August 24, 2006
Elderly less likely to wake to smoke alarm
NEW YORK (Reuters Health) - The high-pitched signal
typically used in smoke alarms may not wake older adults,
according to a study conducted by the Fire Protection Research
Foundation. In comparative tests on various alarm sounds,
adults aged 65 years and older were much more likely to wake to
a mixed-frequency signal than a pure high-frequency signal used
in standard US smoke alarms.
Household smoke alarms reduce the chances of dying in a
fire by up to 50 percent when present and working properly.
However, studies have shown that the elderly do not fully
benefit from smoke alarms, particularly during the overnight
hours when they are asleep.
According to the National Fire Protection Association,
older adults are more than twice as likely to die in a home
fire as the average person.
The current study investigated arousal from sleep in 42
adults aged 65 to 85 years in response to various signals
including the high-frequency signal used in most US smoke
alarms, a mixed-frequency signal, and a male voice saying
"Danger, Fire, Wake Up."
The high-pitched smoke alarm signal was least likely to
wake the study subjects, Dorothy Bruck from Victoria
University, Australia and the study team reports. The male
voice also performed poorly.
The mixed signal was most effective in waking sleeping
The study also found that the volume needed to wake up to
the high-frequency signal was significantly higher than that
needed to wake up to the mixed-frequency signal.
"The high frequency alarm signal currently found in smoke
alarms should be replaced by an alternative signal that
performs significantly better in awakening most of the adult
population, once the nature of the best signal has been
determined," the authors recommend.
In the meantime, they encourage the use of interconnected
smoke alarms that include an alarm in each bedroom to increase
the chance of sleeping individuals being woken by an alarm.
The study also tested the performance abilities of older
adults upon awakening suddenly to a smoke alarm. The results
suggest a decrease in physical functioning of around 10 percent
to 17 percent may be expected during the first five minutes
after waking up. There were, however, "no important" effects on
simple or complex cognitive functioning.