Woolf N K, Ryan A F
Department of Surgery, University of California, San Diego Medical School, La Jolla 92093.
Hear Res. 1988 Sep 15;35(2-3):131-42. doi: 10.1016/0378-5955(88)90112-8.
The contribution of middle ear immaturities to the development of cochlear microphonic potential (CM) responses was studied throughout the ontogeny of auditory function in the Mongolian gerbil. CM produced by direct mechanical stimulation of the stapes was compared with CM generated by acoustic stimulation of the intact ear at various postnatal ages. The results indicated that during development acoustically generated CM reflects middle ear as well as inner ear maturational factors. With direct stapes driving, CM was first elicited at 10 days after birth (DAB), two days earlier than with acoustic stimulation. Controlling for the contributions of middle ear immaturity, maturation of the inner ear accounted for approximately a 75 dB improvement in CM thresholds between 10 and 18 DAB. Comparisons between the results obtained with the acoustic and stapes driving stimulation protocols suggested that the major maturational changes in the middle ear conduction apparatus occurred between 14 and 16 DAB. This period was associated with the final stages of resorption of middle ear mesenchyme and ossicular ossification. Before 16 DAB, acoustically evoked CM thresholds reflect approximately a 25 dB loss in sensitivity due to middle ear immaturity.
在蒙古沙鼠听觉功能的个体发育过程中，研究了中耳发育不成熟对耳蜗微音器电位（CM）反应发展的影响。将直接机械刺激镫骨产生的CM与在不同出生后年龄对完整耳朵进行声刺激产生的CM进行比较。结果表明，在发育过程中，声刺激产生的CM反映了中耳以及内耳的成熟因素。通过直接镫骨驱动，CM在出生后10天（DAB）首次引出，比声刺激早两天。在控制中耳发育不成熟的影响后，内耳的成熟导致CM阈值在10至18 DAB之间提高了约75 dB。声刺激和镫骨驱动刺激方案所得结果的比较表明，中耳传导装置的主要成熟变化发生在14至16 DAB之间。这一时期与中耳间充质吸收和听骨骨化的最后阶段相关。在16 DAB之前，声诱发的CM阈值反映出由于中耳发育不成熟导致的约25 dB的灵敏度损失。
