Normal Values of Auditory Brainstem Responses for Infants of Different Ages / 听力学及言语疾病杂志

ABSTRACT

Objective To find the normal range and features for auditory brainstem responses(ABR)of infants within six months,and the basic parameters for identifying the hearing impaired infants.Methods May 2006 to May 2008,60 normal infants and 20 normal adults received the ABR tests.The infants were divided into three groupsgroup A(6 weeks),group B(3 months)and group C(6 months).Each group consisted of 20 infants(40 ears)and the ABR data were statistically analyzed.Results At 100 dB nHL,the waveⅠ,Ⅲ,Ⅴ latencies of ABR for 6-week infants respectively were 1.49?0.08 ms,4.42?0.16 ms and 6.61?0.25 ms,for 3-month infants,1.47?0.07 ms,4.35?0.20 ms and 6.50?0.25 ms,for 6-month infants,1.45?0.07 ms,4.17?0.15 ms and 6.32?0.22 ms.At 80 dB nHL,the waveⅠ,Ⅲ,Ⅴ latencies of ABR for 6-week infants were 1.63?0.08 ms,4.52?0.17 ms and 6.74?0.26 ms,respectively,for 3-month infants,1.64?0.11 ms,4.44?0.20 ms and 6.67?0.26 ms,for 6-month infants,1.60?0.11 ms,4.27?0.16 ms and 6.43?0.24 ms.As the intensity of stimulating signals decreased,the peak latency of ABR became more delayed.The peak latencies of Ⅲ,Ⅴ waves and interval peak latencies of Ⅰ-Ⅲ and-Ⅴ waves for the infants were more delayed than those for adults,and became shorter with the increase of the infants' ages,but they failed to reach adults' levels even for 6-month infants.However,the length of wave Ⅰ of ABR for infants of different months was close to that for adults.The thresholds of ABR for the infants of different ages were not significantly different,all being close to the values for adults.Conclusion This study has analyzed the ABR wave features for the infants of three ages and this can help to define the reference ranges for the infants and to provide the parameters for early diagnosis of hearing loss among the infants.