聲導(dǎo)抗基礎(chǔ)知識演示文稿

聲導(dǎo)抗基礎(chǔ)知識演示文稿當(dāng)前第1頁\共有32頁\編于星期六\23點聲導(dǎo)抗基礎(chǔ)知識當(dāng)前第2頁\共有32頁\編于星期六\23點Soundtravel聲音傳導(dǎo)當(dāng)前第3頁\共有32頁\編于星期六\23點Gettingsoundintoadifferentmedium

聲音在不同媒介中的傳導(dǎo)Mostofthesoundenergyisreflectedwhenconfrontingaanothermedium...大部分聲能在臨界面處被反射回來…becausedifferentmediaaremoreorlesseasytobringintomotion(impedance)因為不同媒介的聲阻抗是不同的當(dāng)前第4頁\共有32頁\編于星期六\23點Theroleofthemiddleear中耳的作用

當(dāng)前第5頁\共有32頁\編于星期六\23點TheOssicles聽小骨Malleus錘骨Incus砧骨Stapes鐙骨Threesmallbonesformingachainbetweenthetympanicmembraneandtheinnerear聽骨鏈位于鼓膜和內(nèi)耳之間，由3塊聽小骨組成Airbornesoundwaveenergybecomesmechanicalvibration空氣傳導(dǎo)的聲波能量轉(zhuǎn)換為機械振動Compensatesfortheair-fluidimpedancedifference補償氣液相不同媒介的導(dǎo)抗差當(dāng)前第6頁\共有32頁\編于星期六\23點TheMiddleearanatomy中耳解剖AirAirAirpressuremustbenearequalonbothsidesoftheeardruminordertooptimisemobilityofthewholesystem應(yīng)使鼓膜兩側(cè)氣壓接近，從而保證中耳傳聲系統(tǒng)的最佳活動性TheEustachiantube(ET)ventilatesthemiddleearandallowspressureequalisation咽鼓管是中耳的通氣管道，可保證中耳氣壓平衡TheETopenswhenswallowingoryawning吞咽和打哈欠時咽鼓管開放Innerearfluids內(nèi)淋巴當(dāng)前第7頁\共有32頁\編于星期六\23點Gettingsoundintoadifferentmedium

聲音在不同媒介中的傳導(dǎo)The“stiletto”principle:圓錐效應(yīng)Forceiscollectedoveralargerareaandfocusedonasmallerarea(B)作用力在錐底收集后聚焦到錐尖當(dāng)前第8頁\共有32頁\編于星期六\23點Howdowetestthemiddleear?

如何檢測中耳功能當(dāng)前第9頁\共有32頁\編于星期六\23點中耳測試精密的中耳系統(tǒng)高精度的測試高質(zhì)量控制系統(tǒng)當(dāng)前第10頁\共有32頁\編于星期六\23點Partoftheprobetoneisreflected,andsomeisadmittedintothemiddleear一部分探測音被反射回來，另一部分則進入中耳Theadmittanceiscontinuouslymeasuredbyamicrophone聲導(dǎo)納通過麥克風(fēng)持續(xù)測量計算出來Admittance-lettingthesoundwavein

聲導(dǎo)納－將聲波導(dǎo)入當(dāng)前第11頁\共有32頁\編于星期六\23點鼓室圖中耳–勁度TPP(=MEP?)AdmittancePressure當(dāng)前第12頁\共有32頁\編于星期六\23點Tympanometry鼓室聲導(dǎo)抗Admittance-200daPa200daPa0EarcanalpressureAdmittance聲導(dǎo)納-200daPa200daPa0Earcanalpressure外耳道壓強1&3:Pressurestiffensthetympanicmembranesotheprobetonebouncesback,andthesoundlevelinthemiddleeardecreases1和3：大壓強使鼓膜僵硬從而探測音多被反彈回來，進入中耳的聲能減少2:Whenpressureisequalonbothsides,thesoundlevelinthemiddleearisatmaximum2：鼓膜兩側(cè)壓力相等時傳入中耳的聲能最大

