声导抗基础知识

声导抗基础知识培训TympanometryandAcousticReflexMeasurements鼓室声导抗和声反射测试+Infanttestrecommendations婴儿测试的推荐方法Soundtravel声音传导Gettingsoundintoadifferentmedium声音在不同媒介中的传导Mostofthesoundenergyisreflectedwhenconfrontingaanothermedium...大部分声能在临界面处被反射回来…becausedifferentmediaaremoreorlesseasytobringintomotion(impedance)因为不同媒介的声阻抗是不同的Theroleofthemiddleear中耳的作用TheOssicles听小骨Malleus锤骨Incus砧骨Stapes镫骨•Threesmallbonesformingachainbetweenthetympanicmembraneandtheinnerear听骨链位于鼓膜和内耳之间，由3块听小骨组成•Airbornesoundwaveenergybecomesmechanicalvibration空气传导的声波能量转换为机械振动•Compensatesfortheair-fluidimpedancedifference补偿气液相不同媒介的导抗差TheMiddleearanatomy中耳解剖AirAirAirpressuremustbenearequalonbothsidesoftheeardruminordertooptimisemobilityofthewholesystem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TheEustachiantube(ET)ventilatesthemiddleearandallowspressureequalisation咽鼓管是中耳的通气管道，可保证中耳气压平衡TheETopenswhenswallowingoryawning吞咽和打哈欠时咽鼓管开放Innerearfluids内淋巴Gettingsoundintoadifferentmedium声音在不同媒介中的传导The“stiletto”principle:圆锥效应Forceiscollectedoveralargerareaandfocusedonasmallerarea(B)作用力在锥底收集后聚焦到锥尖Howdowetestthemiddleear?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Partoftheprobetoneisreflected,andsomeisadmittedintothemiddleear一部分探测音被反射回来，另一部分则进入中耳Theadmittanceiscontinuouslymeasuredbyamicrophone声导纳通过麦克风持续测量计算出来Admittance-lettingthesoundwavein声导纳－将声波导入鼓室图中耳–劲度TPP(=MEP?)AdmittancePressureTympanometry鼓室声导抗Admittance-200daPa200daPa0EarcanalpressureAdmittance声导纳-200daPa200daPa0Earcanalpressure外耳道压强1&3:Pressurestiffensthetympanicmembranesotheprobetonebouncesback,andthesoundlevelinthemiddleeardecreases1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:Whenpressureisequalonbothsides,thesoundlevelinthemiddleearisatmaximum2：鼓膜两侧压力相等时传入中耳的声能最大123TheTympanogramcurve,ECVandTPP鼓室导抗图形，等效外耳道容积和峰压点TheTPPapproximatesthemiddleearpressure峰压点近似于鼓膜内侧的中耳压力ECVTotalAdmittanceoftheearcanalandthemiddleear外耳道和中耳的声导纳总值TPPPressuresweepThe226Hzadmittanceoftheairintheearcanalisdirectlyproportionaltothevolumeofthatair.ThatgivesustheEquivalentEarCanalVolume,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ECVTotalAdmittanceSATPPSATPPTheTympanogramcurveandbaselinecompensation鼓室导抗图形和基线补偿SubtractionoftheECVcontributiongivesusabaselinecompensatedtympanogram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PeakadmittancebecomesStaticAdmittance,SA该图峰值处的声导纳称为静态声导纳(SA)TheSAistheadmittanceofthemiddleearalone.Nowwecanusethenormativedata!SA等于中耳的声导纳值-2002000TypeAd:OssiculardiscontinuityoragerelatedhypermobilityAd型：听骨链中断或鼓膜松弛-2002000TypeA:NormalA型：正常-2002000TypeB:“Flat”-EffusionorperforatedeardrumdependingonECVvalueB型：平坦型。