Recanzone Gregg
Center for Neuroscience and Department of Neurobiology, Physiology and Behavior, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA.
Hear Res. 2018 Sep;366:99-105. doi: 10.1016/j.heares.2018.05.013. Epub 2018 May 23.
Age-related hearing loss is a prominent deficit, afflicting approximately half of the geriatric population. In many cases, the person may have no deficits in detecting sounds, but nonetheless suffers from a reduced ability to understand speech, particularly in a noisy environment. While rodent models have shown that there are a variety of age-related changes throughout the auditory neuraxis, far fewer studies have investigated the effects at the cortical level. Here I review recent evidence from a non-human primate model of age-related hearing loss at the level of the core (primary auditory cortex, A1) and belt (caudolateral field, CL) in young and aged animals with normal detection thresholds. The findings are that there is an increase in both the spontaneous and driven activity, an increase in spatial tuning, and a reduction in the temporal fidelity of the response in aged animals. These results are consistent with an age-related imbalance of excitation and inhibition in the auditory cortex. These spatial and temporal processing deficits could underlie the major complaint of geriatrics, that it is difficult to understand speech in noise.
年龄相关性听力损失是一种显著的缺陷，影响着约半数老年人群。在许多情况下，患者可能在检测声音方面没有缺陷，但仍存在理解言语的能力下降的问题，尤其是在嘈杂环境中。虽然啮齿动物模型显示，整个听觉神经轴存在多种与年龄相关的变化，但研究皮层水平影响的研究要少得多。在此，我回顾了来自一个非人类灵长类动物年龄相关性听力损失模型的最新证据，该模型研究了具有正常检测阈值的年轻和老年动物在核心（初级听觉皮层，A1）和带状（尾外侧区，CL）水平的情况。研究结果表明，老年动物的自发活动和驱动活动均增加，空间调谐增加，反应的时间保真度降低。这些结果与听觉皮层中与年龄相关的兴奋和抑制失衡一致。这些空间和时间处理缺陷可能是老年人主要抱怨的原因，即在噪声环境中难以理解言语。