123當(dāng)前第13頁\共有32頁\編于星期六\23點TheTympanogramcurve,ECVandTPP

鼓室導(dǎo)抗圖形，等效外耳道容積和峰壓點TheTPPapproximatesthemiddleearpressure峰壓點近似于鼓膜內(nèi)側(cè)的中耳壓力ECVTotalAdmittanceoftheearcanalandthemiddleear外耳道和中耳的聲導(dǎo)納總值TPPPressuresweepThe226Hzadmittanceoftheairintheearcanalisdirectlyproportionaltothevolumeofthatair.ThatgivesustheEquivalentEarCanalVolume,ECV以226Hz為探測音，測試探頭與鼓膜之間的空氣導(dǎo)納值為外耳道容積，即等效外耳道容積當(dāng)前第14頁\共有32頁\編于星期六\23點ECVTotalAdmittanceSATPPSATPPTheTympanogramcurveandbaselinecompensation鼓室導(dǎo)抗圖形和基線補償SubtractionoftheECVcontributiongivesusabaselinecompensatedtympanogram去除外耳道容積成分后的鼓室圖稱為基線補償鼓室導(dǎo)抗圖PeakadmittancebecomesStaticAdmittance,SA該圖峰值處的聲導(dǎo)納稱為靜態(tài)聲導(dǎo)納(SA)TheSAistheadmittanceofthemiddleearalone.Nowwecanusethenormativedata!SA等于中耳的聲導(dǎo)納值當(dāng)前第15頁\共有32頁\編于星期六\23點-2002000TypeAd:OssiculardiscontinuityoragerelatedhypermobilityAd型：聽骨鏈中斷或鼓膜松弛-2002000TypeA:NormalA型：正常-2002000TypeB:“Flat”-EffusionorperforatedeardrumdependingonECVvalueB型：平坦型。鼓室積液或鼓膜穿孔，根據(jù)ECV值區(qū)分-2002000TypeAs:PossibleeffusionorotosclerosisAs型：鼓室積液可能或耳硬化癥-2002000TypeC:AbnormalpressureC型：負(fù)壓型TheTympanogramcurveclassification,Type鼓室導(dǎo)抗圖形分類當(dāng)前第16頁\共有32頁\編于星期六\23點SATWSA/2PressureAdmittanceTheTympanogramcurveandTympanometricWidth

鼓室導(dǎo)抗圖形與鼓室圖寬度（TW）TympanometricWidthquantifythesteepnessofthetympanogramTW決定鼓室導(dǎo)抗圖的坡度Normativedataexistfordifferentagegroups不同年齡組標(biāo)準(zhǔn)化值不同TWandSAarethecriteriausedintheASHAtympanometricscreeningprotocol美國社會衛(wèi)生學(xué)會的鼓室聲導(dǎo)抗篩查方案把TW和SA作為診斷指標(biāo)當(dāng)前第17頁\共有32頁\編于星期六\23點226Hz:Differentconfigurationsoftympanometricresults

