Mills J H, Schmiedt R A, Kulish L F
Department of Otolaryngology and Communicative Sciences, Medical University of South Carolina, Charleston 29425.
Hear Res. 1990 Jul;46(3):201-10. doi: 10.1016/0378-5955(90)90002-7.
The Mongolian gerbil is being evaluated as an animal model of age-related hearing loss (presbyacusis). Part of this evaluation involves estimating auditory thresholds from evoked potentials arising from the auditory nerve and brainstem. The gerbils are born and reared in an environment where the ambient noise level is less than 40 dBA. Some animals are followed longitudinally (8, 19, 23.5 and 36 months), others are studied at 6-8 months (controls), or at 36 months (cross-sectional). Physiological responses are obtained with the animals anesthetized with ketamine and xylazine and transdermal electrodes attached to the head. Auditory signals are tone pips with center frequencies from 1 to 16 kHz in octave steps. Signal levels are varied from 10 to 80 dB SPL in 10 dB steps. For animals (N = 48) in the age range of 6-8 months, mean auditory thresholds were about 20 dB SPL between 2.0 and 8.0 kHz, 25 dB at 16 kHz and 30 dB at 1.0 kHz. By age 22-24 months (N = 15) thresholds had increased by about 10 dB at nearly all frequencies. By age 36 months (N = 37 ears, 32 animals) threshold increases were about 30-35 dB at 8 and 16 kHz, were 25 dB at 4 kHz and 2 kHz, and were 19 dB at 1 kHz. These hearing losses in 36-month gerbil are qualitatively similar to human data for 60-65-year-old males and 70-year-old females. Individual differences in hearing loss were large with the range exceeding 65 dB. While some animals (26/37) had a high-frequency sloping loss, others (11/37) had a bimodal audiometric shape where the hearing loss was smallest at 4 kHz and increased by at least 10 dB at adjacent frequencies.
蒙古沙鼠正被评估为年龄相关性听力损失（老年性聋）的动物模型。该评估的一部分涉及从听神经和脑干产生的诱发电位估计听觉阈值。沙鼠在环境噪声水平低于40 dBA的环境中出生和饲养。一些动物进行纵向跟踪（8、19、23.5和36个月），其他动物在6 - 8个月（对照组）或36个月（横断面研究）时进行研究。在动物用氯胺酮和赛拉嗪麻醉且头部附着经皮电极的情况下获得生理反应。听觉信号是中心频率从1至16 kHz、以倍频程步长变化音调的短声。信号水平以10 dB步长从10至80 dB SPL变化。对于年龄在6 - 8个月的动物（N = 48），在2.0至8.0 kHz之间平均听觉阈值约为20 dB SPL，在16 kHz时为25 dB，在1.0 kHz时为30 dB。到22 - 24个月龄时（N = 15），几乎所有频率的阈值都增加了约10 dB。到36个月龄时（N = 37只耳朵，32只动物），在8和16 kHz时阈值增加约30 - 35 dB，在4 kHz和2 kHz时为25 dB，在1 kHz时为19 dB。36个月龄沙鼠的这些听力损失在质量上与60 - 65岁男性和70岁女性的人类数据相似。听力损失的个体差异很大，范围超过65 dB。虽然一些动物（26/37）有高频斜坡型听力损失，但其他动物（11/37）有双峰听力图形状，其中在4 kHz时听力损失最小，在相邻频率至少增加10 dB。
