Effects of stimulus presentation and instructions on pure-tone thresholds and false-alarm responses.

The effects of three instructional sets (conventional Carhart-Jerger, strict, and lax) and of two stimulus presentation methods (continuous tones, pulsed tones) on pure-tone thresholds and false-alarm responses were determined for 20 male subjects. False alarms were tallied during hearing measurement periods and during 30-second time-out periods totaling nine minutes of time-out per subject. Results showed that 50% of the subjects made false-alarm responses to some extent at 250, 1000, and 4000 Hz. Instructions and stimulus mode, along with frequency, affected the number of false alarms, but thresholds under the experimental conditions were unchanged. It is suggested that a method for assessing and controlling false alarms is an important clinical consideration.