226Hz鼓室聲導(dǎo)抗測試結(jié)果與疾病的關(guān)系Tympanometryisaninvaluablediagnostictoolwhencombinedwithotheraudiologicaltests鼓室聲導(dǎo)抗與其它聽力學(xué)測試結(jié)合是不可替代的診斷工具疾病早期中耳積液中耳積液聽骨鏈中斷鼓膜病變耳硬化癥錘骨固定咽鼓管阻塞鼓膜置管鼓膜穿孔耵聹栓塞、探頭叩堵塞當(dāng)前第18頁\共有32頁\編于星期六\23點Thetwomiddleearmuscles中耳肌121:Tensormuscle鼓膜張肌2:StapediusMuscle鐙骨肌Themusclesarebelievedtostabilisethemechanicalsystemandprotectthecochleafromexcessivelowfrequencyvibration中耳肌可穩(wěn)定中耳機械系統(tǒng)，并保護耳蝸免受低頻強聲損傷當(dāng)前第19頁\共有32頁\編于星期六\23點TheAcousticReflex聲反射Loudsoundsmakethestapediusmusclecontract.Thismakesthemiddleearsystemstiffer...強聲刺激可使鐙骨肌收縮，從而增加中耳傳聲系統(tǒng)的勁度…andlesslowfrequencysoundcangetthroughthemiddleear因而進入中耳的低頻聲波減少當(dāng)前第20頁\共有32頁\編于星期六\23點Stapediusmusclecontrolledbyfacialnerve(CNVII)鐙骨肌由第七對顱神經(jīng)－面神經(jīng)支配Networkinbrainstemconsistsofipsilateralandcontralateralpaths腦干層面由同側(cè)和對側(cè)神經(jīng)通路組成Reflexactivatedonbothears,evenwhenstimulationonlyoccursinoneear一側(cè)耳受到刺激時，雙側(cè)鐙骨肌都會收縮Comparisonofipsilateralvs.contralateralacousticreflexeshelpstodeterminesiteoflesion對比同側(cè)和對側(cè)聲反射有助于判斷病變部位TheMiddleear-Immittancetests中耳聲導(dǎo)納測試Acousticreflexthreshold聲反射閾當(dāng)前第21頁\共有32頁\編于星期六\23點聲反射AdmittanceTimeDeflection0.02蹬骨肌當(dāng)前第22頁\共有32頁\編于星期六\23點0.000.0280dBHL0.000.0285dBHL0.000.0295dBHL0.000.0290dBHLDeflectioncriterion聲導(dǎo)納偏移標(biāo)準(zhǔn)Itisusefultostudythegrowthwithintensitytoconfirmareflexthreshold繼續(xù)增加聲強觀察偏移變化有助于進一步明確聲反射閾?!AcousticReflexThresholds聲反射閾Loudstimuliarepresented,whilsttheadmittanceismeasured強聲刺激出現(xiàn)時，可測試出聲導(dǎo)納值的變化當(dāng)前第23頁\共有32頁\編于星期六\23點聲反射測試–高精度的挑戰(zhàn)鼓膜處壓力為TPP值時中耳蹬骨肌反射狀況最佳正確的聲反射是刺激音引起導(dǎo)納在TPP處的變化耳道或中耳壓力的改變導(dǎo)致錯誤的聲反射對于鼓膜活動度過大可進行TPP補償當(dāng)前第24頁\共有32頁\編于星期六\23點Threshold+10dB,10secondsstimulustime聲反射閾上10dB給聲，刺激時程10s0510secondsAdmittancechangeHalf-LifeTime(HLT),thetimeafterstimulusonsetwhentheadmittancedeflectionhasdecreasedby50%.半衰期是指聲反射振幅減少50％的時程Ahalf-lifetimevalue<5secondsisindicativeoftumour半衰期小于5秒提示蝸后病變，常見的疾病是聽神經(jīng)瘤Noreflexdecaypresent陰性AdmittancechangeMax50%ofMaxHLT0510secondsReflexdecaypresent!陽性AcousticReflexDecay聲反射衰減當(dāng)前第25頁\共有32頁\編于星期六\23點Thereflexshouldbeactivatedinbothearsevenifstimulatedinonlyoneear單耳刺激聲可激活雙耳聲反射Theuppernormalintensitylimitforreflexthresholdsinadultsis95-100dBHL正常成人聲反射閾上限是95－100dBHLReflexthresholdscannotbedeterminedifthereisaproblemwiththemiddleear

中耳疾病時不能測出聲反射閾BroadBandNoiseprovokesareflexatabout10-15dBlowerthanpuretonestimuli寬帶噪聲聲反射閾較純音刺激聲低10－15dBDeterminestypeofhearinglosswhencomparedwiththeaudiogram聲反射閾與聽力圖比較可幫助判斷耳聾類型Decayswithneuralfatigue(typically8thnervetumour)

衰減提示聽神經(jīng)疲勞，是聽神經(jīng)腫瘤的典型表現(xiàn)AcousticReflexfeatures聲反射特征當(dāng)前第26頁\共有32頁\編于星期六\23點DifferentconfigurationsofAcousticReflexresults聲反射結(jié)果與疾病的關(guān)系Usingthiskindoftablemakesreflexinterpretationeasier使用該表格有助于判斷聲反射的臨床意義病變部位/患耳中耳/右中耳/左耳蝸/右耳蝸/左聽神經(jīng)/右聽神經(jīng)/左面神經(jīng)/右面神經(jīng)/左腦干/右腦干/左腦干/中線當(dāng)前第27頁\共有32頁\編于星期六\23點226Hzprobetone:Normaltympanograminabnormalear!226Hz探測音：異常中耳顯示正常鼓室導(dǎo)抗圖Tympanometryininfantsyoungerthan4-7months4－7個月以下嬰兒的鼓室聲導(dǎo)抗226HzprobetoneTheinfantouterandmiddleearsarestilldeveloping,anddonotvibratewithsoundthesamewayadultearsdo.嬰兒外耳和中耳正處于發(fā)育期，與成人的聲波振動方式不