can be used in homes, Comoletti said.

There's a caution, though. There is nothing on the market that compares to the alarms used in the study.

"We can't make any statement about the effectiveness of any alarm currently sold. We think this research says we have a clear direction for more research and clearly identifies that we need to focus on unique developmental needs of children when designing smoke alarms," Comoletti said.

More information

To learn more about fire safety, visit the National Fire Protection Association.

SOURCES: Gary A. Smith, M.D., director, Center for Injury Research and Policy, Children's Hospital, Columbus, Ohio, and chairman, Committee on Injury, Violence and Poison Prevention of the American Academy of Pediatrics; Judy Comoletti, assistant vice president of public education, National Fire Protection Association, Quincy, Mass.; October 2006, Pediatrics

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