Auditory Brainstem Responses of 1~6 Month Normal Infants / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the characteristics of click -auditory brainstem response (ABR) in nor-mal infants of 1 to 6 months old ,and to establish the normative values for latencies of Wave I ,III ,V and interpeak latencies of I- Ⅲ ,III-V and I-V for younger infants .Methods Click auditory brainstem responses were recorded from infants within 6 months166 infants of 1 -months old(269 ears) ,141 2 -month old (226 ears) ,111 3 -months old(177 ears) ,58 4-months old(96 ears) ,78 5-months old(121 ears) and 45 6-months old(76 ears) .We compared the latencies of wave I ,III ,V and interpeak latencies of I - Ⅲ ,III-V ,I-V obtained from infants of differ-ent ages at different stimulus intensities .Results The average threshold of 1 to 6 months infants was 16 .18 ± 5 .35 dB nHL ,the average latency of Wave V was 9 .03 ± 0 .49 ms .The differences among the thresholds were statistical-ly insignificant(P>0 .05) .Wave I ,III and V were noticeable in all ears tested at 80 dB nHL .Wave I disappeared first as the stimulus intensity decreased ,and the latencies of Wave I ,III and V prolonged;on the contrary ,interpeak latencies of I -III ,III-V ,I-V shortened significantly .At the same stimulus intensity ,the latencies of Wave III , V and the interpeak latencies of I - Ⅲ ,III-V ,I-V shortened significantly except for Wave I .When comparing the differences among the testing parameters as a function of each month ,we found that there were statistically signifi-cant differences for the latencies of wave III ,V and the interpeak latencies of I -III ,III-V ,I-V before the 4 months old(P0 .05) .Conclusion It is recommen-ded that 16 .18 ± 5 .35 dB nHL be used as the normative references for the evoked threshold of click auditory brain-stem responses for 1~6 month old infants .The development of central nervous system below the inferior calicles is fast before the 4 months old .