AUDITORY STEADY-STATE RESPONSES TO TONES AMPLITUDE-MODULATED AT 80-110 HZ

Steady-stater esponsesc an be recordedf rom the human scalp in responset o tones that are sinusoidallym odulatedin amplitudea t ratesb etween6 0 and 120 Hz. For 60 dB SPL 1000-Hz tones the maximumb aseline-to-peaakm plitudeo f about0. 06/xV occursf or modulationr atesb etween8 0 and9 5 Hz. The phaseo f the responsed oesn ot changew ith modulationd epthsg reatert han 25% and the amplitudes aturatesa t modulationd epthsg reatert han 50%. The presenceo r absenceo f a responsec an be accuratelyd eterminedb y frequency-domainst atisticsa nd the responseb ecomes clearly recognizablea t intensitiest hat are 16_+8d B aboveb ehavioralt hresholdsW. ith increasing intensityt he responsein creasesin amplitudea t 1.9 nV/dB until an intensityo f 70 dB SPL. As the intensityi ncreasesa bove7 0 dB SPL the responsein creasesin amplitudem ore rapidly at 7.8 nV/dB (at 1000 Hz) andc ontains ignificanetn ergya t harmonicosf them odulationfr equencyT.h iss econd stageo f the intensityf unctioni s more prominentf or stimuliw ith lower carrierf requencies(5 00 more than 1000 more than 2000 Hz) and is attenuatedb y high-passm askingT. heses teady-state responsesh ouldb e helpfuli n evaluatingh umana uditoryp hysiologya nd in objectivea udiometry. © 1995, Acoustical Society of America. All rights reserved.