Abdala C
House Ear Institute, Children's Auditory Research and Evaluation Center, Los Angeles, CA 90057, USA.
Hear Res. 1998 Jul;121(1-2):125-38. doi: 10.1016/s0378-5955(98)00073-2.
Suppression of the 2f1-f2 distortion product otoacoustic emission (DPOAE) provides an effective paradigm for the study of functional cochlear maturation in humans. DPOAE iso-suppression tuning curves (STCs) represent some aspect of peripheral filtering, probably related to the boundaries of distortion generation. Studies conducted thus far suggest that the cochlear tuning assessed by this technique is adult-like in humans by term birth (Abdala et al., Hear. Res. 98 (1996) 38-53; Abdala and Sininger, Ear Hear. 17 (1996) 374-385). However, there have been no studies of cochlear tuning in premature human neonates. DPOAE STCs and suppression growth functions were measured from 14 normal-hearing adults, 33 term and 85 premature neonates to investigate the developmental time course of cochlear frequency resolution and non-linearity. Premature neonates showed non-adult-like DPOAE suppression at f2 of 1500 and 6000 Hz: (1) STCs were narrower in width (Q10) and steeper in slope on the low-frequency flank of the tuning curve; (2) suppressor tones lower in frequency than f2 produced atypically shallow growth of DPOAE suppression. The influence of immature conductive pathways cannot be entirely ruled out as a factor contributing to these results. However, findings may indicate that an immaturity exists in cochlear frequency resolution and non-linearity just prior to term birth. The bases of this immaturity are hypothesized to be outer hair cell in origin.
抑制2f1-f2畸变产物耳声发射（DPOAE）为研究人类耳蜗功能成熟提供了一种有效的范式。DPOAE等抑制调谐曲线（STC）代表了外周滤波的某些方面，可能与畸变产生的边界有关。迄今为止进行的研究表明，通过这种技术评估的耳蜗调谐在足月出生时的人类中已类似成人（阿卜杜拉等人，《听觉研究》98（1996）38 - 53；阿卜杜拉和西宁格，《耳与听觉》17（1996）374 - 385）。然而，尚未有对早产人类新生儿耳蜗调谐的研究。对14名听力正常的成年人、33名足月新生儿和85名早产新生儿测量了DPOAE STC和抑制增长函数，以研究耳蜗频率分辨率和非线性的发育时间进程。早产新生儿在1500 Hz和6000 Hz的f2处表现出非成人样的DPOAE抑制：（1）STC在调谐曲线低频侧的宽度（Q10）更窄且斜率更陡；（2）频率低于f2的抑制音产生的DPOAE抑制增长异常浅。不能完全排除未成熟传导通路作为导致这些结果的一个因素的影响。然而，研究结果可能表明在足月出生前耳蜗频率分辨率和非线性存在不成熟。这种不成熟的基础据推测源于外毛细胞。
