Table S4. Auditory presentation guidelines

VARIABLE	ACCOMMODATION PREFERENCE	PRESENTATION CHOICES
SOUND INTENSITY	BETTER	• Sound signals should be at least 60 dB at the ear of the listener. (Conversational speech is 50 dB.) • Allow for volume adjustments. Use simple instructions and controls with simple movement (e.g. back and forth along graduated level rather than turning knob)
SOUND FREQUENCY	BETTER	• Use sound alerts within frequency range of 500 to 2000 Hz. • Male voices are better than female for announcements.
	WORSE	• High frequencies (avoid frequencies above 4000 Hz) • Artificial (synthesized) speech
DISCRIMINATION OF SOUND CUES	BETTER	• Maximize pitch, spectral or location differences of individual sound cues.
SOUND LOCATION	BETTER	• If you must signal sound location at high frequency (>2000 Hz), use longer duration (>0.5 s)
AUDITORY ATTENTION	BETTER	• Provide redundant cueing through cross-sensory channels (e.g. augment a sound signal [cell phone ring] with vibration; sound alarm with light.) • Provide headphone sets for focused work during group training.
	WORSE	• Background noise or reverberation. (Need to maintain high “signal-to-noise” ratio)
SPEECH RECOGNITION	BETTER	• Reasonable pace • Predictable linguistic structure • Pauses at grammatical boundaries (after phrases, end of sentences)
	WORSE	• Synthesized or robotic speech patterns • Over-exaggerated and patronizing simplicity (‘elderspeak’; ‘mother-ese’)