Patent ID: 7346172

Claim:
A method of distinguishing an auditory alert signal from a background of one or more other auditory signals, the method comprising: providing a selected alert signal for a subject at a first apparent location that is initially angularly displaced relative to a selected axis by a selected first azimuthal angle φ 1 ; causing the first apparent location of the alert signal to change to a second apparent location that is angularly displaced relative to the selected axis by a selected second azimuthal angle φ 2 , where |φ 1 −φ 2 |≧15°, within a selected time interval having a duration Δt lying in a range 0.1 sec≦Δt≦0.5 sec; thereby permitting a subject to distinguish the change of the alert signal from the first apparent location to the second apparent location and to thereby distinguish the alert signal from at least one background signal having an apparent location that does not change.