Effectiveness
Initial research into the effectiveness of the various alerting methods is sparse. From 2005 to 2007, research sponsored by the NFPA focused on understanding the cause of a higher number of deaths seen in high risk groups such as the elderly, those with hearing loss, and those who are intoxicated. Research findings suggest that a low frequency (520 Hz) square wave output is significantly more effective in the high risk individuals at awakening. More recent research suggests that strobe lights are not effective at waking sleeping adults with hearing loss and suggest that a different alarm tone is much more effective. Individuals in the hearing loss community are seeking changes to improved awakening methods.
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