Research on Auditory Steady-state Responses to Multiple Simultaneous Stimuli of Normal-hearing Adults / 听力学及言语疾病杂志

ABSTRACT

Objective To explore some characters of auditory steady-state responses (ASSR) to multiple simultaneous stimuli in a sample of normal-hearing adults.Methods The ASSR to multiple simultaneous stimuli were recorded in a sample of 32 normal-hearing adults (64 ears). Simultaneous carrier tones (0.5, 1, 2 and 4 kHz), modulated in amplitude at different rate of 77, 85,93, 101 Hz for left ear and 79, 87, 95, 103 Hz for right ear, were presented binaurally by the insert phones. For each subject the response thresholds (RTHs) at 0.5, 1, 2 and 4 kHz were determined automatically and compared with the corresponding behavioral thresholds (BTHs).Results ①In the normal-hearing adults, RTHs were on average between 7～19 dB above the BTHs.②2-way repeated measures ANOVA (ear?carrier frequencies) showed significant main effect between carrier frequencies on RTH ( F =31.254; ? 3,179; P =0.000). Post Hoc analysis indicated that this effect was due to the highest threshold found at 0.5 kHz. The test showed no significant difference of threshold between left ear and right ear ( F =1.942; ? 1,179; P =0.165). ③Taking 60 dB SPL as analysis level, 2-way repeated measures ANOVA (gender?carrier frequencies) revealed significant difference of amplitude between male and female( F =16.490; ? 1,175; P =0.000); and difference of amplitude between carrier frequencies ( F =2.948; ?3, 175; P =0.034).④The average testing time was 61 minutes for male and 69 minutes for female. Independent t-test showed statistical significance within sex.⑤Two- way ANOVA (state?frequency)showed that background EEG noise were significantly higher in awake than that in sleep ( F =152.511; P =0.000). There were no appreciable significance in background noise among frequencies. Conclusion The ASSR to multiple simultaneous stimuli was proven to be a frequency specific, objective and valid technique for threshold estimation at least for normal-hearing adults. Issues concern ing clinical use were discussed.