早产儿在不同刺激速率下的脑干听觉诱发电位变化

Brainstem auditory evoked potentials at different of click stimuli rates in preterm infants

目的早产儿的脑干功能发育与足月儿是否存在差异,国外的研究报道并不一致,该文通过分析不同刺激速率下的脑干听觉诱发电位,比较早产儿与足月儿的脑干功能发育状态及增加刺激速率在检测脑干功能中的作用。方法早产儿组30例,无围生期及新生儿期合并症;足月儿组38例,为健康足月儿。两组于胎龄37～42周时进行脑干听觉诱发电位检查,声刺激速率为21.1次/s、51.1次/s和91.1次/s,分析Ⅰ,Ⅲ,Ⅴ波的潜伏期和振幅,ⅠⅢ,ⅢⅤ,ⅠⅤ峰间期以及ⅢⅤ/ⅠⅢ峰间期比值。结果在60dBnHL刺激强度下,随刺激速率增加,两组中Ⅰ,Ⅲ,Ⅴ各波的潜伏期及峰间期均逐渐延长,振幅逐渐下降,潜伏期及峰间期与刺激速率成正相关(P<0.01),振幅与速率成负相关(P<0.01)。两组比较,各频率ⅠⅤ峰间期均无差异,但随刺激速率增高,早产儿组ⅠⅢ峰间期相对缩短(P<0.05)、ⅢⅤ峰间期相对延长(P<0.01),ⅢⅤ/ⅠⅢ峰间期比值增大(P<0.001)。两组振幅无明显差别。结论早产儿脑干听觉通路的近外周部分较近中枢部分提前发育;提高刺激速率有助于发现更多的神经生理变化,提高脑干听觉诱发电位的诊断价值。

Objective There is controversy as to whether there are differences in brainstem development between preterm and term infants. This study examined the brainstem function of preterm infants at term and the effect of increasing stimulus rate in the detection of brainstem function through the recording of and analyzing of brainstem auditory evoked potential （BAEP） at different rates of click stimuli. Methods The study group included 30 preterm babies without any perinatal complication. The controls were 38 healthy term babies. The BAEP was recorded at stimulus rates of 21.1, 51.1 and 91.1/sec in these babies at 37- 42 weeks of postconceptional age. The latencies and amplitudes of Waves Ⅰ , Ⅲ and Ⅴ, the interpeak intervals of Ⅰ- Ⅲ, Ⅲ - Ⅴ and Ⅰ-Ⅴ and Ⅲ - Ⅴ/Ⅰ- Ⅲ interval ratio were analyzed. Results At a click intensity of 60 dBnHL, latencies and interpeak intervals in both groups increased but amplitudes decreased as the stimulus rate was increased. The latencies and interpeak intervals had a positive correlation with stimulus rate. In contrast, the amplitude was negatively correlated with stimulus rate. In preterm babies, Ⅰ-Ⅴ interval did not differ significantly from the controls at all three rates used. As stimulus rate increased, Ⅰ- Ⅲ interval decreased whereas Ⅲ - Ⅴ interval and Ⅲ - Ⅴ/Ⅰ- Ⅲ interval ratio increased in preterm infants. There was no obvious amplitude difference at various stimulus rates between the two groups. Conclusions Preterm infants have an advanced development of peripheral brainstem auditory pathway but a relatively delayed central development. Increasing stimulus rate can detect more neurophysiological changes and enhance the diagnostic value of BAEP.