Efficient stimuli for recording of the amplitude modulation following response

Amplitude modulation following response (AMFR) is a promising tool for objective frequency-specific assessment of hearing thresholds in children. The stimulus generally used for AMFR recording (one amplitude-modulated carrier) activates only a small part of the basilar membrane. Therefore, the response amplitude is small. Combined frequency and amplitude modulation is not significantly more effective. A new stimulus is proposed that is composed of several carriers. All carriers are modulated with the same modulation frequency. The signal to noise ratio of the response to the multiple-carrier stimulus is significantly increased compared with the usual one-carrier stimulus. Therefore, response detection near threshold is expected to be improved. AMFR also seems to be well suited to newborn hearing screening. Simultaneous recording of six responses (three AMFRs from each ear) to 1-, 2-, and 4-kHz multiple-carrier stimuli of a 40 dB HL stimulus level is demonstrated in normally-hearing adults. Verification in babies will be necessary.