Scanning Delay

The time interval a scanning system waits before automatically advancing to highlight the next item. Setting scanning delay appropriately is critical for switch access users: too short causes selection errors because the user cannot respond quickly enough; too long dramatically slows communication. Optimal scanning delay varies by user and changes with fatigue, attention, and task complexity. Research shows expert users can achieve delays as low as 180-250ms, while clinical defaults often start at 600-1200ms. Adaptive scanning systems adjust this parameter in real time based on user performance.