为什么我们有两只耳朵？
我们的两只耳朵就像是收X讯站，将接受到的声音讯息传送至大脑，左耳传至左脑，右耳传至右脑。
当耳朵接收到声音后，大脑可计算出角度，得知声音是从哪裡传过来的。大脑可分辨出邻近声源的耳朵比对侧耳朵几微秒接收到的时间差异。当只有一只耳朵聆听时，声源的分辨就无法达成。更重要的是，两耳同时聆听声音的音质会较佳，只透过单耳接收语音时，声音听起来会比较平坦以及缺乏丰富的声音内容。大多数来说，两耳都有听力损失时，好同时配戴两只助听器。
美国听力学会建议：
双耳佩戴助听器；众所周知，音乐和言语的立体声效果更佳。双耳听力受损的话，双耳佩戴助听器会 产生立体声的效果。如果您的双耳听力受损，建议双耳选配助听器。相比单耳佩戴，双耳佩戴有以下好 处；
对声音准确定位
单耳佩戴者听到背后汽车的声音，确不能判断汽车是从哪一侧开过来，这是件危险的事情；而双耳佩 戴就不会出现这样的情况。
保护剩余听力
仅仅单耳机佩戴，会过度依赖佩戴助听器的一侧耳；对侧耳长期得不到锻炼，残余听力会逐步丧失， 这就是医学中的“听觉剥削”现象。
更容易听清言语的内容
双耳佩戴可以消除“头影效应”，减少头部对高频声音的阻碍，更容易听清和粪便言语的内容。
聆听过程更轻松不费力
单耳佩戴者听小的声音比较费力，耳双耳累加则可以提高声音的总体响度，听小声也不费力。
在噪音环境里更容易听清
双耳聆听会产生立体声效果，您听到的言语声更自然，音乐声更美妙。
CDKN1A encodes a potent cyclin dependent kinase CDK inhibitor, also called p21 WAF1 CIP1, which binds to and inhibits the cyclin CDK2 or CDK4 complexes, preventing the phosphorylation of critical CDK substrates and blocking cell cycle progression 42 comprare cialis online The trial enrolled 18 patients, ages 20 65 years, who could still breathe independently and had no mutations in the FUS or SOD1 genes
20 Although rolofylline showed promise in preliminary studies, 21 the pivotal trial showed no effect on symptom resolution, readmission rate, mortality, or renal functiоn when compared with placebo lasix overdose As the tubule dives into the medulla, or middle zone of the kidney, the tubule becomes narrower and forms a loop Loop of Henle that reenters the cortex as the thick ascending limb TAL that travels back to near the glomerulus
clomid alternative US PH37 210044 V 1
generic cialis 20mg Evidence regarding selective estrogen receptor modulators such as raloxifene has aroused considerable interest at the prospect of being able to treat osteoporosis without increasing the risk of breast cancer in contrast to hormone replacement therapy