声导抗基础知识

The Acoustic Reflex 声反射
Loud sounds make the stapedius muscle contract.This makes the middle ear system stiffer... 强声刺激可使镫骨肌收缩，从而增加中耳传声系统的劲度
…and less low frequency sound can get through the middle ear 因而进入中耳的低频声波减少
耳病 Early ME effusion Middle Ear effusion Ossicular discontinuity TM pathology Otosclerosis Malleus fixation ET blockage Open PE tubes TM Perforation Cerumen blockage or blocked probe tip
The Middle ear - Immittance tests 中耳声导纳测试
Acoustic reflex threshold 声反射阈
Stapedius muscle controlled by facial nerve (CN VII) 镫骨肌由第七对颅神经－面神经支配 Network in brainstem consists of ipsilateral and contralateral paths 脑干层面由同侧和对侧神经通路组成 Reflex activated on both ears, even when stimulation only occurs in one ear 一侧耳受到刺激时，双侧镫骨肌都会收缩 Comparison of ipsilateral vs. contralateral acoustic reflexes helps to determine site of lesion 对比同侧和对侧声反射有助于判断病变部位
Most of the sound energy is reflected when confronting a another medium... 大部分声能在临界面处被反射回来
…because different media are more or less easy to bring into motion (impedance) 因为不同媒介的声阻抗是不同的
226 Hz: Different configurations of tympanometric results 226Hz鼓室声导抗测试结果与疾病的关系 鼓室声导抗测试结果与疾病的关系
疾病 早期中耳积液 中耳积液 听骨链中断 鼓膜病变 耳硬化症 锤骨固定 咽鼓管阻塞 鼓膜置管 鼓膜穿孔 耵聍栓塞、探 头叩堵塞
B型：平坦型。鼓室积液或鼓膜穿孔，根据ECV值区分
-200
Type C: Abnormal pressure C型：负压型
0
200
The Tympanogram curve and Tympanometric Width 鼓室导抗图形与鼓室图宽度（ 鼓室导抗图形与鼓室图宽度（TW） ）
Admittance SA
Inner ear fluids 内淋巴 内淋巴
The Eustachian tube (ET) ventilates the middle ear and allows pressure equalisation 咽鼓管是中耳的通气管道，可保证中耳气压平衡 The ET opens when swallowing or yawning 吞咽和打哈欠时咽鼓管开放
SA/2
Pressure TW
Tympanometric Width quantify the steepness of the tympanogram 室导抗图的坡度 Normative data exist for different age groups 不同年龄组标准化值不同
TW决定鼓
TW and SA are the criteria used in the ASHA tympanometric screening protocol 美国社会卫生学会的鼓室声导抗筛查方案把TW和SA作为诊断指标
-200
0
200
-200
0
200
-200
0
200
Type As: Possible effusion or otosclerosis As型：鼓室积液可能或耳硬化症
Type B: “Flat” -Effusion or perforated ear drum depending on ECV value
外耳道容积 Normal Normal Normal Normal Normal Normal Normal Increased Increased
静态声导纳值 Reduced Reduced / flat Increased Increased Normal / reduced Reduced / flat Normal Flat Flat
The Tympanogram curve classification, Type 鼓室导抗图形分类
-200
Type A: Normal A型：正常
0
200
Type Ad: Ossicular discontinuity or age related hypermobility Ad型：听骨链中断或鼓膜松弛
Getting sound into a different medium 声音在不同媒介中的传导
The “stiletto” principle:圆锥效应 Force is collected over a larger area and focused on a smaller area (B) 作用力在锥底收集后聚焦到锥尖
The Tympanogram curve and baseline compensation 鼓室导抗图形和基线补偿
SA Total Admittance ECV SA
TPP
Subtraction of the ECV contribution gives us a baseline compensated tympanogram 去除外耳道容积成分后的鼓室图称为基线补偿鼓室导抗图 Peak admittance becomes Static Admittance, SA 该图峰值处的声导纳称为静态声导纳(SA) The SA is the admittance of the middle ear alone. Now we can use the normative data! SA等于中耳的声导纳值
How do we test the middle ear? 如何检测中耳功能
中耳测试
精密的中耳系统 高精度的测试 高质量控制系统
Leabharlann Baidu
Admittance - letting the sound wave in 声导纳－ 声导纳－将声波导入
Part of the probe tone is reflected, and some is admitted into the middle ear 一部分探测音被反射回来，另一部分则进入中耳 The admittance is continuously measured by a microphone 声导纳通过麦克风持续测量计算出来
声导抗基础知识培训
Tympanometry and Acoustic Reflex Measurements 鼓室声导抗和声反射测试
+Infant test recommendations 婴儿测试的推荐方法
Sound travel 声音传导
Getting sound into a different medium 声音在不同媒介中的传导
鼓室图型 As C or B Ad Ad A or As As or B C B B B
Decreased Flat
Tympanometry is an invaluable diagnostic tool when combined with other audiological tests 鼓室声导抗与其它听力学测试结合是不可替代的诊断工具
The Tympanogram curve, ECV and TPP 鼓室导抗图形，等效外耳道容积和峰压点
Pressure sweep
ECV
Total Admittance of the ear canal and the middle ear 外耳道和中耳的声导纳总值
TPP
The TPP approximates the middle ear pressure 峰压点近似于鼓膜内侧的中耳压力 The 226 Hz admittance of the air in the ear canal is directly proportional to the volume of that air. That gives us the Equivalent Ear Canal Volume, ECV 以226Hz为探测音，测试探头与鼓膜之间的空气导纳值为外耳道容积，即等效 外耳道容积
峰宽 Widened Widened / X Normal Normal Normal / reduced Increased Normal X X X
静态声压 Normal / positive Negative / X Normal Normal Normal Normal / X Negative X X X
The two middle ear muscles 中耳肌
2 1: Tensor muscle 鼓膜张肌 2: Stapedius Muscle 镫骨肌
1
The muscles are believed to stabilise the mechanical system and protect the cochlea from excessive low frequency vibration 中耳肌可稳定中耳机械系统，并保护耳蜗免受低频强声损伤
The role of the middle ear 中耳的作用
The Ossicles 听小骨
Three small bones forming a chain between the tympanic membrane and the inner ear 听骨链位于鼓膜和内耳之间，由3块听小骨组成 Airborne sound wave energy becomes mechanical vibration 空气传导的声波能量转换为机械振动 Compensates for the air - fluid impedance difference 补偿气液相不同媒介的导抗差
鼓室图
Admittance
中耳 – 劲度
Pressure TPP ( = MEP? )
Tympanometry 鼓室声导抗
Admittance 声导纳
2
3
1
-200 daPa
0 Ear pressure 外耳道压强 Ear canal canal pressure
200 daPa
1 & 3: Pressure stiffens the tympanic membrane so the probe tone bounces back, and the sound level in the middle ear decreases 1和3：大压强使鼓膜僵硬从而探测音多被反弹回来，进入中耳的声能减少 2: When pressure is equal on both sides, the sound level in the middle ear is at maximum 2：鼓膜两侧压力相等时传入中耳的声能最大
Malleus 锤骨
Incus 砧骨
Stapes 镫骨
The Middle ear anatomy 中耳解剖
Air pressure must be near equal on both sides of the ear drum in order to optimise mobility of the whole system 应使鼓膜两侧气压接近，从而保证中耳传 声系统的最佳活动性 Air Air