鼓室积液或鼓膜穿孔，根据ECV值区分-2002000TypeAs:PossibleeffusionorotosclerosisAs型：鼓室积液可能或耳硬化症-2002000TypeC:AbnormalpressureC型：负压型TheTympanogramcurveclassification,Type鼓室导抗图形分类SATWSA/2PressureAdmittanceTheTympanogramcurveandTympanometricWidth鼓室导抗图形与鼓室图宽度（TW）TympanometricWidthquantifythesteepnessofthetympanogramTW决定鼓室导抗图的坡度Normativedataexistfordifferentagegroups不同年龄组标准化值不同TWandSAarethecriteriausedintheASHAtympanometricscreeningprotocol美国社会卫生学会的鼓室声导抗筛查方案把TW和SA作为诊断指标耳病外耳道容积静态声导纳值峰宽静态声压鼓室图型EarlyMEeffusionNormalReducedWidenedNormal/positiveAsMiddleEareffusionNormalReduced/flatWidened/XNegative/XCorBOssiculardiscontinuityNormalIncreasedNormalNormalAdTMpathologyNormalIncreasedNormalNormalAdOtosclerosisNormalNormal/reducedNormal/reducedNormalAorAsMalleusfixationNormalReduced/flatIncreasedNormal/XAsorBETblockageNormalNormalNormalNegativeCOpenPEtubesIncreasedFlatXXBTMPerforationIncreasedFlatXXBCerumenblockageorblockedprobetipDecreasedFlatXXB226Hz:Differentconfigurationsoftympanometricresults226Hz鼓室声导抗测试结果与疾病的关系Tympanometryisaninvaluablediagnostictoolwhencombinedwithotheraudiologicaltests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Thetwomiddleearmuscles中耳肌121:Tensormuscle鼓膜张肌2:StapediusMuscle镫骨肌Themusclesarebelievedtostabilisethemechanicalsystemandprotectthecochleafromexcessivelowfrequencyvibration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TheAcousticReflex声反射Loudsoundsmakethestapediusmusclecontract.Thismakesthemiddleearsystemstiffer...强声刺激可使镫骨肌收缩，从而增加中耳传声系统的劲度…andlesslowfrequencysoundcangetthroughthemiddleear因而进入中耳的低频声波减少•Stapediusmusclecontrolledbyfacialnerve(CNVII)镫骨肌由第七对颅神经－面神经支配•Networkinbrainstemconsistsofipsilateralandcontralateralpaths脑干层面由同侧和对侧神经通路组成•Reflexactivatedonbothears,evenwhenstimulationonlyoccursinoneear一侧耳受到刺激时，双侧镫骨肌都会收缩•Comparisonofipsilateralvs.contralateralacousticreflexeshelpstodeterminesiteoflesion对比同侧和对侧声反射有助于判断病变部位TheMiddleear-Immittancetests中耳声导纳测试Acousticreflexthreshold声反射阈声反射AdmittanceTimeDeflection0.02蹬骨肌0.000.0280dBHL0.000.0285dBHL0.000.0295dBHL0.000.0290dBHLDeflectioncriterion声导纳偏移标准-Itisusefultostudythegrowthwithintensitytoconfirmareflexthreshold-继续增加声强观察偏移变化有助于进一步明确声反射阈?!AcousticReflexThresholds声反射阈Loudstimuliarepresented,whilsttheadmittanceismeasured强声刺激出现时，可测试出声导纳值的变化声反射测试–高精度的挑战•鼓膜处压力为TPP值时中耳蹬骨肌反射状况最佳•正确的声反射是刺激音引起导纳在TPP处的变化•耳道或中耳压力的改变导致错误的声反射•对于鼓膜活动度过大可进行TPP补偿Threshold+10dB,10secondsstimulustime声反射阈上10dB给声，刺激时程10s0510secondsAdmittancechangeHalf-LifeTime(HLT),thetimeafterstimulusonsetwhentheadmittancedeflectionhasdecreasedby50%.半衰期是指声反射振幅减少50％的